Thermal Infrared Constraint to a Planetary Companion of Vega with the MMT Adaptive Optics System

Abstract

Vega may have a massive companion in a wide orbit, as evidenced by structure in its cold dust debris. We have tested this hypothesis by direct imaging with adaptive optics in the M band. The observations were made with a newly commissioned thermal infrared camera, Clio, on the 6.5 MMT AO system with low-background deformable secondary. The observations constrain a planet to be less than 7 M${}_J$ at the approximate position angle expected from the dust structure and at a radius $>$ 20AU (2.5 arcsec) . This result is more stringent than similar previous near-infrared observations of Vega, that achieve limits of 20 and 10 M${}_J$ at separations of 7 arcsec. The higher sensitivity is due both to the more favorable contrast of gas giant planets at M band and to the higher Strehl and more stable point spread function at longer wavelengths. Future L' or M band observations could provide a powerful approach for wide separation planet detection, especially for cooler, and thus older or less massive planets. The natural best targets are nearby stars where planets in the range of 5-15 M${}_J$ and as old as several Gyr are expected to be detectable with this technique.

accepted to ApJ June 6, 2006

References in corpus (1)

• Detection of Thermal Emission from an Extrasolar Planet

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• Deep L' and M-band Imaging for Planets Around Vega and epsilon Eridani
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