J/ApJ/825/19 Mass-radius relationship for planets with Rp<4 (Wolfgang+, 2016)
Probabilistic mass-radius relationship for sub-Neptune-sized planets.
Wolfgang A., Rogers L.A., Ford E.B.
<Astrophys. J., 825, 19-19 (2016)>
=2016ApJ...825...19W 2016ApJ...825...19W (SIMBAD/NED BibCode)
ADC_Keywords: Planets ; Stars, masses ; Stars, diameters
Keywords: methods: statistical; planets and satellites: composition
Abstract:
The Kepler Mission has discovered thousands of planets with radii
<4R{earth}, paving the way for the first statistical studies of the
dynamics, formation, and evolution of these sub-Neptunes and
super-Earths. Planetary masses are an important physical property for
these studies, and yet the vast majority of Kepler planet candidates
do not have theirs measured. A key concern is therefore how to map the
measured radii to mass estimates in this Earth-to-Neptune size range
where there are no Solar System analogs. Previous works have derived
deterministic, one-to-one relationships between radius and mass.
However, if these planets span a range of compositions as expected,
then an intrinsic scatter about this relationship must exist in the
population. Here we present the first probabilistic mass-radius
relationship (M-R relation) evaluated within a Bayesian framework,
which both quantifies this intrinsic dispersion and the uncertainties
on the M-R relation parameters. We analyze how the results depend on
the radius range of the sample, and on how the masses were measured.
Assuming that the M-R relation can be described as a power law with a
dispersion that is constant and normally distributed, we find that
M/M{earth}=2.7(R/R{earth})1.3, a scatter in mass of
1.9M{earth}, and a mass constraint to physically plausible
densities, is the "best-fit" probabilistic M-R relation for the sample
of RV-measured transiting sub-Neptunes (Rpl<4R{earth}). More
broadly, this work provides a framework for further analyses of the
M-R relation and its probable dependencies on period and stellar
properties.
Description:
Table 2 shows all of the masses and radii that we consider, with our
baseline data set denoted with a label of 0; the list was constructed
by starting with the WM14 (Weiss & Marcy, 2014ApJ...783L...6W 2014ApJ...783L...6W) data
set and identifying new planets and updates in the NASA Exoplanet
Archive (last accessed 2015 January 30). We manually double-checked
each planet to verify that the reported measurements were correct. See
section 3 for further details.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 60 90 Masses and radii of small planets
refs.dat 59 46 References
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See also:
J/ApJ/806/183 : Planet radii of Kepler Object of Interest (Wolfgang+, 2015)
J/ApJS/217/31 : Kepler planetary candidates. VI. 4yr Q1-Q16 (Mullally+, 2015)
J/ApJS/217/16 : Kepler planetary candidates. V. 3yr Q1-Q12 (Rowe+, 2015)
J/ApJ/800/135 : HARPS-N radial velocities of KOI-69 (Dressing+, 2015)
J/A+A/573/A124 : Kepler-117 (KOI-209) transit-timing variations (Bruno+, 2015)
J/ApJS/210/20 : Small Kepler planets radial velocities (Marcy+, 2014)
J/ApJS/210/19 : Kepler planetary candidates. IV. 22 months (Burke+, 2014)
J/ApJS/208/16 : Kepler transit timing observations. VIII. (Mazeh+, 2013)
J/ApJ/772/L2 : Keck/HIRES radial velocities for HD 97658 (Dragomir+, 2013)
J/ApJS/204/24 : Kepler planetary candidates. III. (Batalha+, 2013)
J/A+A/546/A27 : Radial velocity and photometry for GJ3470 (Bonfils+, 2012)
J/ApJ/749/15 : The Kepler-20 planetary system (Gautier+, 2012)
J/A+A/539/A28 : New transit photom. for super-Earth 55 Cnc e (Gillon+, 2012)
J/ApJS/197/8 : Kepler's cand. multiple transiting planets (Lissauer+, 2011)
J/ApJ/736/19 : Kepler planetary candidates. II. (Borucki+, 2011)
J/ApJ/728/138 : Follow-up photometry of HAT-P-26 (Hartman+, 2011)
J/ApJ/710/1724 : Follow-up photometry for HAT-P-11 (Bakos+, 2010)
J/A+A/520/A66 : CoRoT-8b light and RV curves (Borde+, 2010)
J/A+A/506/303 : CoRoT-7 radial velocities (Queloz+, 2009)
http://exoplanetarchive.ipac.caltech.edu/ : NASA exoplanet archive
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Planet identifier
14- 20 F7.3 d Period [0.3/267.3] Orbital period
22- 26 F5.2 Mgeo Mobs [-6.4/70]? Observed mass in Earth masses
28- 32 F5.2 Mgeo e_Mobs [0.2/95] The 1σ uncertainty in Mobs
34- 38 F5.3 Rgeo Robs [0.3/6.6] Observed radius in Earth radii
40- 44 F5.3 Rgeo e_Robs [0.01/0.9] The 1σ uncertainty in Robs
46- 50 A5 --- 1Ref First reference (see refs.dat file)
52- 56 A5 --- MRRef Mass and radius reference (see refs.dat file)
58- 60 A3 --- Note [,0-6]? Additional note(s) (1)
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Note (1): Note as follows:
0 = Included in baseline dataset, which consists of RV masses
(see Section 3).
1 = Mass, radius values and their error bars are unchanged
(within rounding error) from WM14.
2 = Mass measured by fitting the observed TTVs to N-body integrations
of the system.
3 = The Kepler-68 planets were repeated twice in the WM14 dataset, so
we use the Marcy et al. (2014, J/ApJS/210/20) values.
4 = The e_Mobs column contains the 2σ upper limit as reported
in the second reference.
5 = Only a 1σ upper limit of 3.78 was given, and no posteriors
were shown; in this analysis, we set the 2σ upper limit at
9 Mgeo to include 1.8 m/s uncertainty quoted in RV semi-amplitude
for the larger Kepler-101 b.
6 = The 2σ upper limit is interpolated from given 1σ and
3σ upper limits.
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference number
4- 24 A21 --- Auth First author's name and year
26- 44 A19 --- BibCode Bibcode of the reference
46- 59 A14 --- Cat VizieR catalog reference
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 22-Aug-2016