Zobrazeno 1 - 10
of 284
pro vyhledávání: '"Jeffery, C S"'
Autor:
Dorsch, M., Jeffery, C. S., Monai, A. Philip, Tout, C. A., Snowdon, E. J., Monageng, I., Scott, L. J. A., Miszalski, B., Woolf, V. M.
Magnetic fields with strengths ranging from 300 to 500 kG have recently been discovered in a group of four extremely similar helium-enriched hot subdwarf (He-sdO) stars. Besides their strong magnetic fields, these He-sdO stars are characterised by co
Externí odkaz:
http://arxiv.org/abs/2410.02737
Heavy metal subdwarfs are a class of hot subdwarfs with very high abundances of heavy elements, typically around 10 000 times solar. They include stars which are strongly enhanced in either lead or zirconium, as well as other elements. Vertical strat
Externí odkaz:
http://arxiv.org/abs/2403.19071
Autor:
Dawson, H., Geier, S., Heber, U., Pelisoli, I., Dorsch, M., Schaffenroth, V., Reindl, N., Culpan, R., Pritzkuleit, M., Vos, J., Soemitro, A. A., Roth, M. M., Schneider, D., Uzundag, M., Vučković, M., Amaral, L. Antunes, Istrate, A. G., Justham, S., Østensen, R. H., Telting, J. H., Djupvik, A. A., Raddi, R., Green, E. M., Jeffery, C. S., Kepler, S. O., Munday, J., Steinmetz, T., Kupfer, T.
We present the first volume-limited sample of spectroscopically confirmed hot subluminous stars out to 500 pc, defined using the accurate parallax measurements from the {\em Gaia} space mission data release 3 (DR3). The sample comprises a total of 39
Externí odkaz:
http://arxiv.org/abs/2403.15513
Publikováno v:
Monthly Notices of the Royal Astronomical Society, Volume 527, Issue 3, January 2024, Pages 5408-5428
Hydrogen deficient stars include the cool R CrB variable (RCBs) and hydrogen-deficient carbon (HdCs) giants through extreme helium stars (EHes) to the very hot helium-rich subdwarfs (He-sdO and O(He) stars) and white dwarfs. With surfaces rich in hel
Externí odkaz:
http://arxiv.org/abs/2310.15869
We have performed a detailed spectral analysis of the helium-rich hot subdwarf EC 20187-4939 using data obtained in the SALT survey of helium-rich hot subdwarfs. We have measured its effective temperature, surface gravity and chemical abundances from
Externí odkaz:
http://arxiv.org/abs/2303.01367
Publikováno v:
MNRAS 519 (2023), 2321-2330
The Southern African Large Telescope (SALT) survey of helium-rich hot subdwarfs aims to explore evolutionary pathways amongst groups of highly-evolved stars. The selection criteria mean that several hot white dwarfs and related objects have also been
Externí odkaz:
http://arxiv.org/abs/2301.03550
BPS CS 22940-0009 is a helium-rich B-star that shares characteristics with both helium-rich B subdwarfs and extreme helium stars. The optical spectrum of BPS CS 22940-0009 has been analysed from SALT observations. The atmospheric parameters were foun
Externí odkaz:
http://arxiv.org/abs/2208.07720
Autor:
Ramsay, G., Woudt, P. A., Kupfer, T., van Roestel, J., Patterson, K., Warner, B., Buckley, D. A. H., Groot, P. J., Heber, U., Irrgang, A., Jeffery, C. S., Motsoaledi, M., Schwartz, M. J., Wevers, T.
Blue Large Amplitude Pulsators (BLAPs) are a relatively new class of blue variable stars showing periodic variations in their light curves with periods shorter than a few tens of mins and amplitudes of more than ten percent. We report nine blue varia
Externí odkaz:
http://arxiv.org/abs/2204.03265
Using light curves with $\sim$3 min cadence and a duration of 2 hrs made using the OmegaWhite survey, we present the results of a search for short-period variable stars in the field of 20 open clusters. We identified 92 variable stars in these fields
Externí odkaz:
http://arxiv.org/abs/2203.11533
Publikováno v:
Astronomy & Astrophysics 654 (2021) A119
Since its discovery about 50 years ago, HD144941 has generally been classified as a peculiar member of the extreme helium (EHe) supergiant stars, a very rare class of low-mass hydrogen-deficient stars. We report the detection of a strong longitudinal
Externí odkaz:
http://arxiv.org/abs/2110.11267