4.7 Article

OGLE-BLG504.12.201843: a possible extreme dwarf nova

Journal

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Volume 517, Issue 2, Pages 2746-2756

Publisher

OXFORD UNIV PRESS
DOI: 10.1093/mnras/stac2864

Keywords

accretion, accretion discs; (stars: ) binaries (including multiple): close; stars: dwarf novae; (stars:) novae, cataclysmic variables

Funding

  1. INTER-EXCELLENCE grant from the Ministry of Education, Youth, and Sports [LTAUSA18093]
  2. Horizon 2020 ERC Starting Grant 'Cat-In-hAT' [803158]
  3. SONATINA grant from the Polish National Science Center [2020/36/C/ST9/00103]
  4. ANID through the FONDECYT regular grant [1191038]
  5. ANID through the Millennium Science Initiative grant [ICN12_009]
  6. Packard Foundation
  7. National Key R&D Program of China [2019YFA0405100]
  8. National Natural Science Foundation of China [12133005]
  9. XPLORER PRIZE
  10. Chilean Time Allocation Committee (CNTAC) [CN2017B-85]
  11. NSF [AST-0407380, AST-0909073, AST-1313370]

Ask authors/readers for more resources

This study analyzes the optical photometry and spectroscopy of the candidate cataclysmic variable star OGLE-BLG504.12.201843. It reveals that the object is an extreme U Gem-type dwarf nova with year-long outbursts originating from an accretion disc. The object gradually brightens before the outburst and exhibits peculiar spectral features during outbursts. It is suggested that OGLE-BLG504.12.201843 is an excellent object for further studies due to its extreme properties.
We present the analysis of existing optical photometry and new optical spectroscopy of the candidate cataclysmic variable star OGLE-BLG504.12.201843. As was shown previously, this object has an orbital period of 0.523419 d and exhibits year-long outbursts with a mean period of 973 d. Using digitized photographic archives, we show that the earliest recorded outburst occurred in 1910. We propose that this object is a U Gem-type dwarf nova (DN) with extreme properties. The orbital variability of the system in outburst shows clear signs of an accretion disc, from which the outburst likely originates. During quiescence, the object slowly brightens by up to 0.75 mag in the I band over 600 d before the outburst and exhibits small flares with amplitude less than or similar to 2 mag in the I band. We interpret the gradual brightening as an increase in the luminosity and temperature of the accretion disc, which is theoretically predicted but only rarely seen in DNe. The origin of small flares remains unexplained. The spectra show Balmer absorption lines both in quiescence and outburst, which can be associated with a bright secondary star or a cold accretion disc. During outbursts, emission lines with full width at half-maximum of about 450 km s(-1) appear; however, they lack typical double-peaked profiles. We suggest that either these lines originate in the disc winds or the orbital inclination is low, the latter being consistent with constrains obtained from the orbital variability of the system. Due to its extreme properties and peculiarities, OGLE-BLG504.12.201843 is an excellent object for further follow-up studies.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.7
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available