A Close Companion Search around L Dwarfs using Aperture Masking Interferometry and Palomar Laser Guide Star Adaptive Optics

We present a close companion search around sixteen known early-L dwarfs using aperture masking interferometry with Palomar laser guide star adaptive optics. The use of aperture masking allows the detection of close binaries, corresponding to projected physical separations of 0.6-10.0 AU for the targ...

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Bibliographic Details
Published in:arXiv.org 2010-04
Main Authors: Bernat, David, Bouchez, Antonin H, Ireland, Michael, Tuthill, Peter, Frantz Martinache, Angione, John, Burruss, Rick S, Cromer, John L, Dekany, Richard G, Guiwits, Stephen R, Henning, John R, Hickey, Jeff, Kibblewhite, Edward, McKenna, Daniel L, Moore, Anna M, Petrie, Harold L, Roberts, Jennifer, Shelton, J Chris, Thicksten, Robert P, Trinh, Thang, Tripathi, Renu, Mitchell, Troy, Truong, Tuan, Velur, Viswa, Lloyd, James P
Format: Article
Language:English
Subjects:
Adaptive optics
Aperture imaging
Companion stars
Hubble Space Telescope
Interferometry
Laser guide stars
Lasers
Masking
Photometry
Searching
Signal to noise ratio
Space telescopes
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Summary:We present a close companion search around sixteen known early-L dwarfs using aperture masking interferometry with Palomar laser guide star adaptive optics. The use of aperture masking allows the detection of close binaries, corresponding to projected physical separations of 0.6-10.0 AU for the targets of our survey. This survey achieved median contrast limits of Delta_K ~ 2.3 for separations between 1.2 - 4 lambda/D, and Delta_K ~ 1.4 at (2/3)lambda/D. We present four candidate binaries detected with moderate to high confidence (90-98%). Two have projected physical separations less than 1.5 AU. This may indicate that tight-separation binaries contribute more significantly to the binary fraction than currently assumed, consistent with spectroscopic and photometric overluminosity studies. Ten targets of this survey have previously been observed with the Hubble Space Telescope as part of companion searches. We use the increased resolution of aperture masking to search for close or dim companions that would be obscured by full aperture imaging, finding two candidate binaries. This survey is the first application of aperture masking with laser guide star adaptive optics at Palomar. Several new techniques for the analysis of aperture masking data in the low signal to noise regime are explored.
ISSN:2331-8422
DOI:10.48550/arxiv.1004.0223