J/AJ/154/188 Radial velocities and photometry of K2-114&K2-115 (Shporer+, 2017)
K2-114b and K2-115b: two transiting warm Jupiters.
Shporer A., Zhou G., Fulton B.J., Vanderburg A., Espinoza N., Collins K.,
Ciardi D., Bayliss D., Armstrong J.D., Bento J., Bouchy F., Cochran W.D.,
Cameron A.C., Colon K., Crossfield I., Dragomir D., Howard A.W.,
Howell S.B., Isaacson H., Kielkopf J.F., Murgas F., Sefako R., Sinukoff E.,
Siverd R., Udry S.
<Astron. J., 154, 188 (2017)>
=2017AJ....154..188S 2017AJ....154..188S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Radial velocities ;
Photometry
Keywords: stars: individual (K2-114, EPIC 211418729, K2-115, EPIC 211442297,
EPIC 212504617)
Abstract:
We report the first results from a search for transiting warm Jupiter
exoplanets-gas giant planets receiving stellar irradiation below about
108 erg/s/cm2, equivalent to orbital periods beyond about 10 days
around Sun-like stars. We have discovered two transiting warm Jupiter
exoplanets initially identified as transiting candidates in K2 photometry.
K2-114b has a mass of 1.85-0.22+0.23 MJ, a radius of
0.942-0.020+0.032 RJ, and an orbital period of 11.4 days.
K2-115b has a mass of 0.84-0.20+0.18 MJ, a radius
of 1.115-0.061+0.057 RJ, and an orbital period of 20.3 days.
Both planets are among the longest-period transiting gas giant planets
with a measured mass, and they are orbiting relatively old host stars.
Both planets are not inflated, as their radii are consistent with
theoretical expectations. Their position in the planet radius-stellar
irradiation diagram is consistent with the scenario where the
radius-irradiation correlation levels off below about 108 erg/s/cm2,
suggesting that for warm Jupiters stellar irradiation does not play a
significant role in determining the planet radius. We also report our
identification of another K2 transiting warm Jupiter candidate,
EPIC 212504617, as a false positive.
Description:
Once we confirmed that the two targets appear isolated in high angular
resolution imaging, we began gathering high-resolution spectra with
the HIRES instrument mounted on the Keck I telescope (Vogt et al.
1994SPIE.2198..362V 1994SPIE.2198..362V). We collected a total of six spectra of K2-114
between 2016 February 2 and 2017 May 13. We collected eight spectra
and seven RV measurements using the iodine cell for K2-115 between
2016 February 4 and 2017 April 10.
While gathering the RVs of the two targets we also acquired ground-based
light curves of additional transit events. Las Cumbres Observatory (LCO)
is a fully robotic network of telescopes deployed at six sites around
the globe in both hemispheres (two more sites are planned to be added
by 2018; Brown et al. 2013PASP..125.1031B 2013PASP..125.1031B). The egress of K2-114b was
observed on 2016 February 17 using a 1 m telescope at the Cerro Tololo
Inter-American Observatory (CTIO), Chile. For K2-115b, LCO observed an
almost complete transit on 2016 February 22 with a 1 m telescope at
the Siding Spring Observatory (SSO), Australia, and an egress on 2016
March 13 with a 1 m telescope at the South African Astronomical
Observatory (SAAO), South Africa. We observed one full transit of K2-115b
with short segments of out-of-transit baselines using the University
of Louisville Manner Telescope (ULMT) located at the Mt. Lemmon summit
of Steward Observatory, AZ, on 2017 February 21 with no filter.
Objects:
--------------------------------------------------------------
RA (ICRS) DE Designation(s)
--------------------------------------------------------------
08 31 31.92 +11 55 20.3 K2-114 = 2MASS J08313191+1155202
08 26 12.82 +12 16 55.1 K2-115 = 2MASS J08261282+1216550
--------------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 31 12 Keck/HIRES Radial Velocities
table4.dat 44 302 Ground-base photometry
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See also:
J/ApJ/809/77 : Transiting Exoplanet Survey Satellite (TESS) (Sullivan+, 2015)
J/ApJS/224/2 : K2 EPIC stellar properties for 138600 targets (Huber+, 2016)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Star Star name (K2-114, K2-115)
8- 20 F13.5 d BJD Barycentric Julian Date
22- 27 F6.1 m/s RV [-194.3/152.4] Radial velocity
29- 31 F3.1 m/s e_RV [5.6/8.2] Uncertainty in RV
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Star Star name (K2-114, K2-115)
8- 16 A9 --- Obs Observatory identifier (LCO, ULMT 0.6m)
18- 30 F13.5 d BJD Barycentric Julian Date
32- 37 F6.4 --- RFlux [0.0068/1.0089] Relative flux
39- 44 F6.4 --- e_RFlux [0.0015/0.0583] Uncertainty in RFlux
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 30-Jul-2018