New slowly pulsating B stars in the field of the young open cluster NGC2244 discovered by the MOST photometric satellite

D. Gruber, H. Saio, R. Kuschnig, L. Fossati, G. Handler, K. Zwintz, W. W. Weiss, J. M. Matthews, D. B. Guenther, A. F.J. Moffat, S. M. Rucinski, D. Sasselov

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

During two weeks of nearly continuous optical photometry of the young open cluster NGC2244 obtained by the Microvariability and Oscillations of STars (MOST) satellite, we discovered two new slowly pulsating B (SPB) stars, GSC 00154-00785 and GSC 00154-01871. We present frequency analyses of the MOST light curves of these stars, which reveal two oscillation frequencies (0.61 and 0.71 cycled -1) in GSC 00154-00785 and two (0.40 and 0.51 cycled -1) in GSC 00154-01871. These frequency ranges are consistent with g modes of ℓ≤ 2 excited in models of main-sequence or pre-main-sequence (PMS) stars of masses 4.5-5M and solar composition (X, Z) = (0.7, 0.02). Published proper motion measurements and radial velocities are insufficient to establish unambiguously cluster membership for these two stars. However, the PMS models which fit best their eigenspectra have ages consistent with NGC2244. If cluster membership can be confirmed, these would be the first known PMS SPB stars, and would open a new window on testing asteroseismically the interior structures of PMS stars.

Original languageEnglish
Pages (from-to)291-298
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Volume420
Issue number1
DOIs
Publication statusPublished - 2012 Feb

Keywords

  • Open clusters and associations: individual: NGC2244
  • Stars: early-type
  • Stars: individual: GSC 00154-00785
  • Stars: individual: GSC 00154-01871
  • Stars: oscillations
  • Stars: pre-main-sequence

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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