Central Bureau for Astronomical Telegrams
IAUC 6259: N Cas 1995; alpha Cen B; 73P
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Circular No. 6259
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
Phone 617-495-7244/7440/7444 (for emergency use only)
NOVA CASSIOPEIAE 1995
U. Munari, Asiago Observatory, Padua; and A. Lepardo, R.
Passuello, and G. Sostero, Associazione Friulana di Astronomia e
Meteorologia (AFAM), communicate: "Photoelectric photometry secured
with the 0.45-m AFAM reflector on Nov. 4.9 UT yields V = 8.45, B-V
= +0.51, U-B = -0.15 (+/- 0.02 mag in all colors). Simultaneous
spectra (range 350-900 nm, resolution 0.04 nm) obtained with the
Asiago 1.82-m telescope (+ echelle spectrograph + CCD) indicate the
object to be a symbiotic nova (similar to PU Vul) and not a
classical nova. All absorption lines of the underlying F continuum
are narrow. H-alpha, H-beta, H-gamma, the Ca II triplet at 850-866
nm, and many Fe II lines appear in moderate emission, while higher
Balmer lines are present in absorption. The profiles consist of
sharp absorptions (FWHM 55 km/s) superimposed onto the blue wing of
narrow emission (FWHM 95 km/s) components, shifted by about -85
km/s from the latter."
alpha CENTAURI B
E. Guinan, Villanova University; and S. Messina, University of
Catania, report on the determination of the rotation period of the
K1 V component of the alpha Cen triple system: "The star was
observed about twice a week over a three-month interval (May-Aug.)
with the IUE satellite (+ LWPHIGH and SWPLOW cameras). These
observations show a 20- to 30-percent modulation in the
chromospheric and transition-region ultraviolet line emissions with
a period of 36.8 +/- 0.4 days. This period is assumed to be the
rotation period, and the modulations of the emission-line strengths
arise as large active sites on the star rotate in and out of view.
A definite determination of the rotation period of alpha Cen B is
important for testing stellar dynamo theories because the age and
physical properties of the alpha Cen system are known with high
precision. Determinations of the rotational periods of alpha Cen A
(G2 V) and alpha Cen C (= Proxima Cen; dM5e) are also being
determined in a similar manner. It is estimated from the
amplitudes of the chromospheric lines' emissions, that alpha Cen B
could show 1- to 2-percent light variations from the rotational
modulation by starspots that commonly accompany plage emissions."
COMET 73P/SCHWASSMANN-WACHMANN 3
Total visual magnitude estimates: Oct. 22.10 UT, 6.3 (J. V.
Scotti, Kitt Peak, AZ, 10x50 binoculars); 28.06, 5.6 (R. Keen, Mt.
Thorodin, CO, 7x50 binoculars); Nov. 8.08, 8.1 (A. Hale,
Cloudcroft, NM, 0.2-m reflector).
1995 November 11 (6259) Daniel W. E. Green
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