Search Publications
A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun
Neuhäuser, R.; Hohle, M. M.; Tetzlaff, N.
Traditionally, runaway stars are O- and B-type stars with large peculiar velocities. We would like to extend this definition to young stars (up to ≈50 Myr) of any spectral type and to identify those present in the Hipparcos catalogue by applying different selection criteria, such as peculiar space velocities or peculiar one-dimensional velocities.…
Random forest automated supervised classification of Hipparcos periodic variable stars
Rimoldini, L.; Mowlavi, N.; Nienartowicz, K. +14 more
We present an evaluation of the performance of an automated classification of the Hipparcos periodic variable stars into 26 types. The sub-sample with the most reliable variability types available in the literature is used to train supervised algorithms to characterize the type dependencies on a number of attributes. The most useful attributes eva…
Bayesian inference of stellar parameters and interstellar extinction using parallaxes and multiband photometry
Bailer-Jones, C. A. L.
Astrometric surveys provide the opportunity to measure the absolute magnitudes of large numbers of stars, but only if the individual line-of-sight extinctions are known. Unfortunately, extinction is highly degenerate with stellar effective temperature when estimated from broad-band optical/infrared photometry. To address this problem, I introduce …
Multidimensional Bayesian membership analysis of the Sco OB2 moving group
Ireland, M. J.; Rizzuto, A. C.; Robertson, J. G.
We present a new high-mass membership of the nearby Sco OB2 association based on Hipparcos positions, proper motions and parallaxes, and radial velocities taken from the 2nd Catalogue of Radial Velocities with Astrometric Data (CRVAD-2). The Bayesian membership selection method developed makes no distinction between subgroups of Sco OB2 and utiliz…
New limb-darkening coefficients and synthetic photometry for model-atmosphere grids at Galactic, LMC and SMC abundances
Howarth, Ian D.
New grids of ATLAS9 models have been calculated using revised convection parameters and updated opacity-distribution functions (ODFs), for chemical compositions intended to be representative of solar, [M/H] =+0.3, +0.5, Large Magellanic Cloud and Small Magellanic Cloud abundances. The grids cover Teff= 3.5-50 kK, from log g= 5.0 to the …
Limits on the local dark matter density
Read, Justin I.; Garbari, Silvia; Lake, George
We revisit systematics in determining the local dark matter density ρdm from the vertical motion of stars in the solar neighbourhood. Using a simulation of a Milky Way like galaxy, we determine the data quality required to detect ρdm at its expected local value. We introduce a new method for recovering ρdm that use…
Ejection velocities of high Galactic latitude runaway stars
Napiwotzki, R.; Silva, M. D. V.
We estimate the distribution of ejection velocities for the known population of high Galactic latitude runaway stars. The initial sample is a collection of 174 early-type stars selected from the literature. The stars are first classified according to their evolutionary status in order to obtain a homogeneous sample of 96 genuine main-sequence star…
On the anomalous secular increase of the eccentricity of the orbit of the Moon
Iorio, L.
A recent analysis of a Lunar Laser Ranging (LLR) data record spanning 38.7 yr revealed an anomalous increase of the eccentricity e of the lunar orbit amounting to ? yr-1. The present-day models of the dissipative phenomena occurring in the interiors of both the Earth and the Moon are not able to explain it. In this paper, we examine sev…
Residual rotation of the Hipparcos/Tycho-2 system as determined from the data of the XPM catalogue
Bobylev, V. V.; Akhmetov, V. S.; Fedorov, P. N.
From a comparison of absolute proper motions of stars from the XPM catalogue with those of the same stars from the PPMXL, UCAC3, Tycho-2 and XC1 catalogues, the equatorial components of the rotation vector of these coordinate systems are determined with respect to the coordinate system specified by positions and proper motions of XPM. These parame…
Candidate subdwarfs and white dwarfs from the 2MASS, Tycho-2, XPM and UCAC3 catalogues
Gontcharov, George A.; Bajkova, Anisa T.; Fedorov, Peter N. +1 more
Photometry from the Two-Micron All-Sky Survey (2MASS), United States Naval Observatory CCD Astrograph Catalog (UCAC3) and SuperCosmos catalogues, together with proper motions from the Tycho-2, Kharkiv Proper Motions (XPM) and UCAC3 catalogues, is used to select all-sky samples of 28 candidate white dwarfs, 1826 evolved and 7641 unevolved subdwarfs…