J/AJ/156/147 RV and activity measurements of Kepler-1656 (Brady+, 2018)
Kepler-1656b: a dense sub-Saturn with an extreme eccentricity.
Brady M.T., Petigura E.A., Knutson H.A., Sinukoff E., Isaacson H.,
Hirsch L.A., Fulton B.J., Kosiarek M.R., Howard A.W.
<Astron. J., 156, 147 (2018)>
=2018AJ....156..147B 2018AJ....156..147B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Radial velocities ; Exoplanets
Keywords: planets and satellites: detection -
planets and satellites: dynamical evolution and stability -
planets and satellites: formation -
planets and satellites: individual (Kepler-1656) -
techniques: photometric - techniques: radial velocities
Abstract:
Kepler-1656b is a 5 R⊕ planet with an orbital period of 32 days
initially detected by the prime Kepler mission. We obtained precision
radial velocities of Kepler-1656 with Keck/HIRES in order to confirm
the planet and to characterize its mass and orbital eccentricity. With
a mass of 48±4 M⊕, Kepler-1656b is more massive than most
planets of comparable size. Its high mass implies that a significant
fraction, roughly 80%, of the planet's total mass is in high-density
material such as rock/iron, with the remaining mass in a low-density
H/He envelope. The planet also has a high eccentricity of 0.84±0.01,
the largest measured eccentricity for any planet less than 100 M⊕.
The planet's high density and high eccentricity may be the result of
one or more scattering and merger events during or after the dispersal
of the protoplanetary disk.
Description:
Kepler-1656 (a.k.a. KOI-367, KIC-4815520) was observed using the High
Resolution Echelle Spectrometer (HIRES; Vogt et al. 1994SPIE.2198..362V 1994SPIE.2198..362V)
on the 10 m Keck Telescope I. We collected 100 spectra between 2016 May 12
and 2017 July 11 through an iodine cell mounted directly in front of
the spectrometer slit. This cell imprinted a dense forest of absorption
lines to be used as a wavelength reference. An exposure meter was used
to achieve a consistent signal-to-noise level of 110 per reduced pixel
on blaze near 550 nm. Our RVs were determined using standard California
Planet Search procedures (Howard et al. 2010, J/other/Sci/330.653). We
also measured the Mount Wilson SHK activity index, which traces the
chromospheric emission in the cores of the Ca II HK lines (Vaughan et al.
1978PASP...90..267V 1978PASP...90..267V)
Objects:
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RA (ICRS) DE Designation(s) (Period)
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18 57 53.32 +39 54 42.5 Kepler-1656 = KOI-367 (P=31.578659)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 43 100 Radial velocity and activity measurements
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See also:
J/other/Sci/330.653 : Detected planets in the Eta-Earth Survey (Howard+, 2010)
J/AJ/153/142 : Radial velocities of systems hosting sub-Saturns
(Petigura+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 F14.6 d BJD Barycentric Julian Date in Barycentric Dynamical
Time (TDB)
16- 25 F10.6 m/s RV [-17.352768/23.427343] Barycentric radial velocity
27- 34 F8.6 m/s e_RV [1.659714/2.78695] Uncertainty in RV
36- 43 F8.6 --- SHK [0.1235/0.1971] Mount Wilson SHK activity index
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 13-Mar-2019