2011MNRAS.412..371R

Query : 2011MNRAS.412..371R

2011MNRAS.412..371R - Mon. Not. R. Astron. Soc., 412, 371-390 (2011/March-3)

Whole Earth Telescope observations of the subdwarf b star KPD 1930+2752: a rich, short-period pulsator in a close binary.

REED M.D., HARMS S.L., POINDEXTER S., ZHOU A.-Y., EGGEN J.R., MORRIS M.A., QUINT A.C., McDANIEL S., BARAN A., DOLEZ N., KAWALER S.D., KURTZ D.W., MOSKALIK P., RIDDLE R., ZOLA S., OSTENSEN R.H., SOLHEIM J.-E., KEPLER S.O., COSTA A.F.M., PROVENCAL J.L., MULLALLY F., WINGET D.W., VUCKOVIC M., CROWE R., TERRY D., AVILA R., BERKEY B., STEWART S., BODNARIK J., BOLTON D., BINDER P.-M., SEKIGUCHI K., SULLIVAN D.J., KIM S.-L., CHEN W.-P., CHEN C.-W., LIN H.-C., JIAN X.-J., WU H., GOU J.-P., LIU Z., LEIBOWITZ E., LIPKIN Y., AKAN C., CAKIRLI O., JANULIS R., PRETORIUS R., OGLOZA W., STACHOWSKI G., PAPARO M., SZABO R., CSUBRY Z., ZSUFFA D., SILVOTTI R., MARINONI S., BRUNI I., VAUCLAIR G., CHEVRETON M., MATTHEWS J.M., CAMERON C. and PABLO H.

Abstract (from CDS):

KPD 1930+2752 is a short-period pulsating subdwarf B (sdB) star. It is also an ellipsoidal variable with a known binary period of 2.3 h. The companion is most likely a white dwarf and the total mass of the system is close to the Chandresekhar limit. In this paper, we report the results of Whole Earth Telescope (WET) photometric observations during 2003 and a smaller multisite campaign of 2002. From 355 h of WET data, we detect 68 pulsation frequencies and suggest an additional 13 frequencies within a crowded and complex temporal spectrum between 3065 and 6343 µHz (periods between 326 and 157 s). We examine pulsation properties including phase and amplitude stability in an attempt to understand the nature of the pulsation mechanism. We examine a stochastic mechanism by comparing amplitude variations with simulated stochastic data. We also use the binary nature of KPD 1930+2752 for identifying pulsation modes via multiplet structure and a tidally induced pulsation geometry. Our results indicate a complicated pulsation structure that includes short-period (≈16 h) amplitude variability, rotationally split modes, tidally induced modes and some pulsations which are geometrically limited on the sdB star.

Abstract Copyright: 2011 The Authors Monthly Notices of the Royal Astronomical Society2011 RAS

Journal keyword(s): binaries: close - stars: general - stars: oscillations - subdwarfs - oscillations: individual: KPD 1930+2752

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 PG 0048+091 HS* 00 51 26.9371074840 +09 21 32.879383380   14.454 14.261 14.505   sdOB+F5V 37 0
2 V* V361 Hya HS* 14 05 33.018072 -27 01 34.01328   15.446 15.258 15.161   sdB+ 129 0
3 PG 1605+072 HS* 16 08 03.6872637792 +07 04 28.748468964   12.53 12.83 13.18   sdB0.2VIHe3 136 0
4 PG 1716+426 HS* 17 18 03.8584522800 +42 34 12.562847292   13.69 13.97     sdB2VIIHe3 122 0
5 KPD 1930+2752 HS* 19 32 14.8088063952 +27 58 35.445679608 12.80 13.75 13.82     sdB 167 0

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