J/A+A/649/A156   Exoplanet host stars SPHERE multiplicity survey (Ginski+, 2021)

How many suns are in the sky? A SPHERE multiplicity survey of exoplanet host stars. I. Four new close stellar companions including a white dwarf. Ginski C., Mugrauer M., Adam C., Vogt N., van Holstein R.G. <Astron. Astrophys. 649, A156 (2021)> =2021A&A...649A.156G 2021A&A...649A.156G (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets Keywords: binaries: close - techniques: high angular resolution - planet-star interactions - planets and satellites: general Abstract: We are studying the influence of stellar multiplicity on exoplanet systems and, in particular, systems that have been detected via radial-velocity searches. We are specifically interested in the closest companions as they would have a strong influence on the evolution of the original planet-forming disks. In this study, we present new companions that have been detected during our ongoing survey of exoplanet hosts with VLT/SPHERE (Spectro-Polarimetric High-Contrast Exoplanet Research). We are using the extreme adaptive optics imager SPHERE at the ESO/VLT to search for faint (sub)stellar companions. We utilized the classical coronagraphic imaging mode to perform a snapshot survey (3-6min integration time) of exoplanet host stars in the KS-band. We detected new stellar companions to the exoplanet host stars HD 1666, HIP 68468, HIP 107773, and HD 109271. With an angular separation of only 0.38arcsec (40au of projected separation), HIP 107773 is among the closest companions found for exoplanet host stars. The presence of the stellar companion explains the linear radial-velocity trend seen in the system. At such a small separation, the companion likely had a significant influence on the evolution of the planet-forming disk around the primary star. We find that the companion in the HD 1666 system may well be responsible for the high orbit eccentricity (0.63) of the detected Jupiter class planet, making this system one of only a few where such a connection can be established. A cross-match with the Gaia DR2 catalog shows, furthermore, that the near infrared faint companion around HD 109271 was detected in the optical and it is significantly brighter than in the near infrared, making it a white dwarf companion. Description: All observations were conducted with SPHERE/IRDIS (Infra-Red Dual Imager and Spectrograph) at the ESO/VLT in field stabilized classical imaging mode with the broad-band Ks filter. The bright primary star was always placed behind an apodized Lyot coronagraph with an inner working angle of 120mas. Individual frame exposure times (3s-16s) were adjusted such that the residual light from the primary star does not reach saturation levels. The total integration time for all targets was between 3.2 and 6 min. Objects: ------------------------------------------------- RA (2000) DE Designation(s) ------------------------------------------------- 00 20 52.34 -19 55 52.4 HD 1666 = HIP 1666 12 33 35.55 -11 37 18.7 HD 109271 = HIP 61300 14 01 03.61 -32 45 25.0 HIP 68468 = HD 122194 21 50 00.12 -64 42 45.1 HIP 107773 = HD 207229 ------------------------------------------------- File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file list.dat 100 4 List of fits images fits/* . 4 Individual fits images -------------------------------------------------------------------------------- Byte-by-byte Description of file: list.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 I2 h RAh Right ascension (J2000) 4- 5 I2 min RAm Right ascension (J2000) 7- 11 F5.2 s RAs Right ascension (J2000) 13 A1 --- DE- Declination sign (J2000) 14- 15 I2 deg DEd Declination (J2000) 17- 18 I2 arcmin DEm Declination (J2000) 20- 23 F4.1 arcsec DEs Declination (J2000) 25- 28 I4 --- Nx Number of pixels along X-axis 30- 33 I4 --- Ny Number of pixels along Y-axis 35- 38 I4 Kibyte size Size of FITS file 40- 52 A13 --- FileName Name of FITS file, in subdirectory fits 54-100 A47 --- Title Title of the FITS file -------------------------------------------------------------------------------- Acknowledgements: Christian Ginski, c.ginski(at)uva.nl
(End) Patricia Vannier [CDS] 05-May-2021
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