- ID:
- ivo://CDS.VizieR/J/A+A/403/637
- Title:
- V and R light curves of GSC 3822-1056
- Short Name:
- J/A+A/403/637
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Here we present the first Johnson-Cousins VR_C_ light curves of the over-contact binary star GSC 3822-1056. A period study and the light curve solution are also given. An extremely high rate of period increase +11.6sec/century was found. The origin of this period change can be: (i) partly covered light-time effect due to the orbital motion around the mass center of a possible third body; (ii) mass transfer between the components. The light curve was solved by the 1998 Wilson-Devinney Code. We examined the light curve with and without third light. Both solutions yielded a contact configuration with high temperature difference between the components. Despite the high degree of the contact (f=0.57), the temperature difference between the components {Delta}T=T_primary_-T_secondary_=1045K. The high mass-ratio of the system and its other unusual properties suggest that GSC 3822-1056 may be a recently formed contact binary.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/other/CoSka/40.19
- Title:
- V466 And UBV(RI)c light curves
- Short Name:
- J/other/CoSka/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the UBV(RI)C photometry of a new dwarf nova V466 And, discovered during its superoutburst on Sept. 1.6, 2008 and classified as a WZ Sge-type object. In the first 11 days of the superoutburst, the early superhumps with the period of 0.056383d were found. In days 13-23 of the superoutburst, the ordinary superhumps with the period of 0.05713d were exposed. They were replaced by late superhumps with the period of 0.056d in days 24-33 of the superoutburst. After one month, the dwarf nova returned to its pre-outburst state. A list of known WZ Sge-type dwarf novae, including suspected ones, is presented. We determined a mean value of superhump period excess for WZ Sge-type objects as {epsilon}=0.019+/-0.003. The multicolour photometry of the field stars enables us to conclude that there is no appreciable interstellar extinction in the direction of V466 And.
- ID:
- ivo://CDS.VizieR/J/A+A/403/247
- Title:
- Variability in the ROSAT All-Sky Survey
- Short Name:
- J/A+A/403/247
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a systematic search for variability among the ROSAT All-Sky Survey (RASS) X-ray sources. We generated lightcurves for about 30000 X-ray point sources detected sufficiently high above background. For our variability study different search algorithms were developed in order to recognize flares, periods and trends, respectively. The variable X-ray sources were optically identified with counterparts in the SIMBAD, the USNO-A2.0 and NED data bases, but a significant part of the X-ray sources remains without cataloged optical counterparts. A complete list of the 1207 variable sources we found is presented here.
- ID:
- ivo://CDS.VizieR/J/A+A/461/183
- Title:
- Variability of classical T Tauri
- Short Name:
- J/A+A/461/183
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a study the long term variability of Classical T Tauri stars (CTTS) over up to 20 years, characterize it from a set of statistical parameters and discuss its origin. We characterize the long term photometric variations of 49 CTTs with sufficient data for allowing a robust statistical analysis and propose an empirical classification scheme. Several patterns of long term photometric variability are identified. The most common pattern, exhibited by a group of 15 stars which includes T Tau itself, consists of low level variability (with V-amplitude less than 0.4mag) with no significant changes occurring from season to season over many years. A related subgroup of 22 stars exhibit a similar stable long term variability pattern, though with larger amplitudes (up to 1.6mag). Besides these representative groups, we identify three smaller groups of 3-5 stars each of which have distinctive photometric properties. The long term variability of most CTTS is fairly stable and merely reflects shorter term variability due to cold and hot surface spots. Only a small fraction of CTTS undergo significant brightness changes on the long term (months, years), which probably arise from slowly varying circumstellar extinction.
- ID:
- ivo://CDS.VizieR/J/AZh/78/408
- Title:
- Variability of Cyg X-1 in 1994-1998
- Short Name:
- J/AZh/78/408
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photoelectric UBVR photometry of Cyg X-1 obtained during the coordinated international campaign 'Optical Monitoring of Unique Astrophysical objects', carried out in observatories of CIS countries (Georgia, Kazakhstan, Russia, Uzbekistanin and Ukraine) 1994-1998 is presented. The data are presented as a single set, taking into account systematic differences between individual data sets. In total 2258 UBVR observations were obtained during 407 nights.
