J/MNRAS/497/2250 Gaia DR2 hot Jupiter hosts and contact binaries (Hwang+, 2020)
Very wide companion fraction from Gaia DR2: A weak or no enhancement for hot
Jupiter hosts, and a strong enhancement for contact binaries.
Hwang H.-C., Hamer J.H., Zakamska N.L., Schlaufman K.C.
<Mon. Not. R. Astron. Soc., 497, 2250-2259 (2020)>
=2020MNRAS.497.2250H 2020MNRAS.497.2250H (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Binaries, eclipsing ; Exoplanets ;
Optical
Keywords: planets and satellites: formation - binaries: close -
binaries: eclipsing
Abstract:
There is an ongoing debate on whether hot Jupiter hosts are more
likely to be found in wide binaries with separations of ∼100AU. In
this paper, we search for comoving, very wide companions with
separations of 103-104AU for hot Jupiter hosts and main-sequence
contact binaries in Gaia DR2, and compare the very wide companion
fractions with their object-by-object-matched field star samples. We
find that 11.9±2.5 per cent of hot Jupiter hosts and 14.1±1.0 per
cent of contact binaries have companions at separations of
103-104AU. While the very wide companion fraction of hot Jupiter
hosts is a factor of 1.9±0.5 larger than their matched field star
sample, it is consistent, within ∼1σ, with that of matched field
stars if the matching is only with field stars without close
companions (within ∼50AU) as is the case for hot Jupiter hosts. The
very wide companion fraction of contact binaries is a factor of
3.1±0.5 larger than their matched field star sample, suggesting that
the formation and evolution of contact binaries are either tied to or
correlated with the presence of wide companions. In contrast, the weak
enhancement of very wide companion fraction for hot Jupiter hosts
implies that the formation of hot Jupiters is not as sensitive to
those environment properties. Our results also hint that the
occurrence rates of dual hot Jupiter hosts and dual contact binaries
may be higher than the expected values from random pairing of field
stars, which may be due to their underlying metallicity and age
dependence.
Description:
We use the sample of main sequence hot Jupiter hosts whose selection
is described in Hamer & Schlaufman (2019AJ....158..190H 2019AJ....158..190H, Cat.
J/AJ/158/190). Briefly, hot Jupiters were selected from the confirmed
planets table of the NASA Exoplanet Archive using the fiducial
definition from Wright et al. (2012ApJ...753..160W 2012ApJ...753..160W), planets having
P<10d and Msini>0.1MJup. Most (∼90 per cent) of these hot Jupiters
were discovered by transiting surveys and further confirmed by
follow-up radial-velocity observations. Therefore, no contamination
from false-positive eclipsing binaries is expected.
Short-period binaries are often compared to hot Jupiters because
historically both their formations are speculated to be due to the
Kozai-Lidov interactions (e.g. Fabrycky & Tremaine
2007ApJ...669.1298F 2007ApJ...669.1298F). Furthermore, a direct comparison of wide
companion fractions between short-period binaries and hot Jupiters
(Moe & Kratter 2021MNRAS.507.3593M 2021MNRAS.507.3593M) provides a probe of the different
formation processes across the mass gap of 4-9MJup (Schlaufman
2018ApJ...853...37S 2018ApJ...853...37S). Therefore, in this paper we compare the
companion fraction between main-sequence hot Jupiter hosts,
main-sequence contact binaries, and field stars. We use the sample of
contact binaries whose selection is detailed in Hwang & Zakamska
(2020MNRAS.493.2271H 2020MNRAS.493.2271H).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
cbcat.dat 60 278 Main-sequence contact binaries catalog
hjcat.dat 60 36 Hot Jupiter hosts catalog
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/AJ/158/190 : Main sequence hot Jupiter hosts with good astrometry
(Hamer+, 2019)
Byte-by-byte Description of file: cbcat.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- GaiaDR2 Gaia DR2 source identifier of the contact
binary
21- 39 I19 --- Companion Gaia ID of contact binary companion
41- 60 F20.14 AU Sep Separation between components
--------------------------------------------------------------------------------
Byte-by-byte Description of file: hjcat.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- GaiaDR2 Gaia DR2 source identifier of the hot
Jupiter host
21- 39 I19 --- Companion Gaia ID of hot Jupiter host companion
41- 60 F20.14 AU Sep Separation between components
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 26-Jul-2023