- ID:
- ivo://CDS.VizieR/J/AJ/101/1352
- Title:
- Observations of variable stars in M9
- Short Name:
- J/AJ/101/1352
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of RR Lyrae variables near the transition between fundamental and first-overtone mode in the Oosterhoff type II (Oo II) globular clusters M80, M9, and NGC 2298 have been analyzed in a search for double-mode pulsators (RRd stars). These three clusters were selected because they have metal abundances that are intermediate between those of the Oo II clusters and the Oo I clusters that are known to have RRd stars. Any RRd stars identified in these three clusters would be useful for verification of a mass-metallicity relation. The analysis was based on published observations for all three clusters, and in addition, 44 CCD frames of M9 and 32 photographs of NGC 2298, all obtained with the University of Toronto telescope at Las Campanas. No new RRd stars were discovered. It is noted that the only globular clusters known to have RRd stars are the most metal poor Oo I clusters and metal poor Oo II clusters. Published observations of the RRd stars in M15 have been analyzed in order to determine accurate periods and period ratios for stars whose periods were previously considered to be uncertain.
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Search Results
- ID:
- ivo://CDS.VizieR/III/199A
- Title:
- Observed Periods of Ap and Bp stars
- Short Name:
- III/199A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalogue of all the periods published up to 31 October 1996 on 364 CP stars is presented; it supersedes the previous version (catalog <III/152>). The paper version (catalog.tex) is arranged in three tables: the bulk of the data, i.e. those referring to CP2, CP3, and CP4 stars, are given in Table 1, while the data concerning He-strong stars are given in Table 2 and those for eclipsing or ellipsoidal variables are collected in Table 3. Notes are also provided at the end of each table, mainly about duplicities. The machine-readable version was arranged in two main parts: the main parameters of the 364 stars (identifiers and names, positions, spectral types, magnitudes and peculiarities) are tabulated in the file 'stars'; periods and the of the observed variations (light, spectrum, magnetic field, etc.) are listed in the 'periods' file. Two other files contains the notes and the references.
- ID:
- ivo://CDS.VizieR/J/AJ/161/27
- Title:
- O-C values of KIC10975348 with Kepler Space Telescope
- Short Name:
- J/AJ/161/27
- Date:
- 11 Mar 2022
- Publisher:
- CDS
- Description:
- In this paper, we analyze the light variations of KIC10975348 using photometric data delivered from the Kepler mission. This star is exceptionally faint (Kp=18.6mag) compared to most well-studied {delta}Scuti stars. The Fourier analysis of the short-cadence data (i.e., Q14, Q15, and Q16, spanning 220days) reveals that the variations are dominated by the strongest mode with a frequency of F0=10.231899/day, which is compatible with that obtained from RATS-Kepler. The other two independent modes with F1(=13.4988/day) and F2(=19.0002/day) are newly detected and have amplitudes two orders of magnitude smaller than F0. We note that, for the first time, this star is identified to be a high-amplitude {delta}Sct (HADS) star with an amplitude of about 0.7mag, and the lower ratio of F0/F1=0.758 suggests that it might be a metal-rich variable star. The frequency F2 may be a third overtone mode, suggesting that this target might be a new radial triple-mode HADS star. We perform an O-C analysis using 1018 newly determined times of maximum light and derive an ephemeris formula of Tmax=2456170.241912(0)+0.097734(1)xE. The O-C diagram shows that the pulsation period of KIC10975348 seems to show no obvious change, which is in contrast to that of the majority of HADS stars. The possible cause of that may be due to the current short time span of the observations. To verify its possible period variations, regular observation from space with a longer time span in the future is needed.
- ID:
- ivo://CDS.VizieR/J/PASJ/58/389
- Title:
- O/Fe abundances of 15 RR Lyrae
- Short Name:
- J/PASJ/58/389
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to study how the conventional spectroscopic method based on the equivalent widths of the Fe I and Fe II lines effectively applies to determining the atmospheric parameters (Teff, logg, v_t_, [Fe/H]) of RR Lyrae variables and how accurately the abundances can be established from such constructed model atmospheres, we analyzed 15 high-dispersion spectrograms of RR Lyr, DX Del, DH Peg, and VY Ser taken at several different phases by using the HDS spectrograph of the Subaru Telescope, and examined the consistency of the resulting phase-to-phase abundances.
- ID:
- ivo://CDS.VizieR/J/ApJ/812/136
- Title:
- OGLE-2013-BLG-446 photometry
- Short Name:
- J/ApJ/812/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For all exoplanet candidates, the reliability of a claimed detection needs to be assessed through a careful study of systematic errors in the data to minimize the false positives rate. We present a method to investigate such systematics in microlensing data sets using the microlensing event OGLE-2013-BLG-0446 as a case study. The event was observed from multiple sites around the world and its high magnification (A_max_~3000) allowed us to investigate the effects of terrestrial and annual parallax. Real-time modeling of the event while it was still ongoing suggested the presence of an extremely low-mass companion (~3M_{Earth}_) to the lensing star, leading to substantial follow-up coverage of the light curve. We test and compare different models for the light curve and conclude that the data do not favor the planetary interpretation when systematic errors are taken into account.
