According to the cooperation between Beijing, San Juan and La Plata Astronomical Observatories, the photoelectric astrolabe Mark II(PAII) of the Beijing Astronomical Observatory was moved and installed at the San Juan Observatory, Argentina in January, 1992 for observations of the catalogue of stars in the southern hemisphere. The first observing period was from Feb. 23, 1992 to Mar. 31, 1997. Using the data observed in San Juan with the instrument during this period, residuals for 11002 stars are reduced from about 405700 observations of stars over 1532 days. The mean precision of the residuals is +/-0.043". The Second Catalogue of Stars (CPASJ2) has been compiled from double transits at both the eastern and western passages. There are 5241 stars in this catalogue, including 1225 FK5/FK4Supp stars, 794 FK5Ext stars, 1084 SRS stars, 937 CAMC4 stars, 310 GC stars and 891 IMF stars. The mean precisions are +/-3.2ms and +/-0.057" in right ascension and declination, respectively. The magnitudes of stars are from 2.0 to 11.5. The declinations are from -3{deg} to -60{deg}. The mean epoch is 1994.9. Finally, systematic corrections of(CPASJ2-FK5) are given.
On the basis of the data observed with the photoelectric astrolabe Mark II(PA II) of Beijing Astronomical Observatory in San Juan of Argentina from Feb. 23, 1992 to Feb. 28, 1995, residuals of 7200 stars are reduced according to about 230000 observations of stars. The mean precision of the residuals is +/-0.046". Using the data, the first catalogue of stars (CPASJ1) have been compiled. There are 2980 stars in this catalogue included 989 FK5/FK4Supp stars, 658 FK5Ext stars, 387 SRS stars, 687 CAMC4 stars, 192 GC stars, and 72 Hipparcos stars. The mean precisions are +/-3.2ms and +/-0.061" in right ascensions and declinations, respectively. The magnitudes of stars are from 2mag to 11.3mag. The declinations are from -3deg to -60deg. The mean epoch is 1993.6. Finally, systematic corrections of(CPASJ1-FK5) are given.
Resulting from the cooperation between Beijing, San Juan and La Plata Astronomical Observatories, the photoelectric astrolabe Mark II(PAII) of the Beijing Astronomical Observatory was moved and installed at the San Juan Observatory, Argentina in January, 1992 for observations of stars in the southern hemisphere. Using the data observed with the instrument from Feb. 23 1992 to Mar. 11, 2000 over 2382 days, the Third San Juan photoelectric astrolabe catalogue has been compiled from double transits at both the eastern and western passages. There are 6762 stars in this catalogue, including 6156 Hipparcos stars (in which there are 69 radio stars), 8 FK5 stars, 47 SRS stars, 551 CAMC4 stars. The mean precisions are +/-3.0ms and +/-0.053"' in right ascension and declination, respectively. The magnitudes of stars are from 1.0 to 11.5. The declinations are from -3{deg} to -60{deg}. The mean epoch is 1996.3. Systematic corrections of (CPASJ3-Hipp) are given.
Using the data observed with the Photoelectric Astrolabe Mark II (PA II) of the Beijing Astronomical Observatory during the period from Feb. 1992 to Oct. 1993 in San Juan of Argentina, the first catalogue of stars (PASJ1, Cat. <J/A+AS/118/1>) have been compiled. It consists of 1400 stars included 682 FK5/FK4 Supp stars. 433 FK5 Ext stars and 285 CAMC stars (1, 1989). The mean precisions of delta alpha's and delta delta's are +/-3.2ms and 0.055", respectively. The mean epoch is 1992.9. Finally, systematic corrections of (PASJ1-FK5) are given.
