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    • Fulltext

       

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      Permanent link:
      https://www.ias.ac.in/article/fulltext/joaa/015/01/0047-0067

    • Keywords

       

      Hydrogen deficient stars; irregular variables; abundances; evolution

    • Abstract

       

      This review presents a selection of recent highlights of observations of R Coronae Borealis variables. Emphasis is placed on an abundance analysis of a complete sample (18 stars) of the warm galactic RCBs. It is shown that 14 of the 18 have very similar compositions: the iron mass fraction ranges about a factor of 3 around the solar value (assuming C/He = 3%) but abundance ratios X/Fe for elements from Na to Ba show little variation. By contrast, the other 4 stars are deficient in iron but not in Na, Si, S and some other elements. With for example, [Si/Fe] ≃ 2, the quartet is indeed ‘peculiar’. One of the quartet, V854 Cen shows depletions of elements (other than CNO) similar to the depletions seen in interstellar medium corresponding to average logn(Htot) = − 1.5. Scenarios for creating RCB from normal single and double stars are summarised.

    • Author Affiliations

       

      David L. Lambert1 N. Kameswara Rao2

      1. Department of Astronomy, University of Texas, Austin, TX, USA
      2. Indian Institute of Astrophysics, Bangalore - 560 034

    • Dates

       
      Published
      March 1994
      Manuscript received
      6 January 1994
      Accepted
      29 January 1994

  • Journal of Astrophysics and Astronomy | News

    • Continuous Article Publication

      Posted on January 27, 2016

      Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately. All these have helped shorten the publication time and have improved the visibility of the articles.

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