dc.contributor.author |
Jeffery, C. S |
|
dc.contributor.author |
Kameswara Rao, N |
|
dc.contributor.author |
Lambert, D. L |
|
dc.date.accessioned |
2021-02-14T06:07:48Z |
|
dc.date.available |
2021-02-14T06:07:48Z |
|
dc.date.issued |
2020-04 |
|
dc.identifier.citation |
Monthly Notices of the Royal Astronomical Society, Vol. 493, No. 2, pp. 3565–3579 |
en_US |
dc.identifier.issn |
1365-2966 |
|
dc.identifier.uri |
http://hdl.handle.net/2248/7639 |
|
dc.description |
Restricted Access |
en_US |
dc.description.abstract |
The hydrogen-deficient star DY Cen has been reported as an R CrB-type variable, an extreme
helium star (with some hydrogen), and as a single-lined spectroscopic binary. It has been
associated with a dramatic change in visual brightness and colour corresponding to a change
in effective temperature ( Teff) of some 20 000 K in the last century. To characterize the binary
orbit and Teff changes more precisely, new high-resolution spectroscopy has been obtained
with SALT. The previous orbital period is not confirmed; previous measurements may have
been confused by the presence of pulsations. Including data from earlier epochs (1987, 2002,
and 2010), self-consistent spectral analyses from all four epochs demonstrate an increase
in Teff from 18 800 to 24 400 K between 1987 and 2015. Line profiles demonstrate that the
surface rotation has increased by a factor of 2 over the same interval. This is commensurate
with the change in Teff and an overall contraction. Rotation will exceed critical if contraction
continues. The 1987 spectrum shows evidence of a very high abundance of the s-process
element strontium. The very rapid evolution, non-negligible surface hydrogen and high surface
strontium point to a history involving a very late thermal pulse. Observations over the next 30
yr should look for a decreasing pulsation period, reactivation of R CrB-type activity as the star
seeks to shed angular momentum and increasing illumination by emission lines from nebular
material ejected in the past |
en_US |
dc.language.iso |
en |
en_US |
dc.publisher |
Oxford University Press on behalf of the Royal Astronomical Society |
en_US |
dc.relation |
https://doi.org/10.1093/mnras/staa406 |
|
dc.rights |
© The Royal Astronomical Society |
|
dc.subject |
stars: chemically peculiar |
en_US |
dc.subject |
stars: individual: DY Cen |
en_US |
dc.subject |
stars: evolution |
en_US |
dc.subject |
stars: variables |
en_US |
dc.subject |
stars: rotation |
en_US |
dc.subject |
stars: abundances |
en_US |
dc.title |
SALT revisits DY Cen: a rapidly evolving strontium-rich single helium star |
en_US |
dc.type |
Article |
en_US |