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This is the laboratory notebook of the PHL, a preprint and technical blog space of ideas and progress reports that could be later incorporated into peer-review research. Its content is mostly oriented to scientists, specially to those involved in our projects. However, many of the entries contain links to images and software that could be of interest to the general scientific community, educators, and public. You can subscribe to it via RSS.
  • The Diversity of Worlds: Comparative Planetology and Habitability A session on the Habitability of Exoplanets at the Astrobiology Science Conference 2015 Organizers: Tyler Robinson, NASA Ames Research Center (   Abel Méndez, University of Puerto ...
    Posted Feb 25, 2015, 12:10 PM by Abel Mendez
  • Another Visualization of the Protoplanetary Disk Around HL Tau Here we show a test of a simple IDL code to analyze and visualize the dust structure of protoplanetary disks. We used the impressive image of HL Tau (Figure 1 ...
    Posted Nov 6, 2014, 8:20 AM by Abel Mendez
  • False Starts: Potentially Habitable Exoplanets Here is a list of the first claims of potentially habitable exoplanets that later were found to be incorrect. Now we know that Gliese 581 c is too hot, Gliese ...
    Posted Oct 28, 2014, 10:59 PM by Abel Mendez
  • The Map to the Stars "There will certainly be no lack of human pioneers when we have mastered the art of flight ...In the meantime, we shall prepare, for the brave sky-travellers, maps of ...
    Posted Oct 6, 2014, 3:23 PM by Abel Mendez
  • We should prepare the map for the future space explorers Map of the constellations around Cygnus published on 1825, the first NASA Kepler Field of View. Credit: LoC.Here are two translations from a passage of an open letter from ...
    Posted Oct 6, 2014, 3:21 PM by Abel Mendez
  • Astrobiology @ AGU Fall Meeting The deadline for abstract submissions is fast approaching for sessions at the American Geophysical Union's (AGU) 47th annual Fall Meeting in San Francisco. Below are some sessions that might ...
    Posted Jul 30, 2014, 2:10 PM by Abel Mendez
  • What is habitability and how is it measured? Three very distinct habitable environments. Puerto Rico's El Yunque Rain Forest and Guánica Dry Forest, and Chile's Atacama Desert. Credit: PHL @ UPR AreciboNot everywhere on Earth is ...
    Posted Jan 9, 2015, 7:30 AM by Abel Mendez
  • Beer with BMSIS: Habitability Metrics for Astrobiology Copyright (2007) Scott Adams, Inc. Used with educational license. Original Source. Quantifying the Unquantifiable!Join the Blue Marble Space Institute of Science (BMSIS) for the next "Beer with BMSIS" seminar ...
    Posted Jul 3, 2014, 7:28 AM by Abel Mendez
  • 4D-Exoplanets: A summary of known exoplanets in four dimensions. This plot summarizes all confirmed exoplanets known today (~1,800) as a function of distance from the Sun (light years), their stellar flux (i.e. the energy that they receive ...
    Posted Jun 29, 2014, 11:28 PM by Abel Mendez
  • Exoplanets: From Exhilarating to Exasperating Here are the abstracts of the exoplanets press-conference of the AAS 224 on Monday, 2 June, 2:15 pm EDT. All findings are embargoed until the time of presentation ...
    Posted Jun 2, 2014, 9:06 AM by Abel Mendez
  • Not all habitable planets are equally ‘habitable’ So far we know of up to 20 potentially habitable planets around other stars out of nearly 2,000 planets that have been detected and confirmed. We expect to find ...
    Posted May 8, 2014, 7:41 PM by Abel Mendez
  • Surface Temperature of Planets The mean global surface temperature of a planet in a circular orbit is given by (adapted from Qiu et al., 2003): (1) where Ts = mean global surface temperature (K ...
    Posted Jan 7, 2014, 6:22 AM by Abel Mendez
  • A New Large Batch of Earth-like Worlds Candidates The NASA Kepler added 1,089 new objects of interest from the Q1-16 release to its KOI database. All are objects of interest pending further verification (not dispositioned) to ...
    Posted Jan 4, 2014, 7:10 AM by Abel Mendez
  • Spatial and Temporal Averages for Elliptical Orbits Mean orbital values for distance, stellar flux, and equilibrium temperature can be computed with respect to spatial or temporal coordinates. Spatial averages are usually calculated with respect to the mean ...
    Posted Jan 4, 2014, 8:50 AM by Abel Mendez
  • SER: First Look at Pluto The Scientific Exoplanets Renderer (SER) is our core software to generate photorealistic-looking images of planets such as the ones for the Visible Paleo-Earth and the Habitable Exoplanets Catalog ...
    Posted Nov 13, 2013, 10:02 AM by Abel Mendez
  • Occurrence of Earth-like planets around GKM Stars Here we combine and interpret results from Kopparapu (2013) and Petigura et al. (2013) on the occurrence of Earth-like planets around red-dwarf (type M) and Sun-like (type ...
    Posted Nov 5, 2013, 8:47 AM by Abel Mendez
  • New Kepler Potential Planet Transit Signals The NASA Kepler team released a revised global list of 16,285 potential planet transit signals (formally known as Threshold-Crossing Events or TCE) from quarters one to sixteen, the ...
    Posted Nov 4, 2013, 8:03 AM by Abel Mendez
  • 50th Anniversary of the Arecibo Observatory The Arecibo Observatory (AO) was inaugurated November 1, 1963. To recognize its 50th year of service to the scientific community, the AO is having a science symposium, “50 Years of ...
    Posted Oct 27, 2013, 7:20 PM by Abel Mendez
  • A Binomial Nomenclature for Common Names of Exoplanets When naming exoplanets create common names for both the stellar system and the exoplanetsThere are nearly one thousand exoplanets already confirmed and many more waiting for confirmation. The general ...
    Posted Sep 27, 2013, 12:20 AM by Abel Mendez
  • About 40 potentially habitable worlds by the end of 2015? We started with just two planets in our Habitable Exoplanets Catalog almost two years ago on December 2011. At that time having a catalog for just two planets was overkill ...
    Posted Sep 20, 2013, 3:12 AM by Abel Mendez
  • One-AU Exoplanets Most known exoplanets are within one astronomical unit (AU) from their stars, a bias of our detection methods. Here are graphical representations of 417 stellar systems with planets within one ...
