The results of high-resolution optical spectroscopy obtained for a recently suggested LBV (luminous blue variable) candidate, MWC 314, are presented. Photospheric lines mostly of N II and S II have been found for the first time with a resolution of 0.4-0.8{AA}. They imply a N/O overabundance previously reported for AG and HR Car since no O II absorptions were detected. Nearly 400 emission lines have been identified in the spectrum between 4190 and 8864{AA} many of which appear double-peaked. No significant P Cygni type absorption components have been found for the optically thick Balmer lines. This suggests that the stellar wind of MWC 314 is non-spherical and the circumstellar envelope is viewed not edge on. The systemic velocity measured using the emission lines of ionized metals turned out to be 55km/s, which corresponds to a distance towards the object of 3.0+/-0.2kpc, according to the galactic rotation curve. Our analysis of the characteristics of both photospheric and wind lines resulted in an estimate of the object's T_eff_ of nearly 25000K, which, however, needs further improvement. The other stellar parameters were found to be as follows: Log(L_bol_/L_{sun}_)=6.1+/-0.3, R_star_=60^+30^_=10_R_{sun}_. Our study confirms that MWC 314 is one of the most luminous stars in the Milky Way.
2nd Cat. of Radial Velocities with Astrometric Data
Short Name:
III/254
Date:
21 Oct 2021
Publisher:
CDS
Description:
The catalogue of radial velocities of Galactic stars with high precision astrometric data, 2nd version (CRVAD-2), is the result of a merging of star lists from the All-Sky Compiled Catalogue of 2.5 Million Stars (ASCC-2.5, Cat. I/280) with the General Catalogue of Radial Velocities (GCRV, Cat. III/213) and with other recently published radial velocity lists and catalogues. Cross identification of objects was carried out with help of coordinate, magnitude, colour and/or spectral type criteria. Data from the Catalogue of Components of Double and Multiple Stars (CCDM, Cat. I/274) were taken into account for the identification of multiple system components. Altogether 54907 stars from the ASCC-2.5 were identified with 51762 stars from the RV source catalogues, 3085 stars have secondary components and 30 stars have 3rd components in multiple systems. The CRVAD-2 includes accurate J2000 equatorial coordinates, proper motions and trigonometric parallaxes in the Hipparcos system, Johnson's BV photometric data, spectral types, radial velocities, multiplicity and variability flags. Stars are sorted in the order of increasing right ascension J2000. This catalogue supersedes the previous version numbered <III/239>.
We present a catalogue of 1715 early-type galaxies from the literature, spanning the luminosity range from faint dwarf spheroidal galaxies to giant elliptical galaxies. The aim of this catalogue is to be one of the most comprehensive and publicly available collections of data on early-type galaxies. The emphasis in this catalogue lies on dwarf elliptical galaxies, for which some samples with detailed data have been published recently. For almost all of the early-type galaxies included in it, this catalogue contains data on their locations, distances, redshifts, half-light radii, the masses of their stellar populations and apparent magnitudes in various passbands. Data on metallicity and various colours are available for a majority of the galaxies presented here. The data on magnitudes, colours, metallicities and masses of the stellar populations is supplemented with entries that are based on fits to data from simple stellar population models and existing data from observations. Also, some simple transformations have been applied to the data on magnitudes, colours and metallicities in this catalog, in order to increase the homogeneity of this data. Estimates on the Sersic profiles, internal velocity dispersions, maximum rotational velocities, dynamical masses and ages are listed for several hundreds of the galaxies in this catalogue. Finally, each quantity listed in this catalogue is accompanied with information on its source, so that users of this catalogue can easily exclude data that they do not consider as reliable enough for their purposes.
Chromospheric activity produces both photometric and spectroscopic variations that can be mistaken as planets. Large spots crossing the stellar disc can produce planet-like periodic variations in the light curve of a star. Moreover, spots clearly affect the spectral line profiles. Such perturbations will in turn affect the line centroids creating a radial velocity jitter that might "contaminate" the variations induced by a planet. Precise chromospheric activity measurements are needed to estimate the activity-induced noise that should be expected for a given star. The purpose of this paper is to obtain precise chromospheric activity measurements and projected rotational velocities for nearby (d<25pc) cool (spectral types F to K) stars, in order to estimate the activity-related jitter that should be expected for them. As a complementary objective, in this paper we aim to obtain relationships between fluxes in different activity indicator lines, which will permit a transformation of traditional activity indicators, i.e, CaII H & K lines, to other which hold noteworthy advantages. We used high resolution (~50000) echelle optical spectra. Standard data reduction was performed using the IRAF echelle package. To reveal the chromospheric emission of the stars in the sample we used the spectral subtraction technique. We measured equivalent widths of the chromospheric emission lines in the subtracted spectrum and transformed them into fluxes by applying empirical equivalent width-flux relationships. Rotational velocities were determined using the cross-correlation technique. To infer activity-related radial velocity (RV) jitter we used empirical relationships between this and the R'HK index. We have measured chromospheric activity, as given by different indicators throughout the optical spectra, and projected rotational velocities for 371 nearby cool stars. We have built empirical relationships among the most important chromospheric emission lines. Finally, we have used the measured chromospheric activity to estimate the expected RV jitter for the active stars in the sample.
