- ID:
- ivo://CDS.VizieR/J/A+AS/125/337
- Title:
- New variables in NGC 288
- Short Name:
- J/A+AS/125/337
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report discovery of 3 new faint variables in the globular cluster NGC 288: 2 SX Phe stars and 1 contact binary. Both SX Phe variables are blue stragglers. The contact binary is located below cluster turnoff, slightly to the red of the main sequence. New photometry of 6 previously known variables is also presented. We note that 26 out of a total 43 SX Phe stars identified recently in {omega} Cen and NGC 288 exhibit V-band light curves with full amplitudes smaller than 0.10mag. The sample of known SX Phe stars is likely to be significantly incomplete in regard to the low amplitude variables.
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842. New variables in ONC
- ID:
- ivo://CDS.VizieR/J/MNRAS/400/603
- Title:
- New variables in ONC
- Short Name:
- J/MNRAS/400/603
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Since 2004, we have been engaged in a long-term observing programme to monitor young stellar objects (YSOs) in the Orion Nebula Cluster (ONC). We have collected about 2000 frames in V, R and I broad-band filters on more than 200 nights distributed over five consecutive observing seasons. The high-quality and time-extended photometric data give us an opportunity to address various phenomena associated with young stars.
- ID:
- ivo://CDS.VizieR/J/A+AS/123/507
- Title:
- New variables in Sagittarius
- Short Name:
- J/A+AS/123/507
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For the coordinates and identification charts of the variables discovered in the other parts of the surveyed region, see references in the publication. A compilation of all the (~4000) variables discovered in the entire 100 square-degree surveyed region in the course of this programme, is in preparation and will be available at CDS in electronic form.
- ID:
- ivo://CDS.VizieR/J/PASP/131/G5001
- Title:
- New variable stars and eclipsing binaries
- Short Name:
- J/PASP/131/G5001
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Evryscope is a telescope array designed to open a new parameter space in optical astronomy, detecting short-timescale events across extremely large sky areas simultaneously. The system consists of a 780 MPix 22-camera array with an 8150 sq. deg. field of view, 13'' per pixel sampling, and the ability to detect objects down to m_g'_~=16 in each 2-minute dark-sky exposure. The Evryscope, covering 18400 sq. deg. with hours of high-cadence exposure time each night, is designed to find the rare events that require all-sky monitoring, including transiting exoplanets around exotic stars like white dwarfs and hot subdwarfs, stellar activity of all types within our galaxy, nearby supernovae, and other transient events such as gamma-ray bursts and gravitational-wave electromagnetic counterparts. The system averages 5000 images per night with ~300000 sources per image, and to date has taken over 3.0M images, totaling 250 TB of raw data. The resulting light curve database has light curves for 9.3M targets, averaging 32600 epochs per target through 2018. This paper summarizes the hardware and performance of the Evryscope, including the lessons learned during telescope design, electronics design, a procedure for the precision polar alignment of mounts for Evryscope-like systems, robotic control and operations, and safety and performance-optimization systems. We measure the on-sky performance of the Evryscope, discuss its data analysis pipelines, and present some example variable star and eclipsing binary discoveries from the telescope. We also discuss new discoveries of very rare objects including two hot subdwarf eclipsing binaries with late M-dwarf secondaries (HW Vir systems), two white dwarf/hot subdwarf short-period binaries, and four hot subdwarf reflection binaries. We conclude with the status of our transit surveys, M-dwarf flare survey, and transient detection.
- ID:
- ivo://CDS.VizieR/J/AZh/91/382
- Title:
- New variable stars in field SA9
- Short Name:
- J/AZh/91/382
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The new stage of work on digitizing the astronomical plates of the Sternberg Astronomical Institute's collection and searching for new variable stars using the digitized photographic plates includes a considerable improvement of the automated search techniques for objects with variable brightnesses. In particular, the technique for taking into account the non-linear response of the photographic light detector has been improved. Applying the improved techniques to 182 digitized images of a 10{deg}x10{deg} field centered at SA9, obtained from scanning photographic plates taken with the Sternberg Astronomical Institute 40-cm astrograph, has enabled the discover and study of 77 new variable stars (MDV 519-595). These include 3 Cepheids, 2 probableBY Draconis stars, 65 eclipsing binaries, 3RR Lyrae stars, 1 high-amplitude {delta} Scuti star (HADS), and 3 irregular variables. Special CCD observations have confirmed the presence of brightness variations in 7 of the 77 variables that were initially considered uncertain.
