- ID:
- ivo://CDS.VizieR/J/ApJ/854/109
- Title:
- Photometry & spectroscopy follow-up of MWC 882
- Short Name:
- J/ApJ/854/109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Disks in binary systems can cause exotic eclipsing events. MWC 882 (BD-224376, EPIC 225300403) is such a disk-eclipsing system identified from observations during Campaign 11 of the K2 mission. We propose that MWC 882 is a post-Algol system with a B7 donor star of mass 0.542+/-0.053M_{sun}_ in a 72-day orbit around an A0 accreting star of mass 3.24+/-0.29M_{sun}_. The 59.9+/-6.2R_{sun}_ disk around the accreting star occults the donor star once every orbit, inducing 19-day long, 7% deep eclipses identified by K2 and subsequently found in pre-discovery All-Sky Automated Survey and All Sky Automated Survey for Supernovae observations. We coordinated a campaign of photometric and spectroscopic observations for MWC 882 to measure the dynamical masses of the components and to monitor the system during eclipse. We found the photometric eclipse to be gray to ~1%. We found that the primary star exhibits spectroscopic signatures of active accretion, and we observed gas absorption features from the disk during eclipse. We suggest that MWC 882 initially consisted of a ~3.6M_{sun}_ donor star transferring mass via Roche lobe overflow to a ~2.1M_{sun}_ accretor in a ~7-day initial orbit. Through angular momentum conservation, the donor star is pushed outward during mass transfer to its current orbit of 72 days. The observed state of the system corresponds with the donor star having left the red giant branch ~0.3Myr ago, terminating active mass transfer. The present disk is expected to be short-lived (10^2^yr) without an active feeding mechanism, presenting a challenge to this model.
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- ID:
- ivo://CDS.VizieR/J/AJ/161/221
- Title:
- Photometry & spectroscopy of 4 binaries stars
- Short Name:
- J/AJ/161/221
- Date:
- 16 Mar 2022 11:53:19
- Publisher:
- CDS
- Description:
- We present the photometric and spectroscopic analysis of four W-UMa binaries J015829.5+260333 (hereinafter as J0158), J030505.1+293443 (hereinafter as J0305), J102211.7+310022 (hereinafter as J1022), and KW-Psc. The VRcIc band photometric observations are carried out with the 1.3m Devasthal Fast Optical Telescope (DFOT). For low-resolution spectroscopy, we used the 2m Himalayan Chandra Telescope (HCT) as well as the archival data from the 4m LAMOST survey. The systems J0158 and J0305 show a period increase rate of 5.26({+/-}1.72)x10^-7^days/yr and 1.78({+/-}1.52)x10^-6^days/yr, respectively. The period of J1022 is found to be decreasing with a rate of 4.22({+/-}1.67)x10^-6^days/yr. The period analysis of KW-Psc displays no change in its period. The PHOEBE package is used for the light-curve modeling and basic parameters are evaluated with the help of the GAIA parallax. The asymmetry of light curves is explained with the assumption of cool spots at specific positions on one of the components of the system. On the basis of temperatures, mass ratios, fill-out factors, and periods, the system J1022 is identified as a W-subtype system while the others show some mixed properties. To probe the chromospheric activities in these W-UMa binaries, their spectra are compared with the known inactive stars' spectra. The comparison shows emission in H{alpha}, H{beta}, and CaII. To understand the evolutionary status of these systems, the components are plotted in mass-radius and mass-luminosity planes with other well characterized binary systems. The secondary components of all the systems are away from ZAMS, which indicates that the secondary is more evolved than the primary component.
- ID:
- ivo://CDS.VizieR/J/A+A/639/A23
- Title:
- Photometry & spectroscopy of EE Cep: 2014-15
- Short Name:
- J/A+A/639/A23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- EE Cep is one of few eclipsing binary systems with a dark, dusty disk around an invisible object similar to epsilon Aur. The system is characterized by grey and asymmetric eclipses every 5.6yr, with a significant variation in their photometric depth, ranging from ~0.5mag to ~2.0mag. The main aim of the observational campaign of the EE Cep eclipse in 2014 was to test the model of disk precession (Galan et al. 2012). We expected that this eclipse would be one of the deepest with a depth of ~2m.mag. We collected multicolor observations from almost 30 instruments located in Europe and North America. This photometric data covers 243 nights during and around the eclipse. We also analyse the low- and high- resolution spectra from several instruments. The eclipse was shallow with a depth of 0m.71 in V-band. The multicolor photometry illustrates small color changes during the eclipse with a total amplitude of order ~+0.15mag in B-I color index. The linear ephemeris for this system is updated by including new times of minima, measured from the three most recent eclipses at epochs E=9, 10 and 11. New spectroscopic observations were acquired, covering orbital phases around the eclipse, which were not observed in the past and increased the data sample, filling some gaps and giving a better insight into the evolution of the H{alpha} and NaI spectral line profiles during the primary eclipse. The eclipse of EE Cep in 2014 was shallower than expected 0.71mag instead of ~2.0mag. This means that our model of disk precession needs revision.
