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24391. VR photometry of type II Cepheids. III
ID:
ivo://CDS.VizieR/J/AJ/130/832
Title:
VR photometry of type II Cepheids. III
Short Name:
J/AJ/130/832
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present 741 new photometric observations for 22 Cepheids with periods between 3 and 8 days. Many of the stars are probable type II Cepheids, but we have included some type I Cepheids for comparison.
24392. VR + velocity variations of IRAS 11472-0800
ID:
ivo://CDS.VizieR/J/A+A/542/A53
Title:
VR + velocity variations of IRAS 11472-0800
Short Name:
J/A+A/542/A53
Date:
21 Oct 2021
Publisher:
CDS
Description:
We focus here on one particular and poorly studied object, IRAS 11472-0800. It is a highly evolved post-asymptotic giant branch (post-AGB) star of spectral type F, with a large infrared excess produced by thermal emission of circumstellar dust. We deployed a multi-wavelength study that includes the analyses of optical and IR spectra as well as a variability study based on photometric and spectroscopic time-series.
24393. V426 Sagittae (HBHA 1704-05) light curves
ID:
ivo://CDS.VizieR/J/A+A/636/A77
Title:
V426 Sagittae (HBHA 1704-05) light curves
Short Name:
J/A+A/636/A77
Date:
21 Oct 2021
Publisher:
CDS
Description:
The star V426 Sge (HBHA 1704-05), originally classified as an emission-line object and a semi-regular variable, brightened at the beginning of August 2018, showing signatures of a symbiotic star outburst. We aim to confirm the nature of V426 Sge as a classical symbiotic star, determine the photometric ephemeris of the light minima, and suggest the path from its 1968 symbiotic nova outburst to the following 2018 Z And-type outburst. We re-constructed an historical light curve (LC) of V426 Sge from approximately the year 1900, and used original low- (R~500-1500; 330-880nm) and high-resolution (R~11000-34000; 360-760nm) spectroscopy complemented with Swift-XRT and UVOT, optical UBVR_C_I_C_ and near-infrared $JHKL$ photometry obtained during the 2018 outburst and the following quiescence. The historical LC reveals no symbiotic-like activity from ~1900 to 1967. In 1968, V426 Sge experienced a symbiotic nova outburst that ceased around 1990. From approximately 1972, a wave-like orbitally related variation with a period of 493.4+/-0.7-days developed in the LC. This was interrupted by a Z And-type outburst from the beginning of August 2018 to the middle of February 2019. At the maximum of the 2018 outburst, the burning white dwarf (WD) increased its temperature to >~2x10^5^K, generated a luminosity of ~7x10^37^(d/3.3kpc}^2^erg/s, and blew a wind at the rate of ~3x10^-6^M_{sun}_/yr. Our spectral energy distribution models from the current quiescent phase reveal that the donor is a normal M4-5 III giant characterised with Teff~3400K, R_G_~106(d/3.3kpc})R_{sun}_ and L_G_~1350(d/3.3kpc})^2^L_{sun}_ and the accretor is a low-mass ~0.5M_{sun}_ WD. During the transition from the symbiotic nova outburst to the quiescent phase, a pronounced sinusoidal variation along the orbit develops in the LC of most symbiotic novae. The following eventual outburst is of Z And-type, when the accretion by the WD temporarily exceeds the upper limit of the stable burning. At this point the system becomes a classical symbiotic star.
24394. V893 Sco long-term photometry
ID:
ivo://CDS.VizieR/J/A+A/566/A101
Title:
V893 Sco long-term photometry
Short Name:
J/A+A/566/A101
Date:
21 Oct 2021
Publisher:
CDS
Description:
The cataclysmic variable V893 Sco is an eclipsing dwarf nova which, apart from outbursts with comparatively low amplitudes, exhibits a particularly strong variability during quiescence on timescales of days to seconds.The present study aims to update the outdated orbital ephemerides published previously, to investigate deviations from linear ephemerides, and to characterize non-random brightness variations in a range of timescales. Light curves of V893 Sco were observed on 39 nights, spanning a total time base of about 14 years. They contain 114 eclipses which were used to significantly improve the precision of the orbital period and to study long-term variations of the time of revolution. Oscillations and similar brightness variations were studied with Fourier techniques in the individual light curves. The orbital period exhibits long-term variations with a cycle time of 10.2 years. They can be interpreted as a light travel time effect caused by the presence of a giant planet with approximately 9.5 Jupiter masses in a 4.5AU orbit around V893 Sco. On some nights transient semi-periodic variations on timescales of several minutes can be seen which may be identified as quasi-periodic oscillations. However, it is difficult to distinguish whether they are caused by real physical mechanisms or if they are the effect of an accidental superposition of unrelated flickering flares. Simulations to investigate this question are presented.
24395. (84922) 2003 VS2 differential light curve
ID:
ivo://CDS.VizieR/J/A+A/505/1283
Title:
(84922) 2003 VS2 differential light curve
Short Name:
J/A+A/505/1283
Date:
21 Oct 2021
Publisher:
CDS
Description:
We compile and analyze an extended database of light curve parameters scattered in the literature to search for correlations and study physical properties, including internal structure constraints.