    Posted Aug 12, 2013, 1:01 PM by Abel Mendez
  • Earth from Near and Deep Space The Cassini spacecraft on Saturn and the Messenger spacecraft on Mercury are taking images of Earth in July 19, 2013. From their vantage point Earth will be just a few ...
    Posted Jul 23, 2013, 3:07 AM by Abel Mendez
  • Statistics of Nearby Earth-like Planets Around M-dwarfs Stars Here is an analysis on the frequency, number, distance, and probability of Earth-like planets (Earth-size within the habitable zone) around M-dwarf stars within 10 parsecs (~33 light ...
    Posted Apr 8, 2013, 1:20 AM by Abel Mendez
  • Transits of Earth-like Exoplanets and Exomoons Here are a few transit simulations of Earth-like planets with and without moons (Figures 1-3) including Avatar's Pandora (Figure 4). All simulations assume long cadence observations (every ...
    Posted Apr 29, 2013, 12:31 AM by Abel Mendez
  • Summary of the Limits of the New Habitable Zone The new habitable zone (Kopparapu et al., 2013) has a narrow and wide definition (Figure 1). The narrower 'conservative habitable zone' is bounded by the 'moist greenhouse' and 'maximum greenhouse ...
    Posted Apr 8, 2013, 12:39 AM by Abel Mendez
  • Conferencia en el IITF El Prof. Abel Méndez ofrecerá una conferencia sobre planetas habitables en el Instituto Internacional de Dasonomía Tropical el jueves, 21 de marzo de 2013 a las 2:30 PM. Para ...
    Posted Mar 19, 2013, 1:20 AM by Abel Mendez
  • Limits of the New Habitable Zone Here are some limits of the new habitable zone (HZ) for main sequence stars (Table 1) from Kopparapu et al. (2013) for six parameters: distance from star (Table 2), stellar ...
    Posted Mar 17, 2013, 9:59 PM by Abel Mendez
  • TCE01: Terrestrial Climatology and Ecology Initial test of reading, plotting, and estimate of NPP. These files are part of a study of terrestrial climatology and ecology and are only intended for the scientisits working on ...
    Posted Mar 17, 2013, 3:01 PM by Abel Mendez
  • KOI-172.02: An excellent candidate for a “Venus-twin” (Reposted from It seems that we have our latest "Earth twin candidate." This time, the planet is in orbit around a star very similar to our Sun. It ...
    Posted Jan 14, 2013, 7:56 PM by Abel Mendez
  • The New Potential Habitable Exoplanets Candidates of NASA Kepler We evaluated the new release of 2740 NASA Kepler Candidates and identified 10 new candidates for potential habitable exoplanets from the previous batch. We also noticed that nine of the ...
    Posted Jan 11, 2013, 4:19 PM by Abel Mendez
  • Current NASA Kepler Confirmed Planets This is a list of 132 confirmed planets by the NASA Kepler mission. The list combines both the Kepler Team and the general scientific community detections. All Kepler stars systems ...
    Posted Jan 10, 2013, 3:30 PM by Abel Mendez
  • Exoplanets @ AAS 221 Here are the presentations program and press information for the 221st American Astronomical Society Meeting (AAS 221) from January 6 to 10, 2013. Below are three press conferences related to ...
    Posted Jan 4, 2013, 2:48 PM by Abel Mendez
  • HEC Dump Files for Confirmed Planets, Kepler Candidates, and TCE Here are the HEC Dump Files with the basic statistics as of Jan 3rd, 2013 for Confirmed Exoplanets, NASA Kepler Candidates, and NASA Kepler TCE. They are used as a ...
    Posted Jan 4, 2013, 7:52 AM by Abel Mendez
  • Science Definition Team for the 2020 Mars Science Rover Call for Letters of Application for Membership on the Science Definition Team for the 2020 Mars Science Rover  Solicitation Number: Posted Date:FedBizOpps Posted Date:Recovery and Reinvestment Act Action ...
    Posted Dec 23, 2012, 9:54 AM by Abel Mendez
  • Planetary Habitability @ AGU 2012 Here is a list of the sessions related to planetary habitability that will be presented in the AGU Fall meeting 2012, from December 3 to 7, 2012 in San Francisco ...
    Posted Nov 30, 2012, 10:06 AM by Abel Mendez
  • Annual Arecibo Observatory Scientific Conference Image Credit: Arecibo ObservatoryIMPORTANT: THIS ACTIVITY HAS BEEN POSTPONEDDecember 27 & 28, 2012 Arecibo Observatory, Arecibo, Puerto Rico Overview We cordially invite Puerto Rican astronomers with interests in astronomy ...
    Posted Dec 20, 2012, 7:59 AM by Abel Mendez
  • Exoplanets at the DPS Annual Meeting Here are the exoplanet oral and poster presentations at the 44th annual meeting of the Division for Planetary Sciences (DPS) of the American Astronomical Society (AAS) in Reno, Nevada, 14 ...
    Posted Oct 14, 2012, 7:32 PM by Abel Mendez
  • Exoplanets and Astrobiology at EPSC These are the presentations related to exoplanets and astrobiology at the European Planetary Science Congress 2012, IFEMA-Feria de Madrid, 23–28 September 2012, Madrid, Spain.Oral Program EX1Observations ...
    Posted Sep 25, 2012, 8:22 AM by Abel Mendez
  • AGU Fall Meeting 2012 Here are most of the proposed sessions related to astrobiology, in no particular order, as part of the next AGU Fall Meeting from December 3-7, 2012 on San Francisco ...
    Posted Jul 8, 2012, 12:15 PM by Abel Mendez
  • 84 New Kepler Exoplanet Candidates Ofir and Dreizler (2012) did an independent analysis to 64 stellar systems from the NASA Kepler dataset. They found 84 new exoplanets candidates in these systems increasing the number of ...
    Posted Aug 7, 2012, 7:10 PM by Abel Mendez
  • Exoplanet Presentations at AAS 220th Here is a list of various sessions with exoplanet presentations on the 220th Meeting of the American Astronomical Society from June 10-14, 2012 in Anchorage, Alaska. Check the ...
    Posted Oct 21, 2012, 2:44 PM by Abel Mendez
  • Reference and Color Calibration for the Visible Daily-Earth This is test image that we are using as landmasses reference and color calibration for the Visible Daily-Earth. It shows computer generated global views of Earth as seen from ...
    Posted Jun 4, 2012, 8:37 PM by Abel Mendez
  • Eclipse of May 20-21, 2012 Here is the shadow over Earth near the maximum during the Annular Solar Eclipse of May 20-21, 2012. This image was generated during a color test of our Visible ...
