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On the evolutionary status and pulsations of the recently discovered blue large-amplitude pulsators (BLAPs)
- Source :
- Repositório Institucional da UFRGS, Universidade Federal do Rio Grande do Sul (UFRGS), instacron:UFRGS, CONICET Digital (CONICET), Consejo Nacional de Investigaciones Científicas y Técnicas, instacron:CONICET
- Publication Year :
- 2018
-
Abstract
- The blue large-amplitude pulsators (BLAPs) constitute a new class of pulsating stars. They are hot stars with effective temperatures of ∼30 000 K and surface gravities of log g ∼ 4.9, that pulsate with periods in the range 20−40 min. Until now, their origin and evolutionary state, as well as the nature of their pulsations, were not been unveiled. In this paper, we propose that the BLAPs are the hot counterpart of the already known pulsating pre-extremely low mass (pre-ELM) white dwarf (WD) stars, that are He-core low-mass stars resulting from interacting binary evolution. Using fully evolutionary sequences, we show that the BLAPs are well represented by pre-ELM WD models with high effective temperature and stellar masses ∼0.34 M⊙. From the analysis of their pulsational properties, we find that the observed variabilities can be explained by high-order non-radial g-mode pulsations or, in the case of the shortest periods, also by low-order radial modes, including the fundamental radial mode. The theoretical modes with periods in the observed range are unstable due to the κ mechanism associated with the Z-bump in the opacity at log T ∼ 5.25.<br />Instituto de Astrofísica de La Plata<br />Facultad de Ciencias Astronómicas y Geofísicas
- Subjects :
- Ciencias Astronómicas
Ciencias Físicas
stars:evolution
FOS: Physical sciences
evolution [Stars]
Astrophysics
01 natural sciences
variables: general [Stars]
purl.org/becyt/ford/1 [https]
0103 physical sciences
Evolucao estelar
Astrophysics::Solar and Stellar Astrophysics
stars:variables:general
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
Solar and Stellar Astrophysics (astro-ph.SR)
Physics
010308 nuclear & particles physics
White dwarf
Astronomy and Astrophysics
purl.org/becyt/ford/1.3 [https]
Astronomía
Amplitude
Astrophysics - Solar and Stellar Astrophysics
Space and Planetary Science
Anãs brancas
Pulsacoes estelares
Astrophysics::Earth and Planetary Astrophysics
pre- white dwarf
CIENCIAS NATURALES Y EXACTAS
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- Repositório Institucional da UFRGS, Universidade Federal do Rio Grande do Sul (UFRGS), instacron:UFRGS, CONICET Digital (CONICET), Consejo Nacional de Investigaciones Científicas y Técnicas, instacron:CONICET
- Accession number :
- edsair.doi.dedup.....a6c7edd135e30db549f66e233ffbf479