New SPB stars in the field of the young open cluster NGC 2244 discovered by the MOST photometric satellite

Abstract

During two weeks of nearly continuous optical photometry of the young open cluster NGC 2244 obtained by the MOST satellite, we discovered two new 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 c/d) in GSC 00154-00785 and two (0.40 and 0.51 c/d) in GSC 00154-01871. These frequency ranges are consistent with g-modes of $\ell \le 2$ excited in models of main-sequence or pre-main-sequence (PMS) stars of masses 4.5 - 5 $M_{\odot }$ 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 NGC 2244. 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.

accepted for publication in MNRAS

References in corpus (7)

• A heuristic derivation of the uncertainty of the frequency determination in time series data
• Most Detects G- and P-Modes in the B Supergiant HD 163899 (B2Ib/II)
• Mass segregation in very young open clusters -- A case study of NGC 2244 and NGC 6530
• Quasi-Periodic Pulsations in Solar Flares: new clues from the Fermi Gamma-Ray Burst Monitor
• Discovery of the new slowly pulsating B star HD 163830 (B5II/III) from MOST spacebased photometry
• Reduction of time-resolved space-based CCD photometry developed for MOST Fabry Imaging data
• uvbybeta photometry of early type open cluster and field stars

Cited by in corpus (14)

• Probing the interior physics of stars through asteroseismology
• The first view of $\delta$ Scuti and $\gamma$ Doradus stars with the TESS mission
• Triple system HD 201433 with a SPB star component seen by BRITE-Constellation: Pulsation, differential rotation, and angular momentum transfer
• Stellar variability in open clusters. I. A new class of variable stars in NGC 3766
• Main-sequence variable stars in young open cluster NGC 1893
• Pulsational instability of pre-main sequence models from accreting protostars. I. Constraining the input physics for accretion with spectroscopic parameters and stellar pulsations
• Pre-main sequence variable stars in young open cluster NGC 1893
• A comprehensive study of young B stars in NGC 2264: I. Space photometry and asteroseismology
• Pulsational instability of pre-main-sequence models from accreting protostars II. Modelling echelle diagrams of $\delta$ Scuti stars without rotational splitting
• Pulsational properties of ten new slowly pulsating B stars
• Massive Star Asteroseismology in Action
• The Pre-main Sequence: Challenges and Prospects for Asteroseismology
• Variable Stars in Young Open Cluster NGC 2244
• The potential of space observations for pulsating pre-main sequence stars