Central Bureau for Astronomical Telegrams
IAUC 3435: CHROMOSPHERIC EVENT IN alpha Aqr; 1979 VA; P/SCHWASSMANN-WACHMANN 1
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Circular No. 3435
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-864-5758
CHROMOSPHERIC EVENT IN alpha AQUARII
A. K. Dupree and S. Baliunas, Center for Astrophysics, report
that IUE observations of alpha Aqr (G2Ib) on Nov. 11 show substantial
changes in the Mg II line profile from measurements 11 months earlier.
The flux in the short-wavelength emission peaks at 279.5 and
280.2 nm has increased and is accompanied by a broadening of the
profile and an increased absorption by the extended stellar wind.
The terminal wind velocity remained constant. The flux of C II
(133.5 nm) and O I (135.7 nm) increased by a factor of about 2 as
compared to the previous measurements, whereas C IV (155.0 nm) and
Si IV (140 nm) increased by lesser amounts. High-dispersion Ca II
K profiles obtained with an intensified Reticon detector and echelle
spectrograph at Mt. Hopkins Observatory reveal a change in the peak
line asymmetry with the blue emission peak becoming substantially
stronger than the red peak between Nov. 4 and 11. By Dec. 8, the
blue emission had weakened again, becoming comparable to the red
emission peak. This is the first quantitative evidence of chromospheric
variability in such a supergiant atmosphere, and the star
should be monitored, for it may be in a phase of activity resulting
from the passage of enhanced flux regions across its disk.
1979 VA
Recent observations indicate that this object is not of Alinda
type (cf. IAUC 3429), or only marginally so. The following ephemeris
is from orbital elements to appear on the 1980 Jan. 1 MPCs
(e = 0.627, P = 4.25 years, aphelion distance Q = 4.27 AU).
1980 ET R. A. (1950) Decl. Delta r Mag.
Jan. 2 3 48.99 +20 52.4 0.604 1.494 17.7
12 4 03.44 +20 54.5
22 4 17.94 +21 04.7 0.887 1.665 18.8
Feb. 1 4 32.79 +21 19.2
11 4 48.03 +21 34.9 1.215 1.834 19.7
PERIODIC COMET SCHWASSMANN-WACHMANN 1
C.-Y. Shao informs us that an exposure with Harvard Observatory's
1.5-m reflector on Dec. 19.3 UT showed a strong condensation
in a coma ~ 1'.5 in diameter with a short tail in p.a. 320o. The
comet's total magnitude was about 15.
1979 December 21 (3435) Brian G. Marsden
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