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IAUC 8669: 2006aa, 2006ab,, 2006ac; theta^1 Ori E

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                                                  Circular No. 8669
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)


SUPERNOVAE 2006aa, 2006ab, AND 2006ac
     Three apparent supernovae have been discovered on unfiltered
KAIT CCD images via the Lick Observatory Supernova Survey (cf. IAUC
8667), as reported by E. Lee, M. Baek, and W. Li:

SN      2006 UT      R.A.  (2000.0)  Decl.    Mag.     Offset
2006aa  Feb. 8.48   11 53 19.89  +20 45 18.2  18.1  6".5 W, 12".2 N
2006ab  Feb. 9.18    2 48 53.92  +53 02 20.8  18.0  9".2 E, 6".2 N
2006ac  Feb. 9.47   12 41 44.86  +35 04 07.1  16.0  4".1 E, 21".7 N

Additional magnitudes of 2006aa in NGC 3947:  Jan. 23.49 UT, [19.0;
Feb. 9.50, 18.0.  Additional magnitudes of 2006ab in PGC 10652:
Jan. 7.20, [18.8; 24.16, [18.6; Feb. 10.18, 18.0.  Additional
magnitudes of 2006ac in NGC 4619, 2004 May 30.21, [19.0; 2006 Feb.
10.40, 15.9.


theta**1 ORIONIS E
     R. Costero, J. Echevarria, M. G. Richer, and A. Poveda,
Universidad Nacional Autonoma de Mexico, report their finding that
the suspected variable star theta**1 Ori E -- the fifth brightest
star in the Orion Trapezium, located about 4" north of component A
[object 1864 of Parenago 1954, Publ. Sternberg Astr. Inst. 25, 342;
also ADS 4186 E, from Aitken's 1932 Double Star Catalogue (Carnegie
Inst. of Wash.), 1, 358; listed as NSV 2291 due to Walker, IBVS
1238] -- is a double-lined spectroscopic binary.  Echelle spectra
(resolution about 20000, range 380-680 nm), obtained on Jan. 8-17
with the 2.1-m telescope of the National Observatory at San Pedro
Martir, Baja California, show both components to be of spectral
type F5.  The Li I 670.8-nm line (equivalent width about 0.14 nm)
is clearly present in the spectra of both members.  The estimated
orbital period of the binary is 10.5 +/- 1.2 days, and the maximum
measured line separation is 154 +/- 4 km/s.  The spectrum of
component E discussed by Herbig (1950, Ap.J. 111, 15) was probably
contaminated by the light of component A; the present
classification of component E is based on on the comparison of its
spectrum with those of several standards of the Morgan and Keenan
system, in the interval F0 V-G0 V, taken with the same instrument.
These results, the suspected variability (0.4 mag), its being one
of the brightest x-ray sources in the Trapezium (Schulz et al. 2003,
Ap.J. 595, 365), and the position of the star well above the zero-
age main sequence lead us to speculate that this object is an
interesting candidate for its being an eclipsing system and/or a
flare star.  Further observations are encouraged.

                      (C) Copyright 2006 CBAT
2006 February 10               (8669)            Daniel W. E. Green

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