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4321. New variable stars in 66 Oph field
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.
4322. New variable stars in Sgr B
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.
4323. New variable stars towards Galactic Bulge
ID:
ivo://CDS.VizieR/J/MNRAS/482/3058
Title:
New variable stars towards Galactic Bulge
Short Name:
J/MNRAS/482/3058
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the detection of 3714 variable stars towards the Galactic bulge, including 2521 previously uncatalogued variables, using time-series photometry extracted from data obtained with the VIMOS imager at the Very Large Telescope. Observations of the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS) field in the Galactic Bulge were taken over 2yr between March and October at a cadence of ~4d, enabling the detection of variables with periods up to ~100d. Many of these were already known, but we detected a significant number of new variables, including 11 Cepheids, a further 88 potential Cepheid candidates, and many contact binaries. Here we publish the catalogue of the new variables, containing coordinates, mean magnitudes as well as periods and classification; full light curves for these variables are also made available electronically.
4324. New V-band photometry of Cyg OB2 5 (V729 Cyg)
ID:
ivo://CDS.VizieR/J/A+A/627/A2
Title:
New V-band photometry of Cyg OB2 5 (V729 Cyg)
Short Name:
J/A+A/627/A2
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Cyg OB2 #5 system is thought to consist of a short-period (6.6d) eclipsing massive binary associated with an OB-star orbiting it with a period of ~6.7yr, themselves orbited by a distant early B-star (with thousands of years period). However, while the inner binary has been studied many times, information is missing on the other stars, in particular the third one whose presence was indirectly postulated from recurrent modulations in the radio domain. Besides, to this date, the X-ray lightcurve could not be fully interpreted, e.g. in the framework of colliding-wind emission linked to one of the systems. We obtained new optical and X-ray observations of Cyg OB2 #5, which we combined to archival data. We performed a thorough and homogeneous investigation of all available data, notably revisiting the times of primary minimum in photometry. In the X-ray domain, XMM-Newton provides scattered exposures over ~5000d whilst Swift provides a nearly continuous monitoring for the last couple of years. Though the X-ray lightcurve reveals clear variability, no significant period can be found hence the high-energy emission cannot be explained solely in terms of colliding winds varying along either the short or intermediate orbits. The optical data reveal for the first time clear signs of reflex motion: the photometry indicates the presence of a 2366d (i.e. 6.5yr) period while the associated radial velocity changes are detected at the 3{sigma} level in the systemic velocity of the HeII 4686 emission line. With the revised period, the radio lightcurve is interpreted consistently in terms of a wind interaction between the inner binary and the tertiary star. From the optical and radio data, we derive constraints on the physical properties of the tertiary star and its orbit.
4325. New velocities for 62 globular clusters in M104
ID:
ivo://CDS.VizieR/J/ApJ/658/980
Title:
New velocities for 62 globular clusters in M104
Short Name:
J/ApJ/658/980
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new velocities for 62 globular clusters in M104 (NGC 4594, the Sombrero Galaxy), 56 from 2dF on the AAT and 6 from Hydra on WIYN. Combined with previous data, we have a total sample of 108 M104 globular cluster velocities, extending to 20' radius (~60kpc), along with BVR photometry for each of these. We use this wide-field data set to study the globular cluster kinematics and dark matter content of M104 out to 10' radius (30kpc).
4326. New very low-mass members in Taurus
ID:
ivo://CDS.VizieR/J/A+A/446/485
Title:
New very low-mass members in Taurus
Short Name:
J/A+A/446/485
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have performed a large scale optical survey of the Taurus cloud, covering a total area of 28deg^2^, and encompassing the densest parts of the cloud as well as their surroundings, down to a mass detection limit of 15 Jupiter masses. We present the optical spectroscopic follow-up observations of 97 photometrically selected potential new low-mass Taurus members, of which 27 are strong late-M spectral type SpType<M4V candidates. We derive spectral types, visual absorption and luminosity class estimates and discuss our criteria to assess Taurus membership. These observations reveal 5 new VLM Taurus members and 12 new brown dwarfs. Combining our observations with previously published results, we derive an updated substellar to stellar ratio in Taurus of Rss=0.23+/-0.05. This ratio now appears consistent with the value previously derived in the Trapezium cluster under similar assumptions of 0.26+/-0.04. We find indications that the relative numbers of brown dwarfs with respect to stars is decreased by a factor 2 in the central regions of the aggregates with respect to the more distributed population. Our findings are best explained in the context of the embryo-ejection model where brown dwarfs originate from dynamical interactions in small N unstable multiple systems.
