- ID:
- ivo://CDS.VizieR/J/A+A/656/A125
- Title:
- ACV variables in the Zwicky Transient Facility
- Short Name:
- J/A+A/656/A125
- Date:
- 16 Mar 2022 00:55:18
- Publisher:
- CDS
- Description:
- The present work presents a case study of known variables from the Zwicky Transient Facility (ZTF) survey, with the aim of investigating the survey's suitability for the detection and study of new ACV variables. Using suitable selection criteria based on the known characteristics of ACV variables, candidate ACV stars were selected from the ZTF Catalog of Periodic Variable Stars. All light curves were inspected in detail to select the most promising candidates. Where available, low-resolution spectra from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) were employed to classify the stars on the MK system and confirm their status as mCP stars. We have identified 86 new promising ACV star candidates. 15 of these stars have LAMOST spectra available, which, in all cases, confirm them as classical mCP stars, which highlights the viability of our approach. We present astrophysical parameters for all sample stars, which can be sorted into four subgroups characterized by distinct light curve shapes. Anti-phase variations in different photometric passbands, in particular, is a unique characteristic of a subset of ACV stars readily usable for their identification. The availability of data in three different passbands (g, r, and i) is a major advantage of the ZTF survey. On the basis of our experience with other photometric surveys and the analysis of light curves, we conclude that the ZTF is well suited for the search for, and the analysis of, ACV variables, which, however, are not considered in the available ZTF variable star catalogues. Further work will be concerned with the development and refinement of a search algorithm to correctly identify these stars in ZTF data and, subsequently, in massive photometric time-series databases in general.
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- ID:
- ivo://CDS.VizieR/J/AJ/156/241
- Title:
- A first catalog of variable stars measured by ATLAS
- Short Name:
- J/AJ/156/241
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Asteroid Terrestrial-impact Last Alert System (ATLAS) carries out its primary planetary defense mission by surveying about 13000 deg^2^ at least four times per night. The resulting data set is useful for the discovery of variable stars to a magnitude limit fainter than r~18, with amplitudes down to 0.02 mag for bright objects. Here, we present a Data Release One catalog of variable stars based on analyzing the light curves of 142 million stars that were measured at least 100 times in the first two years of ATLAS operations. Using a Lomb-Scargle periodogram and other variability metrics, we identify 4.7 million candidate variables. Through the Space Telescope Science Institute, we publicly release light curves for all of them, together with a vector of 169 classification features for each star. We do this at the level of unconfirmed candidate variables in order to provide the community with a large set of homogeneously analyzed photometry and to avoid pre-judging which types of objects others may find most interesting. We use machine learning to classify the candidates into 15 different broad categories based on light-curve morphology. About 10% (427000 stars) pass extensive tests designed to screen out spurious variability detections: we label these as "probable" variables. Of these, 214000 receive specific classifications as eclipsing binaries, pulsating, Mira-type, or sinusoidal variables: these are the "classified" variables. New discoveries among the probable variables number 315000, while 141000 of the classified variables are new, including about 10400 pulsating variables, 2060 Mira stars, and 74700 eclipsing binaries.
- ID:
- ivo://CDS.VizieR/J/AJ/149/68
- Title:
- A-F type variable stars from Kepler
- Short Name:
- J/AJ/149/68
- Date:
- 03 Dec 2021 00:36:02
- Publisher:
- CDS
- Description:
- The light curves of 2768 stars with effective temperatures and surface gravities placing them near the gamma Doradus ({gamma} Dor)/delta Scuti ({delta} Sct) instability region were observed as part of the Kepler Guest Observer program from Cycles 1 through 5. The light curves were analyzed in a uniform manner to search for {gamma} Dor, {delta} Sct, and hybrid star pulsations. The {gamma} Dor, {delta} Sct, and hybrid star pulsations extend asteroseismology to stars slightly more massive (1.4-2.5M_{sun}_) than our Sun. We find 207 {gamma} Dor, 84 {delta} Sct, and 32 hybrid candidate stars. Many of these stars are cooler than the red edge of the {gamma} Dor instability strip as determined from ground-based observations made before Kepler. A few of our {gamma} Dor candidate stars lie on the hot side of the ground-based {gamma} Dor instability strip. The hybrid candidate stars cover the entire region between 6200K and the blue edge of the ground-based {delta} Sct instability strip. None of our candidate stars are hotter than the hot edge of the ground-based {delta} Sct instability strip. Our discoveries, coupled with the work of others, show that Kepler has discovered over 2000 {gamma} Dor, {delta} Sct, and hybrid star candidates in the 116 square degree Kepler field of view. We found relatively few variable stars fainter than magnitude 15, which may be because they are far enough away to lie between spiral arms in our Galaxy, where there would be fewer stars.
