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HOSTS Survey: Evidence for an Extended Dust Disk and Constraints on the Presence of Giant Planets in the Habitable Zone of β Leo

Defrère, D. and Hinz, P. M. and Kennedy, G. M. and Stone, J. and Rigley, J. and Ertel, S. and Gaspar, A. and Bailey, V. P. and Hoffmann, W. F. and Mennesson, B. and Millan-Gabet, R. and Danchi, W. C. and Absil, O. and Arbo, P. and Beichman, C. and Bonavita, M and Brusa, G. and Bryden, G. and Downey, E. C. and Esposito, S. and Grenz, P. and Haniff, C. and Hill, J. M. and Leisenring, J. M. and Males, J. R. and McMahon, T. J. and Montoya, M. and Morzinski, K. M. and Pinna, E. and Puglisi, A. and Rieke, G. and Roberge, A. and Rousseau, H. and Serabyn, E. and Spalding, E. and Skemer, A. J. and Stapelfeldt, K. and Su, K. and Vaz, A. and Weinberger, A. J. and Wyatt, M. C. (2021) HOSTS Survey: Evidence for an Extended Dust Disk and Constraints on the Presence of Giant Planets in the Habitable Zone of β Leo. Astronomical Journal, 161 (4). Art. No. 186. ISSN 0004-6256. doi:10.3847/1538-3881/abe3ff.

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The young (50–400 Myr) A3V star β Leo is a primary target to study the formation history and evolution of extrasolar planetary systems as one of the few stars with known hot (~1600 K), warm (~600 K), and cold (~120 K) dust belt components. In this paper, we present deep mid-infrared measurements of the warm dust brightness obtained with the Large Binocular Telescope Interferometer (LBTI) as part of its exozodiacal dust survey (HOSTS). The measured excess is 0.47% ± 0.050% within the central 1.5 au, rising to 0.81% ± 0.026% within 4.5 au, outside the habitable zone of β Leo. This dust level is 50 ± 10 times greater than in the solar system's zodiacal cloud. Poynting–Robertson drag on the cold dust detected by Spitzer, and Herschel underpredicts the dust present in the habitable zone of β Leo, suggesting an additional delivery mechanism (e.g., comets) or an additional belt at ~5.5 au. A model of these dust components is provided that implies the absence of planets more than a few Saturn masses between ~5 au and the outer belt at ~40 au. We also observationally constrain giant planets with the LBTI imaging channel at 3.8 μm wavelength. Assuming an age of 50 Myr, any planet in the system between approximately 5–50 au must be less than a few Jupiter masses, consistent with our dust model. Taken together, these observations showcase the deep contrasts and detection capabilities attainable by the LBTI for both warm exozodiacal dust and giant exoplanets in or near the habitable zone of nearby stars.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Defrère, D.0000-0003-3499-2506
Ertel, S.0000-0002-2314-7289
Gaspar, A.0000-0001-8612-3236
Bailey, V. P.0000-0002-5407-2806
Mennesson, B.0000-0003-4205-4800
Millan-Gabet, R.0000-0003-0447-5866
Absil, O.0000-0002-4006-6237
Beichman, C.0000-0002-5627-5471
Bonavita, M0000-0002-7520-8389
Bryden, G.0000-0001-5966-837X
Leisenring, J. M.0000-0002-0834-6140
Males, J. R.0000-0002-2346-3441
Morzinski, K. M.0000-0002-1384-0063
Rieke, G.0000-0003-2303-6519
Roberge, A.0000-0002-2989-3725
Skemer, A. J.0000-0001-6098-3924
Stapelfeldt, K.0000-0002-2805-7338
Su, K.0000-0002-3532-5580
Weinberger, A. J.0000-0001-6654-7859
Wyatt, M. C.0000-0001-9064-5598
Additional Information:© 2021. The American Astronomical Society. Received 2020 October 22; revised 2021 January 21; accepted 2021 February 4; published 2021 March 15. 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; Istituto 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. LBTI is funded by a NASA grant in support of the Exoplanet Exploration Program. This research has made use of the Jean-Marie Mariotti Center SearchCal service 21 co-developed by LAGRANGE and IPAG, and of CDS Astronomical Databases SIMBAD and VIZIER. 22 This work was supported by the European Union through ERC grant Nos. 866070 (D.D.) and 279973 (M.C.W.). D.D. and O.A. acknowledge the support of the Belgian National Funds for Scientific Research (FNRS). G.M.K. is supported by the Royal Society as a Royal Society University Research Fellow. M.B. acknowledges funding by the UK Science and Technology Facilities Council (STFC) grant No. ST/M001229/1.
Funding AgencyGrant Number
European Research Council (ERC)866070
European Research Council (ERC)279973
Fonds de la Recherche Scientifique (FNRS)UNSPECIFIED
Science and Technology Facilities Council (STFC)ST/M001229/1
Subject Keywords:Exozodiacal dust; Exoplanets; Direct imaging; Long baseline interferometry
Issue or Number:4
Classification Code:Unified Astronomy Thesaurus concepts: Exozodiacal dust (500); Exoplanets (498); Direct imaging (387); Long baseline interferometry (932)
Record Number:CaltechAUTHORS:20210408-094817149
Persistent URL:
Official Citation:D. Defrère et al 2021 AJ 161 186
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:108654
Deposited By: Tony Diaz
Deposited On:08 Apr 2021 22:14
Last Modified:08 Apr 2021 22:14

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