- ID:
- ivo://CDS.VizieR/J/AJ/120/1548
- Title:
- V523 Cas UBVR_C_I_C_ photometry
- Short Name:
- J/AJ/120/1548
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The cool, overcontact, close binary, V523 Cassiopeiae was observed with the 1 m reflector at the US Naval Observatory, Flagstaff Station. The photometry was very good, with a precision on the order of a few millimagnitudes, but not numerous enough for complete light-curve analyses (e.g., differential corrections). A conventional published synthesis has been found acceptable as a fiducial model, and most of the observational weight has been used to develop a spot model for the stars and to support the validity of theoretical limb-darkening coefficients. Both photospheres and chromospheres contribute to the model. This result indicates that multifilter measures of this and similarly cool binaries are necessary for fuller descriptions of stellar activity cycles. A number of newly determined times of minimum light solidify the published rate of period variability.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/other/RAA/17.20
- Title:
- V977 Cep and V982 Cep long-term photometry
- Short Name:
- J/other/RAA/17.2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Long-term BVRI photometric light curves of the pre-main sequence stars V977 Cep and V982 Cep during the period from 2000 October to 2016 August are presented. The stars are located in the vicinity of the reflection nebula NGC 7129. Our photometric data show that both stars exhibit strong photometric variability in all optical passbands, which is typical for Classical T Tauri stars. Using our observational data we analyze the reasons for the observed brightness variations. In the case of V977 Cep we identify previously unknown periodicity in its light curve.
- ID:
- ivo://CDS.VizieR/J/other/RAA/14.1264
- Title:
- V350 Cep UBVRI long-term photometry
- Short Name:
- J/other/RAA/14.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results from UBVRI optical photometric observations of the pre-main sequence star V350 Cep during the period 2004-2014 are presented. The star was discovered in 1977 due to its remarkable increase in brightness by more than 5mag (R). In previous studies, V350 Cep is considered to be a potential FUor or EXor eruptive variable. Our data suggest that during the period of observations the star keeps its maximum brightness with low amplitude photometric variations. Our conclusion is that V350 Cep is probably an intermediate object between FUors and EXors, similar to V1647 Ori.
- ID:
- ivo://CDS.VizieR/J/A+A/350/513
- Title:
- V368 Cep UBVRI time series
- Short Name:
- J/A+A/350/513
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our time series analysis of V368 Cep photometry ascertains the rotation period of 2.74d uniquely. The manifestations of starspot induced luminosity variations in this chromospherically active star include rapid light curve changes and differential rotation of about 3%. We conclude that the single rapidly rotating variable V368 Cep is a high inclination K1V post T Tauri star.
- ID:
- ivo://CDS.VizieR/J/AN/332/616
- Title:
- V444 Cyg BV differential light curves
- Short Name:
- J/AN/332/616
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric and spectroscopic characteristics of the WN5+O6 binary system, V444 Cyg, were studied. The Wilson-Devinney (WD) analysis, using new BV observations carried out at the Ankara University Observatory, revealed the masses, radii, and temperatures of the components of the system as M_WR_=10.64M_{sun}_, M_O_=24.68M_{sun}_, R_WR_=7.19R_{sun}_, R_O_=6.85R_{sun}_, T_WR_=31000K, and T_O_=40000K, respectively. It was found that both components had a full spherical geometry, whereas the circumstellar envelope of the WR component had an asymmetric structure. The O-C analysis of the system revealed a period lengthening of 0.139+/-0.018s/yr, implying a mass loss rate of (6.76+/-0.39)x10^-6^M_{sun}/yr for the WR component. Moreover, 106 IUE-NEWSIPS spectra were obtained from NASA's IUE archive for line identification and determination of line profile variability with phase, wind velocities and variability in continuum fluxes. The integrated continuum flux level (between 1200-2000{AA}) showed a mild and regular increase from orbital phase 0.00 up to 0.50 and then a decrease in the same way back to phase 0.00. This is evaluated as the O component making a constant and regular contribution to the system's UV light as the dominant source. The CIV line, originating in the circumstellar envelope, had the highest velocity while N IV line, originating in deeper layers of the envelope, had the lowest velocity. The average radial velocity calculated by using the CIV line (wind velocity) was found as 2326km/s.
- ID:
- ivo://CDS.VizieR/J/A+A/542/A43
- Title:
- V2493 Cyg BVRI long term photometry
- Short Name:
- J/A+A/542/A43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new results from optical photometric and spectroscopic observations of the eruptive pre-main sequence star V2493 Cyg (HBC 722). The object has continued to undergo significant brightness variations over the past few months and is an ideal target for follow-up observations.
