The discovery of binary white dwarfs that will merge within 500 Myr

We present radial velocity observations of four extremely low-mass (0.2 M⊙) white dwarfs (WDs). All four stars show peak-to-peak radial velocity variations of 540-710kms-1 with 1.0-5.9hr periods. The optical photometry rules out main-sequence companions. In addition, no millisecond pulsar companions...

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Detalles Bibliográficos
Autores principales: Kilic, M., Brown, W.R., Allende Prieto, C., Kenyon, S.J., Panei, Jorge Alejandro
Formato: Articulo
Lenguaje:Inglés
Publicado: 2010
Materias:
Ciencias Astronómicas
Stars: low-mass
White dwarfs
SDSS J082212.57+275307.4
SDSS J084910.13+044528.7
SDSS J105353.89+520031.0
SDSS J143633.29+501026.8
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/82486
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-82486
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: low-mass
White dwarfs
SDSS J082212.57+275307.4
SDSS J084910.13+044528.7
SDSS J105353.89+520031.0
SDSS J143633.29+501026.8
spellingShingle Ciencias Astronómicas
Stars: low-mass
White dwarfs
SDSS J082212.57+275307.4
SDSS J084910.13+044528.7
SDSS J105353.89+520031.0
SDSS J143633.29+501026.8
Kilic, M.
Brown, W.R.
Allende Prieto, C.
Kenyon, S.J.
Panei, Jorge Alejandro
The discovery of binary white dwarfs that will merge within 500 Myr
topic_facet Ciencias Astronómicas
Stars: low-mass
White dwarfs
SDSS J082212.57+275307.4
SDSS J084910.13+044528.7
SDSS J105353.89+520031.0
SDSS J143633.29+501026.8
description We present radial velocity observations of four extremely low-mass (0.2 M⊙) white dwarfs (WDs). All four stars show peak-to-peak radial velocity variations of 540-710kms-1 with 1.0-5.9hr periods. The optical photometry rules out main-sequence companions. In addition, no millisecond pulsar companions are detected in radio observations. Thus, the invisible companions are most likely WDs. Two of the systems are the shortest period binary WDs yet discovered. Due to the loss of angular momentum through gravitational radiation, three of the systems will merge within 500Myr. The remaining system will merge within a Hubble time. The mass functions for three of the systems imply companions more massive than 0.46 M⊙; thus, those are carbon/oxygen core WDs. The unknown inclination angles prohibit a definitive conclusion about the future of these systems. However, the chance of a supernova Ia event is only 1%-5%. These systems are likely to form single R Coronae Borealis stars, providing evidence for a WD + WD merger mechanism for these unusual objects. One of the systems, SDSS J105353.89+520031.0, has a 70% chance of having a low-mass WD companion. This system will probably form a single helium-enriched subdwarf O star. All four WD systems have unusual mass ratios of ≤0.2-0.8 that may also lead to the formation of AM CVn systems.
format Articulo
Articulo
author Kilic, M.
Brown, W.R.
Allende Prieto, C.
Kenyon, S.J.
Panei, Jorge Alejandro
author_facet Kilic, M.
Brown, W.R.
Allende Prieto, C.
Kenyon, S.J.
Panei, Jorge Alejandro
author_sort Kilic, M.
title The discovery of binary white dwarfs that will merge within 500 Myr
title_short The discovery of binary white dwarfs that will merge within 500 Myr
title_full The discovery of binary white dwarfs that will merge within 500 Myr
title_fullStr The discovery of binary white dwarfs that will merge within 500 Myr
title_full_unstemmed The discovery of binary white dwarfs that will merge within 500 Myr
title_sort discovery of binary white dwarfs that will merge within 500 myr
publishDate 2010
url http://sedici.unlp.edu.ar/handle/10915/82486
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