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- ID:
- ivo://CDS.VizieR/J/ApJ/627/579
- Title:
- Photometry of variables in NGC 3370
- Short Name:
- J/ApJ/627/579
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report observations of two nearby Type Ia supernovae (SNe Ia) for which observations of Cepheid variables in the host galaxies have been obtained with the Hubble Space Telescope: SN 1994ae in NGC 3370 and SN 1998aq in NGC 3982. For NCG 3370, we used the Advanced Camera for Surveys to observe 64 Cepheids that yield a distance of 29 Mpc, the farthest direct measurement of Cepheids.
- ID:
- ivo://CDS.VizieR/J/ApJ/743/19
- Title:
- Photometry of variable star candidates in M31
- Short Name:
- J/ApJ/743/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometry in B, V (down to V~26mag) is presented for two 23'x23' fields of the Andromeda galaxy (M31) that were observed with the blue channel camera of the Large Binocular Telescope during the Science Demonstration Time. Each field covers an area of about 5.1x5.1kpc^2^ at the distance of M31 ({mu}_M31_~24.4mag), sampling, respectively, a northeast region close to the M31 giant stream (field S2) and an eastern portion of the halo in the direction of the galaxy minor axis (field H1). The stream field spans a region that includes Andromeda's disk and giant stream, and this is reflected in the complexity of the color-magnitude diagram of the field. One corner of the halo field also includes a portion of the giant stream. Even though these demonstration time data were obtained under non-optimal observing conditions, the B photometry, which was acquired in time-series mode, allowed us to identify 274 variable stars (among which 96 are bona fide and 31 are candidate RR Lyrae stars, 71 are Cepheids, and 16 are binary systems) by applying the image subtraction technique to the selected portions of the observed fields. Differential flux light curves were obtained for the vast majority of these variables. Our sample mainly includes pulsating stars that populate the instability strip from the Classical Cepheids down to the RR Lyrae stars, thus tracing the different stellar generations in these regions of M31 down to the horizontal branch of the oldest (t~10Gyr) component.
- 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+A/360/472
- Title:
- Proper motions in omega Centauri
- Short Name:
- J/A+A/360/472
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The tables present the photometric and astrometric results of an extensive proper motion study of the globular cluster omega Centauri: information on the photographic plates used, variability analysis, astrometric data for 9847 stars, membership determination and surface density profile, cluster proper motion dispersions and systematics and cross-references with star-numbers used by Norris et al. (1997ApJ...487L.187N) and Lynga (1996A&AS..115..297L).
- ID:
- ivo://CDS.VizieR/J/AJ/130/794
- Title:
- Radial velocities and BV photometry of HD 144110
- Short Name:
- J/AJ/130/794
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New spectroscopic and photometric observations of HD 144110 have been used to obtain an improved orbital element solution and determine some basic properties of the system. This chromospherically active, double-lined spectroscopic binary has an orbital period of 1.6714012days and a circular orbit. We classify the components as G5 V and K0 V and suggest that they are slightly metal-rich. The photometric observations indicate that the rotation of HD 144110 is synchronous with the orbital period. Despite the short orbital period, no evidence of eclipses is seen in our photometry.
- ID:
- ivo://CDS.VizieR/J/AJ/145/134
- Title:
- Radial velocities of 108 stars in Ruprecht 147
- Short Name:
- J/AJ/145/134
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ruprecht 147 is a hitherto unappreciated open cluster that holds great promise as a standard in fundamental stellar astrophysics. We have conducted a radial velocity survey of astrometric candidates with Lick, Palomar, and MMT observatories and have identified over 100 members, including 5 blue stragglers, 11 red giants, and 5 double-lined spectroscopic binaries (SB2s). We estimate the cluster metallicity from spectroscopic analysis, using Spectroscopy Made Easy (SME), and find it to be [M/H]=+0.07+/-0.03. We have obtained deep CFHT/MegaCam g'r'i'z' photometry and fit Padova isochrones to the (g'-i') and Two Micron All Sky Survey (J-K_S_) color-magnitude diagrams, using the {tau}^2^ maximum-likelihood procedure of Naylor, and an alternative method using two-dimensional cross-correlations developed in this work. We find best fits for Padova isochrones at age t=2.5+/-0.25Gyr, m-M=7.35+/-0.1, and A_V_=0.25+/-0.05, with additional uncertainty from the unresolved binary population and possibility of differential extinction across this large cluster. The inferred age is heavily dependent on our choice of stellar evolution model: fitting Dartmouth and PARSEC models yield age parameters of 3Gyr and 3.25Gyr, respectively. At ~300pc and ~3Gyr, Ruprecht 147 is by far the oldest nearby star cluster.
- ID:
- ivo://CDS.VizieR/J/PASP/118/1238
- Title:
- Radial velocity curve of RBS 490
- Short Name:
- J/PASP/118/1238
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- RBS (ROSAT Bright Source) 0490 is a cataclysmic variable star (CV) with unusually strong emission lines. The strength of the emission lines has led to a suggestion that the object is intrinsically faint and correspondingly nearby (33pc), which, if true, would strongly affect estimates of the CV space density. Here we report astrometry, filter photometry, and time-series spectroscopy of this object. The astrometry gives an absolute parallax of 4.5+/-1.5mas and a relative proper motion of 102mas/yr. A Bayesian procedure gives a very uncertain distance estimate of d~300pc, and the small parallax alone implies d>133pc (at 2 standard deviations). The mean V magnitude is 17.4, which implies M_V_=10.9-5log[d/(200pc)], neglecting extinction. At 200pc, the space velocity would be over 90km/s with respect to the local standard of rest. The time-series spectroscopy shows a possible emission-line radial velocity period near 46 minutes. This would be unusually short for an orbital period, and it may represent some other clock in the system.
- ID:
- ivo://CDS.VizieR/J/ApJ/870/115
- Title:
- Reddening, distance modulus & Fe/H of RRLs in w Cen
- Short Name:
- J/ApJ/870/115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We developed a new approach to provide accurate estimates of the metal content, reddening, and true distance modulus of RR Lyrae stars (RRLs). The method is based on homogeneous optical (BVI) and near-infrared (JHK) mean magnitudes and on predicted period-luminosity-metallicity relations (IJHK) and absolute mean magnitude-metallicity relations (BV). We obtained solutions for three different RRL samples in {omega}Cen: first overtone (RRc, 90), fundamental (RRab, 80), and global (RRc+RRab) in which the period of first overtones were fundamentalized. The metallicity distribution shows a well defined peak at [Fe/H]~-1.98 and a standard deviation of {sigma}=0.54dex. The spread is, as expected, metal-poor ([Fe/H]<=-2.3) objects. The current metallicity distribution is ~0.3dex more metal-poor than similar estimates for RRLs available in the literature. The difference vanishes if the true distance modulus we estimated is offset by -0.06/-0.07mag in true distance modulus. We also found a cluster true distance modulus of {mu}=13.720{+/-}0.002{+/-}0.030mag, where the former error is the error on the mean and the latter is the standard deviation. Moreover, we found a cluster reddening of E(B-V)=0.132{+/-}0.002{+/-}0.028mag and spatial variations of the order of a few arcmin across the body of the cluster. Both the true distance modulus and the reddening are slightly larger than similar estimates available in the literature, but the difference is within 1{sigma}. The metallicity dependence of distance diagnostics agrees with theory and observations, but firm constraints require accurate and homogeneous spectroscopic measurements.
