The diffusion-induced nova scenario: CK Vul and PB8 as possible observational counterparts

We propose a scenario for the formation of DA white dwarfs with very thin helium buffers. For these stars we explore the possible occurrence of diffusion-induced CNO-flashes during their early cooling stage. In order to obtain very thin helium buffers, we simulate the formation of low-mass remnants...

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Detalles Bibliográficos
Autores principales: Miller Bertolami, Marcelo Miguel, Althaus, Leandro Gabriel, Olano, Carlos Alberto, Jiménez, Noelia
Formato: Articulo
Lenguaje:Inglés
Publicado: 2011
Materias:
Ciencias Astronómicas
Stars: AGB and post-AGB
Stars: individual: CK Vul
Stars: individual: PB8
Stars: Wolf-Rayet
White dwarfs
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/83994
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-83994
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Astronómicas
Stars: AGB and post-AGB
Stars: individual: CK Vul
Stars: individual: PB8
Stars: Wolf-Rayet
White dwarfs
spellingShingle Ciencias Astronómicas
Stars: AGB and post-AGB
Stars: individual: CK Vul
Stars: individual: PB8
Stars: Wolf-Rayet
White dwarfs
Miller Bertolami, Marcelo Miguel
Althaus, Leandro Gabriel
Olano, Carlos Alberto
Jiménez, Noelia
The diffusion-induced nova scenario: CK Vul and PB8 as possible observational counterparts
topic_facet Ciencias Astronómicas
Stars: AGB and post-AGB
Stars: individual: CK Vul
Stars: individual: PB8
Stars: Wolf-Rayet
White dwarfs
description We propose a scenario for the formation of DA white dwarfs with very thin helium buffers. For these stars we explore the possible occurrence of diffusion-induced CNO-flashes during their early cooling stage. In order to obtain very thin helium buffers, we simulate the formation of low-mass remnants through an asymptotic giant branch (AGB) final/late thermal pulse (AFTP/LTP scenario). Then we calculate the consequent white dwarf cooling evolution by means of a consistent treatment of element diffusion and nuclear burning. Based on physically sound white dwarf models, we find that the range of helium buffer masses for these diffusion-induced novae to occur is significantly smaller than that predicted by the only previous study of this scenario. As a matter of fact, we find that these flashes do occur only in some low-mass (M ≲ 0.6M⊙) and low-metallicity (ZZAMS ≲ 0.001) remnants about 106-107yr after departing from the AGB. For these objects, we expect the luminosity to increase by about 4 orders of magnitude in less than a decade. We also show that diffusion-induced novae should display a very typical eruption light curve, with an increase of about a few magnitudes per year before reaching a maximum ofMV~-5 to -6. Our simulations show that surface abundances after the outburst are characterized by logNH/NHe~-0.15...0.6 and N > C ≳ O by mass fractions. Contrary to previous speculations we show that these events are not recurrent and do not change substantially the final H-content of the cool (DA) white dwarf. Finally, with the aid of model predictions we discuss the possibility that Nova Vul 1670 (CK Vul) and the recently proposed [WN/WC]-central stars of planetary nebulae could be observational counterparts of this diffusion-induced nova scenario. We conclude that, despite discrepancies with observations, the scenario offers one of the best available explanations for CK Vul and, with minor modifications, explains the observed properties of [WN/WC]-central stars of planetary nebulae.
format Articulo
Articulo
author Miller Bertolami, Marcelo Miguel
Althaus, Leandro Gabriel
Olano, Carlos Alberto
Jiménez, Noelia
author_facet Miller Bertolami, Marcelo Miguel
Althaus, Leandro Gabriel
Olano, Carlos Alberto
Jiménez, Noelia
author_sort Miller Bertolami, Marcelo Miguel
title The diffusion-induced nova scenario: CK Vul and PB8 as possible observational counterparts
title_short The diffusion-induced nova scenario: CK Vul and PB8 as possible observational counterparts
title_full The diffusion-induced nova scenario: CK Vul and PB8 as possible observational counterparts
title_fullStr The diffusion-induced nova scenario: CK Vul and PB8 as possible observational counterparts
title_full_unstemmed The diffusion-induced nova scenario: CK Vul and PB8 as possible observational counterparts
title_sort diffusion-induced nova scenario: ck vul and pb8 as possible observational counterparts
publishDate 2011
url http://sedici.unlp.edu.ar/handle/10915/83994
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