A survey of 329 nearby galaxies (redshift z<0.045) has been conducted to study the distribution of mass and light within spiral galaxies over a range of environments. The 18 observed clusters and groups span a range of richness, density, and X-ray temperature and are supplemented by a set of 30 isolated field galaxies. Optical spectroscopy taken with the 200inch (5m) Hale Telescope provides separately resolved H{alpha} and [NII] major-axis rotation curves for the complete set of galaxies, which are analyzed to yield velocity widths and profile shapes, extents, and gradients. HI line profiles provide an independent velocity width measurement and a measure of HI gas mass and distribution. I-band images are used to deconvolve profiles into disk and bulge components, to determine global luminosities and ellipticities, and to check morphological classification. These data are combined to form a unified data set ideal for the study of the effects of environment upon galaxy evolution.
We present the first part of the first large and homogeneous CCD color-magnitude diagram (CMD) data base, comprising 52 nearby Galactic globular clusters (GGC) imaged in the V and I bands using only two telescopes (one for each hemisphere). The observed clusters represent 75% of the known Galactic globulars with (m-M)V<=16.15mag, cover most of the globular cluster metallicity range (-2.2<=[Fe/H]<=-0.4), and span Galactocentric distances from ~1.2 to ~18.5kpc. In this paper, the CMDs for the 39 GGCs observed in the southern hemisphere are presented. The remaining 13 northern hemisphere clusters of the catalog are presented in a companion paper. For four clusters (NGC 4833, NGC 5986, NGC 6543, and NGC 6638) we present for the first time a CMD from CCD data. The typical CMD span from the 22^nd^ V magnitude to the tip of the red giant branch. Based on a large number of standard stars, the absolute photometric calibration is reliable to the ~0.02mag level in both filters. This catalog, because of its homogeneity, is expected to represent a useful data base for the measurement of the main absolute and relative parameters characterizing the CMD of GGCs.
In this paper we present the second and final part of a large and photometrically homogeneous CCD color-magnitude diagram (CMD) data base, comprising 52 nearby Galactic globular clusters (GGC) imaged in the V and I bands. The catalog has been collected using only two telescopes (one for each hemisphere).
Several nearby solar-type dwarfs with variable radial velocity were monitored to find their spectroscopic orbits. Orbital elements of HIP 179, 1989, 2981, 5276, 6439, 11218, 21443, 96434 are determined, as well as tentative orbits for HIP 28678 and 41214. We discuss each of those objects. Three of the four double-lined binaries are twins with nearly equal components. All four orbits with periods shorter than 10d are circular, the remaining orbits are eccentric.
A subset of 51 Hipparcos astrometric binaries among FG dwarfs within 67pc has been surveyed with the Near-Infrared Coronagraphic Imager adaptive optics system at Gemini-S, directly resolving for the first time 17 subarcsecond companions and 7 wider ones. Using these data together with published speckle interferometry of 57 stars, we compare the statistics of resolved astrometric companions with those of a simulated binary population. The fraction of resolved companions is slightly lower than expected from binary statistics. About 10% of astrometric companions could be "dark" (white dwarfs and close pairs of late M-dwarfs). To our surprise, several binaries are found with companions too wide to explain the acceleration. Re-analysis of selected intermediate astrometric data shows that some acceleration solutions in the original Hipparcos catalog are spurious.
We have selected 36 loose groups of galaxies from Ramella et al. 1989, with at least five members, and with mean redshift cz>3200km/s. These groups all lie within the first two "slices" of the CfA redshift survey <VII/164> (RA between 8h and 17h, DE between 2655.5 and 38.5 degrees). For each of these groups, we define the "redshift-space neighbourhood" as a region centered on the group coordinates and delimited by a circle of projected radius 1.5xh^-1^ Mpc on the sky, and by a velocity interval of 3000km/s. Table 2 lists the positions, magnitudes, radial velocities (cz) and their errors, for the members of the groups published in RGH89. Coordinates and magnitudes are from Zwicky's CGCG <VII/4>. Unpublished redshifts are marked with an asterisk in the last column. Table 3 lists galaxies within 1.5Mpc (assuming H0=100) and +/-1500 km/s from the centers of the groups in redshift space. Magnitudes and positions are from the Zwicky-Nielsen merged catalog. Some coordinates are better coordinates than Zwicky's, some come from compilations of redshift data that we have used to complement our measurements. Unpublished redshifts are marked with an asterisk in the last column. In this table some galaxies appear twice because a few groups do overlap. We listed the galaxies in common under the labels of both groups.