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The HOSTS Survey—Exozodiacal Dust Measurements for 30 Stars

Ertel, S. and Beichman, C. and Millan-Gabet, R. (2018) The HOSTS Survey—Exozodiacal Dust Measurements for 30 Stars. Astronomical Journal, 155 (5). Art. No. 194. ISSN 1538-3881. doi:10.3847/1538-3881/aab717.

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The Hunt for Observable Signatures of Terrestrial Systems survey searches for dust near the habitable zones (HZs) around nearby, bright main-sequence stars. We use nulling interferometry in the N band to suppress the bright stellar light and to probe for low levels of HZ dust around the 30 stars observed so far. Our overall detection rate is 18%, including four new detections, among which are the first three around Sun-like stars and the first two around stars without any previously known circumstellar dust. The inferred occurrence rates are comparable for early-type and Sun-like stars, but decrease from 60^(+16)_(-21)% for stars with previously detected cold dust to 8^(+10)_(-3)% for stars without such excess, confirming earlier results at higher sensitivity. For completed observations on individual stars, our sensitivity is five to ten times better than previous results. Assuming a lognormal excess luminosity function, we put upper limits on the median HZ dust level of 13 zodis (95% confidence) for a sample of stars without cold dust and of 26 zodis when focusing on Sun-like stars without cold dust. However, our data suggest that a more complex luminosity function may be more appropriate. For stars without detectable Large Binocular Telescope Interferometer (LBTI) excess, our upper limits are almost reduced by a factor of two, demonstrating the strength of LBTI target vetting for future exo-Earth imaging missions. Our statistics are limited so far, and extending the survey is critical to informing the design of future exo-Earth imaging surveys.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Ertel, S.0000-0002-2314-7289
Beichman, C.0000-0002-5627-5471
Millan-Gabet, R.0000-0003-0447-5866
Additional Information:© 2018 The American Astronomical Society. Received 2017 December 10; revised 2018 March 9; accepted 2018 March 13; published 2018 April 17. The Large Binocular Telescope Interferometer is funded by the National Aeronautics and Space Administration as part of its Exoplanet Exploration Program. The LBT is an international collaboration among institutions in the United States, Italy, and Germany. LBT Corporation partners are The University of Arizona on behalf of the Arizona university system; Instituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University; and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota and University of Virginia. This research has made extensive use of the SIMBAD database (Wenger et al. 2000) and the VizieR catalog access tool (Ochsenbein et al. 2000), both operated at CDS, Strasbourg, France; of Python, including the NumPy, SciPy, Matplotlib (Hunter 2007); and Astorpy (Astropy Collaboration et al. 2013) libraries; and of NASA's Astrophysics Data System Bibliographic Services. G.M.K. is supported by the Royal Society as a Royal Society University Research Fellow. A.S. is partially supported by funding from the Center for Exoplanets and Habitable Worlds. The Center for Exoplanets and Habitable Worlds is supported by the Pennsylvania State University, the Eberly College of Science, and the Pennsylvania Space Grant Consortium. Facility: LBT:LBTI.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Pennsylvania State UniversityUNSPECIFIED
Eberly College of ScienceUNSPECIFIED
Pennsylvania Space Grant ConsortiumUNSPECIFIED
Subject Keywords:circumstellar matter – infrared: stars – planetary systems – techniques: interferometric – zodiacal dust
Issue or Number:5
Record Number:CaltechAUTHORS:20180417-095446869
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Official Citation:S. Ertel et al 2018 AJ 155 194
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:85889
Deposited By: Tony Diaz
Deposited On:17 Apr 2018 17:07
Last Modified:15 Nov 2021 20:33

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