    Posted Jun 4, 2012, 8:38 PM by Abel Mendez
  • Visible Daily-Earth: May 16, 2012 This is a test of the code for our new Visible Daily-Earth project where we will have a true-color global picture of Earth generated daily from geostationary satellites ...
    Posted Jun 4, 2012, 8:39 PM by Abel Mendez
  • Earth Live We are working in a project to put online current daily global satellite images of Earth in true-color (colors as seen by the human eye). Unfortunately, satellites that have ...
    Posted Jun 4, 2012, 8:40 PM by Abel Mendez
  • Three Hot Subterran Exoplanets around KOI-961 Here are some quick stellar and planetary properties (Tables 1 and 2) for the three exoplanets system KOI-961 plus the basic habitability assessment with the Habitable Zone Distance (HZD ...
    Posted Jun 30, 2012, 11:10 AM by Abel Mendez
  • AAS 219 Press Conference: Extraordinary Exoplanets Here are the abstracts of the presentations related to the AAS 219 press conference Extraordinary Exoplanets schedule on Wednesday, January 11, 2012 at 1:00 PM CST (3:00 PM ...
    Posted Jan 11, 2012, 10:15 AM by Abel Mendez
  • Exoplanets with the Most Earth-like Interiors This is a list of exoplanets with the most Earth-like interiors ranked by the Interior Earth Similarity Index (iESI), a measure of how an exoplanet size and bulk density ...
    Posted Aug 11, 2012, 1:56 PM by Abel Mendez
  • Habitability Assessments using Habitable-Space Metrics One of the main problems of measuring habitability, the suitability of an environment to support life, is how to connect the dependency of many environmental variables with life. The best ...
    Posted Jun 30, 2012, 11:16 AM by Abel Mendez
  • Habitable Zone Atmosphere (HZA): A habitability metric for exoplanets The Habitable Zone Atmosphere (HZA) is a measure of the potential of an exoplanet to hold a habitable atmosphere. Most life forms requires some basic atmospheric ingredients like carbon dioxide ...
    Posted Jun 30, 2012, 11:49 AM by Abel Mendez
  • Habitable Zone Composition (HZC): A habitability metric for exoplanets The Habitable Zone Composition (HZC) measures how compatible for life is the bulk composition of an exoplanet within the habitable zone. Life requires a variety of elements from volatiles to ...
    Posted Jul 1, 2012, 11:24 AM by Abel Mendez
  • Standard Mass-Radius Relation for Exoplanets We are trying to develop a standard mass-radius relationship for exoplanets to predict the most likely value from the other. There are very high uncertainties in predicting radius from ...
    Posted Jun 30, 2012, 11:54 AM by Abel Mendez
  • Updates on Kepler-22 b during the First Kepler Science Conference Dec05: The recent confirmation of Kepler-22 b (KOI-087) does not qualify as a potential habitable exoplanet in the Habitable Exoplanets Catalog. It is in the habitable zone of ...
    Posted Jun 30, 2012, 11:56 AM by Abel Mendez
  • Data Comparison of Confirmed Exoplanets with Kepler Candidates Here we show a simple statistical comparison of data for confirmed exoplanets ( and Kepler candidates (Borucki et al., 2011). This analysis was done as a quality test of ...
    Posted Oct 29, 2011, 6:22 AM by Abel Mendez
  • Exoplanets Continuously Within the Habitable Zone There are 83 exoplanets in the habitable zone (HZ) in the currently known 694 exoplanets, but many exhibit wide elliptical orbits that take them just inside or outside the edges ...
    Posted Jun 30, 2012, 12:02 PM by Abel Mendez
  • The Night Sky of Exoplanets We are developing software code to generate photorealistic visualizations of star fields. The code uses information from the stars to generate their visual appearance from any vantage point including relative ...
    Posted Jun 30, 2012, 12:06 PM by Abel Mendez
  • The Periodic Table of Exoplanets This table summarizes in eighteen thermal-mass categories most of the current known exoplanets (as of October 2011). Planets are divided in six mass classes as mercurians, subterrans, terrans, superterrans ...
    Posted Jun 30, 2012, 12:08 PM by Abel Mendez
  • The Apparent Brightness and Size of Exoplanets and their Stars One thing that we are trying to reproduce for the Habitable Exoplanets Catalog is the visual appearance of exoplanets and stars. This includes the color, brightness, and size of the ...
    Posted Jun 30, 2012, 12:10 PM by Abel Mendez
  • Location and Relative Size of Exoplanets on the Night Sky This is a visualization of the location and relative size of current 690 confirmed exoplanet on the night sky, using equatorial coordinates with a rectangular projection. The constellation outlines are ...
    Posted Jun 30, 2012, 12:12 PM by Abel Mendez
  • A Stellar System Map for Exoplanets Here we created a stellar map of 564 exoplanets systems from the latest database of confirmed exoplanets from the Extrasolar Planets Encyclopaedia. The map helps to visualize the relative distance ...
    Posted Jun 30, 2012, 12:19 PM by Abel Mendez
  • Latest List of Potential Habitable Exoplanets and Exomoons We finally identified potential habitable exoplanets and exomoons from three catalogs. This was the first step in the construction of our Habitable Exoplanets Catalog (HEC). No exomoons have been detected ...
    Posted Oct 1, 2011, 8:32 PM by Abel Mendez
  • Earth Around a Red Star The current potential habitable exoplanets, HD 85512 b and Gliese 581 d, orbit red stars. HD 85512 is a K5V and Gliese 581 is a M3V type star, both dimmer ...
    Posted Sep 26, 2011, 1:18 PM by Abel Mendez
  • Earth "Real" Blues Our vision is not only limited by the energy range on the visible spectrum but also by its sensitivity to particular colors. The eyes are more adapted to see green ...
    Posted Sep 26, 2011, 7:29 AM by Abel Mendez
  • Current Number of Habitable Exoplanets: 16 There are now two potential habitable exoplanets out of the confirmed 687, and 14 out of the published 1235 Kepler candidates. The original Kepler paper by Borucki et al. (2011 ...
    Posted Sep 24, 2011, 7:46 PM by Abel Mendez
  • Only 39 Kepler Planet Candidates in the Habitable Zone Last April 2011 the Kepler Mission Team published a paper describing 1235 new planet candidates (Borucki et al., 2011). They argue that 56 of those where in the habitable zone ...
