Search for pulsating pre‐main‐sequence stars in NGC 6383

Monthly Notices of the Royal Astronomical Society (Impact Factor: 5.23). 01/2005; 357(1):345 - 353. DOI: 10.1111/j.1365-2966.2005.08655.x
Source: arXiv

ABSTRACT ABSTRACTA search for pulsating pre-main-sequence (PMS) stars was performed in the young open cluster NGC 6383 using CCD time-series photometry in Johnson B and V filters. With an age of only ∼1.7 Myr all cluster members later than spectral type A0 have not reached the ZAMS yet, hence being ideal candidates for investigating PMS pulsation among A- and F-type stars. In total 286 stars have been analysed using classical Fourier techniques. From about a dozen stars within the boundaries of the classical instability strip, two stars were found to pulsate: NGC 6383 #170, with five frequencies simultaneously, and NGC 6383 #198, with a single frequency. In addition, NGC 6383 #152 is a suspected PMS variable star, but our data remain inconclusive. Linear, non-adiabatic models assuming PMS evolutionary phase and purely radial pulsation were calculated for the two new PMS pulsators. NGC 6383 #170 appears to pulsate radially in third and fifth overtones, while the other three frequencies seem to be of non-radial nature. NGC 6383 #198 pulsates monoperiodically, most probably in the third radial overtone. Magnitudes and B−V colours were available in the literature for only one third of all stars and we used them for calibrating the remaining.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Information on 72 confirmed or candidate pre-main-sequence delta-Scuti stars is collected and analysed to varying degree of sophistication and completeness. A systematic asteroseismic analysis of around 40 of these stars is performed, putting significant luminosity constraints on many of them simply by comparing the pulsation spectra of the stars to the fundamental and acoustic cut-off frequencies of a dense grid of stellar models. One star in particular, V1366 Ori, appears to be pulsating at or near the acoustic cut-off frequency. Many stars are found to otherwise defy proper asteroseismic analysis, in that matches between observed pulsation spectra and computed values are not able to be found. A simple test reveals that the most likely cause for these problems are the high stellar-rotation rates typically found in this class of star, with v sin i most typically between 60 and 200 km/s. The high rotation rates are found to significantly modify the pulsation spectrum of a star compared to a non-rotating star. These collective results reveal the richness and variety of phenomena within this group of stars, with stars pulsating anywhere from the lowest to the highest possible radial orders, including radial orders just below the acoustic cut-off frequency of some stars. Pulsation in non-radial orders is the normal case, not the exception to the rule, with all stars displaying low-amplitude delta-Scuti variability only.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We demonstrate that a seismic analysis of stars in their earliest evolutionary phases is a powerful method to identify young stars and distinguish their evolutionary states. The early star that is born from the gravitational collapse of a molecular cloud reaches at some point sufficient temperature, mass and luminosity to be detected. Accretion stops and the pre-main sequence star that emerges is nearly fully convective and chemically homogeneous. It will continue to contract gravitationally until the density and temperature in the core are high enough to start nuclear burning of hydrogen. We show that there is a relationship for a sample of young stars between detected pulsation properties and their evolutionary status, illustrating the potential of asteroseismology for the early evolutionary phases.
    Science 07/2014; 345(6196). DOI:10.1126/science.1253645 · 31.48 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We present the results of a search for pulsating stars in the region of Carina Nebula which includes three very young open clusters: Trumpler 14, 15 and 16. The search was made with the Wide Field Imager (WFI) on the MPG/ESO 2.2-m telescope in La Silla (Chile). In total, about 16,000 stars have been analyzed using classical Fourier techniques. We found over 20 pulsating delta-Scuti type stars in this region. Most of them are probable members of open clusters at the pre-main sequence evolutionary stage.
    Journal of Physics Conference Series 10/2008; 118(1). DOI:10.1088/1742-6596/118/1/012075

Full-text (4 Sources)

Available from
Jun 5, 2014