A Resolved Molecular Gas Disk around the Nearby A Star 49 Ceti
Open Access
- 1 July 2008
- journal article
- research article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 681 (1), 626-635
- https://doi.org/10.1086/588520
Abstract
The A star 49 Ceti, at a distance of 61 pc, is unusual in retaining a substantial quantity of molecular gas while exhibiting dust properties similar to those of a debris disk. We present resolved observations of the disk around 49 Ceti from the Submillimeter Array in the J = 2–1 rotational transition of CO with a resolution of 1.0'' × 1.2''. The observed emission reveals an extended rotating structure viewed approximately edge-on and clear of detectable CO emission out to a distance of ~90 AU from the star. No 1.3 mm continuum emission is detected at a 3 σ sensitivity of 2.1 mJy beam−1. Models of disk structure and chemistry indicate that the inner disk is devoid of molecular gas, while the outer gas disk between 40 and 200 AU from the star is dominated by photochemistry from stellar and interstellar radiation. We determine parameters for a model that reproduces the basic features of the spatially resolved CO J = 2–1 emission, the spectral energy distribution, and the unresolved CO J = 3–2 spectrum. We investigate variations in disk chemistry and observable properties for a range of structural parameters. The star 49 Ceti appears to be a rare example of a system in a late stage of transition between a gas-rich protoplanetary disk and a tenuous, virtually gas-free debris disk.This publication has 34 references indexed in Scilit:
- A search for near-infrared molecular hydrogen emission in the CTTS LkHα264 and the debris disk 49 CetiAstronomy & Astrophysics, 2007
- Warm Gas in the Inner Disks around Young Intermediate‐Mass StarsThe Astrophysical Journal, 2007
- Dust dynamics during protoplanetary disc clearingMonthly Notices of the Royal Astronomical Society, 2007
- Spitzer IRS Spectroscopy of IRAS ‐discovered Debris DisksThe Astrophysical Journal Supplement Series, 2006
- Photoevaporation of protoplanetary discs – II. Evolutionary models and observable propertiesMonthly Notices of the Royal Astronomical Society, 2006
- CO emission from discs around isolated HAeBe and Vega-excess starsMonthly Notices of the Royal Astronomical Society, 2005
- Tidally Induced Gap Formation in Protostellar Disks: Gap Clearing and Suppression of Protoplanetary GrowthThe Astrophysical Journal, 1999
- Particle emissivity in circumstellar disksThe Astrophysical Journal, 1991
- The relationship between infrared, optical, and ultraviolet extinctionThe Astrophysical Journal, 1989
- Discovery of a shell around Alpha LyraeThe Astrophysical Journal, 1984