- ID:
- ivo://CDS.VizieR/J/A+A/309/521
- Title:
- 55 UMa spectroscopic orbit
- Short Name:
- J/A+A/309/521
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The first investigation of the known triple system 55 UMa (2.55d binary in a ~1870-d orbit with the third star) based on electronic spectra led to several new findings about the system: (1) Discovery of spectral lines of the tertiary and an unambiguous detection of the lines of the secondary. Spectra of both primary and tertiary are of the same strength and correspond to spectral class A0V. The secondary spectrum is about twice fainter in the visual region and belongs probably also to spectral class A. (2) First self-consistent orbital solution describing close and wide orbit and the detection of apsidal motion for the close pair. The orbital period of the close pair was improved to (2.5538380+/-0.0000046d) and basic physical elements for all three stars and the system were estimated. The orbital solution also gives the period of apsidal motion of the close pair of (450+/-60)yr and leads to a good agreement with the published speckle-interferometric orbit for the distant companion if the longitude of periastron passage is increased by 180deg.
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- ID:
- ivo://CDS.VizieR/J/AJ/160/279
- Title:
- Untangling the Galaxy. II. Structure within 3kpc
- Short Name:
- J/AJ/160/279
- Date:
- 09 Mar 2022 22:00:00
- Publisher:
- CDS
- Description:
- We present the results of the hierarchical clustering analysis of the Gaia DR2 data to search for clusters, comoving groups, and other stellar structures. The current paper builds on the sample from the previous work, extending it in distance from 1 to 3kpc and increasing the number of identified structures up to 8292. To aid in the analysis of the population properties, we developed a neural network called Auriga to robustly estimate the age, extinction, and distance of a stellar group based on the input photometry and parallaxes of the individual members. We apply Auriga to derive the properties of not only the structures found in this paper, but also previously identified open clusters. Through this work, we examine the temporal structure of the spiral arms. Specifically, we find that the Sagittarius Arm has moved by >500pc in the last 100Myr and the Perseus Arm has been experiencing a relative lull in star formation activity over the last 25Myr. We confirm the findings of the previous paper on the transient nature of the spiral arms, with the timescale of transition of a few 100Myr. Finally, we find a peculiar ~1Gyr old stream of stars that appears to be heliocentric. Its origin is unclear.
- ID:
- ivo://CDS.VizieR/J/ApJS/235/6
- Title:
- Updated Multiple Star Catalog (MSC): Sept 2021
- Short Name:
- J/ApJS/235/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog of hierarchical stellar systems with three or more components is an update of the original 1997 version (Tokovinin, 1997-1999, J/A+AS/124/75). For 2000 hierarchies, the new Multiple Star Catalog (MSC) provides distances, component masses and periods, and supplementary information (astrometry, photometry, identifiers, orbits, notes). The MSC content and format are explained, and its incompleteness and strong observational selection are stressed. Nevertheless, the MSC can be used for statistical studies and is a valuable source for planning observations of multiple stars. Rare classes of stellar hierarchies found in the MSC (with six or seven components, extremely eccentric orbits, planar and possibly resonant orbits, hosting planets) are briefly presented. High-order hierarchies have smaller velocity dispersion compared to triples and are often associated with moving groups. The paper concludes with an analysis of the ratio of periods and separations between inner and outer subsystems. In wide hierarchies, the ratio of semimajor axes, estimated statistically, is distributed between 3 and 300, with no evidence of dynamically unstable systems.
- ID:
- ivo://CDS.VizieR/J/AJ/145/101
- Title:
- Updated nearby galaxy catalog
- Short Name:
- J/AJ/145/101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an all-sky catalog of 869 nearby galaxies having individual distance estimates within 11Mpc or corrected radial velocities V_LG_<600km/s. The catalog is a renewed and expanded version of the Catalog of Neighboring Galaxies by Karachentsev et al (2004, cat. J/AJ/127/2031). It collects data on the following galaxy observables: angular diameters, apparent magnitudes in far-UV, B, and K_s_bands, H{alpha} and HI fluxes, morphological types, HI-line widths, radial velocities, and distance estimates. In this Local Volume (LV) sample, 108 dwarf galaxies still remain without measured radial velocities. The catalog yields also calculated global galaxy parameters: linear Holmberg diameter, absolute B magnitude, surface brightness, HI mass, stellar mass estimated via K-band luminosity, HI rotational velocity corrected for galaxy inclination, indicative mass within the Holmberg radius, and three kinds of "tidal index," which quantify the local density environment. The catalog is supplemented with data based on the local galaxies, which presents their optical and available H{alpha} images, as well as other services. We briefly discuss the Hubble flow within the LV and different scaling relations that characterize galaxy structure and global star formation in them. We also trace the behavior of the mean stellar mass density, HI-mass density, and star formation rate density within the volume considered.
