arXiv subjects

Alexander Tarasenkov

Publications and source records attributed to Alexander Tarasenkov.

2 recordsLinked to original sources

arXiv2025

Photometric Analysis of TCP J20171288$+$1156589 -- WZ Sge Type Dwarf Nova with Delayed Ordinary Superhumps Emergence

We present the results of photometric analysis of WZ Sge type dwarf nova TCP J20171288$+$1156589. This object exhibited an outburst with a large amplitude of $>7.9$ magnitudes and was observed for over a month. The photometric evolution of the superoutburst was atypical for WZ Sge-type dwarf novae. Periodogram analisys reveals early superhumps with the most probable period of $0.0611\pm0.0001$ days during the initial decline. After a plateau phase of approximately 11 days, ordinary superhumps (likely stage B) emerged with a period of $0.0616\pm0.0001$ days, corresponding to a superhump excess of $\epsilon=0.008$ correspondingly. This delay in the onset of ordinary superhumps is an unusual feature among WZ Sge stars. We evaluated the main parameters of the system: mass ratio $q=M_{RD}/M_{WD}=0.06\pm0.005$, yielding component masses of $M_{WD}\sim1.0\pm0.15M_{\odot}$ for the white dwarf and $M_{RD}=0.06\pm0.01M_{\odot}$ for the donor. The estimated distance to the system is $\sim850$ pc, and the binary separation is $a=0.67\pm0.03R_{\odot}$.

astro-ph.SR↗

arXiv2025

TCP J07222683$+$6220548: a new AM CVn type system with infrequent outbursts

We present the discovery of TCP J07222683$+$6220548, a new ultracompact binary system of the AM CVn type. This system was first identified displaying a $\Delta V = 7.6$ mag outburst on 2025-01-20.9416 UTC by the New Milky Way wide-field survey for transients and later independently detected by ASAS-SN and ZTF. The outburst peaked at $V_{\rm max} = 12.45$ and lasted for seven days, followed by a series of rebrightenings. No previous outbursts are found in archival data. Positive superhumps with a period of $0.032546 \pm 0.000084$ d ($46.87 \pm 0.12$ min), barely detectable during the main outburst, became clearly visible during the first rebrightening that lasted from day 18 to day 24 after the initial outburst. No convincing change in the superhump period was detected. Dense time-series photometry follow-up by a pair of 0.5-m INASAN robotic telescopes, together with VSNET and AAVSO observers, was essential for identifying TCP J07222683$+$6220548 as an AM CVn system and triggering confirmation spectroscopy with the 2.5-m CMO SAI telescope. Some outbursting AM CVn systems lacking such detailed follow-up may remain unrecognized among the newly discovered cataclysmic variable candidates.

astro-ph.SR↗