Comparing the asteroseismic properties of pulsating pre-extremely low mass white dwarf and δ Scuti stars
| Autor: | Alejandro H. Córsico, Julieta Paz Sánchez Arias, Leandro Gabriel Althaus, Ingrid Domingos Pelisoli, Mariela Alejandra Corti, Victoria Antoci, Alejandra D. Romero, Souza Oliveira Kepler |
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| Rok vydání: | 2018 |
| Předmět: |
oscillations [stars]
GAMMA DORADUS STARS Ciencias Físicas OPACITIES FOS: Physical sciences Context (language use) Astrophysics::Cosmology and Extragalactic Astrophysics asteroseismology Astrophysics PG-1159 EVOLUTIONARY MODELS 01 natural sciences Asteroseismology Spectral line purl.org/becyt/ford/1 [https] RED-GIANT STAR Ionization Evolucao estelar 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics ORDER G-MODES 010306 general physics 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics Solar and Stellar Astrophysics (astro-ph.SR) variables: delta Scuti [stars] white dwarfs interiors [stars] Physics AGB STARS OVERSHOOT White dwarf Astronomy and Astrophysics purl.org/becyt/ford/1.3 [https] Astronomía Stars Astrophysics - Solar and Stellar Astrophysics SX PHE STARS Anãs brancas Pulsacoes estelares STELLAR EVOLUTION Space and Planetary Science Asterosismologia variables: delta Scut [Stars] evolution [stars] ROTATION Astrophysics::Earth and Planetary Astrophysics Variable star Low Mass CIENCIAS NATURALES Y EXACTAS |
| Zdroj: | Sanchez Arias, J P, Romero, A D, Corsico, A H, Pelisoli, I, Antoci, V, Kepler, S O, Althaus, L G & Corti, M A 2018, ' Comparing the asteroseismic properties of pulsating pre-extremely low mass white dwarf and delta Scuti stars ', Astronomy & Astrophysics, vol. 616, 80 . https://doi.org/10.1051/0004-6361/201731808 CONICET Digital (CONICET) Consejo Nacional de Investigaciones Científicas y Técnicas instacron:CONICET Repositório Institucional da UFRGS Universidade Federal do Rio Grande do Sul (UFRGS) instacron:UFRGS |
| ISSN: | 1432-0746 0004-6361 |
| DOI: | 10.1051/0004-6361/201731808 |
| Popis: | Pulsating extremely low-mass pre-white dwarf stars (pre-ELMV), with masses between ~0.15 Msun and ~0.30 Msun, constitute a new class of variable stars showing g- and possibly p-mode pulsations with periods between 320 and 6000 s, while main sequence delta Scuti stars, with masses between 1.2-2.5 Msun, pulsate in low-order g and p modes with periods in the range [700-28800] s. Interestingly enough, the instability strips of pre-ELM white dwarf and delta Scuti stars nearly overlap in the Teff vs. log g diagram, leading to a degeneracy when spectroscopy is the only tool to classify the stars and pulsation periods only are considered. We employ adiabatic and non-adiabatic pulsation for models of pre-ELM and delta Scuti stars, and compare their pulsation periods, period spacings and rates of period change. We found substantial differences in the periods spacing of delta Scuti and pre-ELM white dwarf models. Even when the same period range is observed, the modes have distinctive signature in the period spacing and period difference values. For instance, the mean period difference of p- modes of consecutive radial orders for delta Scuti model are at least four times longer than the mean period spacing for the pre-ELM white dwarf model in the period range [2000 - 4600] s. In addition, the rate of period change is two orders of magnitudes larger for the pre-ELM white dwarfs compared to delta Scuti stars. In addition, we also report the discovery of a new variable star, SDSSJ075738.94+144827.50, located in the region of the Teff vs. log g diagram where these two kind of stars coexist. The characteristic spacing between modes of consecutive radial orders (p as well as g modes) and the large differences found in the rates of period change for delta Scuti and pre-ELM white dwarf stars suggest that asteroseismology can be employed to discriminate between these two groups of variable stars. Comment: accepted for publication in Astronomy & Astrophysics |
| Databáze: | OpenAIRE |
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