- ID:
- ivo://CDS.VizieR/J/A+A/519/A12
- Title:
- 1318 new variable stars in Galactic plane
- Short Name:
- J/A+A/519/A12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a deep photometric survey of a 0.5deg*0.5deg area of the Galactic Plane using the WFI instrument on the 2.2-m ESO telescope on La Silla, Chile. The dataset comprises a total of 267 R-band images, 204 from a 16 day observation run in 2005, supplemented by 63 images from a six week period in 2002. Our reduction employed the new numerical kernel difference image analysis method as implemented in the pySIS3 code and resulted in more than 500000 lightcurves of stars down to a magnitude limit of R~24.5. A search for variable stars resulted in the detection of 1318 variables of different types. 1011 of these are eclipsing or contact binary stars. A number of the contact binaries have low mass-ratios and several of the detached binaries appear to have low-mass components. Three candidate contact binaries have periods at the known cut off including two with periods lower than any previously published. Also identified are 3 possible pre-main sequence detached eclipsing binaries.
- ID:
- ivo://CDS.VizieR/J/other/RAA/18.92
- Title:
- New variable stars in 104 Her field
- Short Name:
- J/other/RAA/18.9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using 172 plates taken with the 40-cm astrograph of the Sternberg Astronomical Institute (Lomonosov Moscow University) in 1976-1994 and digitized with a resolution of 2400 dpi, we discovered and studied 275 new variable stars. We present the list of our new variables with all necessary information concerning their brightness variations. As in our earlier studies, the new discoveries show a rather large number of high-amplitude Delta Scuti variables, predicting that many stars of this type remain not detected in the whole sky. We also performed automated classification of the newly discovered variable stars based on the Random Forest algorithm. The results of the automated classification were compared to traditional classification and showed that automated classification was possible even with noisy photographic data. However, further improvement of automated techniques is needed, which is especially important when considering the very large numbers of new discoveries expected from all-sky surveys.
- ID:
- ivo://CDS.VizieR/J/other/RMxAA/44.365
- Title:
- New variable stars in NGC 6366
- Short Name:
- J/other/RMxAA/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New CCD photometry of NGC 6366 has lead to the discovery of some variable stars. Two possible Anomalous Cepheids (or Pop II Cepheids), three long period variables, one SX Phe and one eclipsing binary have been found. Also a list of 10 candidate variables is reported. The light curve of the RRab star, V1, has been decomposed into its Fourier harmonics, and the Fourier parameters were used to estimate the star's metallicity and distance; [Fe/H]=-0.87+/-0.14 and d=3.2+/-0.1kpc. It is argued that V1 may not be a member of the cluster but rather a more distant object. If this is so, an upper limit for the distance to the cluster of 2.8+/-0.1kpc can be estimated. The P-L relationship for SX Phe stars and the identified modes in the newly discovered SX Phe variable, V6, allow yet another independent determination of the distance to the cluster of d=2.7+/-0.1kpc. The M_V_-[Fe/H] relationship for RR Lyrae stars is addressed and the case of V1 is discussed.
- ID:
- ivo://CDS.VizieR/J/AZh/87/1087
- Title:
- New variable stars in 66 Oph field
- Short Name:
- J/AZh/87/1087
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the course of a program to digitize the astronomical plates of the Sternberg Astronomical Institute's plate stacks, we are developing algorithms for searching for new variable stars and studying them using digitized photographic plates. We have discovered and studied 480 new variable stars in a 10{deg}x10{deg} field of view centered on 66 Ophiuchi. The digitized plate negatives used are from the 40-cm astrograph, and are 30x30cm in size. These stars include three new Cepheids of the Galaxy's spherical component, 157 eclipsing binaries, 11 high-amplitude {delta} Scuti stars (HADSs), 144 RR Lyrae stars, 110 irregular variables (109 LB and one white star), and 55 semi-regular red variables.
- ID:
- ivo://CDS.VizieR/J/A+AS/49/715
- Title:
- New variable stars in Sgr B
- Short Name:
- J/A+AS/49/715
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 621 new variable stars have been detected on plates obtained with the Schmidt telescopes of the Mount Palomar Observatory (1968) and of the European Southern Observatory (1976-1980). The astrometric measurements (ESO-CERN) and the photometrical ones (CDCA) which have followed the detection the variable stars (Observatoire de Lyon) have led to determine the parameters {alpha}, {delta}, l, b, R(Max), R(Min), {delta}m. So we notice that: - 379 variable stars have an amplitude of variation in magnitude between 0.5 and 2.0 (delm/N histogram). -The number of variable stars strongly decreases towards the great amplitudes. -The surface density of variable stars by square degree in this central galactic direction increases from 2 to 21 in the explored field of 5.5degx5.5deg size.