4327. New white dwarf pulsators for TESS
ID:
ivo://CDS.VizieR/J/MNRAS/478/2676
Title:
New white dwarf pulsators for TESS
Short Name:
J/MNRAS/478/2676
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of our survey searching for new white dwarf pulsators for observations by the TESS space telescope. We collected photometric time-series data on 14 white dwarf variable candidates at Konkoly Observatory, and found two new bright ZZ Ceti stars, namely EGGR 120 and WD 1310+583. We performed a Fourier analysis of the datasets. In the case of EGGR 120, which was observed on one night only, we found one significant frequency at 1332uHz with 2.3mmag amplitude. We successfully observed WD 1310+583 on eight nights, and determined 17 significant frequencies in the whole dataset. Seven of them seem to be independent pulsation modes between 634 and 2740uHz, and we performed preliminary asteroseismic investigations of the star utilizing six of these periods. We also identified three new light variables on the fields of white dwarf candidates: an eclipsing binary, a candidate delta Scuti/beta Cephei and a candidate W UMa-type star.
4328. New white dwarfs
ID:
ivo://CDS.VizieR/J/AJ/143/103
Title:
New white dwarfs
Short Name:
J/AJ/143/103
Date:
21 Oct 2021
Publisher:
CDS
Description:
By selecting astrometric and photometric data from the Sloan Digital Sky Survey (SDSS, II/306), the Lepine & Shara Proper Motion North Catalog (LSPM-North, I/298), the Two Micron All Sky Survey (2MASS, II/246), and the USNO-B1.0 (I/284) catalog, we use a succession of methods to isolate white dwarf (WD) candidates for follow-up spectroscopy. Our methods include reduced proper motion diagram cuts, color cuts, and atmospheric model adherence. We present spectroscopy of 26 WDs obtained from the CTIO 4m and APO 3.5m telescopes. Additionally, we confirm 28 WDs with spectra available in the SDSS-DR7 database but unpublished elsewhere, presenting a total of 54 WDs. We label one of these as a recovered WD while the remaining 53 are new discoveries. We determine physical parameters and estimate distances based on atmospheric model analyses. Three new WDs are modeled to lie within 25 pc. Two additional WDs are confirmed to be metal-polluted (DAZ). Follow-up time series photometry confirms another object to be a pulsating ZZ Ceti WD.
4329. New white dwarf stars in SDSS DR10
ID:
ivo://CDS.VizieR/J/MNRAS/446/4078
Title:
New white dwarf stars in SDSS DR10
Short Name:
J/MNRAS/446/4078
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of 9088 new spectroscopically confirmed white dwarfs and subdwarfs in the Sloan Digital Sky Survey Data Release 10. We obtain T_eff_, logg and mass for hydrogen atmosphere white dwarf stars (DAs) and helium atmosphere white dwarf stars (DBs), and estimate the calcium/helium abundances for the white dwarf stars with metallic lines (DZs) and carbon/helium for carbon-dominated spectra DQs. We found 1 central star of a planetary nebula, 2 new oxygen spectra on helium atmosphere white dwarfs, 71 DQs, 42 hot DO/PG1159s, 171 white dwarf+main-sequence star binaries, 206 magnetic DAHs, 327 continuum-dominated DCs, 397 metal-polluted white dwarfs, 450 helium-dominated white dwarfs, 647 subdwarfs and 6887 new hydrogen-dominated white dwarf stars.
4330. New WR star in M33
ID:
ivo://CDS.VizieR/J/ApJ/505/793
Title:
New WR star in M33
Short Name:
J/ApJ/505/793
Date:
21 Oct 2021
Publisher:
CDS
Description:
We expect the evolution of massive stars to be strongly influenced by mass loss and hence to be sensitive to metallicity. It should be possible to test this "Conti scenario" be comparing the populations of evolved massive stars among the Local Group galaxies, but such investigations have been hampered by incompleteness. In a previous paper, we presented results of a new survey for red supergiants (RSGs) in selected regions of the Local Group galaxies M33, M31, and NGC 6822. In the present paper, we survey eight fields in M33 for Wolf-Rayet stars (WRs), using interference-filter imaging with a CCD to select candidates. Follow-up spectroscopy is used to confirm 22 newly found WR stars, 21 of WN type. We establish that our survey would readily detect WRs as weak-lined as any known, and we conclude that our survey is essentially complete.