- ID:
- ivo://CDS.VizieR/J/PAZh/26/27
- Title:
- Variability of Cyg X-1 (V1357) in 1995-1996
- Short Name:
- J/PAZh/26/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photoelectric UBVR photometry of Cyg X-1 with 1-m Tian'-Shan' and 48-cm Maidanak Observatory reflectors from October 1995 through November 1996 are presented.
- ID:
- ivo://CDS.VizieR/J/PAZh/36/281
- Title:
- Variability of 3 protoplanetary nebulae
- Short Name:
- J/PAZh/36/281
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new photometric data and analyze long-term UBV observations of three candidates for protoplanetary nebulae - F supergiants with infrared excesses at high Galactic latitudes -IRAS 18095+2704, IRAS 19386+0155, and IRAS 19500-1709. All these stars exhibit quasi-periodic low-amplitude variations caused by pulsations against the background of long-term brightness trends. For IRAS 18095+2704 = V887 Her, we have found a pulsation period of 109 days and revealed a linear brightness trend - the star brightens at constant (within the limits of the measurement errors) yearly mean color indices. The light curve of IRAS 19386+0155 = V1648 Aql in 2000-008 is represented by a wave with a fundamental period of 102 days whose modulation with a close period of 98 days leads to variations with a variable amplitude. V1648 Aql also shows a systematic rise in V brightness along with a reddening. IRAS 19500-1709 = V5112 Sgr exhibits irregular pulsations with periods of 39 and 47 days. The long-term variability component of V5112 Sgr may indicate that the star is binary.
1928. Variability of WR 86
- ID:
- ivo://CDS.VizieR/J/A+A/384/1012
- Title:
- Variability of WR 86
- Short Name:
- J/A+A/384/1012
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The tables present photometric monitoring of WR 86 in the Walraven VBLUW system during two nights in July 1989, three nights in May/June 1990 and six nights in June 1990, together with UBV photometry during one night in 1995. Radial velocity measurements of WR86 for six emission lines in 1989, three emission lines in 1995 and two absorption lines in 1995. Equivalent width measurements of WR86 for five emission lines in 1989 and three emission lines in 1995.
- ID:
- ivo://CDS.VizieR/J/A+A/353/77
- Title:
- Variability & polarization of luminous quasars
- Short Name:
- J/A+A/353/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use 250 radio loud quasars with UBV photometry available and z<1.65, to study whether there is a gap in the distribution of absolute magnitudes, from M_V_~-25.8 (for H_0_=100km/s/Mpc, q_0_=0.5) to -25.3, as was suggested by Teerikorpi (1981A&A....98..309T; Paper I). In Paper I it was also proposed that there is a class of the most luminous radio quasars, differing in some properties from fainter quasars on the other side of the gap. The main conclusion of Paper I remains intact. The gap in the distribution of absolute magnitudes is confirmed with the new formalism of cosmological Malmquist bias (Teerikorpi, 1998A&A...339..647T), which allows one to use heterogeneous samples with magnitude inhomogeneity.
- ID:
- ivo://CDS.VizieR/J/AJ/155/39
- Title:
- Variability properties of TIC sources with KELT
- Short Name:
- J/AJ/155/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Kilodegree Extremely Little Telescope (KELT) has been surveying more than 70% of the celestial sphere for nearly a decade. While the primary science goal of the survey is the discovery of transiting, large-radii planets around bright host stars, the survey has collected more than 10^6^ images, with a typical cadence between 10-30 minutes, for more than four million sources with apparent visual magnitudes in the approximate range 7<V<13. Here, we provide a catalog of 52741 objects showing significant large-amplitude fluctuations likely caused by stellar variability, as well as 62229 objects identified with likely stellar rotation periods. The detected variability ranges in rms-amplitude from ~3 mmag to ~2.3 mag, and the detected periods range from ~0.1 to >~2000 days. We provide variability upper limits for all other ~4000000 sources. These upper limits are principally a function of stellar brightness, but we achieve typical 1{sigma} sensitivity on 30 min timescales down to ~5 mmag at V~8, and down to ~43 mmag at V~13. We have matched our catalog to the TESS Input catalog and the AAVSO Variable Star Index to precipitate the follow-up and classification of each source. The catalog is maintained as a living database on the Filtergraph visualization portal at the URL https://filtergraph.com/kelt_vars.