de Houtman in 1603, Kepler in 1627 and Halley in 1679 published the earliest modern catalogues of the southern sky. We provide machine-readable versions of these catalogues, make some comparisons between them, and briefly discuss their accuracy on the basis of comparison with data from the modern Hipparcos Catalogue. We also compare our results for de Houtman with those by Knobel (1917) finding good overall agreement. About half of the about 200 new stars (with respect to Ptolemaios) added by de Houtman are in twelve new constellations, half in old constellations like Centaurus, Lupus and Argo. The right ascensions and declinations given by de Houtman have error distributions with widths of about 40-arcmin, the longitudes and latitudes given by Kepler have error distributions with widths of about 45-arcmin. Halley improves on this by more than an order of magnitude to widths of about 3-arcmin, and all entries in his catalogue can be identified. The measurement errors of Halley are due to a systematic deviation of his sextant (increasing with angle to 2-arcmin at 60-degrees) and random errors of 0.7-arcmin. The position errors in the catalogue of Halley are dominated by the position errors in the reference stars, which he took from Brahe.
Mass is one of the most important parameters for determining the true nature of an astronomical object. Yet, many published exoplan- ets lack a measurement of their true mass, in particular those detected as a result of radial-velocity (RV) variations of their host star. For those examples, only the minimum mass, or msini, is known, owing to the insensitivity of RVs to the inclination of the detected orbit compared to the plane of the sky. The mass that is given in databases is generally that of an assumed edge-on system (~90{deg}), but many other inclinations are possible, even extreme values closer to 0{deg} (face-on). In such a case, the mass of the published object could be strongly underestimated by up to two orders of magnitude. In the present study, we use GASTON, a recently developed tool taking advantage of the voluminous Gaia astrometric database to constrain the inclination and true mass of several hundreds of published exoplanet candidates. We find 9 exoplanet candidates in the stellar or brown dwarf (BD) domain, among which 6 were never characterized. We show that 30 Ari B b, HD 141937 b, HD 148427 b, HD 6718 b, HIP 65891 b, and HD 16760 b have masses larger than 13.5 M_J_ at 3{sigma}. We also confirm the planetary nature of 27 exoplanets, including HD 10180 c, d and g. Studying the orbital periods, eccentricities, and host-star metallicities in the BD domain, we found distributions with respect to true masses consistent with other publications. The distribution of orbital periods shows of a void of BD detections below ~100d, while eccentricity and metallicity distributions agree with a transition between BDs similar to planets and BDs similar to stars in the range 40-50M_J_.
Delta Equulei is among the most well-studied nearby binary star systems. Results of its observation have been applied to a wide range of fundamental studies of binary systems and stellar astrophysics. It is widely used to calibrate and constrain theoretical models of the physics of stars. We report 27 high-precision differential astrometry measurements of {delta} Equ from the Palomar High-precision Astrometric Search for Exoplanet Systems (PHASES).
We investigate a sample of 2293 ICRF2 extragalactic radio-loud sources with accurate positions determined by VLBI, mostly active galactic nuclei (AGNs) and quasars, which are cross-matched with optical sources in the first Gaia release (Gaia DR1). The distribution of offsets between the VLBI sources and their optical counterparts is strongly non-Gaussian, with powerful wings extending beyond 1 arcsec. Limiting our analysis to only high-confidence difference detections, we find (and publish) a list of 188 objects with normalized variances above 12 and offsets below 1 arcsec. Pan-STARRS stacked and monochromatic images resolve some of these sources, indicating the presence of double sources, confusion sources, or pronounced extended structures. Some 89 high-quality objects, however, do not show any perturbations and appear to be star-like single sources, yet they are displaced by multiples of the expected error from the radio-loud AGN. We conclude that a fraction of luminous AGNs (more than 4%) can be physically dislodged from the optical centers of their parent galaxies.
In the course of other work I have obtained complete identifications for a problematic list of late-type stars by Dolidze (1975AbaOB..47....3D). The charts were used to make the identifications. Since numerous substantial errors were found that have propagated elsewhere in the literature, it was thought useful to publish the list separately. The corrections allow linkage of the stars to other catalogues in the visible and infrared. This complements a second similar list of late-M stars by Dolidze (Dolidze, 1975AbaOB..47..171D, Skiff, 1997IBVS.4417....1S).
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