Article (Scientific journals)
A near-infrared interferometric survey of debris disc stars. III. First statistics based on 42 stars observed with CHARA/FLUOR
Absil, Olivier; Defrere, Denis; Coudé du Foresto, Vincent et al.
2013In Astronomy and Astrophysics, 555, p. 104
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Keywords :
Circumstellar matter; Planetary systems; Binaries: close; Stars: fundamental parameters; Techniques: interferometric
Abstract :
[en] Context. Dust is expected to be ubiquitous in extrasolar planetary systems due to the dynamical activity of minor bodies. Inner dust populations are, however, still poorly known due to the high contrast and small angular separation with respect to their host star. Yet, a proper characterisation of exozodiacal dust is mandatory for the design of future Earth-like planet imaging missions. Aims. We aim to determine the level of near-infrared exozodiacal dust emission around a sample of 42 nearby main sequence stars with spectral types ranging from A to K, and to investigate its correlation with various stellar parameters and with the presence of cold dust belts. Methods. We use high-precision K-band visibilities obtained with the FLUOR interferometer on the shortest baseline of the CHARA array. The calibrated visibilities are compared with the expected visibility of the stellar photosphere to assess the presence of an additional, fully resolved circumstellar emission source. Results. Near-infrared circumstellar emission amounting to about 1% of the stellar flux is detected around 13 of our 42 target stars. Follow-up observations showed that one of them (eps Cep) is associated with a stellar companion, while another one was detected around what turned out to be a giant star (kap CrB). The remaining 11 excesses found around single main sequence stars are most probably due to the presence of hot circumstellar dust, yielding an overall occurrence rate of 28+8-6% for our (biased) sample. We show that the occurrence rate of bright exozodiacal discs correlates with spectral type, K-band excesses being more frequent around A-type stars. It also correlates with the presence of detectable far-infrared excess emission in the case of solar-type stars. Conclusions. This study provides new insights regarding the phenomenon of bright exozodiacal disc, showing that hot dust populations are probably linked to outer dust reservoirs in the case of solar-type stars. In the case of A-type stars, no clear conclusion can be made regarding the origin of the detected near-infrared excesses.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Absil, Olivier  ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS)
Defrere, Denis ;  University of Arizona > Steward Observatory
Coudé du Foresto, Vincent;  Observatoire de Paris > LESIA
Di Folco, Emmanuel;  Université de Bordeaux > OASU
Mérand, Antoine;  European Southern Observatory
Augereau, Jean-Charles;  Université Joseph Fourier - Grenoble 1 - UJF > IPAG
Ertel, Steve;  Université Joseph Fourier - Grenoble 1 - UJF > IPAG
Hanot, Charles
Kervella, Pierre;  Observatoire de Paris > LESIA
Mollier, Benjamin;  Observatoire de Paris > LESIA
Scott, Nicholas;  Georgia State University > CHARA
Che, Xiao;  University of Michigan > Astronomy Department
Monnier, John;  University of Michigan > Astronomy Department
Thureau, Nathalie;  University of St Andrews > Department of Physics and Astronomy
Tuthill, Peter;  University of Sydney > Sydney Institute for Astronomy
ten Brummelaar, Theo;  Georgia State University > CHARA
McAlister, Harold;  Georgia State University > CHARA
Sturmann, Judit;  Georgia State University > CHARA
Sturmann, Laszlo;  Georgia State University > CHARA
Turner, Nils;  Georgia State University > CHARA
More authors (10 more) Less
Language :
English
Title :
A near-infrared interferometric survey of debris disc stars. III. First statistics based on 42 stars observed with CHARA/FLUOR
Publication date :
08 July 2013
Journal title :
Astronomy and Astrophysics
ISSN :
0004-6361
eISSN :
1432-0746
Publisher :
EDP Sciences, Les Ulis, France
Volume :
555
Pages :
A104
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 29 May 2013

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