24396. V340 Ser and V448 Lac light curves
ID:
ivo://CDS.VizieR/J/PAZh/37/691
Title:
V340 Ser and V448 Lac light curves
Short Name:
J/PAZh/37/691
Date:
21 Oct 2021
Publisher:
CDS
Description:
We analyze long-term UBV observations and ASAS-3 photometry for five candidates for protoplanetary nebulae - F and G supergiants with infrared excesses at high Galactic latitudes - V340 Ser, IRAS 05113+1347, V552 Pup, V448 Lac, and RV Col. These stars exhibit quasi-periodic multifrequency light variations caused by pulsations with characteristic time scales from 83 to 139 days, depending on the stellar temperature. Cooler stars undergo variations with larger amplitudes and periods. The variations at close frequencies with a period ratio of 1.03-1.09 are responsible for the amplitude modulation revealed for most program stars.
24397. V356 Sgr optical polarization
ID:
ivo://CDS.VizieR/J/MNRAS/464/1936
Title:
V356 Sgr optical polarization
Short Name:
J/MNRAS/464/1936
Date:
21 Oct 2021
Publisher:
CDS
Description:
We analyse 45 spectropolarimetric observations of the eclipsing, interacting binary star V356 Sgr, obtained over a period of ~21yr, to characterize the geometry of the system's circumstellar material. After removing interstellar polarization from these data, we find that the system exhibits a large intrinsic polarization signature arising from electron scattering. In addition, the lack of repeatable eclipses in the polarization phase curves indicates the presence of a substantial pool of scatterers not occulted by either star. We suggest that these scatterers form either a circumbinary disc coplanar with the gainer's accretion disc or an elongated structure perpendicular to the orbital plane of V356 Sgr, possibly formed by bipolar outflows. We also observe small-scale, cycle-to-cycle variations in the magnitude of intrinsic polarization at individual phases, which we interpret as evidence of variability in the amount of scattering material present within and around the system. This may indicate a mass-transfer or mass-loss rate that varies on the time-scale of the system's orbital period. Finally, we compare the basic polarimetric properties of V356 Sgr with those of the well-studied {beta} Lyr system; the significant differences observed between the two systems suggest diversity in the basic circumstellar geometry of Roche lobe overflow systems.
24398. V4332 Sgr optical spectropolarimetry
ID:
ivo://CDS.VizieR/J/A+A/558/A82
Title:
V4332 Sgr optical spectropolarimetry
Short Name:
J/A+A/558/A82
Date:
21 Oct 2021
Publisher:
CDS
Description:
The eruption of V4332 Sgr was observed in 1994 and was classified as belonging to red transients of the V838 Mon type. Optical spectroscopy obtained a few years after the eruption showed a faint M-type stellar spectrum underlying numerous molecular and atomic emission features. We suggested that the central object in V4332 Sgr is now hidden in a dusty disc and that the photospheric spectrum of this object observed in the optical results from scattering of the radiation of the central star on dust grains in the circumstellar matter. The optical continuum of the object, as resulting from scattering on dust grains, is expected to be polarized. The emission features on the contrary - as observed directly from circumstellar regions, are expected to be unpolarized. We present and analyse spectropolarimetric observations of V4332 Sgr in the optical region. The continuum is linearly polarized with a typical degree of 16.6%. A clear depolarization is observed in the spectral regions where emission features contribute significantly to the observed flux. The only prominent exception is the CaI emission line at 6573{AA}, which is polarized in 21%. The results of our spectropolarimetric observations are in accord with the proposed geometry of the system and the advocated nature of the observed optical spectrum of V4332 Sgr - the continuum is not seen directly but due to scattering on dust within the disk and polar outflow, while most of the gas emission comes from the polar outflow excited by the radiation field of the central source. Additionally, the observed polarization patterns suggest a stratification of the outflow.
24399. vsini of B0-B3 stars in 7 young clusters
ID:
ivo://CDS.VizieR/J/AJ/133/1092
Title:
vsini of B0-B3 stars in 7 young clusters
Short Name:
J/AJ/133/1092
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a study aimed at assessing the differences in the distribution of rotation speeds N(vsini) among young (1-15Myr) B stars spanning a range of masses 6M_{sun}_<M<12M_{sun}_ and located in different environments: seven low-density ({rho}<1M_{sun}_/pc^3^) ensembles that are destined to become unbound stellar associations, and eight high-density ({rho}>>1M_{sun}_/pc^3^) ensembles that will survive as rich, bound stellar clusters for ages well in excess of 10^8^yr.
24400. vsini of binaries with evolved component
ID:
ivo://CDS.VizieR/J/ApJ/578/943
Title:
vsini of binaries with evolved component
Short Name:
J/ApJ/578/943
Date:
21 Oct 2021
Publisher:
CDS
Description:
In the present study we analyze the behavior of the rotational velocity, vsini, for a large sample of 134 spectroscopic binary systems with a giant star component of luminosity class III, along the spectral region from middle F to middle K.

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