Central Bureau for Astronomical Telegrams
IAUC 8265: 2004A; (1089)
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Circular No. 8265
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)
SUPERNOVA 2004A IN NGC 6207
S. Nakano, Sumoto, Japan, reports the discovery by K. Itagaki
(Teppo-cho, Yamagata, Japan) of an apparent supernova (mag 15.7) on
several 30-second unfiltered CCD frames taken with a 0.28-m f/10
reflector on Jan. 9.84 UT. Itagaki found the new object at mag
15.7 on a confirming image taken on Jan. 10.75. SN 2004A is
located at R.A. = 16h43m01s.90, Decl. = +36o50'12".5 (equinox
2000.0), which is approximately 22" west and 17" north of the
center of NGC 6207 (noting that the center of the galaxy is very
difficult to define). Nothing was visible at this position on
Itagaki's CCD frames taken on 2000 Aug. 8, 2002 May 2, and 2003
Feb. 13 (limiting mag 18.5), or on his image from 2003 Dec. 27
(limiting mag 18). Nakano reports that SN 2004A was also observed
at mag 15.7 on an unfiltered CCD image taken by R. Kushida
(Yatsugatake South Base Observatory, 0.40-m f/10 reflector) on Jan.
9.877; from this image, Y. Kushida measured position end figures
01s.90, 12".3 for the new object.
(1089) TAMA
R. Behrend, Geneva Observatory; R. Roy, Blauvac, France; C.
Rinner, Ottmarsheim, France; P. Antonini, Bedoin, France; P. Pravec,
Ondrejov Observatory; A. W. Harris, Space Science Institute; S.
Sposetti, Gnosca, Switzerland; R. Durkee, Minneapolis, MN; and A.
Klotz, Guitalens, France, report that photometric observations of
the minor planet (1089), obtained on five nights between 2003 Dec.
24 and 2004 Jan. 5, strongly suggest that the object is a binary
system showing mutual eclipses and/or occultations. The orbital
period of the system is 0.6852 +/- 0.0002 day. A regular-appearing
lightcurve of amplitude 0.38 mag is synchronized with the eclipse
events, indicating that at least one of the two bodies is elongated
and rotates synchronously with the orbital motion. The sharp
eclipse/occultation events occur at both rotational lightcurve
minima and have a duration of about 0.08 day and depth about 0.5
mag, indicating a secondary-to-primary mean-diameter ratio of about
0.7. The first observed event occurred (centered) on 2003 Dec.
26.03 UT. The orbital separation should be about 20 km, center to
center, corresponding to a maximum separation observed from earth
of about 0".03. Continued photometric monitoring of (1089) is
warranted to confirm the binary nature and to derive geometric and
orbital parameters of the system as the mutual events evolve.
Resolved imaging using adaptive optics or the Hubble Space
Telescope could likewise be of high value.
(C) Copyright 2004 CBAT
2004 January 10 (8265) Daniel W. E. Green
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