Stellar Winds and Mass Loss from Extreme Helium Stars

Autor: Hamann, C. S. Jeffery W. -R.

Extreme helium stars are very rare low-mass supergiants in a late stage of evolution. They are probably contracting to become white dwarfs following a violent phase of evolution which caused them to become hydrogen-deficient giants, possibly R CrB st

Externí odkaz: http://arxiv.org/abs/1001.4399

The OmegaWhite survey for short-period variable stars – VI. Open clusters

Autor: R Toma, G Ramsay, C S Jeffery, S A Macfarlane, P Woudt, P J Groot

Publikováno v: Monthly Notices of the Royal Astronomical Society, 513, 468-486
Monthly Notices of the Royal Astronomical Society, 513, 1, pp. 468-486

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: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::9dfe22e47cc519c47a6c80ab32334fe5
https://doi.org/10.1093/mnras/stac802

The SALT survey of helium-rich hot subdwarfs: methods, classification, and coarse analysis

Autor: E. Snowdon, Brent Miszalski, C. S. Jeffery

Publikováno v: Monthly Notices of the Royal Astronomical Society. 501:623-642

A medium- and high-resolution spectroscopic survey of helium-rich hot subdwarfs is being carried out using the Southern African Large Telescope (SALT). Objectives include the discovery of exotic hot subdwarfs and of sequences connecting chemically-pe

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::8d7db46dbaaf7365942e63af87199d46
https://doi.org/10.1093/mnras/staa3648

K2 observations of the pulsating subdwarf B stars UY Sex and V1405 Ori

Autor: J. Vos, A. Slayton, C. S. Jeffery, Roy Ostensen, Michael D. Reed, J. H. Telting, M. Yeager, Andrzej S. Baran

Publikováno v: Monthly Notices of the Royal Astronomical Society. 492:5202-5217

We processed and analysed K2 observations of the pulsating subdwarf-B (sdBV) stars UY Sex and V1405 Ori. We detect 97 p-mode pulsations in UY Sex while we discover V1405 Ori to be a rare rich hybrid pulsator with over 100 p-mode pulsations and 19 g-m

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::722d761b1d63b79cf276090735b0631a
https://doi.org/10.1093/mnras/staa144

Electron-Impact Excitation of Ge iii and Photoionisation of Ge ii

Autor: Connor Ballance, N. L. Dunleavy, Catherine Ramsbottom, C. S. Jeffery

Publikováno v: Dunleavy, N L, Ballance, C P, Ramsbottom, C A & Jeffery, C S 2021, ' Electron-Impact Excitation of Ge III and Photoionisation of Ge II ', Monthly Notices of the Royal Astronomical Society, vol. 506, no. 4, pp. 5398–5409 . https://doi.org/10.1093/mnras/stab1974

Energy levels, Einstein A-values and oscillator strengths are calculated for doubly-ionised germanium (Ge iii). We have undertaken a study of the electron-impact excitation of Ge iii and have also completed a study of the photoionisation of Ge ii. Ge

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::584348a6c51106e115e79a44e5e764d0
https://doi.org/10.1093/mnras/stab1974