J/AJ/160/214 130 Stellar ages & planetary orbital properties (Safsten+, 2020)
Nature Versus Nurture: a Bayesian framework for assessing apparent correlations
between planetary orbital properties and stellar ages.
Safsten E.D., Dawson R.I., Wolfgang A.
<Astron. J., 160, 214 (2020)>
=2020AJ....160..214S 2020AJ....160..214S
ADC_Keywords: Exoplanets; Stars, ages; Stars, masses
Keywords: Exoplanet evolution ; Bayesian statistics ; Exoplanet systems ;
Stellar ages ; Exoplanet dynamics
Abstract:
Many exoplanets have orbital characteristics quite different from
those seen in our own solar system, including planets locked in
orbital resonances and planets on orbits that are elliptical or highly
inclined from their host star's spin axis. It is debated whether the
wide variety in system architecture is primarily due to differences in
formation conditions (nature) or due to evolution over time (nurture).
Identifying trends between planetary and stellar properties, including
stellar age, can help distinguish between these competing theories and
offer insights as to how planets form and evolve. However, it can be
challenging to determine whether observed trends between planetary
properties and stellar age are driven by the age of the system-
pointing to evolution over time being an important factor-or other
parameters to which the age may be related, such as stellar mass or
stellar temperature. The situation is complicated further by the
possibilities of selection biases, small number statistics,
uncertainties in stellar age, and orbital evolution timescales that
are typically much shorter than the range of observed ages. Here, we
develop a Bayesian statistical framework to assess the robustness of
such observed correlations and to determine whether they are indeed
due to evolutionary processes, are more likely to reflect different
formation scenarios, or are merely coincidental. We apply this
framework to reported trends between stellar age and 2:1 orbital
resonances, spin-orbit misalignments, and hot Jupiters' orbital
eccentricities. We find strong support for the nurture hypothesis only
in the final case.
Description:
We plot stellar age against circularization timescale, assuming
QP=106, for hot Jupiters for which the stellar and planetary
masses, semimajor axis, age, and measured eccentricity are available
on the Extrasolar Planets Encyclopaedia, queried on 2019 May 28. The
sample contains 130 systems in total.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 80 130 Planetary and stellar data
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See also:
J/A+A/398/363 : Statistical properties of exoplanets II (Santos+, 2003)
J/ApJ/622/1102 : The planet-metallicity correlation. (Fischer+, 2005)
J/ApJ/687/1264 : Age estimation for solar-type dwarfs (Mamajek+, 2008)
J/A+A/527/L11 : HAT-P-6 radial velocity curve (Hebrard+, 2011)
J/ApJ/735/24 : HAT-P-30 follow-up photometry (Johnson+, 2011)
J/ApJ/757/18 : Radial velocities 16 hot Jupiter host stars (Albrecht+, 2012)
J/MNRAS/454/28 : Bayesian statistics for massive stars (Mugnes+, 2015)
http://exoplanet.eu/ : The extrasolar planets encyclopaedia
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Planet Planet identifier
18- 24 F7.5 --- e [0/0.57] Eccentricity
26- 31 F6.4 --- e_e [0/0.12] Lower error in e
33- 38 F6.4 --- E_e [0/0.33] Upper error in e
40- 45 F6.3 Gyr Age* [0.1/12.5] Stellar age
47- 53 F7.5 AU a [0.004/0.095] Planetary semi-major axis
55- 60 F6.3 Mjup Mass [0.31/11.8] Planetary mass
62- 72 F11.9 Rjup Rad [0.4/2.1] Planetary radius
74- 78 F5.3 solMass Mass* [0.64/2.82] Stellar mass
80 A1 --- Ecc? [*] Indicates an eccentric orbit (1)
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Note (1): Blank (97 occurrences) indicates a circular orbit. We
consider a planet to have an eccentric orbit if it has e>0 at the
3σ level (33 occurrences). There are two planets, tauBoob and
WASP-10b, that would have been classified as eccentric based on the
data from exoplanet.eu, but which we classified as circular based on
more recent data. Additionally, we classified WASP-18b as circular
because its measured eccentricity is thought to be due to a tidal
bulge.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 20-Jan-2021