Issue |
A&A
Volume 455, Number 2, August IV 2006
|
|
---|---|---|
Page(s) | L21 - L24 | |
Section | Letters | |
DOI | https://doi.org/10.1051/0004-6361:20065799 | |
Published online | 04 August 2006 |
Letter to the Editor
HD 65949: the highest known mercury excess of any CP star?
1
Department of Astronomy, University of Michigan, Ann Arbor, MI 48109-1090, USA e-mail: cowley@umich.edu
2
European Southern Observatory, Casilla 19001, Santiago 19, Chile e-mail: shubrig@eso.org
3
Complejo Astronómico El Leoncito, Casilla 467, 5400 San Juan, Argentina e-mail: fgonzalez@casleo.gov.ar
4
Departamento de Geofísica y Astronomía, Facultad de Ciencias Exactas Físicas y Naturales, Universidad Nacional de San Juan, Argentina
Received:
10
June
2006
Accepted:
29
June
2006
ESO spectra of HD 65949 show it to be
unlike any of the
well-known types within its temperature range
≈13 600 K. It is
neither a silicon, nor a mercury-manganese star, though
it has a huge Hg II line at λ3984. We
estimate . This
is higher than any published stellar mercury abundance.
HD 65949 is a member of a nearby open cluster, NGC 2516, which
is only slightly
older than the Pleiades, and has been of recent interest
because of its numerous X-ray emission stars, including
HD 65949 itself, or a close companion. A
longitudinal magnetic field
of the order of -290 Gauss at the 4.7σ level was very recently diagnosed from accurate circular
spectropolarimetric observations with FORS 1 at the VLT.
The spectral
lines are sharp, allowing a thorough identification study.
Second spectra of Ti, Cr, and Fe are rich. Mn II is well
identified but not unusually strong. Numerous lines of
S II and P II are found, but not Ga II. The resonance
lines of Sr II are strong. While many Y II lines are
identified, and Nb II is very likely present, no
Zr II lines were found. Xe II is well identified. Strong
absorptions from the third spectra of the lanthanides Pr, Nd, and Ho are present, but lines from the second spectra of
lanthanides are extremely weak or absent.
Among lines from the heavier
elements, those of Pt II are clearly present, and the heaviest
isotope, 198Pt, is indicated. The uncommon spectrum of Re II is
certain, while Os II and Te II are highly probable. Several
of the noted anomalies are unusual for a star
as hot as HD 65949.
Key words: stars: chemically peculiar / stars: abundances / stars: individual: HD 65949
© ESO, 2006
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