A Whole Earth Telescope campaign on the pulsating subdwarf B binary system PG 1336-018 (NY Vir)

	A Whole Earth Telescope campaign on the pulsating subdwarf B binary system PG 1336-018 (NY Vir)
	Kilkenny, D ; Reed, MD ; O'Donoghue, D ; Kawaler, SD ; Mukadam, A ; Kleinman, SJ ; Nitta, A ; Metcalfe, TS ; Provencal, JL ; Watson, TK
刊名	MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
	2003-11-01
卷号	345 期号:3 页码:834-846
关键词	stars : individual : PG 1336-018 stars : oscillations stars : variables : other
英文摘要	We present results from a multisite ('Whole Earth Telescope') photometric campaign on PG 1336-018, the close eclipsing binary system containing a pulsating subdwarf B (sdB) star. The main part of the campaign (1999 April) resulted in similar to172 h of observations, representing a coverage of about 47 per cent, and additional data were obtained outside the core campaign. Periodogram analysis shows that the light variations are dominated by three frequencies near 5757, 5585 and 5369 muHz (similar to174, 179 and 186 s, respectively), although many frequencies are present, particularly in the range 5000-6000 muHz (similar to200-170 s). We identify, with some confidence, 28 frequencies down to a semi-amplitude of 0.0005 in fractional intensity (equivalent to about 0.5 mmag). It is clear that the pulsation frequencies of PG 1336-018 have changed substantially since the 1996 discovery observations were made, and that amplitude changes occur, at least in the dominant three frequencies, on relatively short time-scales (of the order of a day). On the assumption that the pulsating star is phase-locked in the binary system, we have searched for rotational splitting of frequencies near the orbital and half of the orbital period, but the results are confused by aliasing at those frequencies (due to the data gaps caused by the eclipses). A preliminary model qualitatively matches the distribution of frequencies in PG 1336-018, with some good individual correspondences, but cannot be considered adequate because geometric cancellation should hide some of the modes which are apparently detected. Analysis of the pulsations during eclipse recovers three of the strongest modes, but the limited eclipse data - which can, at best, be only about 9 per cent of the total - do not allow mode identification at this stage. Simulations indicate that an overall coverage of about 80 per cent would be required for this to be viable. An attempt was made to determine phase shifts in the pulsation frequencies as a way of directly measuring the size of the binary orbit, but the uncertainties in the method are comparable to the light travel time across the orbit (probably less than a second).
收录类别	SCI
语种	英语
WOS记录号	WOS:000186168600015
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/8485]
专题	国家天文台_光学天文研究部
作者单位	1.S African Astron Observ, ZA-7935 Observatory, South Africa 2.SW Missouri State Univ, Dept Phys Astron & Mat Sci, Springfield, MO 65804 USA 3.Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA 4.Univ Texas, Dept Astron, Austin, TX 78712 USA 5.Apache Point Observ, Sunspot, NM 88349 USA 6.Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA 7.Univ Delaware, Newark, DE 19716 USA 8.Southwestern Univ, Georgetown, TX 78626 USA 9.Victoria Univ Wellington, Sch Chem & Phys Sci, Wellington, New Zealand 10.Univ Sydney, Sch Phys, Chatterton Astron Dept, Sydney, NSW 2006, Australia
推荐引用方式 GB/T 7714	Kilkenny, D,Reed, MD,O'Donoghue, D,et al. A Whole Earth Telescope campaign on the pulsating subdwarf B binary system PG 1336-018 (NY Vir)[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,2003,345(3):834-846.
APA	Kilkenny, D.,Reed, MD.,O'Donoghue, D.,Kawaler, SD.,Mukadam, A.,...&Giovannini, O.(2003).A Whole Earth Telescope campaign on the pulsating subdwarf B binary system PG 1336-018 (NY Vir).MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,345(3),834-846.
MLA	Kilkenny, D,et al."A Whole Earth Telescope campaign on the pulsating subdwarf B binary system PG 1336-018 (NY Vir)".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 345.3(2003):834-846.