Open AccessThe domain of γ Doradus variables in the Hertzsprung–Russell diagram
Author(s) -
Handler G.
Publication year - 1999
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.1365-8711.1999.03005.x
Subject(s) - physics , hertzsprung–russell diagram , photometry (optics) , stars , diagram , astrophysics , instability strip , domain (mathematical analysis) , magnitude (astronomy) , astronomy , stellar evolution , cepheid variable , statistics , mathematical analysis , mathematics
70 new γ Doradus candidates were identified from Hipparcos photometry, which represents more than a doubling of the presently known number. Selecting the objects with good evidence for multiperiodicity, it is found that these stars, together with bona fide members of the class, occupy a well‐defined region in a colour–magnitude diagram. This domain corresponds to a range of 7200–7700 K on the zero‐age main sequence (ZAMS) and 6900–7500 K one magnitude above it, which partly overlaps with the instability strip of δ Scuti stars. For the first time, γ Doradus stars can be discussed as a group. They can be found over a significant fraction of the main sequence lifetimes for objects in the relevant temperature range. An upper limit on the surface metallicity of γ Doradus stars is apparent, which may guide the search for their pulsation driving mechanism. The importance of possible objects exhibiting both γ Doradus and δ Scuti‐type pulsations is discussed.