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OGLE-BLG504.12.201843: a possible extreme dwarf nova

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dc.abstract.enWe 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 ≲0.2 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<SUP>-1</SUP> 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.
dc.affiliationUniwersytet Warszawski
dc.contributor.authorLandri, Camille
dc.contributor.authorPejcha, Ondrej
dc.contributor.authorPawlak, Michał
dc.contributor.authorUdalski, Andrzej
dc.contributor.authorPrieto, Jose L.
dc.contributor.authorBarrientos, Manuel
dc.contributor.authorStrader, Jay
dc.contributor.authorDong, Subo
dc.date.accessioned2024-01-25T15:43:28Z
dc.date.available2024-01-25T15:43:28Z
dc.date.copyright2022-10-03
dc.date.issued2022
dc.description.accesstimeBEFORE_PUBLICATION
dc.description.financePublikacja bezkosztowa
dc.description.number2
dc.description.versionORIGINAL_AUTHOR
dc.description.volume517
dc.identifier.doi10.1093/MNRAS/STAC2864
dc.identifier.issn0035-8711
dc.identifier.urihttps://repozytorium.uw.edu.pl//handle/item/114538
dc.identifier.weblinkhttp://adsabs.harvard.edu/abs/2022MNRAS.517.2746L
dc.languageeng
dc.pbn.affiliationastronomy
dc.relation.ispartofMonthly Notices of the Royal Astronomical Society
dc.relation.pages2746-2756
dc.rightsOther
dc.sciencecloudnosend
dc.titleOGLE-BLG504.12.201843: a possible extreme dwarf nova
dc.typeJournalArticle
dspace.entity.typePublication