J/A+A/569/A120 Spectra of wide companions to planet-host stars (Lodieu+ 2014)
Binary frequency of planet-host stars at wide separations.
A new brown dwarf companion to a planet-host star.
Lodieu N., Perez-Garrido A., Bejar V.J.S., Gauza B., Ruiz M.T., Rebolo R.,
Pinfield D.J., Martin E.L.
<Astron. Astrophys. 569, A120 (2014)>
=2014A&A...569A.120L 2014A&A...569A.120L
ADC_Keywords: Surveys ; Stars, late-type ; Spectroscopy
Keywords: stars: low-mass - brown dwarfs - techniques: photometric -
techniques: spectroscopic - surveys
Abstract:
We present the results of a search for wide companions to planet-host
stars to improve our knowledge on their multiplicity at wide physical
separations.
We cross-matched approximately 6200 square degree area of the Southern
sky imaged by the Visible Infrared Survey Telescope for Astronomy
(VISTA) Hemisphere Survey (VHS) with the Two Micron All Sky Survey
(2MASS) to look for wide common proper motion companions to known
planet-host stars. We complemented our astrometric search with
photometric criteria.
We confirmed spectroscopically the co-moving nature of seven sources
out of 16 companion candidates and discarded eight, while the
remaining one stays as a candidate. Among these new wide companions to
planet-host stars, we discovered a T4.5 dwarf companion at 6.3-arcmin
(∼9000AU) from HIP70849, a K7V star which hosts a 9 Jupiter mass
planet with an eccentric orbit. We also report two new stellar M dwarf
companions to one G and one metal-rich K star. We infer stellar and
substellar binary frequencies for our complete sample of 37 targets of
5.4±3.8% and 2.7±2.7% (1 sigma confidence level), respectively,
for projected physical separations larger than ∼60-160AU assuming
the range of distances of planet-host stars (24-75pc). These values
are comparable to the frequencies of non planet-host stars. We find
that the period-eccentricity trend holds with a lack of multiple
systems with planets at large eccentricities (e>0.2) for periods less
than 40-days. However, the lack of planets more massive than 2.5
Jupiter masses and short periods (<40-days) orbiting single stars is
not so obvious due to recent discoveries by ground-based transit
surveys and space missions.
Description:
Optical spectra of 12 wide companions to planet-host stars. We provide
ascii file with the wavelength and the flux in the first and second
column, respectively. Wavelengths are in Angstroms and flux in
ergs/cm2/s/Angstroem.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 67 13 List of studied wide companions to planet-host stars
sp/* . 13 Individual spectra
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name Associated planet-host star name
(from table1 of the paper)
12- 23 A12 --- FileName Name of the spectrum file in subdirectory sp
25- 26 I2 h RAh Wide companion right ascension (J2000)
28- 29 I2 min RAm Wide companion right ascension (J2000)
31- 35 F5.2 s RAs Wide companion right ascension (J2000)
37 A1 --- DE- Wide companion declination sign (J2000)
38- 39 I2 deg DEd Wide companion declination (J2000)
41- 42 I2 arcmin DEm Wide companion declination (J2000)
44- 47 F4.1 arcsec DEs Wide companion declination (J2000)
49- 54 F6.3 mag Jmag Wide companion 2MASS J magnitude
56- 67 A12 --- SpType Wide companion MK spectral type
--------------------------------------------------------------------------------
Byte-by-byte Description of file: sp/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.2 0.1nm lambda [4736/25335] Wavelength λ (Å)
11- 23 E13.7 cW/m2/nm Flux Flux in ergs/cm2/s/Å
--------------------------------------------------------------------------------
Acknowledgements:
Nicolas Lodieu, nlodieu(at)iac.es
(End) Nicolas Lodieu [IAC, Tenerife, Spain], Patricia Vannier [CDS] 06-Aug-2014