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:
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RA (2000) DE Designation(s)
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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
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 100 4 List of fits images
fits/* . 4 Individual fits images
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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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
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Acknowledgements:
Christian Ginski, c.ginski(at)uva.nl
(End) Patricia Vannier [CDS] 05-May-2021