2008A&A...489..627O


Query : 2008A&A...489..627O

2008A&A...489..627O - Astronomy and Astrophysics, volume 489, 627-631 (2008/10-2)

Sub-milliarcsecond precision spectro-astrometry of Be stars.

OUDMAIJER R.D., PARR A.M., BAINES D. and PORTER J.M.

Abstract (from CDS):

The origin of the disks around Be stars is still not known. Further progress requires a proper parametrization of their structure, both spatially and kinematically. This is challenging as the disks are very small. Here we assess whether a novel method is capable of providing these data. We obtained spectro-astrometry around the Paβ line of two bright Be stars, α Col and ζ Tau, to search for disk signatures. The data, with a pixel-to-pixel precision of the centroid position of 0.3..0.4 milliarcsecond is the most accurate such data to date. Artefacts at the 0.85mas level are present in the data, but these are readily identified as they were non-repeatable in our redundant datasets. This does illustrate the need of taking multiple data to avoid spurious detections. The data are compared with model simulations of the spectro-astrometric signatures due to rotating disks around Be stars. The upper limits we find for the disk radii correspond to disk sizes of a few dozen stellar radii if they rotate Keplerian. This is very close to observationally measured and theoretically expected disk sizes, and this paper therefore demonstrates that spectro-astrometry, of which we present the first such attempt, has the potential to resolve the disks around Be stars.

Abstract Copyright:

Journal keyword(s): techniques: high angular resolution - techniques: spectroscopic - stars: individual: α Col, ζ Tau - stars: emission-line, Be

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 * bet Tau PM* 05 26 17.51312 +28 36 26.8262 1.03 1.52 1.65 1.66 1.76 B7III 357 1
2 * zet Tau Be* 05 37 38.6854231 +21 08 33.158804 2.22 2.84 3.03 3.06 3.15 B1IVe_shell 711 0
3 * alf Col Be* 05 39 38.9410319 -34 04 26.794991 2.10 2.53 2.65 2.65 2.74 B9Ve 233 0
4 * alf Leo PM* 10 08 22.31099 +11 58 01.9516 0.88 1.24 1.40 1.37 1.47 B8IVn 829 0
5 * iot Her bC* 17 39 27.8860861 +46 00 22.800110 2.940 3.630 3.800     B3IV 438 1

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2022.05.21-06:01:09

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