[vsnet-alert 5139] DELTA SCORPII CONFIRMATION

The discovery of the Be nature of Delta Scorpii has already been reported to
the IAU.

After the discovery by Sebastián Otero, Liga Ibero-Americana de Astronomia,
of a gradual brightening at optical wavelenghts which starts at least one
month ago, spectroscopic observations were undertaken by Juan Fabregat,
University of Valencia, Spain, and P. Reig, Foundation for Research and
Technology-Hellas and University of Crete, Greece.

Spectra taken with the 1.3m telescope at Skinakas Observatory (Crete,
Greece), with spectral resolution of 0.3 nm. in the range 580-760 nm.,
reveal the H-alpha line in emission. Measured equivalent widths are
-0.34+-0.02 nm. on July 19.89, and -0.33+-0.02 nm. (FWHM 0.69+-0.01
nm.) on July 20.90.

The bright star delta Scorpii (HD 143275, HR 5953, V = 2.32, MK
B0.3IV) is currently undergoing a major optical and H-alpha outburst.

In 1990 Cote and van Kerkwijk (A&A 274, 870, 1993) observed weak emission
on the flanks of the H-alpha line core in absorption, and proposed the
classification of delta Sco as a Be star. All other observations in the
literature present a normal absorption-line spectrum. The observations
reported here constitute the first detection of emission lines in delta
Sco, and confirm its Be star nature.

The A&A paper is at:

I thank John Fabregat and P. Reig for its work.

It seems Delta Sco is well worthy of a GCAS star classification since its
brightening is already detectable with the naked eye, with almost 0.3
magnitudes and counting.

I'll let you know when more information and estimates were made.

[vsnet-alert 5139] DELTA SCORPII CONFIRMATION

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