Eta Carinae and the Luminous Blue Variables
Abstract
We evaluate the place of Eta Carinae (η Car) among the class of luminous blue variables (LBVs) and show that the LBV phenomenon is not restricted to extremely luminous objects like η Car, but extends luminosities as low as log (L / L⊙) ∼ 5.4 - corresponding to initial masses ∼ 25 M⊙, and final masses as low as ∼ 10-15 M⊙. We present a census of S Doradus variability, and discuss basic LBV properties, their mass-loss behavior, and whether at maximum light they form pseudo-photospheres. We suggest that those objects that exhibit giant η Car-type eruptions are most likely related to the more common type of S Doradus variability. Alternative atmospheric models as well as sub-photospheric models for the instability are presented, but the true nature of the LBV phenomenon remains as yet elusive. We end with a discussion of the evolutionary status of LBVs - highlighting recent indications that some LBVs may be in a direct pre-supernova state, in contradiction to the standard paradigm for massive star evolution.
- Publication:
-
Eta Carinae and the Supernova Impostors
- Pub Date:
- 2012
- DOI:
- 10.1007/978-1-4614-2275-4_10
- arXiv:
- arXiv:0905.3338
- Bibcode:
- 2012ASSL..384..221V
- Keywords:
-
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 27 pages, 6 figures, Review Chapter in "Eta Carinae and the supernova imposters" (eds R. Humphreys and K. Davidson) new version submitted to Springer