Open AccessThe calibrating stars of the Mira P – L relation
Author(s) -
Glass I. S.,
Evans T. Lloyd
Publication year - 2003
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2003.06632.x
Subject(s) - physics , large magellanic cloud , stars , astrophysics , galaxy , amplitude , variable star , light curve , astronomy , carbon star , quantum mechanics
Improved light curves extracted from the MACHO data base are used to discuss the periods and amplitudes of the calibrating stars of the Mira P – L relations. Previously unpublished spectral types and positions are given for several of those that lie in the S Dor variable star field. It is found that the periods derived from the discovery observations were generally sufficiently accurate that the K ‐ and m bol –log P relations are not significantly changed by the MACHO results. Furthermore, the periods have remained essentially constant over two to three decades. The MACHO r ‐band amplitudes of the oxygen‐rich Large Magellanic Cloud (LMC) Miras are similar to those in galactic (Baade's window) fields at a given period but there appear to be more shorter‐period stars as a proportion of the whole than in the galaxy. In O‐rich stars, the distinction in amplitude between the Miras and the semiregulars is not as conspicuous at shorter periods (<200 d) as at longer ones. The LMC carbon Miras have smaller amplitudes than their O‐rich counterparts. Of the six stars with P > 420 d that were found to be too luminous to fit the P – L relation, two are now known to be Li‐rich. This tends to confirm the suggestion that they are hot‐bottom burners.