- ID:
- ivo://CDS.VizieR/J/MNRAS/428/3252
- Title:
- Barium abundances in Cepheids
- Short Name:
- J/MNRAS/428/3252
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derived the barium atmospheric abundances for a large sample of Cepheids, comprising 270 stars. The sample covers a large range of Galactocentric distances, from about 4 to 15kpc, so it is appropriate to investigate the existence of radial barium abundance gradients in the Galactic disc. In fact, this is the first time that such a comprehensive analysis of the distribution of barium abundances in the Galactic disc has been carried out. As a result, we conclude that the Ba abundance distribution can be characterized by a zero gradient. This result is compared with derived gradients for other elements, and some reasons are briefly discussed for the independence of the barium abundances from Galactocentric distances.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/112/2769
- Title:
- Behlen Observatory Survey. IV.
- Short Name:
- J/AJ/112/2769
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Finding charts, accurate coordinates, and light curves are presented for 106 variable stars including 6 which are newly discovered. Parameters descriptive of the light curves are tabulated including periods for 16 stars which lacked them. The periods from the General Catalog of Variable Stars for ten stars were found to be seriously in error. The classification of the stars is discussed. Revisions or refinements of the classifications from the General Catalogue of Variable Stars are suggested for 20 stars and classifications are given for 7 which were previously unclassified. 15%-23% of the Bailey type ab RR Lyrae stars show scatter in their light curves which is suggestive of the Blazhko effect.
- ID:
- ivo://CDS.VizieR/J/MNRAS/388/444
- Title:
- Berkeley 58 & CG Cas UBV photometry
- Short Name:
- J/MNRAS/388/444
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photoelectric, photographic and CCD UBV photometry, spectroscopic observations and star counts are presented for the open cluster Berkeley 58 to examine a possible association with the 4.37d Cepheid CG Cas. The cluster is difficult to separate from the early-type stars belonging to the Perseus spiral arm, in which it is located, but has reasonably well-defined parameters: an evolutionary age of ~10^8^yr, a mean reddening of E(B-V)(B0)=0.70+/-0.03 s.e. and a distance of 3.03+/-0.1kpc (V_0_-M_V_=12.40+/-0.12 s.d.). CG Cas is a likely cluster coronal member on the basis of radial velocity, and its period increase of +0.170+/- 0.01s/y and large light amplitude describe a Cepheid in the third crossing of the instability strip lying slightly blueward of strip centre. Its inferred reddening and luminosity are E(B-V)=0.64+/-0.02 s.e. and <M_V_>=-3.06+/-0.12. A possible K supergiant may also be a cluster member.
- ID:
- ivo://CDS.VizieR/J/AJ/151/110
- Title:
- BEST-II catalog of variables: CoRoT SRc02 field
- Short Name:
- J/AJ/151/110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Time-series photometry of the CoRoT field SRc02 was obtained by the Berlin Exoplanet Search Telescope II (BEST II) in 2009. The main aim was to conduct a ground-based follow-up of the CoRoT field in order to detect variable stars with better spatial resolution than what can be achieved with the CoRoT Space Telescope. A total of 1846 variable stars were detected, of which only 30 have been previously known. For nine eclipsing binaries the stellar parameters were determined by modeling their light curves.
- ID:
- ivo://CDS.VizieR/J/AJ/156/204
- Title:
- BEST-II catalog of variables. III. Puppis field
- Short Name:
- J/AJ/156/204
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Berlin Exoplanet Search Telescope II (BEST II) is a ground-based, small aperture, wide-angle telescope used to search for stellar light variations in the southern hemisphere. We report the results of a monitoring campaign observing a field in the Puppis constellation in late 2011/early 2012. Light curves were obtained for 130472 stars, out of which we identify 2169 variables, including 1829 newly discovered, 26 previously known, and 314 suspected variable stars. We determine periods and variability class for two previously known, but only suspected to be, variable stars. For eight individual eclipsing binary stars, including the two previously known but unclassified binaries, the system parameters were derived at the epoch of the observation by modeling the light curves. Eventually, in a catalog for all variable stars, we present coordinates, magnitude, and elements of light variations, e.g., epoch, period, amplitude, type, and light curves. This catalog concludes the BEST/BEST II project.