    Posted Sep 22, 2011, 6:36 AM by Abel Mendez
  • The Exoplanet's Stars We are developing a code to automatically generate updated diagrams and visualizations from various exoplanets catalogs for the Habitable Exoplanet Catalog. Here is a test showing the mass, temperature, and ...
    Posted Sep 18, 2011, 10:11 PM by Abel Mendez
  • The Habitability of "Tatooine" Kepler-16 (AB) b Kepler-16 (AB) b, an exoplanet with a Saturn-like mass, Venus-like orbit, and Mars-like temperatures.Kepler-16 (AB) b, aka "Tatooine," is the first exoplanet detected around ...
    Posted Sep 17, 2011, 12:39 PM by Abel Mendez
  • Habitability Metrics and Classifications for Exoplanets Various habitability metrics can be used to assess and compare the potential for life, as we know it, of exoplanets. The main idea behind these metrics is to simplify the ...
    Posted Sep 6, 2011, 6:50 AM by Abel Mendez
  • The Surface Pressure of Earth-like Exoplanets The total mass of the atmosphere of a planet is very easy to approximate from the surface pressure and radius of the planet, using a simple multiplication of pressure by ...
    Posted Aug 26, 2011, 10:31 PM by Abel Mendez
  • A Mass Classification for both Solar and Extrasolar Planets We will need a simple way to communicate results as part of the Habitable Exoplanets Catalog. Our Habitable Exoplanet Classification focus only on habitable planets and a broader classification will ...
    Posted Oct 2, 2011, 11:18 AM by Abel Mendez
  • The Mass and Radius of Potential Exomoons We barely have the capability to detect Earth-size exoplanets, less moons around them. Small exomoons will be atmosphere-less bodies, like our own Moon that shares with Earth the ...
    Posted Sep 30, 2011, 10:35 AM by Abel Mendez
  • Habitable Zone Distance (HZD): A habitability metric for exoplanets The search for life in the universe requires methods to identify and characterize habitable planets in other stars. The concept of habitable zones (HZ) around stars provides the easiest procedure ...
    Posted Jul 30, 2012, 2:17 PM by Abel Mendez
  • A Thermal Planetary Habitability Classification for Exoplanets Current and future observations by ground and orbital missions will be able to identify habitable exoplanets. As a first assessment, the surface temperature of Earth-like exoplanets is used as ...
    Posted Aug 9, 2011, 10:06 AM by Abel Mendez
  • Vegetation, Ice and Deserts of the Paleo-Earth In our previous post we discussed the distribution of landmasses of the Paleo-Earth. Here we used the Visible Paleo-Earth (VPE) datasets to estimate the global surface coverage of ...
    Posted Jul 29, 2011, 3:46 AM by Abel Mendez
  • Habitability of the Paleo-Earth as a Model for Earth-like Exoplanets The Phanerozoic is the last Eon of Earth history, from 542 million years ago to today. This was the period when large and complex life started to populate the ocean ...
    Posted Aug 6, 2011, 3:05 AM by Abel Mendez
  • Distribution of landmasses of the Paleo-Earth Our planet shows different features as it rotates along its axis, sometimes dominated by land and others by ocean. Land areas are distributed predominantly in the Northern Hemisphere (68%) relative ...
    Posted Jul 8, 2011, 6:53 AM by Abel Mendez
  • The Distribution of Complex Life in the Last 540 Million Years Following our previous post for the paleo-distribution of life, here we show two animations of the distribution of complex life in the last 540 million years based on the ...
    Posted Jul 1, 2012, 7:19 PM by Abel Mendez
  • The Global Paleo-Distribution of Life 120 Ma We will be doing a simple habitability analysis of Earth in the last 750 million years as part of the Visible Paleo-Earth (VPE) project. We are using the fossil ...
    Posted May 30, 2011, 3:26 AM by Abel Mendez
  • Seasonal Surface Temperatures of Dark Earth The Visible Paleo-Earth (VPE) project provides a unique set of data about the evolution of Earth in the last 750 million years that can be used not only to ...
    Posted May 12, 2011, 9:43 PM by Abel Mendez
  • Analysis of the Distribution of Land and Oceans Here we present a quick analysis of the distribution of landmasses from the data generated as part of our Visible Paleo-Earth project. Previous post (here and here) showed the ...
    Posted May 12, 2011, 9:43 PM by Abel Mendez
  • More Preliminary Analysis of Paleomaps Here are six more analysis of paleomaps for the periods 90, 150, 170, 560, 690, and 750 million years ago. For an explanation of the figures see previous post. These ...
    Posted Apr 11, 2011, 4:17 AM by Abel Mendez
  • Preliminary Analysis of Paleocontinents Distribution We are studying Earth's paleoclimate and paleogeography as a base model to characterize future observations of Earth-like exoplanets. We are particularly interested in interpreting the diurnal and seasonal ...
    Posted Apr 2, 2011, 6:24 AM by Abel Mendez
  • Using REDUCE as a computer algebra system (CAS) There are many computer algebra systems (CAS) available for doing math intensive operations. I needed one in MacOS and Linux/Unix platforms for complex operations, and potentially in an iPad ...
    Posted Mar 24, 2011, 3:25 AM by Abel Mendez
  • Conversion from RBG to greyscale images. The following images show the result of converting an RGB image to greyscales using the rgb2grey IDL function (code below). This function is being used to calculate light curves and ...
    Posted Mar 10, 2011, 3:46 PM by Abel Mendez
  • Nearby Stellar Density These plots show some simple statistics for our stellar neighborhood using the HYG Stellar Database v2.0, which combines stellar data from the Hipparcos Catalog, the Yale Bright Star Catalog ...
    Posted Mar 15, 2011, 1:02 PM by Abel Mendez
  • References related to Paleo-Earth, exoplanets light curves, and color This is a reference list of web resources related to ‎the project Simulations of Light Curves from Earth-like Exoplanets‎. This list contains links of introductory materials, research articles, software ...
    Posted Mar 10, 2011, 2:49 PM by Abel Mendez
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The Diversity of Worlds: Comparative Planetology and Habitability

