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Studies of interstellar vibrationally-excited molecules
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Snell, R. L. Ziurys, L. M. Erickson, N. R. |
| Copyright Year | 1986 |
| Description | Several molecules thus far have been detected in the ISM in vibrationally-excited states, including H2, SiO, HC3N, and CH3CN. In order for vibrational-excitation to occur, these species must be present in unusually hot and dense gas and/or where strong infrared radiation is present. In order to do a more thorough investigation of vibrational excitation in the interstellar medium (ISM), studies were done of several mm-wave transitions originating in excited vibrational modes of HCN, an abundant interstellar molecule. Vibrationally-excited HCN was recently detected toward Orion-KL and IRC+10216, using a 12 meter antenna. The J=3-2 rotational transitions were detected in the molecule's lowest vibrational state, the bending mode, which is split into two separate levels, due to l-type doubling. This bending mode lies 1025K above ground state, with an Einstein A coefficient of 3.6/s. The J=3-2 line mode of HCN, which lies 2050K above ground state, was also observed toward IRC+10216, and subsequently in Orion-KL. Further measurements of vibrationally-excited HCN were done using a 14 meter telescope, which include the observations of the (0,1,0) and (0,2,0) modes towards Orion-KL, via their J=3-2 transitions at 265-267 GHz. The spectrum of the J=3-2 line in Orion taken with the 14 meter telescope, is shown, along with a map, which indicates that emission from vibrationally-excited HCN arises from a region probably smaller than the 14 meter telescope's 20 arcsec beam. |
| File Size | 142581 |
| Page Count | 2 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19870005686 |
| Archival Resource Key | ark:/13960/t57d7rt8v |
| Language | English |
| Publisher Date | 1986-10-01 |
| Access Restriction | Open |
| Subject Keyword | Astrophysics Cyanoacetylene Hydrocyanic Acid Interstellar Chemistry Molecular Clouds Acetonitrile Infrared Absorption Chemical Reactions Stellar Evolution Molecular Excitation Activation Energy Interstellar Gas Vibrational Spectra Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
