- ID:
- ivo://CDS.VizieR/J/ApJ/903/96
- Title:
- MUTA; the {mu}Tau Association
- Short Name:
- J/ApJ/903/96
- Date:
- 15 Mar 2022
- Publisher:
- CDS
- Description:
- We present an analysis of the newly identified {mu}Tau Association (MUTA) of young stars at ~150pc from the Sun that is part of the large Cas-Tau structure, coeval and comoving with the {alpha}Persei cluster. This association is also located in the vicinity of the Taurus-Auriga star-forming region and the Pleiades association, although it is unrelated to them. We identify more than 500 candidate members of MUTA using Gaia DR2 data and the BANYAN {Sigma} tool, and we determine an age of 62{+/-}7Myr for its population based on an empirical comparison of its color-magnitude diagram sequence with those of other nearby young associations. The MUTA association is related to the Theia 160 group of Kounkel & Covey and corresponds to the e Tau group of Liu et al. It is also part of the Cas-Tau group of Blaauw. As part of this analysis, we introduce an iterative method based on spectral templates to perform an accurate correction of interstellar extinction of Gaia DR2 photometry, needed because of its wide photometric bandpasses. We show that the members of MUTA display an expected increased rate of stellar activity and faster rotation rates compared with older stars, and that literature measurements of the lithium equivalent width of nine G0- to K3-type members are consistent with our age determination. We show that the present- day mass function of MUTA is consistent with other known nearby young associations. We identify WD0340+103 as a hot, massive white dwarf remnant of a B2 member that left its planetary nebula phase only 270000yr ago, posing an independent age constraint of 60_-6_^+8^ Myr for MUTA, consistent with our isochrone age. This relatively large collection of comoving young stars near the Sun indicates that more work is required to unveil the full kinematic structure of the complex of young stars surrounding {alpha} Persei and Cas-Tau.
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Search Results
- ID:
- ivo://CDS.VizieR/II/331
- Title:
- M68 variable star light curves
- Short Name:
- II/331
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 110 plates of the globular cluster M68, taken during 1951 to 1953 with the 24-inch reflector of the station of Lojano, have been the subject of a photometric investigation.
- ID:
- ivo://CDS.VizieR/J/other/MmSAI/20.63
- Title:
- M30 V1-V3 variable light curves
- Short Name:
- J/other/MmSAI/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 175 plates of the globular cluster M30 in Capricornus, taken mainly in the years 1946, 1947 and 1948, with the 24-inch reflector, have been the object of a photometric investigation.
- ID:
- ivo://CDS.VizieR/J/other/NewA/49.43
- Title:
- MWC 560 UBV(RI)c light curves
- Short Name:
- J/other/NewA/49.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- After 26 years from the major event of 1990, in early 2016 the puzzling symbiotic binary MWC 560 has gone into a new and even brighter outburst. We present our tight BVRCIC photometric monitoring of MWC 560 (451 independent runs distributed over 357 different nights), covering the 2005-2016 interval, and the current outburst in particular. A stricking feature of the 2016 outburst has been the suppression of the short term chaotic variability during the rise toward maximum brightness, and its dominance afterward with an amplitude in excess of 0.5mag. Similar to the 1990 event when the object remained around maximum brightness for ~6 months, at the time Solar conjunction prevented further observations of the current outburst, MWC 560 was still around maximum, three months past reaching it. We place our observations into a long term context by combining with literature data to provide a complete 1928-2016 lightcurve. Some strong periodicities are found to modulate the optical photometry of MWC 560. A period of 1860-days regulate the occurence of bright phases at BVRC bands (with exactly 5.0 cycles separating the 1990 and 2016 outbursts), while the peak brightness attained during bright phases seems to vary with a ~9570-days cycle. A clean 331-day periodicity modulate the Ic lightcurve, where the emission from the M giant dominates, with a lightcurve strongly reminiscent of an ellipsoidal distortion plus irradiation from the hot companion. Pros and cons of 1860 and 331 days as the system orbital period are reviewed, waiting for a spectroscopic radial velocity orbit of the M giant to settle the question (provided the orbit is not oriented face-on).
- ID:
- ivo://CDS.VizieR/J/MNRAS/391/164
- Title:
- MW Lyr BV(RI)c light curves
- Short Name:
- J/MNRAS/391/164
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained the most extensive and most accurate photometric data of a Blazhko variable MW Lyrae (MW Lyr) during the 2006-2007 observing seasons. The data within each 0.05 phase bin of the modulation period (P_m_=1/f_m_) cover the entire light cycle of the primary pulsation period (P_0_=1/f_0_) , making possible a very rigorous and complete analysis.
