1RXH J082623.6–505741: A New Long-period Cataclysmic Variable with an Evolved Donor and a Low Mass-transfer Rate

We report the discovery of 1RXH J082623.6−505741, a 10.4 hr orbital period compact binary. Modeling extensive optical photometry and spectroscopy reveals a ∼0.4 M ⊙ K-type secondary transferring mass through a low-state accretion disk to a nonmagnetic ∼0.8 M ⊙ white dwarf. The secondary is overlumin...

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Bibliographic Details
Published in:The Astrophysical journal 2022-08, Vol.934 (2), p.142
Main Authors: Sokolovsky, Kirill V., Strader, Jay, Swihart, Samuel J., Aydi, Elias, Bahramian, Arash, Chomiuk, Laura, Heinke, Craig O., Hughes, Allison K., Li, Kwan-Lok, de Oliveira, Raimundo Lopes, Miller-Jones, James C. A., Mukai, Koji, Sand, David J., Shishkovsky, Laura, Tremou, Evangelia, Voggel, Karina
Format: Article
Language:English
Subjects:
Accretion disks
Astrophysics
Cataclysmic variable stars
Cataclysmic variables
Dwarf novae
Luminosity
Mass transfer
Orbits
Outbursts
Sciences of the Universe
Spectroscopic binary stars
Spectroscopy
Spectrum analysis
White dwarf stars
X-ray binary stars
XMM (spacecraft)
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Summary:We report the discovery of 1RXH J082623.6−505741, a 10.4 hr orbital period compact binary. Modeling extensive optical photometry and spectroscopy reveals a ∼0.4 M ⊙ K-type secondary transferring mass through a low-state accretion disk to a nonmagnetic ∼0.8 M ⊙ white dwarf. The secondary is overluminous for its mass and dominates the optical spectra at all epochs and must be evolved to fill its Roche Lobe at this orbital period. The X-ray luminosity L X ∼ 1–2 × 10 32 erg s −1 derived from both new XMM-Newton and archival observations, although high compared to most CVs, still only requires a modest accretion rate onto the white dwarf of M ̇ ∼ 3 × 10 −11 to 3 × 10 −10 M ⊙ yr −1 , lower than expected for a cataclysmic variable with an evolved secondary. No dwarf nova outbursts have yet been observed from the system, consistent with the low derived mass-transfer rate. Several other cataclysmic variables with similar orbital periods also show unexpectedly low mass-transfer rates, even though selection effects disfavor the discovery of binaries with these properties. This suggests the abundance and evolutionary state of long-period, low mass-transfer rate cataclysmic variables are worthy of additional attention.
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/ac7b25