|A New Method to Determine the Gas Mass in Protoplanetary Disks
|The mass of planet-forming disks is one of its most fundanmental quantities and can determine the primary mode of planet formation. Because the dominant constituent, H2, is undetectable, we are forced to adopt indirect methods to trace the total gas content. The primary method used is to observe thermal dust continuum emission at submm-mm wavelengths where the dust emission is optically thin. However, mass estimates are highly uncertain because grain evolution can substantially alter the dust opacity coefficient and the gas-to-dust ratio, which are required to convert total flux to mass. We propose here a dedicated program to use PACS spectroscopy to search for the emission of HD J=1-0 at 112 microns and derive the gas mass from a tracer that uniquely probes H2. HD will co-exist with H2 in the gas phase and is the dominant reservoir of deuterium, carrying the cosmic D atom abundance. Our program is a comprehensive effort where observations will be combined with chemical theory and excitation modeling to enable the conversion of integrated emission to mass. This program offers a unique opportunity to derive disk gas masses via an independent method with important implications for the formation of planetary systems.
|A Significantly Low CO Abundance toward the TW Hya Protoplanetary Disk: A Path to Active Carbon Chemistry? . Favre Cécile et al. . The Astrophysical Journal Letters, Volume 776, Issue 2, article id. L38, 5 pp. (2013). . 776 . 10.1088/2041-8205/776/2/L38 . 2013ApJ...776L..38F ,
An old disk still capable of forming a planetary system . Bergin Edwin A. et al. . Nature, Volume 493, Issue 7434, pp. 644-646 (2013). . 493 . 10.1038/nature11805 . 2013Natur.493..644B ,
|Herschel was launched on 14 May 2009! It is the fourth 'cornerstone' mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
|Publisher And Registrant
|European Space Agency
|European Space Agency, 2012, OT1_ebergin_4, SPG v14.2.0. https://doi.org/10.5270/esa-wsqf7wn