Issue |
A&A
Volume 433, Number 1, April I 2005
|
|
---|---|---|
Page(s) | 305 - 312 | |
Section | Stellar atmospheres | |
DOI | https://doi.org/10.1051/0004-6361:20041765 | |
Published online | 14 March 2005 |
Aldebaran's angular diameter: How well do we know it? *
1
European Southern Observatory, Karl-Schwarzschildstr. 2, 85748 Garching bei München, Germany e-mail: arichich@eso.org
2
Dipartimento di Astronomia, Università di Padova, Vicolo dell'Osservatorio 2, 35122 Padova, Italy
Received:
31
July
2004
Accepted:
28
November
2004
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.
Key words: occultations / techniques: high angular resolution / techniques: interferometric / stars: fundamental parameters / stars: individual: α Tau / stars: individual: Aldebaran
© ESO, 2005
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.