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Published December 10, 2011 | Published
Journal Article Open

Multi-epoch Observations of HD 69830: High-resolution Spectroscopy and Limits to Variability

Abstract

The main-sequence solar-type star HD 69830 has an unusually large amount of dusty debris orbiting close to three planets found via the radial velocity technique. In order to explore the dynamical interaction between the dust and planets, we have performed multi-epoch photometry and spectroscopy of the system over several orbits of the outer dust. We find no evidence for changes in either the dust amount or its composition, with upper limits of 5%-7% (1σ per spectral element) on the variability of the dust spectrum over 1 year, 3.3% (1σ) on the broadband disk emission over 4 years, and 33% (1σ) on the broadband disk emission over 24 years. Detailed modeling of the spectrum of the emitting dust indicates that the dust is located outside of the orbits of the three planets and has a composition similar to main-belt, C-type asteroids in our solar system. Additionally, we find no evidence for a wide variety of gas species associated with the dust. Our new higher signal-to-noise spectra do not confirm our previously claimed detection of H_(2)O ice leading to a firm conclusion that the debris can be associated with the break-up of one or more C-type asteroids formed in the dry, inner regions of the protoplanetary disk of the HD 69830 system. The modeling of the spectral energy distribution and high spatial resolution observations in the mid-infrared are consistent with a ~1 AU location for the emitting material.

Additional Information

© 2011 American Astronomical Society. Received 2011 June 10; accepted 2011 August 16; published 2011 November 23. We are grateful to an anonymous referee for a careful reading of this manuscript that led to significant improvements. This publication makes use of services provided by the NASA Exoplanet Science Institute at the California Institute of Technology (NExScI) and data products from the NASA/NExScI Star & Exoplanet Database (NStED), the Two Micron All Sky Survey (2MASS), and the NASA/IPAC Infrared Science Archive (IRSA). Thanks to Ben Oppenheimer, Dimitar Sasselov, and Dave Latham for their hospitality and support during extended visits to AMNH and CfA, respectively. Some of the research described in this publication was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The Keck Interferometer is funded by the National Aeronautics and Space Administration as part of its Exoplanet Exploration program. The authors recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Government sponsorship acknowledged. Facilities: Spitzer, Gemini:Gillett (Michelle), Keck: Interferometer

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August 22, 2023
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