posted Dec 21, 2014, 11:59 PM by Abel Mendez   [ updated Feb 25, 2015, 12:10 PM ]

A session on the Habitability of Exoplanets at the Astrobiology Science Conference 2015

Organizers: Tyler Robinson, NASA Ames Research Center (
  Abel Méndez, University of Puerto Rico Arecibo (
  Rene Heller, McMaster University (
  Dirk Schulze-Makuch, Washington State University (

Abstract: Near-future telescopes will observe the atmospheres of rocky exoplanets to search for signs of habitability and global biospheres. Interpreting the spectral signatures from these worlds will be a difficult task, especially considering the range of potentially habitable or inhabited worlds, from desert planets devoid of life to super-habitable worlds. By studying Earth’s biosphere as well as the similarities and differences in the rules that govern the atmospheres and interiors of solar system worlds, we can begin to understand how planets, as systems, work. However, holes exist in our understanding of many key atmospheric and geophysical processes relevant to the origin, maintenance, and development of life on a planet. We invite presentations on observations and models of the processes that influence planetary habitability and its evolution through time, as well as studies of prototype biospheres that produce spectral or photometric signatures that could be detected by the next generation of exoplanet characterization missions.

Another Visualization of the Protoplanetary Disk Around HL Tau

posted Nov 6, 2014, 8:13 AM by Abel Mendez   [ updated Nov 6, 2014, 8:20 AM ]

Here we show a test of a simple IDL code to analyze and visualize the dust structure of protoplanetary disks. We used the impressive image of HL Tau (Figure 1) taken by ALMA for this test. This is not a scientifically calibrated image and we will have to wait to early 2015 for a scientific product. The code averages the radial brightness from the center of the star to get an average radial profile of the disk (Figure 2, top). The anomaly of this profile, with respect to an a priori gaussian model, is created to compare the relative density of the dust regions (Figure 2, bottom). How this relative density relates to the actual density of dust in the disk is another problem. This analysis was done as part of project on interpretations and visualizations of protoplanetary disks (Figure 3).

Figure 2. Average radial profiles of the relative brightness of dust around HL Tau. The profile shows at least three distinct gaps (bottom image) were planets might be forming (9.9, 24.3, 47.1, and 67.6 AU), but other smaller gaps are notable (minimas from the curve). Note that this profile is based on a press release image not calibrated for scientific purposes. Therefore, the relative brightness and the location of the gaps might change with the release of the scientific verification data.

Figure 3. Simple brightness model of the protoplanetary disk around HL Tau derived from the average radial profile. It ignores that some of the dust regions from Figure 1 also show interesting gaps within them. The image is similar to a top view of Figure 1. For reference, the orbit of Neptune is at 30 AU. The size scale is approximate.

False Starts: Potentially Habitable Exoplanets

posted Oct 28, 2014, 10:57 PM by Abel Mendez   [ updated Oct 28, 2014, 10:59 PM ]

Here is a list of the first claims of potentially habitable exoplanets that later were found to be incorrect. Now we know that Gliese 581 c is too hot, Gliese 581 d and g do not exist, and HD 85012 is too hot. Only Gliese 667C c survives today as the first confirmed potentially habitable exoplanet. Exoplanet detection and characterization is a very hard science. Original press release and paper links included.
  1. Gliese 581 c (too hot): Astronomers find first habitable Earth-like planet. (24-Apr-2007). Paper
  2. Gliese 581 d (does not exist)Gliese 581: 1 planet might indeed be habitable (13-Dec-2007). Paper
  3. Gliese 581 g (does not exist)Newly discovered planet may be first truly habitable exoplanet (29-Sep-2010). Paper
  4. HD 85512 b (too hot)50 new exoplanets discovered by HARPS (12-Sep-2011). Paper
  5. Gliese 667C c (so far ok): New super-Earth detected within the habitable zone of a nearby cool star (2-Feb-2012). Paper
This list was created as part of a presentation on the history of the search for habitable worlds.

The Map to the Stars

posted Oct 6, 2014, 3:00 PM by Abel Mendez   [ updated Oct 6, 2014, 3:23 PM ]

"There will certainly be no lack of human pioneers when we have mastered the art of flight ...
In the meantime, we shall prepare, for the brave sky-travellers, maps of the celestial bodies."

This is a map of the over one thousand stellar systems with known exoplanets. The map helps to visualize the relative distance and location of exoplanets systems with respect to Earth using a flattened polar projection (i.e. zero declination) with a logarithmic distance scale. Those systems with potentially habitable exoplanets are highlighted with a red circle. You will need to enlarge to see details (probably something good for a Prezi presentation). The map can be printed 27" x 27" @ 300dpi. Check the original poster from 2011 for comparison.

We should prepare the map for the future space explorers

posted Oct 2, 2014, 2:27 AM by Abel Mendez   [ updated Oct 6, 2014, 3:21 PM ]

Map of the constellations around Cygnus published on 1825, the first NASA Kepler Field of View. Credit: LoC.

Here are two translations from a passage of an open letter from Kepler to Galileo published in the Conversation with the Star Messenger on April 19, 1610. We are still creating the maps of the universe for the future space explorers after four hundred years.

"There will certainly be no lack of human pioneers when we have mastered the art of flight. Who would have thought that navigation across the vast ocean is less dangerous and quieter than in the narrow, threatening gulfs of the Adriatic, or the Baltic, or the British straits? Let us create vessels and sails adjusted to the heavenly ether, and there will be plenty of people unafraid of the empty wastes. In the meantime, we shall prepare, for the brave sky-travellers, maps of the celestial bodies – I shall do it for the moon, you Galileo, for Jupiter." (1)

"But as soon as somebody demonstrates the art of flying, settlers from our species of man will not be lacking. Who would once have thought that the crossing of the wide ocean was calmer and safer than of the narrow Adriatic Sea, Baltic Sea, or English Channel? Given ships or sails adapted to the breezes of heaven, there will be those who will not shrink from even that vast expanse. Therefore, for the sake of those who, as it were, will presently be on hand to attempt this voyage, let us establish the astronomy, Galileo, you of Jupiter, and me of the moon." (2)
(1) Koestler, A., & Butterfield, H. (1959). The Sleepwalkers: A History of Man's Changing Vision of the Universe. Arthur Koestler. Introduction by Herbert Butterfield, Hutchinson.

(2) Kepler, J., & Rosen, E. (1965). Kepler's Conversation with Galileo's Sidereal messenger. 1st complete translation, with an introd. and notes. New York, Johnson Reprint Corp., 1965., 1.

Astrobiology @ AGU Fall Meeting

posted Jul 30, 2014, 2:09 PM by Abel Mendez   [ updated Jul 30, 2014, 2:10 PM ]

The deadline for abstract submissions is fast approaching for sessions at the American Geophysical Union's (AGU) 47th annual Fall Meeting in San Francisco. Below are some sessions that might be relevant to the astrobiology community and you can look here for the complete list of sessions accepting abstracts.

Make sure to submit your abstracts by August 6, 23:59 EDT!

