Analysis of Hydrogen Cyanide Hyperfine Spectral Components towards Star Forming Cores
Although hydrogen cyanide has become quite a common molecular tracing species for a variety of astrophysical sources, it, however, exhibits dramatic non-LTE behaviour in its hyperfine line structure. Individual hyperfine components can be strongly boosted or suppressed. If these so-called hyperfine...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
De Gruyter
2011-12-01
|
| Series: | Open Astronomy |
| Subjects: | |
| Online Access: | https://doi.org/10.1515/astro-2017-0336 |
| _version_ | 1818908039500005376 |
|---|---|
| author | Loughnane R. M. Redman M. P. Keto E. R. Lo N. Cunningham M. R. |
| author_facet | Loughnane R. M. Redman M. P. Keto E. R. Lo N. Cunningham M. R. |
| author_sort | Loughnane R. M. |
| collection | DOAJ |
| description | Although hydrogen cyanide has become quite a common molecular tracing species for a variety of astrophysical sources, it, however, exhibits dramatic non-LTE behaviour in its hyperfine line structure. Individual hyperfine components can be strongly boosted or suppressed. If these so-called hyperfine line anomalies are present in the HCN rotational spectra towards low or high mass cores, this will affect the interpretation of various physical properties such as the line opacity and excitation temperature in the case of low mass objects and infall velocities in the case of their higher mass counterparts. Anomalous line ratios are present either through the relative strengths of neighboring hyperfine lines or through the varying widths of hyperfine lines belonging to a particular rotational line. This work involves the first observational investigation of these anomalies in two HCN rotational transitions, J=1→0 and J=3→2, towards both low mass starless cores and high mass protostellar objects. The degree of anomaly in these two rotational transitions is considered by computing the ratios of neighboring hyperfine lines in individual spectra. Results indicate some degree of anomaly is present in all cores considered in our survey, the most likely cause being line overlap effects among hyperfine components in higher rotational transitions. |
| first_indexed | 2024-12-19T22:04:41Z |
| format | Article |
| id | doaj.art-4428f4a56d184ceaa1b8c0acf8b7200c |
| institution | Directory Open Access Journal |
| issn | 2543-6376 |
| language | English |
| last_indexed | 2024-12-19T22:04:41Z |
| publishDate | 2011-12-01 |
| publisher | De Gruyter |
| record_format | Article |
| series | Open Astronomy |
| spelling | doaj.art-4428f4a56d184ceaa1b8c0acf8b7200c2022-12-21T20:04:04ZengDe GruyterOpen Astronomy2543-63762011-12-0120455856510.1515/astro-2017-0336astro-2017-0336Analysis of Hydrogen Cyanide Hyperfine Spectral Components towards Star Forming CoresLoughnane R. M.0Redman M. P.1Keto E. R.2Lo N.3Cunningham M. R.4Centre for Astronomy, School of Physics, National University of Ireland, University Road, Newcastle, Galway, IrelandCentre for Astronomy, School of Physics, National University of Ireland, University Road, Newcastle, Galway, IrelandHavard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, United States of AmericaDepartamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Casilla 36-D, Chile FranceSchool of Physics, University of New South Wales, Sydney, NSW 2052, AustraliaAlthough hydrogen cyanide has become quite a common molecular tracing species for a variety of astrophysical sources, it, however, exhibits dramatic non-LTE behaviour in its hyperfine line structure. Individual hyperfine components can be strongly boosted or suppressed. If these so-called hyperfine line anomalies are present in the HCN rotational spectra towards low or high mass cores, this will affect the interpretation of various physical properties such as the line opacity and excitation temperature in the case of low mass objects and infall velocities in the case of their higher mass counterparts. Anomalous line ratios are present either through the relative strengths of neighboring hyperfine lines or through the varying widths of hyperfine lines belonging to a particular rotational line. This work involves the first observational investigation of these anomalies in two HCN rotational transitions, J=1→0 and J=3→2, towards both low mass starless cores and high mass protostellar objects. The degree of anomaly in these two rotational transitions is considered by computing the ratios of neighboring hyperfine lines in individual spectra. Results indicate some degree of anomaly is present in all cores considered in our survey, the most likely cause being line overlap effects among hyperfine components in higher rotational transitions.https://doi.org/10.1515/astro-2017-0336ismmoleculesmolecular cloudsstarsformation |
| spellingShingle | Loughnane R. M. Redman M. P. Keto E. R. Lo N. Cunningham M. R. Analysis of Hydrogen Cyanide Hyperfine Spectral Components towards Star Forming Cores Open Astronomy ism molecules molecular clouds stars formation |
| title | Analysis of Hydrogen Cyanide Hyperfine Spectral Components towards Star Forming Cores |
| title_full | Analysis of Hydrogen Cyanide Hyperfine Spectral Components towards Star Forming Cores |
| title_fullStr | Analysis of Hydrogen Cyanide Hyperfine Spectral Components towards Star Forming Cores |
| title_full_unstemmed | Analysis of Hydrogen Cyanide Hyperfine Spectral Components towards Star Forming Cores |
| title_short | Analysis of Hydrogen Cyanide Hyperfine Spectral Components towards Star Forming Cores |
| title_sort | analysis of hydrogen cyanide hyperfine spectral components towards star forming cores |
| topic | ism molecules molecular clouds stars formation |
| url | https://doi.org/10.1515/astro-2017-0336 |
| work_keys_str_mv | AT loughnanerm analysisofhydrogencyanidehyperfinespectralcomponentstowardsstarformingcores AT redmanmp analysisofhydrogencyanidehyperfinespectralcomponentstowardsstarformingcores AT ketoer analysisofhydrogencyanidehyperfinespectralcomponentstowardsstarformingcores AT lon analysisofhydrogencyanidehyperfinespectralcomponentstowardsstarformingcores AT cunninghammr analysisofhydrogencyanidehyperfinespectralcomponentstowardsstarformingcores |