Astronomy and Astrophysics – Astrophysics – Solar and Stellar Astrophysics
Scientific paper
2011-09-11
Astronomy and Astrophysics
Astrophysics
Solar and Stellar Astrophysics
Accepted for publication in ApJ Letters, 8 pages, 3 figures, 1 tables (emulateapj style)
Scientific paper
Gas-rich primordial disks and tenuous gas-poor debris disks are usually considered as two distinct evolutionary phases of the circumstellar matter. Interestingly, the debris disk around the young main-sequence star 49 Ceti possesses a substantial amount of molecular gas, and possibly represents the missing link between the two phases. Motivated to understand the evolution of the gas component in circumstellar disks via finding more 49 Ceti-like systems, we carried out a CO J=3-2 survey with Atacama Pathfinder EXperiment, targeting 20 infrared-luminous debris disks. These systems fill the gap between primordial and old tenuous debris disks in terms of fractional luminosity. Here we report on the discovery of a second 49 Ceti-like disk around the 30 Myr old A3-type star HD21997, a member of the Columba Association. This system was also detected in the CO(2-1) transition, and the reliable age determination makes it an even clearer example of an old gas-bearing disk than 49 Ceti. While the fractional luminosities of HD21997 and 49 Ceti are not particularly high, these objects seem to harbor the most extended disks within our sample. The double-peaked profiles of HD21997 were reproduced by a Keplerian disk model combined with the LIME radiative transfer code. Based on their similarities, 49 Ceti and HD21997 may be the first representatives of a so far undefined new class of relatively old (>~8 Myr), gaseous dust disks. From our results, neither primordial origin nor steady secondary production from icy planetesimals can unequivocally explain the presence of CO gas in the disk of HD21997.
Ábrahám Peter
Apai Daniel
Csengeri Timea
Grady Carol
Henning Th
No associations
LandOfFree
Molecular gas in young debris disks does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Molecular gas in young debris disks, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Molecular gas in young debris disks will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-20026