Zet Oph litterature history

(article à traduire en français)

zet Oph, HD 149757, HR 6175

Information : Observation every year as soon as possible (march-april) is needed to see the evolution of W every year

What we know

One of the most rapidly rotating Be stars known and a runaway star with high proper motion.

Is it the result of the evolution of a close binary system ? (Villamariz et al., A&A, 442, 263)

Activity 1971 july : no emission

1973 july-september : Ha with double emission profile (Irvine, ApJ, 188, L19 and Nimalä, ApJ, 187, L23)

1974 march-april : Ha changed from double emission to absorption (Barker et al., ApJ, 192, L11)

1974 august-september : no emission (Dachs, 1977)

1977 : absorption (Slettebak 1978)

1990 may : reapearance of the weak double emission component in Ha (IAUC 5015)

1990 july : no emission (IAUC 5049)

1995 july to 1998 june : absorption

1998 june (11-12) : brief appearance of a central emission ?

2007 july- 2010 july : no emission

Conclusion :

Have we missed an emission near 2005-2006 ? Evolution and period for emission are very incertain. If it exists, this period is probably large (near 16 years ??). Observation every year as soon as possible (march-april) is needed to see the evolution of W.

version 20110303