First Attempt at Spectroscopic Detection of Gravity Modes in a Long-Period Pulsating Subdwarf B Star -- PG 1627+017

Simple item page
dc.creatorFor, B. -Q.
dc.creatorGreen, E. M.
dc.creatorO'Donoghue, D.
dc.creatorKiss, L. L.
dc.creatorRandall, S. K.
dc.creatorFontaine, G.
dc.creatorJacob, A. P.
dc.creatorO'Toole, S. J.
dc.creatorHyde, E. A.
dc.creatorBedding, T. R.
dc.date2006-01-27
dc.date.accessioned2026-07-07T12:49:57Z
dc.date.available2026-07-07T12:49:57Z
dc.descriptionIn the first spectroscopic campaign for a PG 1716 variable (or long-period pulsating subdwarf B star), we succeeded in detecting velocity variations due to g-mode pulsations at a level of 1.0-1.5 km/s.The observations were obtained during 40 nights on 2-m class telescopes in Arizona, South Africa,and Australia. The target,PG1627+017, is one of the brightest and largest amplitude stars in its class.It is also the visible component of a post-common envelope binary.Our final radial velocity data set includes 84 hours of time-series spectroscopy over a time baseline of 53 days. Our derived radial velocity amplitude spectrum, after subtracting the orbital motion, shows three potential pulsational modes 3-4 sigma above the mean noise level, at 7201.0s,7014.6s and 7037.3s.Only one of the features is statistically likely to be real,but all three are tantalizingly close to, or a one day alias of, the three strongest periodicities found in the concurrent photometric campaign. We further attempted to detect pulsational variations in the Balmer line amplitudes. The single detected periodicity of 7209 s, although weak, is consistent with theoretical expectations as a function of wavelength.Furthermore, it allows us to rule out a degree index of l= 3 or l= 5 for that mode. Given the extreme weakness of g-mode pulsations in these stars,we conclude that anything beyond simply detecting their presence will require larger telescopes,higher efficiency spectral monitoring over longer time baselines,improved longitude coverage, and increased radial velocity precision.
dc.description39 pages, 9 figures, 4 tables, ApJ accepted. See postscript for full abtract
dc.identifierhttps://arxiv.org/abs/astro-ph/0601636
dc.identifierhttp://arxiv.org/abs/astro-ph/0601636
dc.identifierAstrophys.J.642:1117-1130,2006
dc.identifierdoi:10.1086/501418
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/222546
dc.subjectAstrophysics
dc.titleFirst Attempt at Spectroscopic Detection of Gravity Modes in a Long-Period Pulsating Subdwarf B Star -- PG 1627+017
dc.typetext

Files

Collections

arXiv