- ID:
- ivo://CDS.VizieR/J/PAZh/41/665
- Title:
- V1016 Cyg light curves and spectroscopy
- Short Name:
- J/PAZh/41/665
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As a result of the next cycle of our long-term monitoring, we present our UBV JHKLM photometry for the symbiotic nova V1016 Cyg in 2008-2014. The star continued to systematically fade and redden in UBV: over this period, the brightness declined by 0.1m in V and by 0.2m in B and U ,the B-V color index increased by 0.1m, and U-B barely changed. On the color-color (U-B, B-V) diagram, the star moved approximately horizontally rightward with a slight bluing in U-B starting from 2000. Our JHKLM photometry has shown a decline in the mean infrared (IR) brightness and a rise in the mean IR color indices after 2004 due to an increase in the optical depth of the dust envelope. The brightness decline and reddening of the Mira in the near infrared reached their extreme values over the entire period of the system's observations by the end of 2014. The pulsation period of the Mira is determined with confidence: P=465+/-5-days. The distance to the Mira, D=2.92+/-0.16kpc, ant its parameters, the radius R*=(470+/-50)R_{sun}_ and luminosity L*=(9200+/=1900)L_{sun}_, have been estimated from the observations of V1016 Cyg at its maximum J brightness and at its minimum J-H color index. The temperature of the star during its pulsations varied within the range T* =2100-2700K. We have estimated the parameters of the dust envelope near its maximum (in 2004) and minimum (in 2012-2014) IR brightness. The mass of the dust envelope almost doubled in ten years, with the rate of dust supply being {Delta}Md~10^-7^M_{sun}_/yr. Using a low-resolution spectrograph, we performed absolute spectrophotometry for V1016 Cyg in 1995-2013 in the range {lambda}4340-7130{AA}. We have shown that almost all absolute fluxes in lines and in continuum at {lambda}4400{AA} decrease monotonically after 2000, while the relative intensities of [OIII], [FeVII], and [CaVII] lines increase after the minimum that probably occurred in the 1990s. The significant (approximately by a factor of 10 from 1995 to 2013) decrease of the flux in the Raman OVI {lambda}6825 line reflects a change of conditions in the formation zone of this line due to the absorption of some OVI {lambda}1032 photons in the newly forming dust envelope of the cool component.
- ID:
- ivo://CDS.VizieR/J/PAZh/42/831
- Title:
- V1027 Cygni UBV and JHKLM photometry
- Short Name:
- J/PAZh/42/831
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of our UBV and JHKLM photometry for the semiregular pulsating variable V1027 Cyg, a supergiant with an infrared excess, over the period from 1997 to 2015 (UBV) and in 2009-2015 (JHKLM). Together with the new data, we analyze the photometric observations of V1027 Cyg that we have obtained and published previously. Our search for a periodicity in the UBV brightness variations has led to several periods from P=212d to 320d in different time intervals. We have found the period P=237d based on our infrared photometry. The variability amplitude, the lightcurve shape, and the magnitude of V1027 Cyg at maximum light change noticeably from cycle to cycle.
- ID:
- ivo://CDS.VizieR/J/PAZh/41/148
- Title:
- V1329 Cyg UBV light curves and spectrum
- Short Name:
- J/PAZh/41/148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The photoelectric UBV observations of the peculiar symbiotic star V1329 Cyg performed at the Crimean Station of the SAI-MSU during 245 nights over the period 2003-2014 are presented. The star's light curves since 1973 from the Crimean observations are shown. The brightness decline after its outburst over the last 40 years was 0.8m-1.0m. The phase color curves at phases 0.2 and 0.8 have maxima. Their qualitative interpretation in terms of the model of interacting winds in symbiotic binary star systems is proposed. The orbital period of the binary system has been redetermined. The spectroscopic observations at the 125-cm telescope of the Crimean Station from 1994 to 2014 have confirmed the change in the system's emission spectrum with orbital phase.
- ID:
- ivo://CDS.VizieR/J/other/NewA/31.32
- Title:
- V729 Cyg UBVRI light curves
- Short Name:
- J/other/NewA/31.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present multicolor photometry of the massive interacting close binary system V729 Cyg. The light variations of V729 Cyg were observed in the Bessel U, B, V, R and I bands over 65 nights between August 2010 and October 2011.