- ID:
- ivo://CDS.VizieR/J/A+A/327/145
- Title:
- Photopolarimetric activity of RR Tauri
- Short Name:
- J/A+A/327/145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of coordinated Crimea-Dodaira simultaneous multi-bands photometric and polarimetric observations of the classical Herbig Ae/Be star RR Tau which cover fully the observed interval of its brightness changes are presented. Within the observed interval of its light variations the linear polarization of RR Tau anti-correlates with its brightness changes.
- ID:
- ivo://CDS.VizieR/J/AZh/77/420
- Title:
- Photopolarimetric activity of SV Cep
- Short Name:
- J/AZh/77/420
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of the eleven-years (1987-98) photopolarimetric patrol observations of Herbig Ae star SV Cep are presented. Only one deep brightness minimum of star were observed during this time interval. The decrease of the SV Cep brightness during this minimum was accompanied by increase of its linear polarization. The similar behaviour of linear polarization with the brightness changes was found earlier in other young stars with the non-periodic Algol-type minima. The most probable interpretation of this phenomenon is based on the model in which the source of intrinsic linear polarization is the scattered radiation of circumstellar disk-like dust envelope (probably the proto-planetary disk). The deposition of this source increases during the brightness minima when the direct (non-polarized) stellar radiation are absorbed in the CS dust clouds intersected the line-of-sight.
- ID:
- ivo://CDS.VizieR/J/A+AS/112/457
- Title:
- Photopolarimetry of BM And
- Short Name:
- J/A+AS/112/457
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of photoelectric UBV observations of the T Tauri type variable BM And made during 1983-1991, as well as of simultaneous photopolarimetric UBVRI observations of this star for 1990-93 are given.
- ID:
- ivo://CDS.VizieR/J/other/PBeiO/16.18
- Title:
- Physical data of the FK stars
- Short Name:
- J/other/PBeiO/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The precise positions and proper motions (J2000.0) of 1535 Basic FK5 (FK4) stars in FK5 system (Cat. <I/149>) have been used in the reduction of local vertical monitoring and catalog observations at the Beijing Astronomical Observatory. The same data of 1987 FK4Sup stars, in which 980 stars denoted with "F" will be included in FK5, are also available recently from Heidelberg by courtesy of Prof Tong Fu, the Director of the Purple Mountain Observatory. The positions and proper motions of the other 1007 FK4Sup stars in FK5 system have been given by the Astronomisches Rechen-Institut in Heidelberg with comparatively low accuracy. However, the physical data, such as the visual magnitudes and the spectral types of these stars with rather larger uncertainties are originated from the Henry Draper Catalogue since the compilation of FK4 and FK4Sup (Cat. <I/143>). The more accurate visual magnitudes are available in the well-defined photoelectric system and the spectral types in MK-system that may be found, for example, in the Bright Star Catalogue (Cat. <V/50>) and a Supplement to this catalogue (Cat. <V/36>).
- ID:
- ivo://CDS.VizieR/J/A+A/497/497
- Title:
- Physical parameters from JHK flux
- Short Name:
- J/A+A/497/497
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The effective temperature scale of FGK stars, especially at the lowest metallicities remains a major problem in the chemical abundance analysis of metal-poor stars. We present a new implementation of the infrared flux method (IRFM) using the 2MASS catalogue.
- ID:
- ivo://CDS.VizieR/J/A+A/531/A141
- Title:
- Physical parameters of PMS in open clusters
- Short Name:
- J/A+A/531/A141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our aims are twofold: To determine the physical parameters of PMS members in young open clusters (YOCs), and to check and compare the performances of different model isochrones. We compare UBVRI photometric observations of eleven YOCs to theoretical isochrones in the photometric diagrams. The comparison simultaneously provides membership assignments for MS and PMS stars and estimates for the masses, ages, and spatial distribution of the candidate members. The relations found between the different cluster parameters show that the procedure applied to assign cluster membership, and to measure physical parameters for the selected members, is well founded.
- ID:
- ivo://CDS.VizieR/J/A+A/620/A141
- Title:
- Physical properties of AM CVn stars
- Short Name:
- J/A+A/620/A141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- AM CVn binaries are hydrogen deficient compact binaries with an orbital period in the 5-65min range and are predicted to be strong sources of persistent gravitational wave radiation. Using Gaia, Data Release 2, we present the parallaxes and proper motions of 41 out of the 56 known systems. Compared to the parallax determined using the HST, Fine Guidance Sensor we find that the archetype star, AM CVn, is significantly closer than previously thought. This resolves the high luminosity and mass accretion rate which models had difficulty in explaining. Using Pan-STARRS1 data we determine the absolute magnitude of the AM CVn stars. There is some evidence that donor stars have a higher mass and radius than expected for white dwarfs or that the donors are not white dwarfs. Using the distances to the known AM CVn stars we find strong evidence that a large population of AM CVn stars has yet to be discovered. As this value sets the background to the gravitational wave signal of LISA, this is of wide interest. We determine the mass transfer rate for 15 AM CVn stars and find that the majority has a rate significantly greater than expected from standard models. This is further evidence that the donor star has a greater size than expected.
