Mercury in the HgMn stars chi Lupi and HR 7775
(1999) In Astrophysical Journal 512(2). p.942-960- Abstract
- Observations of mercury lines in the HgMn stars chi Lupi and HR 7775 made with the Hubble Space Telescope Goddard High Resolution Spectrograph are presented and analyzed. In chi Lupi we find that all observed lines are consistent with the same isotopic mixture (essentially pure (204)Hg). Strong ionization anomalies are present, with UV Hg I lines being too weak and Hg III lines too strong for the abundance derived from lines of the majority ionization state, Hg rr. Observations of mercury in I;IR 7775 show less extreme isotope and ionization anomalies. We find that the ionization anomaly in the Hg I resonance lines can be plausibly explained as a non-LTE effect, but the same non-LTE calculations show that the Hg III ionization anomaly in... (More)
- Observations of mercury lines in the HgMn stars chi Lupi and HR 7775 made with the Hubble Space Telescope Goddard High Resolution Spectrograph are presented and analyzed. In chi Lupi we find that all observed lines are consistent with the same isotopic mixture (essentially pure (204)Hg). Strong ionization anomalies are present, with UV Hg I lines being too weak and Hg III lines too strong for the abundance derived from lines of the majority ionization state, Hg rr. Observations of mercury in I;IR 7775 show less extreme isotope and ionization anomalies. We find that the ionization anomaly in the Hg I resonance lines can be plausibly explained as a non-LTE effect, but the same non-LTE calculations show that the Hg III ionization anomaly in chi Lupi cannot be explained in this way. Radiative force calculations show that the observed mercury abundance cannot be supported in the atmosphere by the radiative forces alone. We suggest that weak mixing brings mercury into the line-forming region from below the photosphere, while a wind of order 10(-14) M. yr(-1) supports a cloud of Hg III at very small optical depths. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/3919505
- author
- Proffitt, CR ; Brage, Tomas LU ; Leckrone, DS ; Wahlgren, Glenn LU ; Brandt, JC ; Sansonetti, CJ ; Reader, J and Johansson, Sveneric LU
- organization
- publishing date
- 1999
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- HR 7775), stars : peculiar, stars : individual (chi Lupi, diffusion, stars : abundances
- in
- Astrophysical Journal
- volume
- 512
- issue
- 2
- pages
- 942 - 960
- publisher
- American Astronomical Society
- external identifiers
-
- wos:000079809000036
- scopus:0033585746
- ISSN
- 0004-637X
- DOI
- 10.1086/306783
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Lund Observatory (000006111), Physics, science (011013100), Science (000006100)
- id
- 975579f1-35a9-4860-80d8-51a03e55a9e0 (old id 3919505)
- date added to LUP
- 2016-04-01 15:53:18
- date last changed
- 2024-01-10 21:35:14
@article{975579f1-35a9-4860-80d8-51a03e55a9e0, abstract = {{Observations of mercury lines in the HgMn stars chi Lupi and HR 7775 made with the Hubble Space Telescope Goddard High Resolution Spectrograph are presented and analyzed. In chi Lupi we find that all observed lines are consistent with the same isotopic mixture (essentially pure (204)Hg). Strong ionization anomalies are present, with UV Hg I lines being too weak and Hg III lines too strong for the abundance derived from lines of the majority ionization state, Hg rr. Observations of mercury in I;IR 7775 show less extreme isotope and ionization anomalies. We find that the ionization anomaly in the Hg I resonance lines can be plausibly explained as a non-LTE effect, but the same non-LTE calculations show that the Hg III ionization anomaly in chi Lupi cannot be explained in this way. Radiative force calculations show that the observed mercury abundance cannot be supported in the atmosphere by the radiative forces alone. We suggest that weak mixing brings mercury into the line-forming region from below the photosphere, while a wind of order 10(-14) M. yr(-1) supports a cloud of Hg III at very small optical depths.}}, author = {{Proffitt, CR and Brage, Tomas and Leckrone, DS and Wahlgren, Glenn and Brandt, JC and Sansonetti, CJ and Reader, J and Johansson, Sveneric}}, issn = {{0004-637X}}, keywords = {{HR 7775); stars : peculiar; stars : individual (chi Lupi; diffusion; stars : abundances}}, language = {{eng}}, number = {{2}}, pages = {{942--960}}, publisher = {{American Astronomical Society}}, series = {{Astrophysical Journal}}, title = {{Mercury in the HgMn stars chi Lupi and HR 7775}}, url = {{http://dx.doi.org/10.1086/306783}}, doi = {{10.1086/306783}}, volume = {{512}}, year = {{1999}}, }