- ID:
- ivo://CDS.VizieR/J/MNRAS/504/356
- Title:
- Updated parameters of 1743 open clusters
- Short Name:
- J/MNRAS/504/356
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this study, we follow up our recent paper (Monteiro et al., )2020MNRAS.499.1874M and present a homogeneous sample of fundamental parameters of open clusters in our Galaxy, entirely based on Gaia DR2 data. We used published membership probability of the stars derived from Gaia DR2 data and applied our isochrone fitting code, updated as in Monteiro et al. (2020MNRAS.499.1874M), to G_BP_ and G_RP_Gaia DR2 data for member stars. In doing this, we take into account the nominal errors in the data and derive distance, age, and extinction of each cluster. This work therefore provides parameters for 1743 open clusters and, as a by-product, a list of likely not physical or dubious open clusters is provided as well for future investigations. Furthermore, it was possible to estimate the mean radial velocity of 831 clusters (198 of which are new and unpublished so far), using stellar radial velocities from Gaia DR2 catalogue. By comparing the open cluster distances obtained from isochrone fitting with those obtained from a maximum likelihood estimate of individual member parallaxes, we found a systematic offset of (-0.05 {\pm} 0.04) mas.
- ID:
- ivo://CDS.VizieR/J/ApJ/745/56
- Title:
- Upper Sco members rotational velocities
- Short Name:
- J/ApJ/745/56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present projected rotational velocities for 20 early-type (B8-A9) and 74 late-type (F2-M8) members of the ~5 Myr old Upper Scorpius OB Association derived from high-dispersion optical spectra obtained with the High Resolution Echelle Spectrometer on Keck I and the Magellan Inamori Kyocera Echelle on the Magellan Clay telescope. The spectroscopic sample is composed of stars and brown dwarfs with infrared signatures of circumstellar disks, both primordial and debris, and non-excess sources of comparable spectral type. We merge projected rotational velocities, accretion diagnostics, and Spitzer Space Telescope Infrared Array Camera and Multiband Imaging Photometer for Spitzer 24 {mu}m photometry to examine the relationship between rotation and circumstellar disks. The rotational velocities are strongly correlated with spectral type, a proxy for mass, such that the median vsin i for B8-A9-type stars is: 195+/-70km/s, F2-K4: 37.8+/-7.4km/s, K5-K9: 13.8^+21.3^_-8.2_km/s, M0-M5: 16.52+/-5.3km/s, and M5.5-M8: 17.72+/-8.1km/s. We find with a probability of >=0.99 that M-type stars and brown dwarfs having infrared excess suggestive of circumstellar disks rotate more slowly than their non-excess counterparts. A similar correlation is present among F2-K9-type stars, but only at the ~97% confidence level. Among the early-type (B8-A9) members, rotational velocities of the debris-disk and non-disk populations are indistinguishable. Considering the late-type (F2-M8) stars and brown dwarfs, we find a low fraction of slowly rotating, non-excess sources relative to younger star-forming regions, suggesting that most have spun up following disk dissipation. The few late-type (F2-M5) debris disk sources, which may be representative of stars that have recently dispersed their inner disks, are evenly divided between slow and moderate rotators.
