- ID:
- ivo://CDS.VizieR/J/A+A/586/A125
- Title:
- Neutron-capture elements abundances in Cepheids
- Short Name:
- J/A+A/586/A125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new accurate abundances for five neutron-capture (Y, La, Ce, Nd, Eu) elements in 73 classical Cepheids located across the Galactic thin disk. Individual abundances are based on high spectral resolution (R~38000) and high signal-to-noise ratio (S/N~50-300) spectra collected with UVES at ESO VLT for the DIONYSOS project. Taking account for similar Cepheid abundances provided either by our group (111 stars) or available in the literature, we end up with a sample of 435 Cepheids covering a broad range in iron abundances (-1.6<[Fe/H]<0.6). We found, using homogeneous individual distances and abundance scales, well defined gradients for the above elements. However, the slope of the light s-process element (Y) is at least a factor of two steeper than the slopes of heavy s- (La, Ce, Nd) and r- (Eu) process elements. The s to r abundance ratio ([La/Eu]) of Cepheids shows a well defined anticorrelation with of both Eu and Fe. On the other hand, Galactic field stars attain an almost constant value and only when they approach solar iron abundance display a mild enhancement in La. The [Y/Eu] ratio shows a mild evidence of a correlation with Eu and, in particular, with iron abundance for field Galactic stars. We also investigated the s-process index -- [hs/ls] -- and we found a well defined anticorrelation, as expected, between [La/Y] and iron abundance. Moreover, we found a strong correlation between [La/Y] and [La/Fe] and, in particular, a clear separation between Galactic and Sagittarius red giants. Finally, the comparison between predictions for low-mass asymptotic giant branch stars and the observed [La/Y] ratio indicate a very good agreement over the entire metallicity range covered by Cepheids. However, the observed spread, at fixed iron content, is larger than predicted by current models.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AcA/60/261
- Title:
- New bright periodic variables toward Galactic Bulge
- Short Name:
- J/AcA/60/261
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on photometric I-band observations of 147 bright (8<I<13) periodic variable stars toward the Galactic bulge including 76 new discoveries. We used one of the HATnet telescopes to obtain 151 exposures spanning 88 nights in 2005 of an 8.4{deg}x8.4{deg} field of view (FOV) approximately centered on (l,b)=(1.73,-4.68). We observed the Galactic bulge in 2005 as part of a microlensing feasibility study, and here we discuss the periodic variable stars we found in our data. Among our discoveries we count 52 new eclipsing binaries and 24 other periodic variable stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/421/3325
- Title:
- 2 new candidate luminous blue variables
- Short Name:
- J/MNRAS/421/3325
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of two new Galactic candidate luminous blue variable (LBV) stars via detection of circular shells (typical of confirmed and candidate LBVs) and follow-up spectroscopy of their central stars. The shells were detected at 22um in the archival data of the Mid-Infrared All Sky Survey carried out with the Wide-field Infrared Survey Explorer (WISE). Follow-up optical spectroscopy of the central stars of the shells conducted with the renewed Southern African Large Telescope (SALT) showed that their spectra are very similar to those of the well-known LBVs P Cygni and AG Car, and the recently discovered candidate LBV MN112, which implies the LBV classification for these stars as well.
- ID:
- ivo://CDS.VizieR/J/AJ/145/132
- Title:
- New catalog of 1578 {delta} Scuti stars
- Short Name:
- J/AJ/145/132
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present statistical characteristics of 1578 {delta} Scuti stars including nearby field stars and cluster member stars within the Milky Way. We obtained 46% of these stars (718 stars) from work by Rodriguez and collected the remaining 54% of stars (860 stars) from other literature. We updated the entries with the latest information of sky coordinates, color, rotational velocity, spectral type, period, amplitude, and binarity. The majority of our sample is well characterized in terms of typical period range (0.02-0.25days), pulsation amplitudes (<0.5mag), and spectral types (A-F type). Given this list of {delta} Scuti stars, we examined relations between their physical properties (i.e., periods, amplitudes, spectral types, and rotational velocities) for field stars and cluster members, and confirmed that the correlations of properties are not significantly different from those reported in Rodriguez's work. All the {delta} Scuti stars are cross-matched with several X-ray and UV catalogs, resulting in 27 X-ray and 41 UV-only counterparts. These counterparts are interesting targets for further study because of their uniqueness in showing {delta} Scuti-type variability and X-ray/UV emission at the same time. The compiled catalog can be accessed through the Web interface http://stardb.yonsei.ac.kr/DeltaScuti.
