Issue |
A&A
Volume 423, Number 1, August III 2004
|
|
---|---|---|
Page(s) | L1 - L4 | |
Section | Letters | |
DOI | https://doi.org/10.1051/0004-6361:20040193 | |
Published online | 29 July 2004 |
Letter to the Editor
η Carinae: The 1998 brightening and the smearing-out effect
1
Leiden Observatory, Postbus 9513, 2300RA Leiden, The Netherlands e-mail: genderen@strw.leidenuniv.nl
2
Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
Received:
15
March
2004
Accepted:
11
June
2004
A comparison of broad-band photometry of the Homunculus (ground-based data) and of broad-band and narrow-band photometry of the central region (HST-based) from 1997 to 2003 reveals that, apart from the brightening in 1998, the Homunculus as well as the central star varied in a very similar way. This excludes smearing-out effects as an explanation for the difference between the brightening of the central region and that of the Homunculus during 1998. A plausible reason for the homologous light behaviour is enhanced extinction decrease in the line-of-sight to the central region during a global brightening occurring after the 1998.0 spectroscopic event. From 1998 to 2004 there is indeed a brightness excess of ~03 between the Homunculus and the extrapolated secular brightening. We also illustrate that ground-based aperture photometry of the Homunculus is a reliable diagnostic tool for studying the variability of the central star.
Key words: technique: photometric - stars: individual: η Carinae - variables - supergiants
© ESO, 2004
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