Search

Start Over Subject astrometry Content Level Research
641. US Naval Observatory Pleiades Catalog
ID:
ivo://CDS.VizieR/I/163
Title:
US Naval Observatory Pleiades Catalog
Short Name:
I/163
Date:
21 Oct 2021
Publisher:
CDS
Description:
This catalog is a special subset of the Eichhorn et al. (1970) Pleiades catalog (see <I/90>) updated to B1950.0 positions and with proper motions added. It was prepared for the purpose of predicting occultations of Pleiades stars by the Moon, but is useful for general applications because it contains many faint stars not present in the current series of large astrometric catalogs.
642. U.S. Naval Observatory Zodiacal Zone Catalog
ID:
ivo://CDS.VizieR/I/157
Title:
U.S. Naval Observatory Zodiacal Zone Catalog
Short Name:
I/157
Date:
21 Oct 2021
Publisher:
CDS
Description:
The catalog provides positions and proper motions at equinox and epoch J2000.0, on the FK5 system, for stars in the magnitude range 4-10, lying within 16 degrees of the ecliptic and north of declination -30 degrees. In order that references to earlier catalogs can be made, the B1950.0 positions and proper motions are given in both the FK5 and the FK4 systems. Other useful information, such as visual magnitudes and spectral types, is also provided. Stellar identification is strictly by Durchmusterung number, and the catalog is ordered by J2000.0 right ascension. It is important to understand that the present catalog does not cover the entire zodiacal zone, since stars south of zone -29 degrees could not be observed from the Washington site. These will be observed from the USNO Black Birch station in New Zealand commencing in 1991.
643. USNO Martian observations
ID:
ivo://CDS.VizieR/J/A+A/582/A36
Title:
USNO Martian observations
Short Name:
J/A+A/582/A36
Date:
21 Oct 2021
Publisher:
CDS
Description:
Accurate positional measurements of planets and satellites are used to improve their orbits, our knowledge of their dynamics and to infer the accuracy of the planet and satellite ephemerides. In the framework of the European FP7 ESPaCE program, we provide the positions of Mars, Phobos, and Deimos taken with the U.S. Naval Observatory 61-inch astrometric reflector and 26-inch refractor from 1967 to 1997. 425 astrophotographic plates were measured with the digitizer of the Royal Observatory of Belgium and reduced through an optimal process which includes image, instrumental, and spherical corrections using the UCAC4 catalog to provide the most accurate equatorial (RA, DEC) positions.
644. USNO Saturnian observations 1974-1998
ID:
ivo://CDS.VizieR/J/A+A/596/A37
Title:
USNO Saturnian observations 1974-1998
Short Name:
J/A+A/596/A37
Date:
21 Oct 2021
Publisher:
CDS
Description:
Accurate positional measurements of planets and satellites are used to improve our knowledge of both their orbits and their dynamics and to infer the accuracy of the planet and satellite ephemerides. In the framework of the European FP7 ESPaCE program, we provide the positions of Saturn and its major satellites taken with the U.S. Naval Observatory 26-inch refractor from 1974 to 1998. 526 astrophotographic plates were measured with the digitizer of the Royal Observatory of Belgium and reduced through an optimal process that includes image, instrumental, and spherical corrections using the UCAC4 catalog to provide the most accurate equatorial (RA, DEC) positions.
645. UTMOST pulsar timing programme. I.
ID:
ivo://CDS.VizieR/J/MNRAS/484/3691
Title:
UTMOST pulsar timing programme. I.
Short Name:
J/MNRAS/484/3691
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an overview and the first results from a large-scale pulsar timing programme that is part of the UTMOST project at the refurbished Molonglo Observatory Synthesis Radio Telescope (MOST) near Canberra, Australia. We currently observe more than 400 mainly bright southern radio pulsars with up to daily cadences. For 205 (8 in binaries, 4 millisecond pulsars), we publish updated timing models, together with their flux densities, flux density variability, and pulse widths at 843 MHz, derived from observations spanning between 1.4 and 3 yr. In comparison with the ATNF pulsar catalogue, we improve the precision of the rotational and astrometric parameters for 123 pulsars, for 47 by at least an order of magnitude. The time spans between our measurements and those in the literature are up to 48 yr, which allow us to investigate their long-term spin-down history and to estimate proper motions for 60 pulsars, of which 24 are newly determined and most are major improvements. The results are consistent with interferometric measurements from the literature. A model with two Gaussian components centred at 139 and 463km/s fits the transverse velocity distribution best. The pulse duty cycle distributions at 50 and 10 per cent maximum are best described by lognormal distributions with medians of 2.3 and 4.4 per cent, respectively. We discuss two pulsars that exhibit spin-down rate changes and drifting subpulses. Finally, we describe the autonomous observing system and the dynamic scheduler that has increased the observing efficiency by a factor of 2-3 in comparison with static scheduling.