- ID:
- ivo://CDS.VizieR/J/AJ/150/27
- Title:
- New catalog of variable stars in M37 field
- Short Name:
- J/AJ/150/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive re-analysis of stellar photometric variability in the field of the open cluster M37 following the application of a new photometry and de-trending method to the MMT/Megacam image archive. This new analysis allows a rare opportunity to explore photometric variability over a broad range of timescales, from minutes to a month. The intent of this work is to examine the entire sample of more than 30000 objects for periodic, aperiodic, and sporadic behaviors in their light curves. We show a modified version of the fast {chi}^2^ periodogram algorithm (F{chi}^2^) and change-point analysis as tools for detecting and assessing the significance of periodic and non-periodic variations. The benefits of our new photometry and analysis methods are evident. A total of 2306 stars exhibit convincing variations that are induced by flares, pulsations, eclipses, starspots, and unknown causes in some cases. This represents a 60% increase in the number of variables known in this field. Moreover, 30 of the previously identified variables are found to be false positives resulting from time-dependent systematic effects. The new catalog includes 61 eclipsing binary systems, 92 multiperiodic variable stars, 132 aperiodic variables, and 436 flare stars, as well as several hundreds of rotating variables. Based on extended and improved catalog of variables, we investigate the basic properties (e.g., period, amplitude, type) of all variables. The catalog can be accessed through the web interface (http://stardb.yonsei.ac.kr/).
- ID:
- ivo://CDS.VizieR/II/219
- Title:
- New Catalogue of Suspected Variable Stars Supplement
- Short Name:
- II/219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog is a compilation of 11206 stars suspected of variability and not finally designated as variables prior to 1997. It is the supplementary part to the "New Catalogue of Suspected Variable Stars" published in 1982 (Kukarkin et al., file "nsv.dat" included here). Data contained in the present catalog include positions, magnitudes, variability types, references to the literature, spectra and cross-identifications. The computer version of the NSV Supplement contains principally the same data as the printed catalog, the data tables with the textual material (bibliography, remarks) are included.
- ID:
- ivo://CDS.VizieR/J/other/IBVS/5586
- Title:
- New elements for 80 eclipsing binaries V.
- Short Name:
- J/other/IBVS/558
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This research presents new elements for 80 eclipsing binaries found with the help of the ASAS-3 (Cat. <II/264>), Hipparcos (Cat. <I/239>) and NSVS (2004AJ....127.2436W) databases.
- ID:
- ivo://CDS.VizieR/J/other/PZP/9.6
- Title:
- New light elements for 28 red periodic var.
- Short Name:
- J/other/PZP/9.6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We could study the variables thanks to the publicly available electronic archives of CCD observations of the ASAS-3 project (Pojmanski 2002, Cat. <II/264>) and to images of the US Naval Observatory Image and Catalogue Archive (https://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/icas). We recovered the variables NSV 07168, NSV 07291, NSV 07352, NSV 07388 and NSV 07406 suspected by Luyten (1933AN....249..395L); NSV 07161, NSV 07188, NSV 07203, NSV 07208, NSV 07260, NSV 07286, NSV 07347, NSV 07387, NSV 07392 and NSV 07422 suspected by Luyten (1933AN....250..259L); NSV 07130, NSV 07228, NSV 07238 and NSV 07425 suspected by Luyten (1934AN....253..135L); NSV 07117, NSV 07131, NSV 07137 and NSV 07382 suspected by Luyten (1935AN....256..325L); NSV 07411 suspected by Luyten (1936AN....258..121L); NSV 07309 suspected by Luyten (1937AN....261..451L); NSV 07353 suspected by Luyten (1937AN....263..181L). Finding charts for these suspected variables have never been published.
- ID:
- ivo://CDS.VizieR/J/other/OEJV/149
- Title:
- New Miras in Galactic Bulge
- Short Name:
- J/other/OEJV/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 500 new Mira variables in the direction of the Galactic Bulge are presented, which were found in the MACHO database.
- ID:
- ivo://CDS.VizieR/J/other/JAVSO/34.222
- Title:
- New Northern Hemisphere Variables
- Short Name:
- J/other/JAVSO/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A survey looking for previously unknown variable stars has been carried out in the declination range 30-39 degrees and in the R.A. range 0-24 hours. The survey was done in I-band, and was carried out from October 2003 to December of 2004. Seventy-five new and previously suspected variable stars were detected. This paper presents a brief description of the survey and identifies the new variables.
