2005/02/09 by A. Richichi, V. Roccatagliata · 5 citations
Engineering · Mathematics · Physics and Astronomy · #Angular diameter #Angular resolution (graph drawing) #Angular velocity #Astronomical Observations and Instrumentation #Astrophysics #Classical mechanics #Combinatorics #History and Developments in Astronomy #Interferometry #Mathematics #Optics #Physics #Stars #Statistics #Stellar, planetary, and galactic studies #Value (mathematics) #Wavelength #astro-ph
paper · pdf · doi:10.1051/0004-6361:20041765
8 pages, 4 figures, accepted for publication in A&A
arxiv created 2005/02/09 · openalex publication_date 2005/03/14 · arxiv updated 2009/12/01 · openalex created_date 2020/11/23 · openalex updated_date 2026/08/05
The bright, well-known K5 giant Aldebaran, α Tau, is probably the star with the largest number of direct angular diameter determinations, achieved over a long time by several authors using various techniques. In spite of this wealth of data, or perhaps as a direct result of it, there is not a very good agreement on a single angular diameter value. This is particularly unsettling if one considers that Aldebaran is also used as a primary calibrator for some angular resolution methods, notably for optical and infrared long baseline interferometry. Directly connected to Aldebaran's angular diameter and its uncertainties is its effective temperature, which also has been used for several empirical calibrations. Among the proposed explanations for the elusiveness of an accurate determination of the angular diameter of Aldebaran are the possibility of temporal variations as well as a possible dependence of the angular diameter on the wavelength. We present here a few, very accurate new determinations obtained by means of lunar occultations and long baseline interferometry. We derive an average value of milliarcsec for the uniform disk diameter. The corresponding limb-darkened value is milliarcsec, or . We discuss this result, in connection with previous determinations and with possible problems that may affect such measurements.