J/AJ/161/202 Transit timing variations of Kepler-90g and h (Liang+, 2021)
Kepler-90: giant transit-timing variations reveal a super-puff.
Liang Y., Robnik J., Seljak U.
<Astron. J., 161, 202 (2021)>
=2021AJ....161..202L 2021AJ....161..202L
ADC_Keywords: Exoplanets; Stars, double and multiple
Keywords: Transit timing variation method ; Orbital evolution ;
Orbital resonances
Abstract:
Exoplanet transit-timing variations (TTVs) caused by gravitational
forces between planets can be used to determine planetary masses and
orbital parameters. Most of the observed TTVs are small and sinusoidal
in time, leading to degeneracies between the masses and orbital
parameters. Here we report a TTV analysis of Kepler-90g and
Kepler-90h, which exhibit large TTVs up to 25hr. With optimization, we
find a unique solution that allows us to constrain all of the orbital
parameters. The best-fit masses for Kepler-90g and 90h are
15.0-0.8+0.9M⊕ (Earth mass) and 203-5+5M_⊕,
respectively, with Kepler-90g having an unusually low apparent density
of 0.15±0.05g/cm3. The uniqueness of orbital parameter solution
enables a long-term dynamical integration, which reveals that although
their periods are close to 2:3 orbital resonance, they are not locked
in resonance, and the configuration is stable over billions of years.
The dynamical history of the system suggests that planet interactions
are able to raise the eccentricities and break the resonant lock after
the initial formation.
Description:
The Kepler-90 system has more known transiting planets than almost any
other system. Among its seven confirmed planets, the inner five have
orbital periods ranging from 7 to 125 days, while the outer two are
90g and 90h with orbital periods of 210.5 days and 331.6 days,
respectively. Based on the six recorded transits of 90g and 3 transits
of 90h during the four years of Kepler observations, both planets show
significant transit-timing variations.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig1.dat 94 9 Raw transit timings and durations of Kepler 90g & h
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See also:
J/ApJ/790/146 : Planets in Kepler's multi-transiting systems (Fabrycky+, 2014)
J/ApJ/785/15 : Transit times Kepler-79's known planets (Jontof-Hutter+, 2014)
J/ApJS/225/9 : Kepler TTVs IX. The full long-cadence data set (Holczer+, 2016)
J/A+A/587/A64 : Physical properties of giant exoplanets (Santerne+, 2016)
J/AJ/154/5 : Transit timing variations of 145 Kepler planets (Hadden+, 2017)
J/ApJS/234/9 : A spectral approach to transit timing variations (Ofir+, 2018)
J/AJ/156/89 : RVs & predicted transit-times for K2-24 system (Petigura+,2018)
Byte-by-byte Description of file: fig1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Planet Planet observed
12- 30 F19.14 d HJD [140/1467] Absolute transit time; HJD-2454833
32- 52 F21.19 d e_HJD [0.001/0.003] Error in HJD
54- 72 F19.17 d Dur [0.47/0.59] Transit Duration
74- 94 F21.19 d e_Dur [0.001/0.006] Error in Dur
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie FIX [CDS], 04-Aug-2021