- ID:
- ivo://CDS.VizieR/J/A+A/652/A49
- Title:
- CzeV404 Her light curves and spectra
- Short Name:
- J/A+A/652/A49
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present a new study of the eclipsing cataclysmic variable CzeV404 Her (Porb=0.098d) located in the period gap. This report aims to determine the object's origin, system parameters and probe the system's accretion flow structure. We conducted simultaneous time-resolved photometric and spectroscopic observations of CzeV404 Her. We applied our light curve modeling techniques and the Doppler tomography method to determine the system parameters and analyse the structure of the accretion disk. We found that the system has a massive white dwarf M_WD_=1.00(2)M_{sun}_, a mass ratio of q=0.16, and a relatively hot secondary with an effective temperature T_2_=4100(50)K. The system inclination is 78{deg}. The accretion disk spreads out to the tidal limitation radius and has an extended hot spot/line region. The hot spot/line is hotter than the rest of the disk's outer part in quiescence or intermediate state but does not stand out completely from the disk flux in (super)outbursts. We claim that this object represents a link between two distinct classes of SU UMa-type and SW Sex-type cataclysmic variables. The accretion flow structure in the disk corresponds to the SW Sex systems, but the physical conditions inside the disk passed into behaviors of SU UMa-type objects.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/492/L40
- Title:
- Disentangling cataclysmic variables in Gaia DR2
- Short Name:
- J/MNRAS/492/L40
- Date:
- 07 Dec 2021 09:36:41
- Publisher:
- CDS
- Description:
- Cataclysmic Variables (CVs) are interacting binaries consisting of at least three components that control their colour and magnitude. Using Gaia we here investigate the influence of the physical properties of these binaries on their position in the Hertzsprung-Russell diagram (HR-diagram). The CVs are on average located between the main sequence and the white dwarf regime, the maximum density being at G_BP_-G_RP_~=0.56 and G_abs_~10.15. We nd a trend of the orbital period with colour and absolute brightness: with decreasing period, the CVs become bluer and fainter. We also identify the location of the various CV sub-types in the HR-diagram and discuss the possible location of detached CVs, going through the orbital period gap.
- ID:
- ivo://CDS.VizieR/J/AJ/141/122
- Title:
- DK Lac V light curves
- Short Name:
- J/AJ/141/122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on extensive photometry of DK Lac obtained during the interval 1990-2009, which includes a 2mag low state during 2001-2003. Much of the photometry consists of exposures obtained with a typical spacing of several days, but also includes 26 sequences of continuous photometry each lasting 2-7hr. We find no evidence for periodicities in our data.
- ID:
- ivo://CDS.VizieR/J/MNRAS/460/2526
- Title:
- Dwarf novae outbursts properties
- Short Name:
- J/MNRAS/460/2526
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a statistical study of all measurable photometric features of a large sample of dwarf novae during their outbursts and superoutbursts. We used all accessible photometric data for all our objects to make the study as complete and up to date as possible. Our aim was to check correlations between these photometric features in order to constrain theoretical models which try to explain the nature of dwarf novae outbursts. We managed to confirm a few of the known correlations, that is the Stolz and Schoembs relation, the Bailey relation for long outbursts above the period gap, the relations between the cycle and supercycle lengths, amplitudes of normal and superoutbursts, amplitude and duration of superoutbursts, outburst duration and orbital period, outburst duration and mass ratio for short and normal outbursts, as well as the relation between the rise and decline rates of superoutbursts. However, we question the existence of the Kukarkin-Parenago relation but we found an analogous relation for superoutbursts. We also failed to find one presumed relation between outburst duration and mass ratio for superoutbursts. This study should help to direct theoretical work dedicated to dwarf novae.
- ID:
- ivo://CDS.VizieR/J/MNRAS/494/4110
- Title:
- DW Cnc H{alpha} and HeI RV curves
- Short Name:
- J/MNRAS/494/4110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present extensive radial velocity observations of the intermediate polar DW Cnc during its 2018-2019 low state. We show that the 86 min signal associated with the orbital period is strong in our radial velocity analysis, power spectrum search, and in our Doppler tomography. However, we find that the velocity modulation associated with the 70 min beat period and the 38 min spin cycle is dramatically weaker than that previously observed. We put forward two interpretations for this change. The first is that a sudden drop into a low state detected in 2018-2019 caused an episode of low mass transfer from the companion, thus inhibiting the lighthouse effect produced by the rebound emission. The second is that this is a consequence of a rare outburst detected in 2007 by Crawford et al. (2008, J. Am. Assoc. Var. Star Obs., 36, 60). We find this post-outburst hypothesis to be less likely. If the first scenario is correct, we predict that DW Cnc will recover its intermediate polar characteristics. A new ephemeris is presented by combining Patterson et al. (2004PASP..116..516P) radial velocities with ours.
- ID:
- ivo://CDS.VizieR/J/A+A/459/875
- Title:
- Early spectral evolution of Nova Sgr 2004
- Short Name:
- J/A+A/459/875
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical and near-infrared spectral evolution of the Galactic nova V5114 Sgr (2004) during few months after the outburst. We use multi-band photometry and line intensities derived from spectroscopy to put constrains on the distance and the physical conditions of the ejecta of V5114 Sgr.
