J/A+A/668/A26 KIC 3526061 and HD 187878 RV curves (Karjalainen+, 2022)
Companions to Kepler giant stars: A long-period eccentric sub-stellar companion
to KIC 3526061 and a stellar companion to HD 187878.
Karjalainen M., Karjalainen R., Hatzes A.P., Lehmann H., Kervella P.,
Hekker S., Van Winckel H., Ueberlauer J., Vitkova M., Skarka M., Kabath P.,
Prins S., Tkachenko A., Cochran W.D., Jorissen A.
<Astron. Astrophys. 668, A26 (2022)>
=2022A&A...668A..26K 2022A&A...668A..26K (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant ; Radial velocities ; Optical
Keywords: methods: observational - techniques: radial velocities -
techniques: spectroscopic - stars: individual: KIC 3526061 -
stars: individual: HD 187878 - brown dwarfs
Abstract:
Our knowledge of populations and the occurrence of planets orbiting
evolved intermediate-mass stars is still incomplete. In 2010 we
started a planet search programme among 95 giant stars observed by the
Kepler mission to increase the sample of giant stars with planets and
with reliable estimates of stellar masses and radii.
We present the two systems from our planet search programme whose
companions we were able to characterise: KIC 3526061 and HD 187878.
We used precise stellar radial velocity measurements taken with four
different echelle spectrographs to derive an orbital solution. We used
Gaia astrometric measurements to obtain the inclination of the HD
187878 system and Kepler photometric observations to estimate the
stellar mass and radius.
We report the discovery of a sub-stellar companion and a stellar
companion around two intermediate-mass red giant branch stars. KIC
3526061 b is most likely a brown dwarf with a minimum mass of 18.15
Jupiter masses in a long-period eccentric orbit, with orbital period
3552 d and orbital eccentricity 0.85. It is the most evolved system
found having a sub-stellar companion with such a high eccentricity and
wide separation. HD 187878 B has a minimum mass of 78.4 Jupiter
masses. Combining the spectroscopic orbital parameters with the
astrometric proper motion anomaly, we derived an orbital inclination
9.8 deg, which corresponds to the companion's mass in the stellar
regime of 0.51 Sun mass.
A sub-stellar companion of KIC 3526061 extends the sample of known red
giant branch stars with sub-stellar companions on very eccentric wide
orbits and might provide a probe of the dynamical evolution of such
systems over time.
Description:
Radial velocity measurements of KIC 3526061 and HD 187878, taken with
four different echelle spectrographs. These measurements were used to
derive an orbital solution. At the McDonald Observatory, TLS and
Ondrejov we used an iodine cell which resulted to radial velocities
relative to a stellar template, while for the Mercator telescope
radial velocities are absolute. Radial velocities were corrected for
the barycentre motion, using the program BarCor
(https://stelweb.asu.cas.cz/~marie/Barcor/). The RV uncertainties
correspond to instrumental errors.
Objects:
----------------------------------------------------------
RA (2000) DE Designation(s)
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19 00 44.73 +38 36 39.9 KIC 3526061 = TIC 399793957
19 50 25.52 +43 39 40.3 HD 187878 = TIC 273237514
----------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 38 25 Radial velocity measurements of KIC 3526061
table2.dat 38 100 Radial velocity measurements of HD 187878
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Byte-by-byte Description of file: table1.dat table2.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Inst Instrument (1)
10- 23 F14.6 d BJD Barycentric Julian Date
25- 32 F8.1 m/s RV Barycentric radial velocity (2)
35- 38 F4.1 m/s e_RV Barycentric radial velocity uncertainty
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Note (1): Instruments are
HERMES, McDonald for table 1 (KIC 3526061),
HERMES, Ondrejov, TLS new and TLS old for table2 (HD 187878).
Note (2): For table 1 (KIC 3526061):
at T0=2458708.1, RV0(McDonald)=9.7m/s, RV0(HERMES)=-27557.9m/s
For table2 (HD 187878):
at T0=2455836.0, RV0(HERMES)=-18285.3m/s, RV0(Ondrejov)=16.4m/s,
RV0(TLS old)=-78.2m/s, RV0(TLS new)=-42.8m/s.
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Acknowledgements:
Marie Karjalainen, marie.karjalainen(at)asu.cas.cz
(End) M. Karjalainen [CAS, Czech Republic], P. Vannier [CDS] 05-Oct-2022