- ID:
- ivo://CDS.VizieR/J/A+A/421/509
- Title:
- AGAPE catalogue of M31 variables
- Short Name:
- J/A+A/421/509
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the AGAPE astrometric and photometric catalogue of 1579 variable stars in a 14' x 10' field centred on M31. Each variable star in the catalogue is identified as AGPVm, m running from 1 to 1579. Then are given: Fn(x,y) (F being the letter of identification of AGAPE field and n the variable star number in this field; x and y being the pixel coordinates in the reference frame), right ascension and declination for 2000.0, R_max_ magnitude at observed maximum, and L the likelihood function. When the variable star is a nova discovered by eye, no L value is given.
- ID:
- ivo://CDS.VizieR/J/A+AS/145/11
- Title:
- AGAPEROS: variable stars in the LMC Bar
- Short Name:
- J/A+AS/145/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 91-92 EROS-1 data set has been used to select Long Timescale and Long Period Variables (LT&LPV). We choose to perform a selection of variable objects as comprehensive as possible, independent of periodicity and of their position on the colour magnitude diagram, and produce a catalogue of 632 variable objects. Table 2 provides the parameters of the variable objects detected in this paper. They are sorted in order of increasing right ascension. The columns contains the name of the variable including the RA,DEC (J2000.0) coordinates, the number of the chip and (x,y) position, the blending flags (PhiC/Phi0)_B_, (PhiC/Phi0)_R_ in both colours, the B_EROS_ and R_EROS_ magnitude, the number of star N_star_B, N_star_R found in the superpixel, the magnitude B_EROS_DAO and R_EROS_DAO estimated with DAOPHOT, and when available the cross-identifications with previous catalogue.
- ID:
- ivo://CDS.VizieR/J/ApJ/748/107
- Title:
- A global model for MC and Galactic Cepheids
- Short Name:
- J/ApJ/748/107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform a global fit to ~5000 radial velocity and ~177000 magnitude measurements in 29 photometric bands covering 0.3{mu}m to 8.0{mu}m distributed among 287 Galactic, Large Magellanic Cloud, and Small Magellanic Cloud Cepheids with P>10 days. We assume that the Cepheid light curves and radial velocities are fully characterized by distance, reddening, and time-dependent radius and temperature variations. We construct phase curves of radius and temperature for periods between 10 and 100 days, which yield light-curve templates for all our photometric bands and can be easily generalized to any additional band. With only four to six parameters per Cepheid, depending on the existence of velocity data and the amount of freedom in the distance, the models have typical rms light and velocity curve residuals of 0.05mag and 3.5km/s. The model derives the mean Cepheid spectral energy distribution and its derivative with respect to temperature, which deviate from a blackbody in agreement with metal-line and molecular opacity effects. We determine a mean reddening law toward the Cepheids in our sample, which is not consistent with standard assumptions in either the optical or near-IR. Based on stellar atmosphere models, we predict the biases in distance, reddening, and temperature determinations due to the metallicity and quantify the metallicity signature expected for our fit residuals.
- ID:
- ivo://CDS.VizieR/J/MNRAS/420/585
- Title:
- AKARI observations of SMC Cepheids
- Short Name:
- J/MNRAS/420/585
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work we matched the AKARI archival data to the Optical Gravitational Lensing Experiment III (OGLE-III) catalogue to derive the mid-infrared period-luminosity (PL) relations for Small Magellanic Cloud (SMC) Cepheids. Mismatched AKARI sources were eliminated using random-phase colours obtained from the full I-band light curves from OGLE-III. It was possible to derive PL relations in the N3 and N4 bands only, although the S7-, S11-, L15- and L24-band data were also tested. Random-phase correction was included when deriving the PL relation in the N3 and N4 bands using the available time of observations from AKARI data. The final adopted PL relations were N3=-3.370logP+16.527 and N4=-3.402logP+16.556. However, these PL relations may be biased due to the small number of Cepheids in the sample.