Session 1492: Enceladus: A Habitable World
This special session will focus on topics relating to the origin and state of the moon's geologically active south polar terrain (SPT). We also welcome studies addressing future spaceflight missions and the moon's potential for biological activity.
Conveners: Christopher P McKay, NASA Ames Research Center, and Carolyn Porco, Space Science Institute

Session 2464: Icy World Eruptions and Their Analogues
The potential existence of large plumes of water emitted from Europa's surface has exciting implications for assessing the habitability of this icy world. This session examines the mechanisms for plume formation and dispersal; geological signatures of eruptions; inorganic and organic composition of materials ejected from the surface and subsurface; and implications for habitability and life detection.
Conveners: Steve Vance, NASA JPL, and Cynthia B Phillips, SETI Institute

Session 2511: Increasing and Measuring the Impact of Education and Public Outreach
More than ever, young scientists coming up through the ranks have an ethos to improve the STEM knowledge and skills of today’s youth, and they are dedicating increasing amounts of their time and energy to education and outreach work. This session solicits abstracts that discuss practical tools for scientists and education public outreach professionals to use evaluation to increase and effectively measure impact.
Conveners: Hilarie B Davis, Technology for Learning, and Daniella Scalice, NASA Astrobiology Institute

Session 2526: Evolutions, Interactions and Origins of Outer Planet Satellites
This session explores current and past planetary processes that lead to unique present day conditions on outer planet satellites. The session will consist of invited and contributed talks that highlight geological and geophysical modeling and interpretation of both remote-sensed and in-situ data.
Conveners: Amanda R Hendrix, Planetary Science Institute Tucson, and Krishan K Khurana, University of California at Los Angeles

Session 2682: Rapid Environmental Change and the Fate of Planetary Habitability
Rapid environmental change can be used as a scientific bridge, relating astrobiology to earth, planetary, and space sciences in the study of how life may adapt through abrupt climate crises. Abstracts on the intertwined aspects of changing habitability, including the complex interactions among astronomical, geological, and climatic forces, on the Earth and beyond, are welcome.
Conveners: Franck Marchis and Cynthia B Phillips, SETI institute, and Nathalie A Cabrol, NASA Ames Research Center & SETI institute

Session 3102: Proof of Life: Cutting-Edge Tools for Metabolic Rate Measurements in Environmental Microbiology and Astrobiology
As the characterization of low-energy environments continually pushes the limits of microbiological possibility, the metabolic activity of microbial constituents - not their mere presence - has emerged as the driving question of biogeochemical investigation. This session will examine the latest advances in cultivation-independent methods for the detection of catabolic and/or anabolic activity, the determination of "maintenance" energy, and the quantification of metabolic rates, among other topics.
Conveners: Jeffrey Marlow and Shawn McGlynn, California Institute of Technology

Session 3262: Cross-cutting in situ earth and planetary science instruments
There are common observational needs for both earth science and planetary investigations. Interchange between the two communities does not always occur. In this session we will highlight systems, instruments, sensors or components that have been or could be used in both applications.
Conveners: Max Coleman and Andrew Aubrey, NASA JPL

Session 3387: Looking For Life: Formation, Preservation and Detection of Biosignatures in Terrestrial Analogue Environments
Interpreting in situ enigmatic features (body or trace fossils, isotopic or molecular signatures, chemical disequilibria, or conspicuous mineralization) as indicators of biological activity is a notoriously difficult task. Understanding and recognizing the biogeochemical process that result in biosignatures, both in the lab and in field-based studies of terrestrial analogues of potentially habitable environments beyond Earth, will provide valuable information for future life detection missions.
Conveners: Alexandra Pontefract and Haley Sapers, University of Western Ontario

Session 3438: Reconstructing Habitable Environments on Ancient Mars
Ongoing rover and satellite investigations of the martian surface have revealed diverse aqueous environments, but these environments most likely had highly variable implications for habitability and organic preservation potential. We invite abstracts using data from landed and/or satellite missions, and encourage abstracts that address possible ExoMars and Mars2020 landing sites.
Conveners: Briony Horgan, Purdue University, and Melissa Rice, Western Washington University

Session 3669: Iron cycling in extreme environments
Iron is a highly abundant redox-reactive element on Earth, and is known to support energy acquisition through oxidation and reduction by a diverse array of microorganisms. However studies of biogeochemical iron cycling in extreme environments are scarce, and the contribution of these environments to iron and related biogeochemical cycles remains poorly defined. This session will draw upon recent research in microbiology, geochemistry and related disciplines spanning laboratory, field and modeling approaches.
Conveners: Sophie Nixon, University of Edinburgh, Eric Roden, University of Wisconsin, Jemma L Wadham, University of Bristol, and Charles S Cockell, University of Edinburgh

Session 3709: Upstairs Downstairs: Consequences of Internal Evolution for the Habitability of Planetary Surfaces
The chemistry and physics of planetary interiors shapes and is shaped by conditions at their surfaces. The nature and extent of these interactions are not well understood. This session seeks to bring together geochemists, geophysicists, geobiologists, and others who are building knowledge about the complex relationships between the surface habitability and internal evolution of Earth and Earth-like worlds.
Conveners: Ariel D Anbar, Arizona State University, Christopher Ballentine, University of Oxford, Christy B. Till, Arizona State University, and David C Catling, University of Washington

Session 3732: Preparing for Mars sample return: Geobiological approaches to discovering the history of life on Mars
The incorporation of coring and caching capability on a proposed Mars 2020 rover would be a landmark step toward the return to Earth of samples from Mars. A primary goal of the analyses that will ensue will be the search for evidence of past life. The objective of this session is to create a venue where the best approaches for discovery can be presented and discussed. Contributions will be welcome from the broad range of geobiological techniques as applied throughout the geological record.
Conveners: Michael Tuite and Kenneth Williford, Jet Propulsion Laboratory

Source: NAI

What is habitability and how is it measured?

posted Jul 8, 2014, 10:45 AM by Abel Mendez   [ updated Jan 9, 2015, 7:30 AM ]

Three very distinct habitable environments. Puerto Rico's El Yunque Rain Forest and Guánica Dry Forest, and Chile's Atacama Desert. Credit: PHL @ UPR Arecibo

Not everywhere on Earth is equally habitable. From deserts to rain forest there is an obvious habitability gradient, from worst to best for life. We are using the presence of life as a ‘proxy for habitability’ to recognize similar pattern, assuming that a place with more life is more habitable than the other, an assumption not always correct. This type of patterns helps to correlate what environmental factors control conditions which support the presence of more life. Scientists use this type of information to create models to predict from the environment how much life they can potentially support.

A habitable environment is just an environment that might support some form of life, not necessarily one with life. Earth today is not that good for life if we consider its extensive areas of dry and cold deserts compared to rain forests. Mars is a certainly a desert planet but Earth today is more like a dry forest planet, on average. Imagine a rain forest planet, where most of its land areas support abundance life. That will be more habitable than Earth, again using the abundance for life as a proxy for habitability.

