ArasBeAm

Zet Oph litterature history

Saturday 12 March 2011 by Jean-Noël Terry

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


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