- ID:
- ivo://CDS.VizieR/J/AcA/50/177
- Title:
- All Sky Automated Survey Catalog
- Short Name:
- J/AcA/50/177
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of the first two years of observations using the All Sky Automated Survey prototype camera are presented. More than 140000 stars in 50 Selected Fields covering 300 square degrees were monitored each clear night in the I-band resulting in the ASAS Photometric I-band Catalog containing over 5*10^7^ individual measurements. Nightly monitoring of over 100 standard stars confirms that most of our data remains within {sigma}_I_=0.03mag of the standard I system. Search for the stars varying on the time scales longer than a day revealed about 3800 variable stars (mostly irregular, pulsating and binaries) brighter than 13mag. Only 630 of them are known or suspected variables included in the GCVS (Kholopov 1985, Cat. <II/214>). Among the stars brighter than I~7.5 (which are saturated on our frames) we have found about 50 variables (12 are in the GCVS, 6 others in the Hipparcos catalog (Cat. <I/239>). Because of the large volume of data we present here only selected tables and light curves, but the complete ASAS Catalog of Variable Stars (currently divided into Periodic and Miscellaneous sections) and all photometric data are available on the Internet http://www.astrouw.edu.pl/~gp/asas/asas.html or http://archive.princeton.edu/~asas/
- ID:
- ivo://CDS.VizieR/J/AcA/48/35
- Title:
- All Sky Automated Survey variable stars
- Short Name:
- J/AcA/48/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of the first two months of observations using the All Sky Survey prototype camera are presented. More than 45000 stars in 24 Selected Fields covering 140 square degrees were monitored a few times per night resulting in the I-band catalog containing 10^7^ individual measurements. Period search revealed 126 variable stars brighter than 13mag with periods less than 20d. Only 30 of them are known variable stars included in the General Catalogue of Variable Stars (<II/214>). The other 90 objects are newly detected variable stars - mainly eclipsing binaries (75%) and pulsating stars (17%). We estimate that completeness of the current catalogs of variable stars is smaller than 50% already for the stars brighter than 9mag. The catalog is accessible over the WWW: http://www.astrouw.edu.pl/~gp/asas/asas.html
- ID:
- ivo://CDS.VizieR/I/280B
- Title:
- All-Sky Compiled Catalogue of 2.5 million stars
- Short Name:
- I/280B
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The All-Sky Compiled Catalogue of 2501313 stars (ASCC-2.5) with the limiting magnitude V=12-14 is a result of a merging of star lists from present day large high-precision catalogues from space (Hipparcos- Tycho family catalogues: Hipparcos main catalogue including Multiple System Annex [I/239], Tycho-1 [I/239], Tycho-2 [I/259], ACT-RC [I/246], TRC [I/250]) and ground-based (PPM-N [I/146], PPM-S [I/193], PPM-add [I/208], CMC11 [I/256]) observations and reduction to standard systems of corresponding stellar data. The data from the Tycho-2 Spectral Type Catalog [III/231], and the 2MASS All-Sky Catalog of Point Sources [II/246] are added. The basic stellar data presented in the ASCC-2.5 are the equatorial coordinates (J2000, epoch 1991.25), proper motions in the Hipparcos system, B and/or V stellar magnitudes in the Johnson system. Additionally, for some stars we give trigonometric parallaxes, spectral classes in the MK or HD system, multiplicity and variability flags, Hipparcos, Tycho-2, HD, DM designations. Equatorial coordinates and their standard errors were taken from the source catalogues in accordance with the priority: Hipparcos [I/239/hip_main], Tycho-2 [I/259], Tycho-1 [I/239/tyc_main], CMC11 [I/256], PPM [I/146,I/193,I/208]. Proper motions from the source catalogues were compared with Hipparcos data.The compiled proper motions in the Hipparcos system and their standard errors were computed as the weighted means. The weights were set in accordance with the proper motion errors listed for individual stars in the source catalogues. Trigonometric parallaxes are taken from the Hipparcos and Tycho-1 catalogues. Stellar B, V magnitudes were determined on the basis of the ground- based photometric data taken from CMC11, Hipparcos, as well as space BT, VT from Tycho-1, Tycho-2. Magnitudes from the PPM catalogue were used if no other photometric data were available. Tycho data were transformed to the Johnson system via: V = VT - 0.09 (B-V)T + dV, (B-V) = 0.850 (B-V)T + d(B-V), i.e. using the recommendations from the Introduction to the Tycho catalogue and including additional corrections dV and d(B-V). These additional corrections were determined by comparison with ground-based data in the Johnson system. These corrections depend non-linearly on colour and reach 0.02 and 0.04 mag, respectively. Infrared stellar magnitudes J, H, K_s_ and their errors were copied from the 2MASS catalogue. Spectral classes in the MK or HD systems were taken from Hipparcos, CMC11, PPM, and Tycho-2 Spectral Type catalogues. Multiplicity and variability flags were taken from Tycho-1, Tycho-2, Hipparcos, CMC11, and PPM catalogues. The 1st version of the ASCC-2.5 contained some errors in the zones -1 to +1 degree which have been corrected (see details in the "History" section below). The 2nd version included a new file (ccadd.dat) containing the previously missing stars (including components of multiple systems). Note that the ASCC numbers did not change between the two versions, but additional numbers (2600001 to 2603318) were assigned. In the present 3rd version of the ASCC-2.5 the stars from file ccadd.dat are inserted in the basic files in accordance with their coordinates. Stars in the ASCC-2.5 are divided into 30 files ordered by declination (North and South polar caps and 28 bands of 5 degrees width), then sorted in order of right ascension within each file.