How exactly do we measure or quantify habitability? Habitability metrics is an emerging field within astrobiology, or more correctly a re-emerging field since the basis for it were established more than three decades ago. One of the most frequent questions in the astrobiology field is how to measure habitability. Some people even take the concept as difficult to define as life. The true is that biologists already tackled this problem successfully during the ’70 and ’80 but is still seldom known by the astrobiology community. There are various reasons for this.

First, habitability metrics originated within the field of ecology and population dynamics to understand the distribution of wild animals and plants. This seems to have no relation to astrobiology since it focuses more on microbial life. Second, this is a very specialized field within theoretical ecology and even not taught and used by all ecologists. Third, biologist calls it differently. We use the generic word ‘habitability’ but it is formally called ‘habitat suitability’ by biologists. So if an astrobiologist tries to look for scientific references on how to measure habitability he/she would probably miss the ‘habitat suitability’ concept or seem as irrelevant since it focus now on animal and plant life.

The definition and core mathematical framework of ‘habitat suitability models’ is something that can be extended to all forms of life, including microbial life, and to the astrobiology field. That is precisely one of the reason we established the Planetary Habitability Laboratory on 2010, to adapt and apply this framework to the astrobiology field, as we call it ‘habitability metrics for astrobiology.’ Our first application was the Earth Similarity Index (ESI), a measure of Earth-likeness for planets based on a given set of planetary parameters. This index was inspired by the diversity and similarity indices used in ecology to compare populations. Similarity indices are also used in many other applications such as pattern recognition (e.g. face recognition). Still, this approach is an indirect measure of habitability and we want more direct measures.

Habitability or ‘habitat suitability’ is defined as the suitability of an environment for life. This definition has three components, an environment, a life, and a suitability (see figure). All three need to be defined for a proper assessment of habitability. The ‘environment component’ is a description of the physical, chemical, or even biological location of life under consideration, the habitat. It is constrained by some space and time limits (e.g. surface of Earth today). This is the astronomy, planetary science, or geology part of the metric. The other two components contain the biology. The ‘life components’ requires the selection and knowledge of an individual species or community (i.e. aggregate of two or more species) as the test subject for the habitat. Therefore, given some habitat any habitability measure is always relative to the species or community under consideration. Finally, the ‘suitability component’ is the tricky part because it defines the connection between the environment and life. This is the ‘proxy for habitability’.

The suitability for life, or ‘proxy for habitability’, could be direct or indirect. An indirect suitability does not necessarily specify how exactly the environment component affects life. For example, we know that the environment requires liquid water but we don’t care about the specific differences on the quantity or quality of this water for life (e.g. salinity, temperature). This is the case of current efforts searching for habitable environments in planetary environments such as exoplanets. The occurrence of Earth-size planets in the habitable zone of stars (Eta-Earth) is in fact an indirect measure of stellar habitability, the suitability of stars for planets with life. The ESI is also an indirect measure, but of planetary habitability, the suitability of a planet for Earth-like life. Thus, indirect measures of habitability rely on occurrences (aka presence/absent in biology), a similarity, or probability of some necessary conditions for life. It is recommended that these values be expressed with a common scale as a fraction for consistency, where zero denotes a non-habitable environment and one denotes a highly habitable environment. Negative values could be used to rate the magnitude of the damaging effect of a non-habitable environment (e.g. both the surface of Mars and Venus are non-habitable, but Venus is worst). Values over one could represent super-habitable conditions.

The hardest part is to define direct measures of habitability, which are more biologically meaningful. These require much more knowledge of the interaction of life and the environment. There are some specific universal biological quantities that can be used as the ‘proxy for habitability’ such as growth rate, carrying capacity, metabolic rate, or productivity. Therefore, to construct a direct measure of habitability requires knowing how the environment affects one of these biological quantities for some species or community. We don't need to specifically estimate these quantities but only how the environment proportionally affects them. For example, we know how temperature affects the productivity of primary producers such as plants and phytoplankton. Most require temperatures between 0° to 50° C, but they do better (i.e. highest productivity) near 25°C. Their ‘thermal habitability function’ looks like a bell-shaped curve centered at their optimum productivity temperature. Direct measures of habitability are also better represented as a fraction from zero to one.

Another problem is how to combine the effect of many environmental variables into a single direct or indirect habitability index. These are called aggregation methods in theoretical ecology. There are many ways to do this. Probabilities are simple to combine since they are multiply to each other. Similarity indices are easier to construct and combine too. The use of any direct methods already defines how the environmental variables are combined since they are based on biophysical principles. In practice, we recommend biological productivity as the best ‘habitability proxy’ since we know how to calculate it for microbial to complex life, it is relatively easy to measure or estimate, and there are even ways to measure it via remote sensors. The NASA’s Terrestrial Ecology Program uses the TERRA and AQUA satellites to monitor the global land and ocean primary productivity of Earth. This is a measure of ‘global health’ or ‘terrestrial habitability’ since primary producers are the base of the food chain.

Unfortunately, most applications of habitability metrics in astrobiology are limited to indirect measures of habitability. This is especially true for exoplanets since we don't have enough information about them to appropriately weight how terrestrial life, life as we know it, could be affected by their planetary environment. There is no single quantitative measure of habitability but a collection of metrics for different types of environments and life. Nevertheless, habitability metrics are easy to compare and combine since they use the same scale and meaning (e.g. a value between zero and one). It doesn't matter the application, everybody would understand the meaning of an environment with habitability close to one. The next logical question after this statement is what are the limits of this value, in other words, what is the environment, reference life, and selected suitability under consideration.

Habitability metrics provide an excellent way to understand and compare habitable environments, and prioritize targets for exploration within Earth, the Solar System, and beyond. Biologists have been using them, as 'habitat suitability models' for more than three decades to understand the distribution of terrestrial complex life from local to global environments. It is only a matter of adapting this mathematical framework to the needs of the astrobiology science.

Abel Méndez (First Draft, July 8, 2014)

Beer with BMSIS: Habitability Metrics for Astrobiology

posted Jun 30, 2014, 6:25 AM by Abel Mendez   [ updated Jul 3, 2014, 7:28 AM ]
Copyright (2007) Scott Adams, Inc. Used with educational license. Original Source.
Quantifying the Unquantifiable!