- ID:
- ivo://CDS.VizieR/J/ApJ/715/1203
- Title:
- {upsilon} Andromedae system with HST
- Short Name:
- J/ApJ/715/1203
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used high-cadence radial velocity (RV) measurements from the Hobby-Eberly Telescope with existing velocities from the Lick, Elodie, Harlan J. Smith, and Whipple 60" telescopes combined with astrometric data from the Hubble Space Telescope Fine Guidance Sensors to refine the orbital parameters and determine the orbital inclinations and position angles of the ascending node of components {upsilon} And A c and d. With these inclinations and using M*=1.31M_{sun}_ as a primary mass, we determine the actual masses of two of the companions: {upsilon} And A c is 13.98^+2.3^_-5.3_M_Jup_, and {upsilon} And A d is 10.25^+0.7^_-3.3_M_Jup_. These measurements represent the first astrometric determination of mutual inclination between objects in an extrasolar planetary system, which we find to be 29.9+/-1{deg}. The combined RV measurements also reveal a long-period trend indicating a fourth planet in the system. We investigate the dynamic stability of this system and analyze regions of stability, which suggest a probable mass of {upsilon} And A b. Finally, our parallaxes confirm that u And B is a stellar companion of {upsilon} And A.
- ID:
- ivo://CDS.VizieR/J/AJ/143/5
- Title:
- uvby photometry and RVs of HD 74057
- Short Name:
- J/AJ/143/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained Stromgren b and y differential photometric observations of the solar-type eclipsing binary HD 74057 plus follow-up high-resolution, red wavelength spectroscopic observations. The system has an orbital period of 31.2198 days, a high eccentricity of 0.47, and is seen almost exactly edge on with an inclination of 89.8{deg}. The two main-sequence G0 stars are nearly identical in all physical characteristics. We used the Wilson-Devinney program to obtain a simultaneous solution of our photometric and spectroscopic observations. The resulting masses of the components are M1=1.138+/-0.003M_{sun}_ and M2=1.131+/-0.003M_{sun}_, and the radii are R1=1.064+/-0.002R_{sun}_ and R2=1.049+/-0.002R_{sun}_. The effective temperatures are 5900K (fixed) and 5843K, and the iron abundance, [Fe/H], is estimated to be +0.07. A comparison with evolutionary tracks suggests that the system may be even more metal rich. The components rotate with periods of 8.4 days, significantly faster than the predicted pseudosynchronous period of 12.7days. We see evidence that one or both components have cool spots. Both stars are close to the zero-age main sequence and are about 1.0Gyr old.
- ID:
- ivo://CDS.VizieR/J/A+A/389/931
- Title:
- uvby photometry & radial velocities of R 81
- Short Name:
- J/A+A/389/931
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- File table1.dat contains the photometric uvby data of the eclipsing binary hypergiant R81 (B2.5 Ia-O) of the Large Magellanic Cloud. The data have been obtained with the Danish 50 cm telescope at ESO, La Silla, and cover more than one orbital cycle of 74.59 days. File table2.dat contains radial velocity measurements of photospheric lines of this star. The spectra have been obtained simultaneously with the photometry. The Feros spectrograph at the ESO 1.52m telescope was used. The quoted radial velocities are averages over the best photospheric lines.
- ID:
- ivo://CDS.VizieR/J/MNRAS/363/529
- Title:
- uvby, UBV and radial velocity of WW Aur
- Short Name:
- J/MNRAS/363/529
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- WW Aurigae is a detached eclipsing binary composed of two metallic- lined A-type stars orbiting each other every 2.5 days. We have determined the masses and radii of both components to accuracies of 0.4% and 0.6%, respectively. From a cross-correlation analysis of high-resolution spectra we find masses of 1.964+/-0.007M_{sun}_ for the primary star and 1.814+/-0.007M_{sun}_ for the secondary star. From an analysis of photoelectric uvby and UBV light curves we find the radii of the stars to be 1.927+/-0.011R_{sun}_ and 1.841+/-0.011R_{sun}_, where the uncertainties have been calculated using a Monte Carlo algorithm. Fundamental effective temperatures of the two stars have been derived, using the Hipparcos parallax of WW Aur and published ultraviolet, optical and infrared fluxes, and are 7960+/-420 and 7670+/-410K. The masses, radii and effective temperatures of WW Aur are only matched by theoretical evolutionary models for a fractional initial metal abundance, Z, of approximately 0.06 and an age of roughly 90Myr. This seems to be the highest metal abundance inferred for a well-studied detached eclipsing binary, but we find no evidence that it is related to the metallic-lined nature of the stars. The circular orbit of WW Aur is in conflict with the circularization timescales of both the Tassoul and the Zahn tidal theories and we suggest that this is due to pre-main-sequence evolution or the presence of a circular orbit when the stars were formed.
