Search Publications
Stellar diameters and temperatures - VI. High angular resolution measurements of the transiting exoplanet host stars HD 189733 and HD 209458 and implications for models of cool dwarfs
López-Morales, Mercedes; Kane, Stephen R.; Brewer, John +24 more
We present direct radii measurements of the well-known transiting exoplanet host stars HD 189733 and HD 209458 using the CHARA Array interferometer. We find the limb-darkened angular diameters to be θLD = 0.3848 ± 0.0055 and 0.2254 ± 0.0072 mas for HD 189733 and HD 209458, respectively. HD 189733 and HD 209458 are currently the only two…
Towards a fully consistent Milky Way disc model - III. Constraining the initial mass function
Rybizki, J.; Just, A.
We use our vertical Milky Way disc model together with Galaxia to create mock observations of stellar samples in the solar neighbourhood. We compare these to the corresponding volume complete observational samples of dereddened and binary accounted data from Hipparcos and the Catalogue of Nearby Stars. Sampling the likelihood in the parameter spac…
New members of the TW Hydrae Association and two accreting M-dwarfs in Scorpius-Centaurus
Murphy, Simon J.; Bento, Joao; Lawson, Warrick A.
We report the serendipitous discovery of several young mid-M stars found during a search for new members of the 30-40 Myr-old Octans Association. Only one of the stars may be considered a possible Octans(-Near) member. However, two stars have proper motions, kinematic distances, radial velocities, photometry and Li I λ6708 measurements consistent …
Confirming HD 23478 as a new magnetic B star hosting an Hα-bright centrifugal magnetosphere
Wade, G. A.; Bohlender, D. A.; Neiner, C. +11 more
In this paper, we report 23 magnetic field measurements of the B3IV star HD 23478: 12 obtained from high-resolution Stokes V spectra using the ESPaDOnS (Canada-France-Hawaii Telescope) and Narval (Télescope Bernard Lyot) spectropolarimeters, and 11 from medium-resolution Stokes V spectra obtained with the DimaPol spectropolarimeter (Dominion Astro…
On the distances of planetary nebulae
Smith, Haywood
Past calibrations of statistical distance scales for planetary nebulae have been problematic, especially with regard to `short' versus `long' scales. Reconsidering the calibration process naturally involves examining the precision and especially the systematic errors of various distance methods. Here, we present a different calibration strategy, n…
Climbing the cosmic ladder with stellar twins
Gilmore, G.; Soubiran, C.; Jofré, P. +3 more
Distances to stars are key to revealing a three-dimensional view of the Milky Way, yet their determination is a major challenge in astronomy. Whilst the brightest nearby stars benefit from direct parallax measurements, fainter stars are subject of indirect determinations with uncertainties exceeding 30 per cent. We present an alternative approach …
The local stellar luminosity function and mass-to-light ratio in the near-infrared
Rybizki, J.; Dettbarn, C.; Jahreiß, H. +3 more
A new sample of stars, representative of the solar neighbourhood luminosity function (LF), is constructed from the Hipparcos catalogue and the Fifth Catalogue of Nearby Stars. We have cross-matched to sources in the Two Micron All Sky Survey catalogue so that for all stars individually determined near-infrared (NIR) photometry is available on a ho…
Line-depth-ratio temperatures for the close binary ν Octantis: new evidence supporting the conjectured circumstellar retrograde planet
Ramm, D. J.
We explore the possibly that either star-spots or pulsations are the cause of a periodic radial velocity (RV) signal (P ∼ 400 d) from the K-giant binary ν Octantis (P ∼ 1050 d, e ∼ 0.25), alternatively conjectured to have a retrograde planet. Our study is based on temperatures derived from 22 line-depth ratios (LDRs) for ν Oct and 20 calibration s…
The velocity distribution in the solar neighbourhood from the LAMOST pilot survey
Zhang, Yong; Xu, Yan; Mao, Shude +5 more
We use about 15 000 F/G nearby dwarf stars selected from the LAMOST pilot survey to map the U-V velocity distribution in the solar neighbourhood. An extreme deconvolution algorithm is applied to reconstruct an empirical multi-Gaussian model. In addition to the well-known substructures, e.g. Sirius, Coma Berenices, Hyades-Pleiades overdensities, se…
Evolutionary status of the active star PZ Mon
Semenko, E. A.; Bondar', N. I.; Gorynya, N. A. +2 more
We use original spectra and available photometric data to recover the parameters of the stellar atmosphere of PZ Mon, formerly referred to as an active red dwarf. The derived effective temperature Teff = 4700 K and gravity log g = 2.8 suggest that PZ Mon is a K2III giant. Stellar atmosphere parameters (Teff and log g), along …