- ID:
- ivo://CDS.VizieR/J/MNRAS/504/5907
- Title:
- OGLE Bulge short-period sample
- Short Name:
- J/MNRAS/504/5907
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the third of a series of papers that presents an algorithm to search for close binaries with massive, possibly compact, unseen secondaries. The detection of such a binary is based on identifying a star that displays a large ellipsoidal periodic modulation, induced by tidal interaction with its companion. In the second paper of the series, we presented a simple approach to derive a robust modified minimum mass ratio (mMMR), based on the observed ellipsoidal amplitude, without knowing the primary mass and radius, assuming the primary fills its Roche lobe. The newly defined mMMR is always smaller than the actual mass ratio. Therefore, a binary with an mMMR larger than unity is a good candidate for having a massive secondary, which might be a black hole or a neutron star. This paper considers 10956 OGLE short-period ellipsoidals observed towards the Galactic bulge. We re-analyse their modulation and identify 136 main-sequence systems with mMMR significantly larger than unity as candidates for having compact-object secondaries, assuming their observed periodic modulations reflect indeed the ellipsoidal effect. Obviously, one needs follow-up observations to find out the true nature of these companions.
- ID:
- ivo://CDS.VizieR/J/AcA/51/317
- Title:
- OGLE DIA. Catalog of LMC and SMC images
- Short Name:
- J/AcA/51/317
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first edition of a catalog of variable stars found in the Magellanic Clouds using OGLE-II data obtained during four years: 1997-2000. The catalog covers about 7 square degrees of the sky - 21 fields in the Large Magellanic Cloud and 11 fields in the Small Magellanic Cloud. All variables were found with the Difference Image Analysis (DIA) software. The catalog is divided into two sections. The DC section contains FITS reference images (obtained by co-adding 20 best frames for each field) and profile photometry (DOPHOT) of all variable stars on those images. The AC section contains flux variations and magnitudes of detected variable stars obtained with DIA as well as with DOPHOT. The errors of magnitude measurements are 0.005mag for the brightest stars (I<16mag) then grow to 0.08mag at 19mag stars and to 0.3mag at 20.5mag. Typically, there are about 400 I-band data points and about 30 V and B-band data points for more than 68 000 variables. The stars with high proper motions were excluded from this catalog and will be presented in a separate paper. A detailed analysis and classification of variable stars will be presented elsewhere. The catalog is available in electronic form via FTP and through WWW interface from the OGLE Internet archive. The FTP catalog contains approximately 2 GB of data.
- ID:
- ivo://CDS.VizieR/J/ApJ/651/197
- Title:
- OGLE fundamental-mode RR Lyrae in Galactic Bulge
- Short Name:
- J/ApJ/651/197
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 1888 fundamental-mode RR Lyrae stars detected in the Galactic bulge fields of the second phase of the Optical Gravitational Lensing Experiment (OGLE). The catalog includes basic parameters of the light curves, identifications of Blazhko frequencies, V-I colors at minimum light (for most stars), and other information for each star. We detect a high rate of incidence of the Blazhko phenomenon (at least 27.6%), including unprecedentedly many frequency triplets, which we attribute to our sensitive search method. We find that the minimum light V-I color (useful as a reddening indicator) grows slowly redder with increasing period and exhibits a star-to-star scatter of approximately 0.07mag. We use this color to evaluate the zero-point accuracy of the reddening map of the Galactic bulge derived from OGLE data and find that in addition to low-level random errors or resolution effects (responsible for much of the scatter), the map may systematically over-represent E(V-I) by approximately 0.05mag in most fields.
- ID:
- ivo://CDS.VizieR/J/AcA/62/219
- Title:
- OGLE: Gaia South Ecliptic Pole Field
- Short Name:
- J/AcA/62/219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive analysis of the Gaia South Ecliptic Pole (GSEP) field, 5.3 square degrees area around the South Ecliptic Pole on the outskirts of the LMC, based on the data collected during the fourth phase of the Optical Gravitational Lensing Experiment, OGLE-IV. The GSEP field will be observed during the commissioning phase of the ESA Gaia space mission for testing and calibrating the Gaia instruments. We provide the photometric maps of the GSEP region containing the mean VI photometry of all detected stellar objects and their equatorial coordinates. We show the quality and completeness of the OGLE-IV photometry and color-magnitude diagrams of this region. We conducted an extensive search for variable stars in the GSEP field leading to the discovery of 6789 variable stars. In this sample we found 132 classical Cepheids, 686 RR Lyr type stars, 2819 long-period, and 1377 eclipsing variables. Several objects deserving special attention were also selected, including a new classical Cepheid in a binary eclipsing system.
- ID:
- ivo://CDS.VizieR/II/213
- Title:
- OGLE Galactic Bulge periodic variables
- Short Name:
- II/213
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Catalog of Periodic Variable Stars in the Galactic Bulge. The Catalog is based on observations collected during the OGLE (Optical Graviational Lensing Experiment) microlensing search: (1) 213 periodic variable stars brighter than Imag=18mag: 31 pulsating, 116 eclipsing and 66 miscellaneous type variables from the Baade's Window BWC field are presented. (2) 800 variable stars found in four Baade's Window fields BW1, BW2, BW3 and BW4 are presented. Among them 71 are classified as pulsating, 465 as eclipsing and 264 as miscellaneous type. (3) 644 variable stars: 64 pulsating, 352 eclipsing and 228 miscellaneous type were detected in four Baade's Window fields BW5, BW6, BW7 and BW8. Analysis of periodic variable stars found in overlapping regions of the Baade's Window fields yields an average completeness of the Catalog equal to about 80% of periodic variables objects registered in the OGLE databases and about 65% of all periodic variable stars in the observed region of the sky. (4) 631 variable stars: 59 pulsating, 348 eclipsing and 224 miscellaneous type were detected in third Baade's Window fields BW9, BW10, and BW11. (5) 574 variables stars: 44 pulsating, 369 eclipsing and 161 miscellaneous type were detected in four fields located symmetrically in the galactic latitude around the Galactic center: MM5-A, MM5-B, MM7-A and MM7-B.
