J/A+A/662/A15 Catalogue of tidally locked rocky exoplanets (McIntyre, 2022)
Tidally driven tectonic activity as a parameter in exoplanet habitability.
McIntyre S.R.N.
<Astron. Astrophys. 662, A15 (2022)>
=2022A&A...662A..15M 2022A&A...662A..15M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets
Keywords: astrobiology - planets and satellites: general -
planets and satellites: interiors - planets and satellites: tectonics
Abstract:
Habitability of an exoplanet is defined by its ability to support
surface liquid water. The long-term carbon cycle plays an important
role in regulating planetary temperature, thus aiding the conditions
for the preservation of surface liquid water and,consequently, the
habitability of exoplanets.
On Earth, plate tectonics play an integral role in driving the
long-term carbon cycle; however, on tidally locked rocky
exoplanets alternative tectonic mechanisms driven by tidal stress and
tidal heating could serve in an analogous way.
We calculate tidal stress and tidal heating rates to model the
likelihood of tectonic activity maintaining stable climates suitable
for surface liquid water on tidally locked rocky exoplanets with radii
Rp≤1.23R⊕.
Applying the tidal models to our sample of 767 tidally locked rocky
exoplanets reveals that ∼10% of exoplanets, including Proxima Cen b
and GJ 1061 d from the circumstellar habitable zone (CHZ), pass the
tidal stress subduction threshold for mobile lid tectonic activity and
reside within the optimal tidal heating zone. This subset of
exoplanets could sustain tidally induced temperate mobile lid tectonic
activity comparable to plate tectonics on Earth, aiding in maintaining
the presence of surface liquid water. Further-more, ∼40% of exoplanets
from our sample located in the CHZ would be unable to maintain the
tectonic activity needed to stabilise the climate and are unlikely to
retain surface liquid water. When broadening our modelling to
establish the overlap between tidal stress, tidal heating, and the CHZ,
to discover optimal regions to target for future observations, we
determine that tidally driven tec-tonic activity conducive to the
maintenance of surface liquid water occurs predominantly around M
dwarfs, and identify intersections,where both mobile lid and optimal
tidal heating could be sustained on eccentric (e>0.1) Earth-sized
exoplanets (Rp=1.0-1.23R⊕)orbiting in the CHZ of low mass M
dwarfs.
Description:
Catalogue of 767 tidally locked rocky exoplanets (Rp≤1.23R⊕),
with a subset of 14 planets inhabiting the circumstellar habitable
zone (CHZ) of their host stars. For each exoplanet in our sample,
parameters for planetary mass, planetary radius, semi-major axis,
eccentricity, stellar mass, and stellar age are given. We execute
10000 Monte Carlo simulations that include uncertainties on all
parameters to determine the median and 68% confidence intervals on
tidal stress and tidal heating rates.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 151 767 Sample of 767 tidally locked rocky exoplanets
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Planet Planet Name
19- 20 A2 --- n_Planet [+* ] Note on Planet (1)
21- 26 F6.3 Mgeo Mp Planetary Mass
28- 35 F8.3 Mgeo e_Mp Planetary Mass error
37- 41 F5.3 Rgeo Rp Planetary Radius
43- 47 F5.3 Rgeo e_Rp Planetary Radius error
49- 56 F8.6 AU a Semi-major axis
58- 65 F8.6 AU e_a Semi-major axis error
67- 72 F6.4 --- e Eccentricity
74- 79 F6.4 --- e_e Eccentricity error
81- 85 F5.3 Msun M* Stellar Mass
87- 91 F5.3 Msun e_M* Stellar Mass error
93- 96 F4.1 Gyr Age Stellar Age
98-107 F10.8 --- h Tidal stress
109-118 F10.8 --- e_h Tidal stress error
120-135 F16.7 W/m2 H Tidal heating
137-151 F15.7 W/m2 e_H Tidal heating error
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Note (1): Note as follows:
* = stars with no age estimates for which we assume a lower age limit of 1Gyr
+ = planets located in the optimistic CHZ.
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Acknowledgements:
Sarah R.N. McIntyre, sarah.mcintyre(at)anu.edu.au
(End) Sarah RN McIntyre [ANU], Patricia Vannier [CDS] 04-Apr-2022