ORFEUS II echelle spectra: deuterium and molecular hydrogen in the ISM towards BD +39 3226
| dc.creator | Bluhm, H. | |
| dc.creator | Marggraf, O. | |
| dc.creator | de Boer, K. S. | |
| dc.creator | Richter, P. | |
| dc.creator | Heber, U. | |
| dc.date | 1999-11-05 | |
| dc.date.accessioned | 2026-07-07T02:34:16Z | |
| dc.date.available | 2026-07-07T02:34:16Z | |
| dc.description | In ORFEUS II spectra of the sdO star BD +39 3226 interstellar hydrogen and deuterium is detected. From Ly alpha profile fitting and a curve of growth analysis of the Lyman series of H I and D I we derive the column densities N(H)=1.20(+0.28/-0.22)*10^20 cm^(-2) and N(D)=1.45(+0.50/-0.38)*10^(15) cm^(-2). From the analysis of metal absorption lines in ORFEUS and IUE spectra we obtain column densities for 11 elements. In addition, we examine absorption lines of H_2 for rotational excitation states up to J=7. We find an H_2 ortho-to-para ratio of 2.5, the fractional abundance of molecular hydrogen has a low value of log f=-4.08 for a total amount of N(H_2)=4.8(+2.0/-1.6)*10^15 cm^(-2). The column densities of the excitation states reveal a moderate Boltzmann excitation temperature of 130 K and an equivalent excitation temperature for the excited upper states due to UV pumping of <1800 K. | |
| dc.description | 10 pages, 10 figures, accepted for publication in A&A main journal | |
| dc.identifier | https://arxiv.org/abs/astro-ph/9911097 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/9911097 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/15174 | |
| dc.subject | Astrophysics | |
| dc.title | ORFEUS II echelle spectra: deuterium and molecular hydrogen in the ISM towards BD +39 3226 | |
| dc.type | text |