HNC IN PROTOPLANETARY DISKS

Journal Article · Wed Jul 01 04:00:00 EDT 2015 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/807/1/L15· OSTI ID:22518942

Graninger, Dawn; Öberg, Karin I.; Qi, Chunhua ^[1]; Kastner, Joel ^[2]

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1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
2. Center for Imaging Science, School of Physics and Astronomy, and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States)

The distributions and abundances of small organics in protoplanetary disks are potentially powerful probes of disk physics and chemistry. HNC is a common probe of dense interstellar regions and the target of this study. We use the Submillimeter Array (SMA) to observe HNC 3–2 toward the protoplanetary disks around the T Tauri star TW Hya and the Herbig Ae star HD 163296. HNC is detected toward both disks, constituting the first spatially resolved observations of HNC in disks. We also present SMA observations of HCN 3–2 and IRAM 30 m observations of HCN and HNC 1–0 toward HD 163296. The disk-averaged HNC/HCN emission ratio is 0.1–0.2 toward both disks. Toward TW Hya, the HNC emission is confined to a ring. The varying HNC abundance in the TW Hya disk demonstrates that HNC chemistry is strongly linked to the disk physical structure. In particular, the inner rim of the HNC ring can be explained by efficient destruction of HNC at elevated temperatures, similar to what is observed in the ISM. However, to realize the full potential of HNC as a disk tracer requires a combination of high SNR spatially resolved observations of HNC and HCN and disk-specific HNC chemical modeling.

• OSTI ID: 22518942
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 807; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COSMOCHEMISTRY
ELEMENT ABUNDANCE
EMISSION
HERBIG-HARO OBJECTS
HYDROCYANIC ACID
INTERSTELLAR SPACE
MOLECULES
PROBES
PROTOPLANETS
RESONANCE IONIZATION MASS SPECTROSCOPY
T TAURI STARS