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/).
This file mainly provides a standardized description of the tabular material composing the NSV catalogue; please refer to files: * "intro": the original 1981 introduction by the authors * "adc.doc" (plain ascii) or "doc.tex" (LaTeX version): the documentation for the machine-readable version by W.H. Warren
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.
Gliese 876 harbors one of the most dynamically rich and well-studied exoplanetary systems. The nearby M4V dwarf hosts four known planets, the outer three of which are trapped in a Laplace mean-motion resonance. A thorough characterization of the complex resonant perturbations exhibited by the orbiting planets, and the chaotic dynamics therein, is key to a complete picture of the system's formation and evolutionary history. Here we present a reanalysis of the system using 6 yr of new radial velocity (RV) data from four instruments. These new data augment and more than double the size of the decades-long collection of existing velocity measurements. We provide updated estimates of the system parameters by employing a computationally efficient Wisdom-Holman N-body symplectic integrator, coupled with a Gaussian process (GP) regression model to account for correlated stellar noise. Experiments with synthetic RV data show that the dynamical characterization of the system can differ depending on whether a white-noise or correlated-noise model is adopted. Despite there being a region of stability for an additional planet in the resonant chain, we find no evidence for one. Our new parameter estimates place the system even deeper into resonance than previously thought and suggest that the system might be in a low-energy, quasi-regular double apsidal corotation resonance. This result and others will be used in a subsequent study on the primordial migration processes responsible for the formation of the resonant chain.
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.
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.
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.
Two selection statistics are used to extract new candidate periodic variables from the epoch photometry of the Hipparcos catalogue. The primary selection criterion is a signal-to-noise ratio. The dependence of this statistic on the number of observations is calibrated using about 30000 randomly permuted Hipparcos data sets. A significance level of 0.1 per cent is used to extract a first batch of candidate variables. The second criterion requires that the optimal frequency be unaffected if the data are de-trended by low-order polynomials. We find 2675 new candidate periodic variables, of which the majority (2082) are from the Hipparcos unsolved variables. Potential problems with the interpretation of the data (e.g. aliasing) are discussed.
The Table2 summarizes the photographic magnitudes obtained over 24 years at the Skalnate Pleso (1979-1993) and Asiago (1969-1988) observatories for 17 variable stars of different types: Miras (7), Semi-regular (4), Cepheids (3), RR Lyr (2), Eclipsing binary (1). The cross-reference between star No., designation according to Margoni and Stagni (1984A&AS...56...87M) and catalogue one (provided it has already been adopted for a given star) according to the GCVS (See Cat. <II/214>) and IBVS (Kholopov al., 1987, See Cat. <II/195>) is given in Table3 as well as the equatorial coordinates for the epoch 1950.0 for each star, which is compatible with the GCVS. In this table are shown the basic characteristics of the observational material for each star: the number of data points and interval of magnitudes obtained at the Asiago Observatory (A) and Skalnate Pleso Observatory (SP) respectively.