- ID:
- ivo://CDS.VizieR/J/A+A/506/569
- Title:
- BEST-II periodic variables in CoRoT LRa02 field
- Short Name:
- J/A+A/506/569
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Berlin Exoplanet Search Telescope II (BEST II) is a small wide field-of-view photometric survey telescope system located at the Observatorio Cerro Armazones, Chile. The high duty cycle combined with excellent observing conditions and millimagnitude photometric precision makes this instrument suitable for ground based support observations for the CoRoT space mission. Photometric data of the CoRoT LRa02 target field collected between November 2008 and March 2009 were analysed for stellar variability. The presented results will help in the future analysis of the CoRoT data, particularly in additional science programs related to variable stars. BEST II observes selected CoRoT target fields ahead of the space mission. The photometric data acquired are searched for stellar variability, periodic variable stars are identified with time series analysis of the obtained stellar light curves. We obtained the light curves of 104335 stars in the CoRoT LRa02 field over 41 nights. Variability was detected in light curves of 3726 stars of which 350 showed a regular period. These stars are, with the exception of 5 previously known variable stars, new discoveries.
- ID:
- ivo://CDS.VizieR/J/AJ/143/140
- Title:
- BEST-II periodic variables in CoRoT LRa02 field. II.
- Short Name:
- J/AJ/143/140
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The CoRoT (Convection, Rotation and planetary Transit) field LRa02 has been observed with the Berlin Exoplanet Search Telescope II (BEST II) during the southern summer 2007/2008. A first analysis of stellar variability led to the publication of 345 newly discovered variable stars. Now, a deeper analysis of this data set was used to optimize the variability search procedure. Several methods and parameters have been tested in order to improve the selection process compared to the widely used J index for variability ranking. This paper describes an empirical approach to treat systematic trends in photometric data based upon the analysis of variance statistics that can significantly decrease the rate of false detections. Finally, the process of reanalysis and method improvement has virtually doubled the number of variable stars compared to the first analysis by Kabath et al. (Paper I, 2009, Cat. J/A+A/506/569). A supplementary catalog of 272 previously unknown periodic variables plus 52 stars with suspected variability is presented. Improved ephemerides are given for 19 known variables in the field. In addition, the BEST II results are compared with CoRoT data and its automatic variability classification.
- ID:
- ivo://CDS.VizieR/J/AJ/134/1560
- Title:
- BEST periodic variable stars in IR01 field
- Short Name:
- J/AJ/134/1560
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on observations of the COROT IR01 field with the Berlin Exoplanet Search Telescope (BEST). BEST is a small-aperture telescope with a wide field of view (FOV). It is dedicated to searching for variable stars within the target fields of the COROT space mission to aid in minimizing false-alarm rates, and identifying potential targets for additional science. COROT's observational program started in 2007 February, with the "initial run" field (IR01) observed for about 2 months. BEST observed this field for 12 nights spread over 3 months in winter 2006. From the total of 30,426 stars observed in the IR01 field, 3769 were marked as suspected variable stars, and 54 of these showed clear periodicity. From these, 19 periodic stars are within the part of the COROT FOV covered in our data set.
- ID:
- ivo://CDS.VizieR/J/AJ/136/654
- Title:
- BEST periodic variable stars in LRa1 field
- Short Name:
- J/AJ/136/654
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we report on observations of the CoRoT LRa1 field with the Berlin Exoplanet Search Telescope (BEST). The current paper is part of a series of papers describing the results of our stellar variability survey. The BEST is a small aperture telescope with a wide field of view (FOV). It is dedicated to searching for stellar variability within the target fields of the CoRoT space mission to aid in minimizing false-alarm rates and identify potential targets for additional science. The LRa1 field is CoRoT's second long run field located in the galactic anticenter direction. We observed the LRa1 stellar field on 23 nights between November and March 2005/2006. From 6099 stars marked as variable, 39 were classified as periodic variable stars and 27 of them are within the CoRoT FOV. We also confirmed the variability for four stars listed in the General Catalogue of Variable Stars (GCVS).
- ID:
- ivo://CDS.VizieR/J/AJ/137/3911
- Title:
- BEST periodic variable stars in LRc2 field
- Short Name:
- J/AJ/137/3911
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on photometric observations of the CoRoT LRc2 field with the new robotic Berlin Exoplanet Search Telescope II (BEST II). The telescope system was installed and commissioned at the Observatorio Cerro Armazones, Chile, in 2007. BEST II is a small aperture telescope with a wide field of view dedicated to the characterization of the stellar variability primarily in CoRoT target fields with high stellar densities. The CoRoT stellar field LRc2 was observed with BEST II up to 20 nights in 2007 July and August. From the acquired data containing about 100,000 stars, 426 new periodic variable stars were identified and 90% of them are located within the CoRoT exoplanetary CCD segments and may be of further interest for CoRoT additional science programs.