- ID:
- ivo://CDS.VizieR/J/AJ/137/2949
- Title:
- MY Cyg differential light curves
- Short Name:
- J/AJ/137/2949
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Differential UBV photoelectric photometry for the eclipsing binary MY Cyg is presented. The Wilson-Devinney program is used to simultaneously solve the three light curves together with previously published radial velocities. A comparison is made with the previous solution found with the Russell-Merrill method. We examine the long-term apsidal motion of this well-detached, slightly eccentric system. We determine absolute dimensions, discuss metallicity/Am-star issues, and estimate the evolutionary status of the stars.
- ID:
- ivo://CDS.VizieR/J/AJ/126/175
- Title:
- M31Y eclipsing binaries and Cepheids
- Short Name:
- J/AJ/126/175
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The DIRECT Project aims to obtain direct distances to two Local Group galaxies, M31 and M33, which occupy a crucial position near the base of the cosmological distance ladder. The first step is to search for detached eclipsing binaries (DEBs) and Cepheids using 1m class telescopes to select good candidates, which will be followed up spectroscopically on 6.510m class telescopes. In this ninth paper, we present a catalog of variable stars discovered with image subtraction in field M31Y (RA=10.97{deg}, DE=41.69{deg}; J2000.0). The data were obtained with the Fred Lawrence Whipple Observatory 1.2m telescope on 25 nights, over a period of 6 months. In our search covering 22x22, we discovered 41 eclipsing binaries, 126 Cepheids, and 97 other periodic or nonperiodic variables, including a luminous blue variable candidate, a nova, and a Galactic cataclysmic variable. The catalog of variables, as well as their photometry and finding charts, is available electronically via anonymous ftp and the World Wide Web, at http://cfa-www.harvard.edu/~kstanek/DIRECT . The complete set of the CCD frames is available upon request.
- ID:
- ivo://CDS.VizieR/J/A+A/590/A116
- Title:
- Nainital-Cape Survey. IV.
- Short Name:
- J/A+A/590/A116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Nainital-Cape Survey is a dedicated ongoing Survey programme to search for and study pulsational variability in chemically peculiar (CP) stars to understand their internal structure and evolution. The main aims of this Survey are to find new pulsating Ap and Am stars in the northern and southern hemisphere and to perform asteroseismic studies of these new pulsators. The Survey is conducted using high-speed photometry. The candidate stars were selected on the basis of having Stromgren photometric indices similar to those of known pulsating CP stars. Over the last decade a total of 337 candidate pulsating CP stars were observed for the Nainital-Cape Survey, making it one of the longest ground-based surveys for pulsation in CP stars in terms of time span and sample size. The previous papers of this series presented seven new pulsating variables and 229 null results. In this paper we present the light curves, frequency spectra and various astrophysical parameters of the 108 additional CP stars observed since the last reported results. We also tabulated the basic physical parameters of the known roAp stars. As a part of establishing the detection limits in the Nainital-Cape Survey, we investigated the scintillation noise level at the two observing sites used in this Survey, Sutherland and Nainital, by comparing the combined frequency spectra stars observed from each location. Our analysis shows that both the sites permit the detection of variations of the order of 0.6-milli-magnitude (mmag) in the frequency range 1-4mHz, Sutherland is on average marginally better.
- ID:
- ivo://CDS.VizieR/J/ApJS/247/7
- Title:
- Narrowband Ca photometry for dwarf spheroidal galaxies
- Short Name:
- J/ApJS/247/7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A few dozen dwarf satellite galaxies of the Milky Way have been discovered, which are often viewed as the remaining building blocks of our Galaxy. The follow-up spectroscopy showed that dwarf galaxies have a sizeable spread in their metallicities. Several scenarios were suggested to explain the metallicity spread, which can be tested by the structural patterns of stellar subpopulations with distinct metallicities. However, such chemical plus structural examination, which we refer to as "chemostructural study", is hindered by the lack of stars with spectroscopic metallicity. Here we propose the Ca-by photometry as an alternative way to secure metallicities for a 2-3 orders of magnitude larger stellar sample than the spectroscopic sample and thus enable us to perform a chemostructural study on dwarf galaxies. In particular, we use the hk index [=(Ca-b)-(b-y)], whose validity as a photometric metallicity indicator (and crass insensitivity to age) for red-giant-branch stars was upheld via Galactic globular clusters, and observe three dwarf spheroidal galaxies-Draco, Sextans, and Canes Venatici I (CVnI)-with Subaru/Suprime-Cam. We find that in all the galaxies the metal-rich stellar populations are more centrally concentrated than the metal-poor counterparts, suggesting that the central regions of the galaxies underwent extended star formation. Such a negative radial metallicity gradient for Sextans and CVnI opposes the traditional spectroscopic results. We also find that their metallicity distribution functions (MDFs) can be characterized by a unimodal, skewed Gaussian shape with a metal-rich peak and a metal-poor tail.
- ID:
- ivo://CDS.VizieR/III/254
- Title:
- 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>.
