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UBV(RI)C JHK observations of Hipparcos-selected nearby stars
Kilkenny, D.; Marang, F.; Koen, C. +1 more
We present homogeneous, standardized UBV(RI)C photometry for over 700 nearby stars selected on the basis of Hipparcos parallaxes. Additionally, we list JHK photometry for about half of these stars, as well as L photometry for 86 of the brightest. A number of stars with peculiar colours or anomalous locations in various colour-magnitude …
Low-velocity streams in the solar neighbourhood caused by the Galactic bar
Siebert, A.; Minchev, I.; Bienayme, O. +1 more
We find that a steady-state bar induces transient features at low velocities in the solar neighbourhood velocity distribution due to the initial response of the disc, following the formation of the bar. We associate these velocity streams with two quasi-periodic orbital families, librating around the stable x1(1) and x1(2) or…
Towards a fully consistent Milky Way disc model - I. The local model based on kinematic and photometric data
Jahreiß, H.; Just, A.
We present a fully consistent evolutionary disc model of the solar cylinder. The model is based on a sequence of stellar subpopulations described by the star formation history (SFR) and the dynamical heating law [given by the age-velocity dispersion relation (AVR)]. The stellar subpopulations are in dynamical equilibrium and the gravitational pote…
Discovery of a strong magnetic field in the rapidly rotating B2Vn star HR 7355
Manset, N.; Wade, G. A.; Marcolino, W. L. F. +5 more
We report the detection of a strong, organized magnetic field in the He-variable early B-type star HR 7355 using spectropolarimetric data obtained with ESPaDOnS on the 3.6-m Canada-France-Hawaii Telescope within the context of the Magnetism in Massive Stars (MiMeS) Large Program. HR 7355 is both the most rapidly rotating known main-sequence magnet…
Observation and modelling of main-sequence star chromospheres - XIV. Rotation of dM1 stars
Houdebine, E. R.
We have measured v sin i for a selected sample of dM1-type stars. We give 114 measurements of v sin i for 88 different stars, and six upper detection limits. These are the first measurements of v sin i for most of the stars studied here. This represents the largest sample of v sin i measurements for M dwarfs at a given spectral type. For these mea…
Accurate fundamental parameters for A-, F- and G-type Supergiants in the solar neighbourhood
Lambert, David L.; Lyubimkov, Leonid S.; Rostopchin, Sergey I. +2 more
The following parameters are determined for 63 Galactic supergiants in the solar neighbourhood: effective temperature Teff; surface gravity logg iron abundance logɛ(Fe) microturbulent parameter Vt; mass M/Msolar age t and distance d. A significant improvement in the accuracy of the determination of logg, and all pa…
Period-luminosity relations of pulsating M giants in the solar neighbourhood and the Magellanic Clouds
Derekas, A.; Kiss, L. L.; Bedding, T. R. +3 more
We analyse the results of a 5.5-yr photometric campaign that monitored 247 southern, semiregular variables with relatively precise Hipparcos parallaxes to demonstrate an unambiguous detection of red giant branch (RGB) pulsations in the solar neighbourhood. We show that Sequence A' contains a mixture of asymptotic giant branch and RGB stars, as ind…
C, N and O abundances in red clump stars of the Milky Way
Ilyin, I.; Edvardsson, B.; Tautvaišienė, G. +2 more
The Hipparcos orbiting observatory has revealed a large number of helium-core-burning ‘clump’ stars in the Galactic field. These low-mass stars exhibit signatures of extra mixing processes that require modelling beyond the first dredge-up of standard models. The 12C/13C ratio is the most robust diagnostic of deep mixing becau…
Estimating the masses of extra-solar planets
Dhillon, V. S.; Littlefair, S. P.; Collier Cameron, A. +2 more
All extra-solar planet masses that have been derived spectroscopically are lower limits since the inclination of the orbit to our line-of-sight is unknown except for transiting systems. In theory, however, it is possible to determine the inclination angle, i, between the rotation axis of a star and an observer's line-of-sight from measurements of …
The quest for the Sun's siblings: an exploratory search in the Hipparcos Catalogue
Brown, Anthony G. A.; Portegies Zwart, Simon F.; Bean, Jennifer
We describe the results of a search for the remnants of the Sun's birth cluster among stars in the Hipparcos Catalogue. This search is based on the predicted phase-space distribution of the Sun's siblings from simple simulations of the orbits of the cluster stars in a smooth Galactic potential. For stars within 100 pc, the simulations show that it…