A young contracting white dwarf in the peculiar binary HD 49798/RX J0648.0-4418?
Date Issued
2018
Author(s)
Abstract
HD 49798/RX J0648.0-4418 is a peculiar X-ray binary with a hot subdwarf (sdO) mass donor. The nature of the accreting compact object is not known, but its spin period P = 13.2 s and \dot{P} =-2.15 × 10^{-15} s s-1 proves that it can be only either a white dwarf or a neutron star. The spin-up has been very stable for more than 20 yr. We demonstrate that the continuous stable spin-up of the compact companion of HD 49798 can be best explained by contraction of a young white dwarf with an age ∼2 Myr. This allows us to interpret all the basic parameters of the system in the framework of an accreting white dwarf. We present examples of binary evolution, which result in such systems. If correct, this is the first direct evidence for a white dwarf contraction in early evolutionary stages.
Volume
474
Issue
2
Start page
2750
Issn Identifier
0035-8711
Ads BibCode
2018MNRAS.474.2750P
Rights
open.access
File(s)![Thumbnail Image]()
Loading...
Name
popov_etal2018.pdf
Description
Pdf editoriale
Size
1.01 MB
Format
Adobe PDF
Checksum (MD5)
928325b576389a725913931f4de4078d