An Unbiased 1.3 mm Emission Line Survey of the Protoplanetary Disk Orbiting LkCa 15
Journal
Date Issued
2015
Author(s)
Description
This work is based on observations carried out with the IRAM 30 m Telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain). This research is supported by National Science Foundation grant AST-1108950 to RIT. The authors thank Charlie Qi for helpful discussions.
Abstract
The outer (>30 AU) regions of the dusty circumstellar disk orbiting the ̃2-5 Myr old, actively accreting solar analog LkCa 15 are known to be chemically rich, and the inner disk may host a young protoplanet within its central cavity. To obtain a complete census of the brightest molecular line emission emanating from the LkCa 15 disk over the 210-270 GHz (1.4-1.1 mm) range, we have conducted an unbiased radio spectroscopic survey with the Institute de Radioastronomie Millimétrique (IRAM) 30 m telescope. The survey demonstrates that in this spectral region, the most readily detectable lines are those of CO and its isotopologues 13CO and C18O, as well as HCO+, HCN, CN, C2H, CS, and H2CO. All of these species had been previously detected in the LkCa 15 disk; however, the present survey includes the first complete coverage of the CN (2-1) and C2H (3-2) hyperfine complexes. Modeling of these emission complexes indicates that the CN and C2H either reside in the coldest regions of the disk or are subthermally excited, and that their abundances are enhanced relative to molecular clouds and young stellar object environments. These results highlight the value of unbiased single-dish line surveys in guiding future high-resolution interferometric imaging of disks.
Volume
805
Issue
2
Start page
147
Issn Identifier
0004-637X
Ads BibCode
2015ApJ...805..147P
Rights
open.access
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