Search Publications
The Hipparcos Pleiades Parallax Error is Also a Proper Motion Error
Makarov, V. V.
The mean parallax of the Pleiades open cluster from the Hipparcos catalog is larger than the true value by approximately 1 mas. The origin of this error, as well as a possible algorithm of correcting it, was proposed by Makarov (2002). The problem is reassessed using the more accurate Gaia data with a focus on the predicted correction to the Pleia…
Mass Ratios of Long-Period Binary Stars Resolved in Precision Astrometry Catalogs of Two Epochs
Makarov, V. V.
Mass ratios of widely separated, long-period, resolved binary stars can be directly estimated from the available data in major space astrometry catalogs, such as the ESA's Hipparcos and Gaia mission results. The method is based on the universal principle of inertial motion of the system's center of mass in the absence of external forces, and is in…
δ Mus Revisited: Rectifying a 82 yr-old Mistake
Boffin, Henri M. J.; Pourbaix, Dimitri
The red giant δ Muscae is known since 1919 to be a spectroscopic binary, and the first and only orbit was determined in 1936, claiming the period to be 847 days. This was discrepant with the Hipparcos determined astrometric orbit. Using the latest data available for this object - leading to a 100 yr time-span - we show here that the correct period…
The Kinematics and Velocity Ellipsoid of the G III Stars
Branham, R. L., Jr.
To study the kinematics of the G giant stars (luminosity class III) use is made of proper motions and parallaxes taken from van Leeuwen's new reduction of the Hipparcos catalog. 3,075 stars, of which 658 have radial velocities, were used in the final study. The solution gives: solar velocity of 16.72±0.41 km s-1; Oort's constant's, in u…
Radio Proper Motions of Wolf-Rayet Stars
Rodríguez, L. F.; Dzib, S.
We present the analysis of observations taken from the Very Large Array archive of six Wolf-Rayet stars with radio emission, with the purpose of determining their proper motions. Typically, these observations cover periods of 10 to 20 years. To verify the method, we included WR 140 in the sample, and found that the proper motions determined by us …
Kinematics and Velocity Ellipsoid of the K Giants
Branham, R. L., Jr.
To study the kinematics of the K giant stars (luminosity class III) use is made of proper motions taken from van Leeuwen's new reduction of the Hipparcos catalog. 11,372 stars, of which 880 have radial velocities, were used in the final study. Semi-definite programming solves for the kinematical parameters such as the Oort constants and simultaneo…
Kinematics and Velocity Ellipsoid of M Giants
Branham, R. L., Jr.
To study the kinematics of M giant stars (luminosity class III) use is made of 1,532 stars with proper motions taken from the Hipparcos catalog, of which 480 have radial velocities. Stars farther off than 700 pc were excluded because they induce a noticeable tilt in the distribution of the stars. Various solutions were performed, and the one calcu…
Radio Continuum Sources Associated with AB Aur
Rodríguez, L. F.; Ho, P. T. P.; Zapata, L.
We present high angular resolution, high-sensitivity Very Large Array observations at 3.6 cm of the Herbig Ae star AB Aur. This star is of interest since its circumstellar disk exhibits characteristics that have been attributed to the presence of an undetected low mass companion or giant gas planet. Our image confirms the continuum emission known …
Orbit, Masses and Spectral Analysis of the Visual Binary A 2329
Andrade, M.
A revised orbit for the visual binary A 2329, calculated taking into account a set of interferometric measures distributed over one orbital revolution, is presented. On the basis of new orbital elements and the Hipparcos parallax, a dynamical mass of the system of 1.25+/-0.14 M_⊙ is obtained. By considering new spectral data, we confirm its MK spe…
uvby - β Photoelectric Photometry of the Open Cluster α Per
Sareyan, J. -P.; Peña, J. H.
Absolute photoelectric photometry of stars in the direction of the Open Cluster α Per has been secured and is presented along with an analysis reinforced with all the available data in Strömgren uvby-β photometry compiled from the literature. Cluster membership is analyzed and the physical characteristics of the stars have been deduced. The member…