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371. Observations of 50 TNOs and Centaurs
ID:
ivo://CDS.VizieR/J/A+A/584/A96
Title:
Observations of 50 TNOs and Centaurs
Short Name:
J/A+A/584/A96
Date:
21 Oct 2021
Publisher:
CDS
Description:
The prediction of stellar occultations by trans-Neptunian objects (TNOs) and Centaurs is a difficult challenge that requires accuracy both in the occulted star position and in the object ephemeris. Until now, the most used method of prediction, involving dozens of TNOs/Centaurs, has been to consider a constant offset for the right ascension and for the declination with respect to a reference ephemeris, usually the latest public version. This offset is determined as the difference between the most recent observations of the TNO/Centaur and the reference ephemeris. This method can be successfully applied when the offset remains constant with time, i.e. when the orbit is stable enough. In this case, the prediction even holds for occultations that occur several days after the last observations. This paper presents an alternative method of prediction, based on a new accurate orbit determination procedure, which uses all the available positions of the TNO from the Minor Planet Center database, as well as sets of new astrometric positions from unpublished observations. Orbits were determined through a numerical integration procedure called NIMA, in which we developed a specific weighting scheme that considers the individual precision of the observation, the number of observations performed during one night by the same observatory, and the presence of systematic errors in the positions.
372. 1996-2006 observations of Triton
ID:
ivo://CDS.VizieR/J/MNRAS/376/1707
Title:
1996-2006 observations of Triton
Short Name:
J/MNRAS/376/1707
Date:
21 Oct 2021
Publisher:
CDS
Description:
Astrometric positions of the Neptunian Satellite Triton are given for the opposition of Neptune for the years 1996, 2003, 2005 and 2006. The 943 observed positions were obtained at the Cassegrain focus of a 156-cm reflector. In our reduction, the up-to-date catalogue of stars UCAC2 was chosen to ensure a proper astrometric calibration. Our observed positions are compared to theoretical positions provided from JPL and IMCCE ephemerides. The observed minus calculated residuals have s.d. values of the order of 0.04arcsec.
373. Observations of Triton and Proteus
ID:
ivo://CDS.VizieR/J/A+A/425/1107
Title:
Observations of Triton and Proteus
Short Name:
J/A+A/425/1107
Date:
21 Oct 2021
Publisher:
CDS
Description:
Earth based observations of Proteus are made highly difficult by the magnitude difference with Neptune, and the closeness to the planet. To overcome these difficulties, observation campaigns using a Hg-mask coronograph developed for astrometry are being pursued at the Laboratorio Nacional de Astrofisica, Brazil. The observations are made at visible light wavelengths with the 1.6 m reflector telescope. The large 4'x4' field of view of the camera makes it possible to image a sufficient number of background stars that are used to carry out the astrometric analysis of these data. The first results of the campaigns are presented in this paper. They include 45 independent observations made over 2 nights in 2002. The positions are referred to the Hipparcos/Tycho2 (<I/239>/<I/259>)frame. The mean offsets relative to the JPL ephemeris are =0.083" ({sigma}=0.148") in the x={DELTA}RAcosDE direction, and -0.051" ({sigma}=0.115") in the y={DELTA}DE direction. Additional astrometric data need to be collected in order to investigate further the possible offset of Proteus with respect to the Voyager ephemerides.
374. Obs. with Differential Speckle Survey Instrument. X.
ID:
ivo://CDS.VizieR/J/AJ/161/295
Title:
Obs. with Differential Speckle Survey Instrument. X.
Short Name:
J/AJ/161/295
Date:
09 Mar 2022 22:00:00
Publisher:
CDS
Description:
This paper details speckle observations of binary stars taken at the Lowell Discovery Telescope, the WIYN telescope, and the Gemini telescopes between 2016 January and 2019 September. The observations taken at Gemini and Lowell were done with the Differential Speckle Survey Instrument (DSSI), and those done at WIYN were taken with the successor instrument to DSSI at that site, the NN-EXPLORE Exoplanet Star and Speckle Imager (NESSI). In total, we present 378 observations of 178 systems, and we show that the uncertainty in the measurement precision for the combined data set is ~2mas in separation, ~1{deg}-2{deg} in position angle depending on the separation, and ~0.1mag in magnitude difference. Together with data already in the literature, these new results permit 25 visual orbits and one spectroscopic- visual orbit to be calculated for the first time. In the case of the spectroscopic-visual analysis, which is done on the ternary star HD173093, we calculate masses with a precision of better than 1% for all three stars in that system. Twenty-one of the visual orbits calculated have a K-dwarf as the primary star; we add these to the known orbits of K-dwarf primary stars and discuss the basic orbital properties of these stars at this stage. Although incomplete, the data that exist so far indicate that binaries with K-dwarf primaries tend not to have low-eccentricity orbits at separations of one to a few tens of astronomical units, that is, on solar system scales.
375. OGLE General Catalog of Stars. I.
ID:
ivo://CDS.VizieR/I/244A
Title:
OGLE General Catalog of Stars. I.
Short Name:
I/244A
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper present the first part of the Optical Gravitational Lensing Experiment (OGLE) General Catalog of Stars in the Galactic Bulge. The catalog is based on observations collected during the OGLE microlensing search. This part contains 33196 stars brighter than I=18mag identified in the Baade's Window BWC field. Stars from remaining 20 OGLE fields will be presented in similar form in the next parts of the Catalog.
