[IAUC] IAUC 8946: LUMINOUS TRANSIENT IN NGC 300; C/2008 J1 [25139-2008/05-R1]

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                                                  Circular No. 8946
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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LUMINOUS TRANSIENT IN NGC 300
     L. A. G. Monard, Pretoria, South Africa, reports his discovery
of a variable object (mag 14.2) on unfiltered CCD images taken on
May 14.14 UT, the object located at R.A. = 0h54m34s.16, Decl. =
-37o38'28".6, which is 227" west and 153" north of the core of the
Sculptor-group galaxy NGC 300.  Nothing is visible at this position
on a red Digitized Sky Survey image (limiting mag about 20.5).
Additional approximate magnitudes for the variable from Monard's
earlier images:  2007 Dec. 30.8, [18.5; 2008 Feb. 8.75, [18.0; Apr.
17.1, [15.5; 24.16, 16.5; May 15.14, 14.2.
     Following posting of this object on the Central Bureau's
unconfirmed-objects webpage, H. E. Bond, Space Telescope Science
Institute; F. M. Walter, Stony Brook University; and J. Velasquez,
Cerro Tololo Interamerican Observatory, report that a spectrum
(resolution 1.72 nm), obtained on May 15.4 UT with the SMARTS 1.5-m
telescope at Cerro Tololo, shows emission lines of H_alpha, H_beta,
the Ca II triplet at 854.2, 849.8, and 866.2 nm, and -- remarkably
-- strong emission at the forbidden [Ca II] doublet at 729.1 and
732.3 nm.  Ca II H and K are seen in absorption.  The Balmer lines
are only slightly resolved at the velocity resolution (790 km/s) of
the spectra.  The mean heliocentric radial velocity of the features
is about +430 km/s, probably consistent with membership in NGC 300.
At an optical absolute magnitude of -12.5, the object is
photometrically and spectroscopically not a classical nova,
luminous blue variable, or supernova.  The spectrum is fairly
similar to that of V838 Mon on 2002 Feb. 13 (Wisniewski et al. 2003,
Ap.J. 588, 486, Fig. 5) -- an object suggested to represent the
collision or merger of two stars.  Continued spectroscopic and
photometric monitoring of this transient in NGC 300 is urged.


COMET C/2008 J1 (BOATTINI)
     Improved parabolic orbital elements for this comet (cf. IAUC 8940)
from MPEC 2008-J55:

     T = 2008 July 13.387 TT          Peri. =  68.253
                                      Node  = 273.511   2000.0
     q = 1.72402 AU                   Incl. =  61.854

                      (C) Copyright 2008 CBAT
2008 May 16                    (8946)            Daniel W. E. Green