Join the Blue Marble Space Institute of Science (BMSIS) for the next "Beer with BMSIS" seminar on Thursday, July 3rd at 11:00 AM Pacific / 2:00 PM Eastern. This month we feature a conversation with Prof. Abel Mendez, Director of the Planetary Habitability Laboratory of the University @ UPR Arecibo. He will talk about the use of methods to quantify the unquantifiable, a planet's habitability. Beverage introduction by Craig Hardgrove.

"Beer with BMSIS" is an informal scientific conversation series on a broad set of topics relevant to the research undertaken by the Blue Marble Space Institute of Science. Each show lasts about 45 minutes and begins with a description of a tasty beverage by one of our members or friends. The featured speaker then talks for about 20 minutes, which is followed by a conversation with the audience for the next 20 minutes or so. These conversations are recorded and also published as a podcast series on iTunes.

If you would like to join our live conversations each month, subscribe to the Friends of BMSIS group to receive updates about seminars and more. Send a message to to join this group.

Connection Details

Meeting Number: 25059399
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Summary Slide

4D-Exoplanets: A summary of known exoplanets in four dimensions.

posted Jun 27, 2014, 7:49 AM by Abel Mendez   [ updated Jun 29, 2014, 11:28 PM ]

This plot summarizes all confirmed exoplanets known today (~1,800) as a function of distance from the Sun (light years), their stellar flux (i.e. the energy that they receive from the star where one equals the energy Earth receives from the Sun), their approximate size (see legend top left), and those in the habitable zone (green). Hot planets are red and cold planets are blue. Note that planets in the HZ are close to the 'Solar Flux' line. Click the image for larger version (warning, large graphic).
Interactive web version of the plot above. Those exoplanets in the warm zone (i.e. habitable zone) are shown in green with those potentially habitable (i.e. < 2.5 Earth radii) in a darker shade of green (see legend top right).

Exoplanets: From Exhilarating to Exasperating

posted May 30, 2014, 3:29 AM by Abel Mendez   [ updated Jun 2, 2014, 9:06 AM ]

Here are the abstracts of the exoplanets press-conference of the AAS 224 on Monday, 2 June, 2:15 pm EDTAll findings are embargoed until the time of presentation at the meeting.

Rates of Large Flares in Old Solar-like Stars in Kepler Clusters
Ofer Cohen (Harvard-Smithsonian Center for Astrophysics)

We hope to better estimate the rate of very strong (Carrington event-type) flares in the Sun by studying flares of stars in several open clusters with well determined ages using Kepler data. Here we derive white light flare distributions for a sample of near-solar-mass (G0-G5) dwarfs in NGC 6811 (age ~ 1 Gyr) and NGC 6819 (~ 2.5 Gyr). We compare these with solar white light flare rates and, by estimating X-ray emission from the same flares using a solar-based relationship, we compare the Kepler results to other solar and stellar X-ray flare data. We explore implications of our results for the rates of large solar flares. This research was supported by Kepler grant NNX13AC29G.

Press ReleaseHarsh space weather may doom potential life on red-dwarf planets

Kepler 56: Present & Future Configuration & Obliquity
Gongjie Li (Harvard-Smithsonian Center for Astrophysics)

Kepler-56 is an interesting multi-planet system with two coplanar inner planets that are highly misaligned with their parent star, and accompanied by an outer 3.3 Jupiter mass planet with an unknown inclination. Determining the true spin orbit angle and the inclination of the outer companion is valuable to study the physical processes that can produce the misalignment. Here, using the observed line of sight measurements, we can constrain the true spin orbit angle and the inclination of the outer companion. These depend on the initial configuration of the system. We consider two inherent scenarios: the first scenario assumes the stellar spin axis to be initially aligned with the inner two planets' angular momentum, and it favors a large range of mutual inclination (~20 -160 degree) between the inner planets and the outer companion. Tighter constraints can be achieved if the true spin orbit angle can be measured (from both asteroseismology and Rossiter-McLaughlin measurements). The second scenario assumes the stellar spin axis to be aligned with the total angular momentum of the system, and it favors the mutual inclination to be around ~40 or ~130 degree. Future observation of the mutual inclination may distinguish the two scenarios and uncover the formation processes of this system. In addition, by modeling the stellar evolution and its tidal effects on the system, we predict that the innermost planet will be engulfed within ~130 Myr.

Press ReleaseBecause you can't eat just one: Star will swallow two planets

Three Distinct Exoplanet Regimes Inferred from Host Star Metallicities
Lars A. Buchhave (Harvard-Smithsonian Center for Astrophysics)

The occurrence rate of exoplanets smaller than 4 Earth radii (RE) in short orbits is ~50%. Despite their sheer abundance, the compositions of planets populating this regime are largely unknown. The available evidence suggests the existence of a compositional range, from small high-density rocky planets to low-density planets consisting of rocky cores surrounded by thick H/He gas envelopes. Understanding the transition from the gaseous planets to Earth-like rocky worlds is important to estimate the number of potentially habitable planets in our Galaxy and provide constraints on planet formation theories. Here, we report the abundances of heavy elements (metallicities) of over 400 stars hosting 600 exoplanet candidates discovered by the Kepler Mission and find that the exoplanets can be categorized into three populations defined by statistically distinct (~ 4.5σ) metallicity regions. We interpret these regions as reflecting the formation regimes of terrestrial-like planets (RP < 1.7 RE), gas-dwarf planets with rocky cores and H/He envelopes (1.7 < RP < 3.9 RE) and ice/gas-giant planets (RP > 3.9 RE). These transitions resonate well with those inferred from dynamical mass estimates, implying that host-star metallicity – a proxy for the initial solid inventory of the protoplanetary disk – is a key ingredient regulating the structure of planetary systems.

Press Release'Neapolitan' exoplanets come in three flavors

ArXiv Paper: Three regimes of extrasolar planets inferred from host star metallicities

HARPS-N Contributions to the Mass-Radius Diagram for Rocky Planets
Dimitar Sasselov (Harvard-Smithsonian Center for Astrophysics)

Science operations began with HARPS-N on the TNG in August 2012. About half of the 80 nights per year allocated to the HARPS-N Collaboration have been dedicated to follow-up observations of bright Kepler Objects of Interest that showed promise of being rocky. In this presentation we show how mass determinations from HARPS-N are improving our understanding of the mass-radius diagram for rocky exoplanets, including recent results for Kepler 78 and Kepler 10.

Press ReleaseAstronomers find a new type of planet: The 'mega-Earth'

ArXiv Paper: The Kepler-10 planetary system revisited by HARPS-N: A hot rocky world and a solid Neptune-mass planet

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