646. Vanishing and appearing sources using USNO data
ID:
ivo://CDS.VizieR/J/AJ/159/8
Title:
Vanishing and appearing sources using USNO data
Short Name:
J/AJ/159/8
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper we report the current status of a new research program. The primary goal of the "Vanishing and Appearing Sources during a Century of Observations" project is to search for vanishing and appearing sources using existing survey data to find examples of exceptional astrophysical transients. The implications of finding such objects extend from traditional astrophysics fields to the more exotic searches for evidence of technologically advanced civilizations. In this first paper we present new, deeper observations of the tentative candidate discovered by Villarroel et al. (2016AJ....152...76V). We then perform the first searches for vanishing objects throughout the sky by comparing 600 million objects from the US Naval Observatory Catalogue (USNO) B1.0 (Cat. I/284) down to a limiting magnitude of ~20-21 with the recent Pan-STARRS Data Release-1 (DR1, Cat. II/349) with a limiting magnitude of ~23.4. We find about 150000 preliminary candidates that do not have any Pan-STARRS counterpart within a 30" radius. We show that these objects are redder and have larger proper motions than typical USNO objects. We visually examine the images for a subset of about 24000 candidates, superseding the 2016 study with a sample 10 times larger. We find about 100 point sources visible in only one epoch in the red band of the USNO, which may be of interest in searches for strong M-dwarf flares, high-redshift supernovae, or other categories of unidentified red transients.
647. Variable Stars in the Sculptor dwarf galaxy
ID:
ivo://CDS.VizieR/J/A+AS/112/407
Title:
Variable Stars in the Sculptor dwarf galaxy
Short Name:
J/A+AS/112/407
Date:
21 Oct 2021
Publisher:
CDS
Description:
The central area of the Sculptor dwarf galaxy was surveyed for variable stars as a side-program of the OGLE project. Light curves in the V band were obtained for 226 RR Lyr stars and for 3 anomalous cepheids. The data on RR Lyr variables in four nearby dwarf galaxies are summarized and discussed briefly.
648. Vatican AC Zone Data Reduced to ACRS
ID:
ivo://CDS.VizieR/I/226
Title:
Vatican AC Zone Data Reduced to ACRS
Short Name:
I/226
Date:
21 Oct 2021
Publisher:
CDS
Description:
The U.S. Naval Observatory is in the process of making new reductions of the Astrographic Catalogue (AC) using a modern reference system, the ACRS, which represents the system of the FK5. The data from the Vatican Zone, whose plates are centered between declinations +55 and +64 degrees (eq. 1900), have been analyzed for scale, rotation, tilt, coma, magnitude equation, radial distortion and distortions introduced by the use of reseaux in the Carte du Ciel program. The result is a positional catalog of over 256,000 stars on eq. J2000.0, epoch of observation. Additionally, all stars have been matched with the Tycho Input Catalog (revised); those numbers have been added for additional identification purposes.
649. 454 VCC galaxies revised coordinates
ID:
ivo://CDS.VizieR/J/A+A/552/A8
Title:
454 VCC galaxies revised coordinates
Short Name:
J/A+A/552/A8
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study the dust content of a large optical input sample of 910 early-type galaxies (ETG) in the Virgo cluster, also extending to the dwarf ETG, and examine the results in relation to those on the other cold ISM components. We have searched for far-infrared emission in all galaxies in the input sample using the 250um image of the Herschel Virgo Cluster Survey (HeViCS). This image covers a large fraction of the cluster with an area of ~55 square degrees. For the detected ETG we measured fluxes in five bands from 100 to 500um, and estimated the dust mass and temperature with modified black-body fits. Dust is detected above the completeness limit of 25.4mJy at 250um in 46 ETG, 43 of which are in the optically complete part of the input sample. In addition, dust is present at fainter levels in another six ETG. We detect dust in the four ETG with synchrotron emission, including M 87.
650. VIsual Binary Exoplanet survey with SPHERE
ID:
ivo://CDS.VizieR/J/A+A/643/A98
Title:
VIsual Binary Exoplanet survey with SPHERE
Short Name:
J/A+A/643/A98
Date:
21 Oct 2021
Publisher:
CDS
Description:
Recent surveys indicate that planets in binary systems are more abunda- nt than previously thought, which is in agreement with theoretical work on disc dynamics and planet formation in binaries. So far, most observational surveys, however, have focused on short-period planets in binaries, thus little is known about the occurrence rates of planets on longer periods (>10au). In order to measure the abundance and physical characteristics of wide-orbit giant exoplanets in binary systems, we have designed the 'VIsual Binary Exoplanet survey with Sphere' (VIBES) to search for planets in visual binaries. It uses the SPHERE instrument at VLT to search for planets in 23 visual binary and four visual triple systems with ages of <145Myr and distances of <150pc. We used the IRDIS dual-band imager on SPHERE to acquire high-contrast images of the sample targets. For each binary, the two components were observed at the same time with a coronagraph masking only the primary star. For the triple star, the tight components were treated as a single star for data reduction. This enabled us to effectively search for companions around 50 individual stars in binaries and four binaries in triples. We derived upper limits of <13.7% for the frequency of sub-stellar companions around primaries in visual binaries, <26.5% for the fraction of sub-stellar companions around secondaries in visual binaries, and an occurrence rate of <9.0% for giant planets and brown dwarfs around either component of visual binaries. We have combined our observations with literature measurements to astrometrically confirm, for the first time, that 20 binaries and two triple systems, which were previously known, are indeed physically bound. Finally, we discovered a third component of the binary HD 121336. The upper limits we derived are compatible with planet formation through the core accretion and the gravitational instability processes in binaries. These limits are also in line with limits found for single star and circumbinary planet search surveys.