- ID:
- ivo://CDS.VizieR/J/MNRAS/461/1576
- Title:
- EX Hya mid-eclipse timings
- Short Name:
- J/MNRAS/461/1576
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A study on the intermediate polar EX Hya is presented, based on simultaneous photometry and high-dispersion spectroscopic observations, during four consecutive nights. The strong photometric modulation related to the 67-min spin period of the primary star is clearly present, as well as the narrow eclipses associated with the orbital modulation. Since our eclipse timings have been obtained almost 91000 cycles since the last reported observations, we present new linear ephemeris, although we cannot rule out a sinusoidal variation suggested by previous authors.
- ID:
- ivo://CDS.VizieR/J/MNRAS/421/2414
- Title:
- Faint cataclysmic variables from SDSS
- Short Name:
- J/MNRAS/421/2414
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-speed photometric observations of 20 faint cataclysmic variables (CVs) selected from the Sloan Digital Sky Survey (SDSS) and Catalina catalogues. Measurements are given of 15 new directly measured orbital periods, including four eclipsing dwarf novae (SDSS 0904+03, CSS 0826-00, CSS 1404-10 and CSS 1626-12), two new polars (CSS 0810+00 and CSS 1503-22) and two dwarf novae with superhumps in quiescence (CSS 0322+02 and CSS 0826-00). Whilst most of the dwarf novae presented here have periods below 2h, SDSS 0805+07 and SSS 0617-36 have relatively long orbital periods of 5.489 and 3.440h, respectively. The double-humped orbital modulations observed in SSS 0221-26, CSS 0345-01, CSS 1300+11 and CSS 1443-17 are typical of low-mass transfer rate dwarf novae. The white dwarf primary of SDSS 0919+08 is confirmed to have non-radial oscillations, and quasi-periodic oscillations were observed in the short-period dwarf nova CSS 1028-08 during outburst. We further report the detection of a new nova-like variable (SDSS 1519+06). The frequency distribution of orbital periods of CVs in the Catalina Real-time Transient Survey (CRTS) has a high peak near ~80min orbital period, independently confirming that found by Gansicke et al. (2009MNRAS.397.2170G) from SDSS sources. We also observe a marked correlation between the median in the orbital period distribution and the outburst class, in the sense that dwarf novae with a single observed outburst (over the 5-year baseline of the CRTS coverage) occur predominantly at shortest orbital period.
- ID:
- ivo://CDS.VizieR/J/MNRAS/443/3174
- Title:
- 72 faint CV candidates in CRTS
- Short Name:
- J/MNRAS/443/3174
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Over six years of operation, the Catalina Real-time Transient Survey (CRTS) has identified 1043 cataclysmic variable (CV) candidates - the largest sample of CVs from a single survey to date. Here, we provide spectroscopic identification of 85 systems fainter than g>=19, including three AM Canum Venaticorum binaries, one helium-enriched CV, one polar and one new eclipsing CV. We analyse the outburst properties of the full sample and show that it contains a large fraction of low-accretion-rate CVs with long outburst recurrence times. We argue that most of the high-accretion-rate dwarf novae in the survey footprint have already been found and that future CRTS discoveries will be mostly low-accretion-rate systems. We find that CVs with white-dwarf-dominated spectra have significantly fewer outbursts in their CRTS light curves compared to disc-dominated CVs, reflecting the difference in their accretion rates. Comparing the CRTS sample to other samples of CVs, we estimate the overall external completeness to be 23.6 per cent, but show that as much as 56 per cent of CVs have variability amplitudes that are too small to be selected using the transient selection criteria employed by current ground-based surveys. The full table of CRTS CVs, including their outburst and spectroscopic properties examined in this paper, is provided in the online materials.
- ID:
- ivo://CDS.VizieR/J/A+A/644/A49
- Title:
- Gaia18aen light and velocity curves
- Short Name:
- J/A+A/644/A49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Besides the astrometric mission of the Gaia satellite, its repeated and high-precision measurements also serve as an all-sky photometric transient survey. The sudden brightenings of the sources are published as Gaia Photometric Science Alerts and are made publicly available, allowing the community to photometrically and spectroscopically follow up on the object. The goal of this paper is to analyze the nature and derive the basic parameters of Gaia18aen, a transient detected at the beginning of 2018. This object coincides with the position of the emission-line star WRAY 15-136. The brightening was classified as a "nova?" on the basis of a subsequent spectroscopic observation. We analyzed two spectra of Gaia18aen and collected the available photometry of the object covering the brightenings in 2018 and also the preceding and following periods of quiescence. Based on this observational data, we derived the parameters of Gaia18aen and discussed the nature of the object. Gaia18aen is the first symbiotic star discovered by Gaia satellite. The system is an S-type symbiotic star and consists of an M giant of a slightly super-solar metallicity, where Teff~3500K, a radius of ~230R_{sun}_, and a high luminosity L~7400L_{sun}_. The hot component is a hot white dwarf. We tentatively determined the orbital period of the system 487d. The main outburst of Gaia18aen in 2018 was accompanied by a decrease in the temperature of the hot component. The first phase of the outburst was characterized by the high luminosity L~27000L_{sun}_, which remained constant for about three weeks after the optical maximum, later followed by the gradual decline of luminosity and increase of temperature. Several re-brightenings have been detected on the timescales of hundreds of days.
