首页    期刊浏览 2024年11月24日 星期日
登录注册

文章基本信息

  • 标题:Variability in the Massive Open Cluster NGC 1817 from K2: A Rich Population of Asteroseismic Red Clump, Eclipsing Binary, and Main-sequence Pulsating Stars
  • 本地全文:下载
  • 作者:Eric L.Sandquist ; Dennis Stello ; Torben Arentoft
  • 期刊名称:The Astronomical journal
  • 印刷版ISSN:0004-6256
  • 电子版ISSN:1538-3881
  • 出版年度:2020
  • 卷号:159
  • 期号:3
  • 页码:1294-1313
  • DOI:10.3847/1538-3881/ab68df
  • 语种:English
  • 出版社:American Institute of Physics
  • 摘要:We present a survey of variable stars detected in K2 Campaign 13 within the massive intermediate-age (~1 Gyr) open cluster NGC 1817.We identify a complete sample of 44 red clump stars in the cluster, and have measured asteroseismic quantities (νmax and/or Δν) for 29 of them.Five stars showed suppressed dipole modes, and the occurrence rates indicate that mode suppression is unaffected by evolution through core helium burning.A subset of the giants in NGC 1817 (and in the similarly aged cluster NGC 6811) have νmax and Δν values at or near the maximum observed for core helium–burning stars, indicating they have core masses near the minimum for fully nondegenerate helium ignition.Further asteroseismic study of these stars can constrain the minimum helium core mass in red clump stars and the physics that determines this limit.Two giant stars show photometric variations on timescales similar to previously measured spectroscopic orbits.Thirteen systems in the field show eclipses, but only five are probable cluster members.We identify 32 δ Sct pulsators, 27 γ Dor candidates, and 7 hybrids that are probable cluster members, with most being new detections.We used the ensemble properties of the δ Sct stars to identify stars with possible radial pulsation modes.Among the oddities we have uncovered are: an eccentric orbit for a short-period binary containing a δ Sct pulsating star; a rare subgiant within the Hertzsprung gap showing δ Sct pulsations; and two hot γ Dor pulsating star candidates.
  • 关键词:Eclipsing binary stars;Spectroscopic binary stars;Open star clusters;Asteroseismology;Low mass stars;Stellar distance;Stellar evolution
国家哲学社会科学文献中心版权所有