2006/06/26 by Gavin Ramsay, R. Napiwotzki, Ralf Napiwotzki +3 · 14 citations
Physics and Astronomy · #Amplitude #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Cepheid variable #Instability strip #Light curve #Optics #Photometry (optics) #Physics #Spectral line #Stars #Stellar, planetary, and galactic studies #Subdwarf #Surface gravity #Telescope #Variable star #White dwarf #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2006.10728.x
published in Monthly Notices of the Royal Astronomical Society 371(2), 957-962 (Oxford University Press) · Accepted MNRAS 7 pages
arxiv created 2006/06/26 · openalex publication_date 2006/07/26 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The Rapid Temporal Survey (RATS) is a survey to detect objects whose optical intensity varies on time-scales of less than ∼70 min. In our pilot data set taken with the Isaac Newton Telescope and the Wide Field Camera in 2003 November, we discovered nearly 50 new variable objects. Many of these varied on time-scales much longer than 1 h. However, only four objects showed a modulation on a time-scale of 1 h or less. This paper presents followup optical photometry and spectroscopy of these four objects. We find that RAT J0455 + 1305 is a pulsating (on a period of 374 s) subdwarf B star of the EC 14026 type. We have modelled its spectrum and determine Teff= 29 200 ± 1900 K and log g= 5.2 ± 0.3 which locates it on the cool edge of the EC 14026 instability strip. It has a modulation amplitude which is one of the highest of any known EC 14026 star. Based on their spectra, photometric variability and their infrared colours, we find that RAT J0449 + 1756, J0455 + 1254 and J0807 + 1510 are likely to be SX Phe stars – dwarf δ Sct stars. Our results show that our observing strategy is a good method for finding rare pulsating stars.