A CLOSE COMPANION SEARCH AROUND L DWARFS USING APERTURE MASKING INTERFEROMETRY AND PALOMAR LASER GUIDE STAR ADAPTIVE OPTICS

Journal Article · Tue Jun 01 00:00:00 EDT 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/715/2/724· OSTI ID:21450935

Bernat, David ^[1]; Bouchez, Antonin H; Cromer, John L; Dekany, Richard G; Moore, Anna M ^[2]; Ireland, Michael; Tuthill, Peter ^[3]; Martinache, Frantz ^[4]; Angione, John; Burruss, Rick S; Guiwits, Stephen R; Henning, John R; Hickey, Jeff; Kibblewhite, Edward; McKenna, Daniel L; Petrie, Harold L; Roberts, Jennifer; Shelton, J Chris; Thicksten, Robert P; Trinh, Thang ^[5]

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1. Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States)
2. California Institute of Technology, Pasadena, CA 91125 (United States)
3. Sydney Institute for Astrophysics, School of Physics, University of Sydney (Australia)
4. National Astronomical Observatory of Japan, Subaru Telescope, Hilo, HI 96720 (United States)
5. Palomar Laser Guide Star Adaptive Optics Team, Palomar Observatory, California Institute of Technology, Palomar Mountain, CA 92060 (United States)

We present a close companion search around 16 known early L dwarfs using aperture masking interferometry with Palomar laser guide star adaptive optics (LGS AO). 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 {approx} 2.3 for separations between 1.2 {lambda}/D-4{lambda}/D and {Delta}K {approx} 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 LGS AO at Palomar. Several new techniques for the analysis of aperture masking data in the low signal-to-noise regime are explored.

• OSTI ID: 21450935
• Journal Information: Astrophysical Journal, Vol. 715, Issue 2; Other Information: DOI: 10.1088/0004-637X/715/2/724; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
DWARF STARS
INTERFEROMETRY
MASS
OPTICS
RESOLUTION
SIGNALS
TELESCOPES
STARS