Open AccessCarbon‐rich Mira variables: kinematics and absolute magnitudes
Author(s) -
Feast Michael W.,
Whitelock Patricia A.,
Menzies John W.
Publication year - 2006
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 - 10.1111/j.1365-2966.2006.10324.x
Subject(s) - physics , astrophysics , large magellanic cloud , luminosity , stars , velocity dispersion , differential rotation , astronomy , radial velocity , galaxy
The kinematics of Galactic C‐Miras are discussed on the basis of the bolometric magnitudes and radial velocities of Papers I and II of this series. Differential Galactic rotation is used to derive a zero‐point for the bolometric period–luminosity relation which is in satisfactory agreement with that inferred from the Large Magellanic Cloud (LMC) C‐Miras. We find for the Galactic Miras, M bol =−2.54 log P + 2.06(±0.24) , where the slope is taken from the LMC. The mean velocity dispersion, together with the data of Nordström et al. and the Padova models, leads to a mean age for our sample of C‐Miras of 1.8 ± 0.4 Gyr and a mean initial mass of 1.8 ± 0.2 M ⊙ . Evidence for a variation of velocity dispersion with period is found, indicating a dependence of period on age and initial mass, the longer period stars being younger. We discuss the relation between the O‐ and C‐Miras and also their relative numbers in different systems.