arXiv subjects

Pavol Dubovsky

Publications and source records attributed to Pavol Dubovsky.

6 recordsLinked to original sources

arXiv2026

Spectroscopic Analysis of the 2025 Eclipse of the Symbiotic Binary V1413 Aquilae

We report on a coordinated campaign by amateur astronomers using a combination of high and low resolution spectroscopy to observe the 2025 eclipse of the symbiotic binary V1413 Aql shortly after a probable Z And-type symbiotic outburst. We measured the eclipse time of minimum and computed an updated eclipse ephemeris. Our spectra were calibrated in absolute flux and multi-Gaussian fits were used to resolve and quantify components of the H{\alpha} emission line. We measured the radial velocity curve of the white dwarf and determined the semi-amplitude as 25.7 km/s and the systemic radial velocity as 95.1 km/s. We found the spectral continuum was consistent with that of a late F or early G type giant star.

astro-ph.SR↗

arXiv2022

The Periodic Signals of Nova V1674 Herculis (2021)

We present time-series photometry during eruption of the extremely fast nova V1674 Herculis (Nova Her 2021). The 2021 light curve showed periodic signals at 0.152921(3) d and 501.486(5) s, which we interpret as respectively the orbital and white dwarf spin-periods in the underlying binary. We also detected a sideband signal at the /difference/ frequency between these two clocks. During the first 15 days of outburst, the spin-period appears to have increased by 0.014(1)%. This increase probably arose from the sudden loss of high-angular-momentum gas ("the nova explosion") from the rotating, magnetic white dwarf. Both periodic signals appeared remarkably early in the outburst, which we attribute to the extreme speed with which the nova evolved (and became transparent to radiation from the inner binary). After that very fast initial increase of ~71 ms, the spin-period commenced a steady decrease of ~160 ms/year -- about 100x faster than usually seen in intermediate polars. This is probably due to high accretion torques from very high mass-transfer rates, which might be common when low-mass donor stars are strongly irradiated by a nova outburst.

astro-ph.SR↗

arXiv2015

Results of a campaign to observe outbursts of the dwarf nova CSS 121005:212625+201948

A monitoring programme of CSS 121005:212625+201948 covering nearly two observing seasons has shown that it is a typical SU UMa dwarf nova, but it has one of the shortest supercycles of its class, at 66.9(6) d. The superoutbursts are interspersed with 3 to 7 short duration (~2 days) normal outbursts each of which are separated by a mean interval of 11 days, but can be as short as 2 days. The most intensively studied superoutburst was that of 2014 November, which lasted 14 days and had an outburst amplitude of >4.8 magnitudes, reaching magnitude 15.7 at its brightest. Time resolved photometry revealed superhumps with a peak-to-peak amplitude of 0.2 magnitudes, later declining to 0.1 magnitude. The superhump period was Psh = 0.08838(18) d. Time resolved photometry was conducted during several other superoutbursts, which gave broadly similar results.

astro-ph.SR↗

arXiv2014

Optical outbursts of the cataclysmic variable 1RXS J140429.5+172352

We present the nine-year light curve of the cataclysmic variable 1RXS J140429.5+172352 from 2005 April to 2014 July. We identified four dwarf nova-like outbursts, which typically lasted 3 to 5 days, with an amplitude of 3.1 to 5.3 magnitudes. Time resolved photometry during two outbursts revealed small hump-like structures with peak-to-peak amplitude up to 0.5 mag. They occurred on timescales of 20 min to an hour, but did not exhibit a stable period. We suggest that the system might be an Intermediate Polar.

astro-ph.SR↗

arXiv2013

Is There a Third Component in the Intermediate Polar V405 Aur?

Variability of the spin period of the white dwarf in the V405 Aur (RX J0558.0+5353) system using our observations and previously published maxima timings is analyzed. As the phase light curve contains two nearly equal photometric waves, one maximum was set as a "primary" one. The ephemeris for the maxima of the "spin variability" (due to rotation of the magnetized white dwarf) for recent seasons 2010-2012 is Tmax = HJD 2455882.470614(25)+0.00631314602(46)E. This corresponds to a significant negative trend at the "O-C" diagram. Due to significant gaps in the observational data and statistical error of timings, there may be some suggestions on the spin period variability - a fast period "jump" in 2007y; secular period variations; a cubic ephemeris (which may be interpreted by a precession of the magnetic white dwarf at a time-scale of decades) or a periodic change with a period of 6.2 years and semi-amplitude of 17.2\pm1.8 sec. For the present observations, more reliable are two latter models. To distinguish between them, a continuation of monitoring is needed. The periodic variations may be interpreted by a light time effect caused by a third body of mass (M3 > 0.09M\odot), which corresponds to a low-mass star, but not to an extra-solar planet. In this case, the system belongs to a rare class of cataclysmic variables with a third body.

astro-ph.SR↗

arXiv2012

Photometric Study of Two Recently Discovered Variable Stars in the Field of BS Cas

Two recently discovered variable stars (CzeV134 = GSC 3682 0018 = USNO-A2.0 1425-1870026 and CzeV135 = GSC 3682 2051 = USNO-A2.0 1425-1825909 = V1094 Cas), which have been identified in the field of the W UMa variable star BS Cas, are studied in the present paper. The phase curves and finding charts for these stars are presented. The ephemeris and other photometric parameters were computed. The phenomenological features indicate that the first star (CzeV134) is probably a low-amplitude RRc Lyrae - type variable star with the period P = 0.419794\pm0.000029 d and the initial epoch T0 = HJD2453236.50412\pm0.00056. The amplitude and the shape of the light curve are variable possibly indicating the Blazhko phenomenon. The second star (CzeV135) was classified as an EW-type binary system of subtype A. However, a β Lyrae type may not be excluded, as various classification parameters lie in a range of overlapping values for both classes. The period P=0.51429090\pm0.00000012 d and the initial epoch T0 = HJD2454543.7920\pm0.0006. The O'Connell effect is clearly visible. There are slight changes of this effect, noticeable while comparing different seasons of observations. O-C diagrams for these stars were analyzed.

astro-ph.SR↗