J/A+A/589/A58 High-resolution imaging of TEP systems (HITEP) (Evans+, 2016)
High-resolution Imaging of Transiting Extrasolar Planetary systems (HITEP).
I. Lucky imaging observations of 101 systems in the southern hemisphere.
Evans D.F., Southworth H., Maxted P.F.L., Skottfelt J., Hundertmark M.,
Jorgensen U.G., Dominik M., Alsubai K.A., Andersen M.I., Bozza V.,
Bramich D.M., Burgdorf M.J., Ciceri S., D'Ago G., Figuera Jaimes R.,
Gu S.H., Haugbolle T., Hinse T.C., Juncher D., Kains N., Kerins E.,
Korhonen H., Kuffmeier M., Peixinho N., Popovas A., Rabus M., Rahvar S.,
Schmidt R.W., Snodgrass C., Starkey D., Surdej J., Tronsgaard R.,
von Essen C., Wang Y.B., Wertz O.
<Astron. Astrophys. 589, A58 (2016)>
=2016A&A...589A..58E 2016A&A...589A..58E (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Positional data ;
Photometry
Keywords: planets and satellites: dynamical evolution and stability -
planets and satellites: formation -
techniques: high angular resolution - binaries: visual
Abstract:
Wide binaries are a potential pathway for the formation of hot
Jupiters. The binary fraction among host stars is an important
discriminator between competing formation theories, but has not been
well characterised. Additionally, contaminating light from unresolved
stars can significantly affect the accuracy of photometric and
spectroscopic measurements in studies of transiting exoplanets.
We observed 101 transiting exoplanet host systems in the Southern
hemisphere in order to create a homogeneous catalogue of both bound
companion stars and contaminating background stars, in an area of the
sky where transiting exoplanetary systems have not been systematically
searched for stellar companions. We investigate the binary fraction
among the host stars in order to test theories for the formation of
hot Jupiters.
Lucky imaging observations from the Two Colour Instrument on the
Danish 1.54m telescope at La Silla were used to search for previously
unresolved stars at small angular separations. The separations and
relative magnitudes of all detected stars were measured. For 12
candidate companions to 10 host stars, previous astrometric
measurements were used to evaluate how likely the companions are to be
physically associated.
We provide measurements of 499 candidate companions within 20
arcseconds of our sample of 101 planet host stars. 51 candidates are
located within 5 arcseconds of a host star, and we provide the first
published measurements for 27 of these. Calibrations for the plate
scale and colour performance of the Two Colour Instrument are
presented.
We find that the overall multiplicity rate of the host stars is
38+17%, consistent with the rate among solar-type stars in our
sensitivity range, suggesting that planet formation does not
preferentially occur in long period binaries compared to a random
sample of field stars. Long period stellar companions (P>10yr) appear
to occur independently of short period companions, and so the
population of close-in stellar companions is unconstrained by our
study.
Description:
Table 1 contains the summary of observations undertaken in this work,
listing each observation, the target, and exposure time in one (red)
or two (red and visible) cameras. Table 4 contains a set of distances
derived to the exoplanet host stars, using the K-band calibration of
Kervella et al. (2004A&A...426..297K 2004A&A...426..297K). Table 8 gives the raw
measurements of each detected companion on each observation, which
include observing date, separation and position angle, and magnitude
relative to the exoplanet host star in one (red) or two (red and
visible) cameras.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 32 279 Summary of observations of TEP host stars
for 101 stars
table4.dat 24 70 Derived K-band distances to TEP host stars
table8.dat 83 1507 Measured properties of all candidate companions
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Target name
13- 24 F12.4 d BJD Barycentric Julian Date
26- 28 I3 s ExpRed Exposure time with red camera
30- 32 I3 s ExpVis ? Exposure time with visible camera
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Target name
13- 18 F6.1 pc Dist Distance to system
20- 24 F5.1 pc e_Dist Error in distance
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Target name
14- 15 I2 --- CompID ID of the candidate companion
17- 22 F6.3 arcsec Sep Separation between target and companion
24- 28 F5.3 arcsec e_Sep Error in separation
30- 34 F5.1 deg PA Position angle of companion, measured from N
36- 38 F3.1 deg e_PA Error in position angle
40- 47 F8.4 mag redmag Brightness in red relative to TEP host
49- 54 F6.4 mag e_redmag Error in red brightness
56- 63 F8.4 mag vismag ? Brightness in visual relative to TEP host
65- 70 F6.4 mag e_vismag ? Error in visual brightness
72- 83 F12.4 d BJD Barycentric Julian Date
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Acknowledgements:
Daniel Evans, d.f.evans(at)keele.ac.uk
(End) Daniel Evans [Keele University], Patricia Vannier [CDS] 09-Mar-2016