Abstract
Context. For over 12 yr, we have carried out a precise radial velocity (RV) survey of a sample of 373 G-and K-giant stars using the Hamilton Échelle Spectrograph at the Lick Observatory. There are, among others, a number of multiple planetary systems in our sample as well as several planetary candidates in stellar binaries. Aims. We aim at detecting and characterizing substellar and stellar companions to the giant star HD 59686 A (HR 2877, HIP 36616). Methods. We obtained high-precision RV measurements of the star HD 59686 A. By fitting a Keplerian model to the periodic changes in the RVs, we can assess the nature of companions in the system. To distinguish between RV variations that are due to non-radial pulsation or stellar spots, we used infrared RVs taken with the CRIRES spectrograph at the Very Large Telescope. Additionally, to characterize the system in more detail, we obtained high-resolution images with LMIRCam at the Large Binocular Telescope. Results. We report the probable discovery of a giant planet with a mass of mp sin i = 6.92-0.24+0.18 MJup orbiting at ap = 1.0860-0.0007+0.0006 au from the giant star HD 59686 A. In addition to the planetary signal, we discovered an eccentric (eB = 0.729-0.003+0.004) binary companion with a mass of mB sin i = 0.5296-0.0008+0.0011 M⊙ orbiting at a close separation from the giant primary with a semi-major axis of aB = 13.56-0.14+0.18 au. Conclusions. The existence of the planet HD 59686 Ab in a tight eccentric binary system severely challenges standard giant planet formation theories and requires substantial improvements to such theories in tight binaries. Otherwise, alternative planet formation scenarios such as second-generation planets or dynamical interactions in an early phase of the system's lifetime need to be seriously considered to better understand the origin of this enigmatic planet.
| Original language | English (US) |
|---|---|
| Article number | A55 |
| Journal | Astronomy and Astrophysics |
| Volume | 595 |
| DOIs | |
| State | Published - Nov 1 2016 |
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Keywords
- Planetary systems
- Planets and satellites: detection
- Planets and satellites: formation
- Planets and satellites: fundamental parameters
- Planets and satellites: gaseous planets
- Planets and satellites: general
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
Cite this
Precise radial velocities of giant stars : IX. HD 59686 Ab: A massive circumstellar planet orbiting a giant star in a ~ 13.6 au eccentric binary system. / Ortiz, Mauricio; Reffert, Sabine; Trifonov, Trifon; Quirrenbach, Andreas; Mitchell, David S.; Nowak, Grzegorz; Buenzli, Esther; Zimmerman, Neil; Bonnefoy, Mickaël; Skemer, Andy; Defrère, Denis; Lee, Man Hoi; Fischer, Debra A.; Hinz, Philip M.
In: Astronomy and Astrophysics, Vol. 595, A55, 01.11.2016.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Precise radial velocities of giant stars
T2 - IX. HD 59686 Ab: A massive circumstellar planet orbiting a giant star in a ~ 13.6 au eccentric binary system
AU - Ortiz, Mauricio
AU - Reffert, Sabine
AU - Trifonov, Trifon
AU - Quirrenbach, Andreas
AU - Mitchell, David S.
AU - Nowak, Grzegorz
AU - Buenzli, Esther
AU - Zimmerman, Neil
AU - Bonnefoy, Mickaël
AU - Skemer, Andy
AU - Defrère, Denis
AU - Lee, Man Hoi
AU - Fischer, Debra A.
AU - Hinz, Philip M
PY - 2016/11/1
Y1 - 2016/11/1
N2 - Context. For over 12 yr, we have carried out a precise radial velocity (RV) survey of a sample of 373 G-and K-giant stars using the Hamilton Échelle Spectrograph at the Lick Observatory. There are, among others, a number of multiple planetary systems in our sample as well as several planetary candidates in stellar binaries. Aims. We aim at detecting and characterizing substellar and stellar companions to the giant star HD 59686 A (HR 2877, HIP 36616). Methods. We obtained high-precision RV measurements of the star HD 59686 A. By fitting a Keplerian model to the periodic changes in the RVs, we can assess the nature of companions in the system. To distinguish between RV variations that are due to non-radial pulsation or stellar spots, we used infrared RVs taken with the CRIRES spectrograph at the Very Large Telescope. Additionally, to characterize the system in more detail, we obtained high-resolution images with LMIRCam at the Large Binocular Telescope. Results. We report the probable discovery of a giant planet with a mass of mp sin i = 6.92-0.24+0.18 MJup orbiting at ap = 1.0860-0.0007+0.0006 au from the giant star HD 59686 A. In addition to the planetary signal, we discovered an eccentric (eB = 0.729-0.003+0.004) binary companion with a mass of mB sin i = 0.5296-0.0008+0.0011 M⊙ orbiting at a close separation from the giant primary with a semi-major axis of aB = 13.56-0.14+0.18 au. Conclusions. The existence of the planet HD 59686 Ab in a tight eccentric binary system severely challenges standard giant planet formation theories and requires substantial improvements to such theories in tight binaries. Otherwise, alternative planet formation scenarios such as second-generation planets or dynamical interactions in an early phase of the system's lifetime need to be seriously considered to better understand the origin of this enigmatic planet.
AB - Context. For over 12 yr, we have carried out a precise radial velocity (RV) survey of a sample of 373 G-and K-giant stars using the Hamilton Échelle Spectrograph at the Lick Observatory. There are, among others, a number of multiple planetary systems in our sample as well as several planetary candidates in stellar binaries. Aims. We aim at detecting and characterizing substellar and stellar companions to the giant star HD 59686 A (HR 2877, HIP 36616). Methods. We obtained high-precision RV measurements of the star HD 59686 A. By fitting a Keplerian model to the periodic changes in the RVs, we can assess the nature of companions in the system. To distinguish between RV variations that are due to non-radial pulsation or stellar spots, we used infrared RVs taken with the CRIRES spectrograph at the Very Large Telescope. Additionally, to characterize the system in more detail, we obtained high-resolution images with LMIRCam at the Large Binocular Telescope. Results. We report the probable discovery of a giant planet with a mass of mp sin i = 6.92-0.24+0.18 MJup orbiting at ap = 1.0860-0.0007+0.0006 au from the giant star HD 59686 A. In addition to the planetary signal, we discovered an eccentric (eB = 0.729-0.003+0.004) binary companion with a mass of mB sin i = 0.5296-0.0008+0.0011 M⊙ orbiting at a close separation from the giant primary with a semi-major axis of aB = 13.56-0.14+0.18 au. Conclusions. The existence of the planet HD 59686 Ab in a tight eccentric binary system severely challenges standard giant planet formation theories and requires substantial improvements to such theories in tight binaries. Otherwise, alternative planet formation scenarios such as second-generation planets or dynamical interactions in an early phase of the system's lifetime need to be seriously considered to better understand the origin of this enigmatic planet.
KW - Planetary systems
KW - Planets and satellites: detection
KW - Planets and satellites: formation
KW - Planets and satellites: fundamental parameters
KW - Planets and satellites: gaseous planets
KW - Planets and satellites: general
UR - http://www.scopus.com/inward/record.url?scp=84993978033&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84993978033&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201628791
DO - 10.1051/0004-6361/201628791
M3 - Article
AN - SCOPUS:84993978033
VL - 595
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
SN - 0004-6361
M1 - A55
ER -