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4 Her - litterature and history
Friday 11 February 2011 by Jean-Noël Terry
4 Her, HD 142926, HR 5938
Information:
In emission since 1996, we are waiting for an absorption return in 2011-2012.
What we know
Spectroscopic binary P=46.023d (Pédoussant et al., 1977)
P=46.194 (Heard et al., 1975)
Activity 1921: Ha absorption
1939: Ha emission
1940: Ha emission , Hb absorption (Heard, A&A, 42,47)
1949: weaker emission
1953-63: Ha absorption (Hubert, A&A, 11,100)
1964: Ha strong emission
1967-68: Ha two peaks emission (Cowler et al., PASP, 80, 685)
1969-71: Ha emission (Harmanec et al., BAICz, 27, 47)
1982:Ha emission (Andrillat et al., A&AS,48,93)
1989-91: Ha no emission detected (Koubsky et al., A&A, 277, 521 and A&A, 328,551)
1996-2010: Ha emission in BESS
Hubert suggests a 28 years period (13 for emission, 15 for absorption) Non emission phase coincide with maximum brigthness and blueshift of the star
Conclusion:
P, if exists, is very uncertain.
In emission since 1996, we are waiting for an absorption return in 2011-2012.