Long-lived, long-period radial velocity variations in Aldebaran: A planetary companion and stellar activity

  title={Long-lived, long-period radial velocity variations in Aldebaran: A planetary companion and stellar activity},
  author={A. P. Hatzes and William D. Cochran and Michael Endl and E. W. Guenther and Phillip J. MacQueen and Michael Hartmann and Mathias Zechmeister and Inwoo Han and B.-C. Lee and G. A. H. Walker and S. Yang and Ana M. Larson and K.-M. Kim and David Mkrtichian and M. Doellinger and Attila E. Simon and L. Girardi},
  journal={arXiv: Solar and Stellar Astrophysics},
We investigate the nature of the long-period radial velocity variations in Alpha Tau first reported over 20 years ago. We analyzed precise stellar radial velocity measurements for Alpha Tau spanning over 30 years. An examination of the Halpha and Ca II 8662 spectral lines, and Hipparcos photometry was also done to help discern the nature of the long-period radial velocity variations. Our radial velocity data show that the long-period, low amplitude radial velocity variations are long-lived and… 
The Radial Velocity Variability of the K-giant γ Draconis: Stellar Variability Masquerading as a Planet
We present precise stellar radial velocity (RV) measurements of γ Dra taken from 2003 to 2017. The data from 2003 to 2011 show coherent, long-lived variations with a period of 702 days. These
Precise radial velocities of giant stars
Context. Using the Hamilton Échelle Spectrograph at Lick Observatory, we have obtained precise radial velocities (RVs) of a sample of 373 G- and K-giant stars over more than 12 yr, leading to the
The discovery of a planetary candidate around the evolved low-mass Kepler giant star HD 175370
We report on the discovery of a planetary companion candidate with a minimum mass M sin i = 4.6 +/- 1.0 M-Jupiter orbiting the K2 III giant star HD 175370 (KIC 007940959). This star was a target in
Search for Exoplanets around Northern Circumpolar Stars- II. The Detection of Radial Velocity Variations in M Giant Stars HD 36384, HD 52030, and HD 208742
We present the detection of long-period RV variations in HD 36384, HD 52030, and HD 208742 by using the high-resolution, fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) for the precise
Search for exoplanets around northern circumpolar stars III. long-period radial velocity variations in hd 18438 and hd 158996
Detecting exoplanets around giant stars sheds light on the later-stage evolution of planetary systems. We observed the M giant HD 18438 and the K giant HD 158996 as part of a Search for Exoplanets
A historical problem for indirect exoplanet detection has been contending with the intrinsic variability of the host star. If the variability is periodic, it can easily mimic various exoplanet
A Search for Exoplanets around Northern Circumpolar Stars. IV. Six Planet Candidates to the K Giants, HD 44385, HD 97619, HD 106574, HD 118904, HD 164428, and HD 202432
We report the discovery of long-period radial velocity (RV) variations in six intermediate-mass K-giant stars using precise RV measurements. These discoveries are part of the Search for Exoplanets
Aldebaran b’s Temperate Past Uncovered in Planet Search Data
The nearby red giant Aldebaran is known to host a gas giant planetary companion from decades of ground-based spectroscopic radial velocity measurements. Using Gaussian Process-based Continuous
Evidence of asymmetries in the Aldebaran photosphere from multiwavelength lunar occultations
We have recorded three lunar occultations of Aldebaran (α Tau) at different telescopes and using various band-passes, from the ultraviolet to the far red. The data have been analysed using both
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
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 Echelle Spectrograph at the Lick Observatory. There are,


Confirmation of the planet hypothesis for the long-period radial velocity variations of β Geminorum
Aims. Our aim is to confirm the nature of the long period radial velocity measurements for β Gem first found by Hatzes & Cochran (1993). Methods. We present precise stellar radial velocity
Discovery of a planet around the K giant star 4 Ursae Majoris
For the past 3 years we have been monitoring a sample of 62 K giant stars using precise stellar radial velocity measurements with high accuracy taken at the Thuringer Landessternwarte Tautenburg. We
Precise radial velocities with BOES : Detection of low-amplitude pulsations in the K-giant α arietis
We present the first results from a high-precision radial velocity study of the K2 III giant star α Ari. Observations were acquired over 6 nights in 2004 using the new high-resolution spectrograph
No planet for HD 166435
The G0 V star HD 166435 has been observed by the ber-fed spectrograph ELODIE as one of the targets in the large extra-solar planet survey that we are conducting at the Observatory of Haute-Provence.
Precise radial velocities of giant stars. II. Pollux and its planetary companion
It has long been speculated that the observed periodic radial velocity pattern for the K giant Pollux might be explained in terms of an orbiting planetary companion. We have collected 80
The shape of the Ti i 6303.8-A spectral line of Aldebaran as measured by the line bisector was investigated using high signal-to-noise ratio, high-resolution data. The goal of this study was to
A low-amplitude periodicity in the radial velocity and chromospheric emission of beta Geminorum
Using high-quality spectra obtained with the hydrogren fluoride technique at the Canada-France-Hawaii 3.6-meter telescope and Dominion Astrophysical Observatory 1.22-meter telescope, we have detected
Long-Period Radial Velocity Variations in Three K Giants
Precise relative radial velocities (σ∼20 m s −1 ) are presented for three K giants: α Tau, α Boo, and β Gem. The data reveal periods of 233 days for α Boo, 643 days for α Tau, and 558 days for β Gem.
A giant planet around the massive giant star HD 13189
Most extrasolar planet discoveries using radial velocity measurements have been for solar-like G-stars. In order to understand better the role stellar mass for the formation of planets we must learn
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  • Physics, Geology
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High-precision radial-velocity observations of the solar-type star 16 Cygni B (HR 7504, HD 186427), taken at McDonald Observatory and at Lick Observatory, have each independently discovered periodic