Regular Frequency Patterns In The Young Delta Scuti Star HD 261711 Observed By The CoRoT And MOST Satellites

dc.contributor.utaustinauthorBarnes, T. G.en_US
dc.creatorZwintz, K.en_US
dc.creatorFossati, L.en_US
dc.creatorGuenther, D. B.en_US
dc.creatorRyabchikova, T.en_US
dc.creatorBaglin, A.en_US
dc.creatorThemessl, N.en_US
dc.creatorBarnes, T. G.en_US
dc.creatorMatthews, J. M.en_US
dc.creatorAuvergne, M.en_US
dc.creatorBohlender, D.en_US
dc.creatorChaintreuil, S.en_US
dc.creatorKuschnig, R.en_US
dc.creatorMoffat, A. F. J.en_US
dc.creatorRowe, J. F.en_US
dc.creatorRucinski, S. M.en_US
dc.creatorSasselov, D.en_US
dc.creatorWeiss, W. W.en_US
dc.description.abstractContext. The internal structure of pre-main-sequence (PMS) stars is poorly constrained at present. This could change significantly through high-quality asteroseismological observations of a sample of such stars. Aims. We concentrate on an asteroseismological study of HD261711, a rather hot delta Scuti-type pulsating member of the young open cluster NGC 2264 located at the blue border of the instability region. HD261711 was discovered to be a PMS delta Scuti star using the time series photometry obtained by the MOST satellite in 2006. Methods. High-precision, time-series photometry of HD261711 was obtained by the MOST and CoRoT satellites in four separate new observing runs that are put into context with the star's fundamental atmospheric parameters obtained from spectroscopy. Frequency Analysis was performed using Period04. The spectral analysis was performed using equivalent widths and spectral synthesis. Results. With the new MOST data set from 2011/12 and the two CoRoT light curves from 2008 and 2011/12, the delta Scuti variability was confirmed and regular groups of frequencies were discovered. The two pulsation frequencies identified in the data from the first MOST observing run in 2006 are confirmed and 23 new delta Scuti-type frequencies were discovered using the CoRoT data. Weighted average frequencies for each group were determined and are related to l = 0 and l = 1 p-modes. Evidence for amplitude modulation of the frequencies in two groups is seen. The effective temperature (T-eff) was derived to be 8600 +/- 200K, log g is 4.1 +/- 0.2, and the projected rotational velocity (upsilon sin i) is 53 +/- 1 km s(-1). Using our T-eff value and the radius of 1.8 +/- 0.5 R-circle dot derived from spectral energy distribution (SED) fitting, we get a luminosity log L/L-circle dot of 1.20 +/- 0.14 which agrees well to the seismologically determined values of 1.65 R-circle dot and, hence, a log L/L-circle dot of 1.13. The radial velocity of 14 +/- 2 km s(-1) we derived for HD261711, confirms the star's membership to NGC 2264. Conclusions. Our asteroseismic models suggest that HD261711 is a delta Scuti-type star close to the zero-age main sequence (ZAMS) with a mass of 1.8 to 1.9 M-circle dot. With an age of about 10 million years derived from asteroseismology, the star is either a young ZAMS star or a late PMS star just before the onset of hydrogen-core burning. The observed splittings about the l = 0 and 1 parent modes may be an artifact of the Fourier derived spectrum of frequencies with varying amplitudes.en_US
dc.description.sponsorshipResearch Foundation - Flanders (FWO)en_US
dc.description.sponsorshipAustrian Fonds zur Forderung der wissenschaftlichen Forschung P 21830-N16, P22691-N16en_US
dc.description.sponsorshipRussian Academy of Sciences >Non-stationary phenomena in the Universe>en_US
dc.description.sponsorshipNatural Sciences and Engineering Research Council (NSERC) of Canadaen_US
dc.description.sponsorshipAustrian Research Promotion Agency-ALRen_US
dc.identifier.citationZwintz, Konstanze, L. Fossati, D. B. Guenther, T. Ryabchikova, A. Baglin, N. Themessl, T. G. Barnes et al. >Regular frequency patterns in the young δ Scuti star HD 261711 observed by the CoRoT and MOST satellites.> Astronomy & Astrophysics, Vol. 552 (Apr., 2013): A68.en_US
dc.relation.ispartofserialAstronomy & Astrophysicsen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.subjectstars: variables: delta scutien_US
dc.subjectstars: oscillationsen_US
dc.subjectstars: individual:en_US
dc.subjecttechniques: photometricen_US
dc.subjecttechniques: spectroscopicen_US
dc.subjectcluster ngc 2264en_US
dc.subjectmodel atmospheresen_US
dc.subjectstellar evolutionen_US
dc.subjectpraesepe clusteren_US
dc.subjectastronomy & astrophysicsen_US
dc.titleRegular Frequency Patterns In The Young Delta Scuti Star HD 261711 Observed By The CoRoT And MOST Satellitesen_US

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