HST/GHRS Observations of TL II (Z=81) In The Ultraviolet Spectrum of the HgMn Star, chi LUPI

Details HST/GHRS Observations of TL II (Z=81) In The Ultraviolet Spectrum of the HgMn Star, chi LUPI HST/GHRS Observations of TL II (Z=81) In The Ultraviolet Spectrum of the HgMn Star, chi LUPI

May 1994

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994aas...184.0704l&link_type=abstract

American Astronomical Society, 184th AAS Meeting, #07.04; Bulletin of the American Astronomical Society, Vol. 26, p.869

Other

2

Scientific paper

It is now well established that the photosphere of the cool HgMn star, chi Lupi, possesses overabundances of Pt (Z=78, [Pt II/H]=+4.1), Au (Z=79, [Au II/H]=+4.3), and Hg (Z=80, [Hg II/H]=+5.0). In each case only one isotope of the element is observed, the heaviest isotopes of Pt (198) and Hg (204), and Au (197), which is naturally monoisotopic. We announce here the detection of two hyperfine lines of the heaviest isotope of singly-ionized Tl (Z=81), mass number 205. New laboratory measurements of the spectrum of Tl, carried out at the University of Lund, provide wavelengths for the hyperfine components of both Tl (203) and Tl (205) for the 6s(2) (1) S_0 - 6s6p 3P_1(o) lambda 1908 Angstroms raie ultime transition, which are accurate to +/-0.0003 Angstroms. The isotopic components are separated by 0.011 Angstroms while the hyperfine components are separated by 0.136 Angstroms. Oscillator strengths have been obtained through ab initio, multiconfiguration Dirac-Fock (MCDF) calculations to an estimated uncertainty of 20%. We have established the absolute wavelength scale of the GHRS observations to an accuracy of +/-0.001 Angstroms, so that the uncertainty in the match to the Tl (205) wavelengths is very much less than the separation of the isotopic components. Attempts to synthesize the observed features with both isotopes blended in solar-system proportions (30% 203, 70% 205) yields a poor match to the observations. The best fit is indistinguishable from the case of pure Tl (205), and yields an abundance of log N(Tl II)=4.66 (on a scale where log N(H) = 12.00) and [Tl II/H]=+3.8+/-0.1. Diffusion models or other theoretical scenarios must be prepared to explain not only the enormous overabundances of these very heavy elements, but also the fact that only a single isotope (the heaviest isotope) is invariably present.

Affiliated with

Also associated with

No associations

Rating

HST/GHRS Observations of TL II (Z=81) In The Ultraviolet Spectrum of the HgMn Star, chi LUPI does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with HST/GHRS Observations of TL II (Z=81) In The Ultraviolet Spectrum of the HgMn Star, chi LUPI, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and HST/GHRS Observations of TL II (Z=81) In The Ultraviolet Spectrum of the HgMn Star, chi LUPI will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-880900