Search: onr:"swepub:oai:DiVA.org:su-180134" >
The OmegaWhite Surv...
The OmegaWhite Survey for Short-period Variable Stars. V. Discovery of an Ultracompact Hot Subdwarf Binary with a Compact Companion in a 44-minute Orbit
-
Kupfer, T. (author)
-
Ramsay, G. (author)
-
van Roestel, J. (author)
-
show more...
-
Brooks, J. (author)
-
MacFarlane, S. A. (author)
-
Toma, R. (author)
-
Groot, P. J. (author)
-
Woudt, P. A. (author)
-
Bildsten, L. (author)
-
Marsh, T. R. (author)
-
Green, M. J. (author)
-
Breedt, E. (author)
-
Kilkenny, D. (author)
-
Freudenthal, J. (author)
-
Geier, S. (author)
-
Heber, U. (author)
-
Bagnulo, S. (author)
-
Blagorodnova, N. (author)
-
Buckley, D. A. H. (author)
-
Dhillon, V. S. (author)
-
Kulkarni, S. R. (author)
-
- Lunnan, Ragnhild (author)
- Stockholms universitet,Institutionen för astronomi,Oskar Klein-centrum för kosmopartikelfysik (OKC),California Institute of Technology, USA
-
Prince, T. A. (author)
-
show less...
-
(creator_code:org_t)
- 2017-12-07
- 2017
- English.
-
In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 851:1
- Related links:
-
https://authors.libr...
-
show more...
-
https://urn.kb.se/re...
-
https://doi.org/10.3...
-
show less...
Abstract
Subject headings
Close
- We report the discovery of the ultracompact hot subdwarf (sdOB) binary OW J074106.0-294811.0 with an orbital period of P-orb = 44.66279 +/- 1.16 x 10(-4) minutes, making it the most compact hot subdwarf binary known. Spectroscopic observations using the VLT, Gemini and Keck telescopes revealed a He-sdOB primary with an intermediate helium abundance, T-eff = 39 400 +/- 500 K and log g = 5.74 +/- 0.09. High signal-to-noise ratio light curves show strong ellipsoidal modulation resulting in a derived sdOB mass M-sdOB= 0.23 +/- 0.12 M-circle dot with a WD companion (M-WD = 0.72 +/- 0.17 M-circle dot). The mass ratio was found to be q = M-sdOB/M-WD = 0.32 +/- 0.10. The derived mass for the He-sdOB is inconsistent with the canonical mass for hot subdwarfs of approximate to 0.47 M-circle dot. To put constraints on the structure and evolutionary history of the sdOB star we compared the derived T-eff, log g, and sdOB mass to evolutionary tracks of helium stars and helium white dwarfs calculated with Modules for Experiments in Stellar Astrophysics (MESA). We find that the best-fitting model is a helium white dwarf with a mass of 0.320 M-circle dot, which left the common envelope approximate to 1.1 Myr ago, which is consistent with the observations. As a helium white dwarf with a massive white dwarf companion, the object will reach contact in 17.6 Myr at an orbital period of 5 minutes. Depending on the spin-orbit synchronization timescale the object will either merge to form an R CrB star or end up as a stably accreting AM CVn-type system with a helium white dwarf donor.
Subject headings
- NATURVETENSKAP -- Fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences (hsv//eng)
Keyword
- binaries (including multiple): close
- stars: individual (OWJ074106.0-294811.0)
- subdwarfs
- white dwarfs
Publication and Content Type
- ref (subject category)
- art (subject category)
Find in a library
To the university's database
- By the author/editor
-
Kupfer, T.
-
Ramsay, G.
-
van Roestel, J.
-
Brooks, J.
-
MacFarlane, S. A ...
-
Toma, R.
-
show more...
-
Groot, P. J.
-
Woudt, P. A.
-
Bildsten, L.
-
Marsh, T. R.
-
Green, M. J.
-
Breedt, E.
-
Kilkenny, D.
-
Freudenthal, J.
-
Geier, S.
-
Heber, U.
-
Bagnulo, S.
-
Blagorodnova, N.
-
Buckley, D. A. H ...
-
Dhillon, V. S.
-
Kulkarni, S. R.
-
Lunnan, Ragnhild
-
Prince, T. A.
-
show less...
- About the subject
-
- NATURAL SCIENCES
-
NATURAL SCIENCES
-
and Physical Science ...
- Articles in the publication
-
Astrophysical Jo ...
- By the university
-
Stockholm University