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Limits of the New Habitable Zone

posted Mar 17, 2013, 9:44 PM by Abel Mendez   [ updated Mar 17, 2013, 9:59 PM ]
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 flux (Table 3), equilibrium temperature (Table 4), period (Table 5), transit probability (Table 6), and maximum transit duration (Table 7). The 'conservative habitable zone' is delimited by the 'moist greenhouse' and the 'maximum greenhouse' limits. The 'optimistic habitable zone' by the 'recent Venus' and 'early Mars' limits. All calculated values include minor updates to the HZ definition from the original paper (Kopparapu, personal communication).

Table 1. Stellar properties of representative main-sequence stars. An Earth-size planet transiting around these F-, G-, K-, or M-stars should have a full transit depth of 43, 83, 119, and 939 ppm, respectively.

Star Type

Name

Mass (SU)

Radius (SU)

Teff (K)

Luminosity (SU)

F

Ups And A

1.310

1.383

6213

2.554

G

Sun

1.000

1.000

5780

1.000

K

HD 40307

0.740

0.839

4977

0.387

M

Gliese 581

0.310

0.299

3498

0.012

note: SU = solar units, stellar data from exoplanets.org


Table 2. Distance limits (AU) for the Habitable Zone of main-sequence stars.

 

Inner Edge

Outer Edge

Star Type

Recent Venus

Runaway Greenhouse

Moist Greenhouse

Maximum Greenhouse

Early Mars

F

1.18

1.53

1.56

2.60

2.84

G

0.75

0.98

0.99

1.69

1.84

K

0.48

0.64

0.64

1.13

1.23

M

0.09

0.12

0.12

0.22

0.24


Table 3. Stellar flux limits (Solar Units) for the Habitable Zone of main-sequence stars.

 

Inner Edge

Outer Edge

Star Type

Recent Venus

Runaway Greenhouse

Moist Greenhouse

Maximum Greenhouse

Early Mars

F

1.8383

1.0945

1.0500

0.3765

0.3163

G

1.7763

1.0385

1.0146

0.3507

0.2946

K

1.6668

0.9511

0.9521

0.3053

0.2565

M

1.5252

0.8736

0.8712

0.2451

0.2060


Table 4. Expected equilibrium temperatures (K) for a planet within the Habitable Zone limits of main-sequence stars (assuming a 0.3 bond albedo).

 

Inner Edge

Outer Edge

Star Type

Recent Venus

Runaway Greenhouse

Moist Greenhouse

Maximum Greenhouse

Early Mars

F

296

260

257

199

191

G

294

257

255

196

187

K

289

251

251

189

181

M

283

246

246

179

171


Table 5. Expected periods (days) for a planet within the Habitable Zone limits of main-sequence stars.

 

Inner Edge

Outer Edge

Star Type

Recent Venus

Runaway Greenhouse

Moist Greenhouse

Maximum Greenhouse

Early Mars

F

408

602

621

1341

1529

G

237

355

361

801

913

K

142

216

216

507

578

M

17

26

26

68

77


Table 6. Expected transit probabilities (%) for a planet within the Habitable Zone limits of main-sequence stars.

 

Inner Edge

Outer Edge

Star Type

Recent Venus

Runaway Greenhouse

Moist Greenhouse

Maximum Greenhouse

Early Mars

F

0.55

0.42

0.41

0.25

0.23

G

0.62

0.47

0.47

0.28

0.25

K

0.81

0.61

0.61

0.35

0.32

M

1.57

1.19

1.19

0.63

0.58


Table 7. Expected maximum transit durations (hours) for an Earth-size planet within the Habitable Zone limits of main-sequence stars.

 

Inner Edge

Outer Edge

Star Type

Recent Venus

Runaway Greenhouse

Moist Greenhouse

Maximum Greenhouse

Early Mars

F

17.2

19.5

19.7

25.5

26.6

G

11.4

13.0

13.1

17.0

17.8

K

8.9

10.2

10.2

13.6

14.2

M

2.1

2.5

2.5

3.4

3.5