- 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.
Number of results to display per page
Search Results
- 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.
- 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.
- 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.
- 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.
- ID:
- ivo://CDS.VizieR/J/A+A/458/895
- Title:
- vsini of evolved metal-poor stars
- Short Name:
- J/A+A/458/895
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Precise rotational velocities vsini are presented for a large sample of 100 metal-poor stars, most of them evolving off the main-sequence. The survey was carried out with the FEROS and CORALIE spectrometers. For the vsini measurements, obtained from spectral synthesis, we estimate an uncertainty of about 2.0km/s. For the large majority of the stars composing the present sample rotational velocities have been measured for the first time.
- ID:
- ivo://CDS.VizieR/J/ApJ/601/979
- Title:
- vsini of Orion low-mass stars
- Short Name:
- J/ApJ/601/979
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Projected rotational velocities (vsini) have been measured for a sample of 145 stars with masses between 0.4 and greater than 10M_{sun}_ (median mass 2.1M_{sun}_) located in the Orion star-forming complex. These measurements have been supplemented with data from the literature for Orion stars with masses as low as 0.1M_{sun}_.
23178. VSOP 5 GHz AGN Survey
- ID:
- ivo://CDS.VizieR/J/PASJ/52/997
- Title:
- VSOP 5 GHz AGN Survey
- Short Name:
- J/PASJ/52/997
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The VSOP mission is a Japanese-led project to image radio sources with sub-milliarcsec resolution by correlating the signal from the orbiting 8-m telescope, HALCA, with a global array of telescopes. Twenty- five percent of the scientific time of this mission is devoted to a survey of 402 bright, small-diameter extra-galactic radio sources at 5-GHz. The major goals of the VSOP Survey are statistical in nature: to determine the brightness temperature and approximate structure; to provide a source list for use with future space VLBI missions; and to compare radio properties with other data throughout the EM spectrum. This paper describes: the compilation of a complete list of radio sources associated with active galactic nuclei (AGN); the selection of the subsample of sources to be observed with VSOP; the extensive ground resources used for the Survey; the status of the observations as of 2000 July; the data-analysis methods; and several examples of results from the VSOP Survey. More detailed results from the full sample will be given in future papers.
23179. VSOP 5 GHz AGN Survey. III
- ID:
- ivo://CDS.VizieR/J/ApJS/155/33
- Title:
- VSOP 5 GHz AGN Survey. III
- Short Name:
- J/ApJS/155/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The VLBI Space Observatory Programme (VSOP) mission is a Japanese-led project to study radio sources with sub-milliarcsec resolution using an orbiting 8m telescope, HALCA, along with global arrays of Earth-based telescopes. Approximately 25% of the observing time is devoted to a survey of compact active galactic nuclei (AGNs) that are stronger than 1Jy at 5GHz - the VSOP AGN Survey. This paper, the third in the series, presents the results from the analysis of the first 102 Survey sources.
23180. VSOP 5GHz AGN Survey. IV
- ID:
- ivo://CDS.VizieR/J/ApJ/616/110
- Title:
- VSOP 5GHz AGN Survey. IV
- Short Name:
- J/ApJ/616/110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The VLBI Space Observatory Programme (VSOP) mission is a Japanese-led project to study radio sources with submilliarcsecond angular resolution, using an orbiting 8m telescope on board the satellite HALCA with a global Earth-based array of telescopes. A major program is the 5GHz VSOP Survey Program, which we supplement here with Very Long Baseline Array observations to produce a complete and flux density-limited sample. Using statistical methods of analysis of the observed visibility amplitude versus projected (u, v) spacing, we have determined the angular size and brightness temperature distribution of bright radio emission from active galactic nuclei.