376. Open cluster properties with Gaia and LAMOST
ID:
ivo://CDS.VizieR/J/A+A/640/A127
Title:
Open cluster properties with Gaia and LAMOST
Short Name:
J/A+A/640/A127
Date:
01 Mar 2022 11:35:22
Publisher:
CDS
Description:
In Gaia DR2, an unprecedented high level of precision has been reached at sub-milliarcsecond for astrometry and millimagnitudes for photometry. Using cluster members identified with the astrometry and photometry in Gaia DR2, we can obtain a reliable determination of cluster properties. However, because of the shortcomings of Gaia spectroscopic observations in dealing with densely crowded cluster regions, the RVs and metallicity values for cluster member stars from Gaia DR2 are still lacking. It is necessary to combine the Gaia data with the data from large spectroscopic surveys, such as LAMOST, APOGEE, GALAH, and Gaia-ESO. In this study, we aim to improve the cluster properties by combining the LAMOST spectra. In particular, we provide the list of cluster members with spectroscopic parameters as an add-value catalog in LAMOST DR5, which can be used to perform detailed study for a better understanding on the stellar properties, by using their spectra and fundamental properties from the host cluster. We cross-matched the spectroscopic catalog in LAMOST DR5 (Luo et al., 2019, Cat. V/164) with the identified cluster members in Cantat-Gaudin et al. (2018, Cat. J/A+A/615/A49). We then used members with spectroscopic parameters to derive statistical properties of open clusters.We obtained a list of 8811 members with spectroscopic parameters and a catalog of 295 cluster properties. In addition, we study the radial and vertical metallicity gradient and age-metallicity relation with the compiled open clusters as tracers, finding slopes of -0.053+/-0.004dex/kpc, -0.252+/-0.039dex/kpc and 0.022+/-0.008dex/Gyr, respectively. Both slopes of metallicity distribution relation for young clusters (0.1Gyr<Age<2Gyr) and the age-metallicity relation for clusters within 6Gyr are consistent with literature results. In order to fully study the chemical evolution history in the disk, more spectroscopic observations for old and distant open clusters are needed for further investigation.
377. Open clusters near eta Car
ID:
ivo://CDS.VizieR/J/AJ/105/1822
Title:
Open clusters near eta Car
Short Name:
J/AJ/105/1822
Date:
21 Oct 2021
Publisher:
CDS
Description:
Proper motions and photographic photometry have been derived for nearly 600 stars with 7.5 < V < 15.5 in the region of the very young open clusters Tr 14, Tr 16, and Cr 232 based on 26 plates dating from 1893 to 1990. Cluster membership probabilities have been derived from the proper motions and color-magnitude diagrams of probable members of each cluster are presented. In contrast to a few of the previous studies we find all three clusters to lie at the same distance.
378. Optical coordinates of southern PNe
ID:
ivo://CDS.VizieR/J/other/RMxAA/37.115
Title:
Optical coordinates of southern PNe
Short Name:
J/other/RMxAA/37
Date:
21 Oct 2021
Publisher:
CDS
Description:
A homogeneous set of new measurements of nearly all (995 out of 1007) objects from the Strasbourg-ESO Catalogue of Galactic Planetary Nebulae (Cat. <V/100>) or in the first supplement of this catalogue in the area covered by the DENIS survey (<B/denis>) ({delta}<+2{deg}) is given here. A list of 24 new and 27 wrong cross-identifications with sources in the IRAS PSC catalogue and some confusion in the literature is listed as well.
379. Optical positions of ICRF sources
ID:
ivo://CDS.VizieR/J/AJ/125/2728
Title:
Optical positions of ICRF sources
Short Name:
J/AJ/125/2728
Date:
21 Oct 2021
Publisher:
CDS
Description:
New optical positions on the 30mas precision level have been obtained for 172 extragalactic International Celestial Reference Frame (ICRF) sources mainly in the range -30{deg}<=DE<=+25{deg}. Results are presented from a pilot investigation including four Cerro Tololo (CTIO) 0.9m runs (1999-2001). Reference stars in the R~10-16.5mag used. Systematic errors have been investigated, and a field distortion pattern based on the residuals has been removed. The errors of the fainter stars in the CTIO data were assessed by evaluating an auxiliary set of CCD observations of common ICRF sources, taken at the 1.60m Cassegrain telescope of the Laboratorio Nacional de Astrofisica, Brazil. A significant improvement in the optical positions was achieved over a previous determination of source positions. The mean optical positions are compared with the ICRF radio positions. The overall optical minus radio offsets are -6 and -15mas for right ascension and declination, respectively. The formal internal error of these mean offsets is ~2.3mas. his indicates a possible systematic error in the UCAC declinations of 10 to 15mas. Both the optical counterpart observations and the optical reference stars are observed about 9 yr after the Hipparcos mean epoch, and our results set an upper limit for a possible Hipparcos system rotation with respect to the International Celestial Reference System for the z-axis of about 0.7mas/yr.
380. Optical positions of radio emitting stars
ID:
ivo://CDS.VizieR/J/A+AS/117/335
Title:
Optical positions of radio emitting stars
Short Name:
J/A+AS/117/335
Date:
21 Oct 2021
Publisher:
CDS
Description:
In order to contribute to the alignment of the radio and optical reference frames, 50 stars with confirmed radio emission and published radio positions were observed by astrographical means. Additionally, two confirmed radio-stars of fainter magnitude were observed using a CCD direct camera with a long focus, large aperture telescope. The reductions are made relative to four catalogues: the Carlsberg Meridian Catalogue #4, the International Reference Stars Catalogue, the Positions and Proper Motion Catalogue and the Astrographical Catalogue of Reference Stars. The best results were obtained with the CAMC catalogue. The plate error of a radio star position is 0.07" for both right ascension and declination, rising to 0.10"-0.20" for bright stars. Ten of the program stars are not in the HIPPARCOS Input Catalogue and 12 do not belong to any of the major reference catalogues used. As soon as the HIPPARCOS results become available, its reference stars already measured in the plates will enable us to get positions for those 10 radio stars in the HIPPARCOS system.

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