Central Bureau for Astronomical Telegrams

IAUC 6922: 1998ce; XTE J2012+381

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                                                 Circular No. 6922
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)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html
Phone 617-495-7244/7440/7444 (for emergency use only)


SUPERNOVA 1998ce IN MCG -4-24-19
     F. Patat, European Southern Observatory (ESO); and M. Turatto,
Osservatorio Astronomico di Padova, report that they observed this
object (cf. IAUC 6912, 6917) with the ESO 3.6-m telescope (+ EFOSC2;
range 330-1000 nm, resolution 1.8 nm) on May 29.01 UT under
nonphotometric conditions.  A full reduction of the CCD spectrogram
shows that this object is a type-II supernova, about 10 days past
maximum light.  The spectrum is dominated by P-Cyg profiles,
superimposed on a relatively blue continuum.  The most prominent
features are identified as the Balmer lines of hydrogen, Ca II H
and K, and a number of Fe II lines.  The expansion velocities
deduced from the minima of H-alpha, H-beta, Ca II H and K, and Fe
II 516.9-nm are 11 200, 9200, 9000, and 7600 km/s, respectively.
Estimates of the supernova's magnitudes are B = 15.9, V = 15.6, and
R = 15.3.


XTE J2012+381
     F. E. Marshall and T. Strohmayer, Goddard Space Flight Center,
on behalf of the RXTE Science Operations Center, report an improved
position for this x-ray transient:  R.A. = 20h12m43s, Decl. =
+38o11'.0 (equinox 2000.0); the estimated uncertainty is 1', based
on scans across the source with the Proportional Counter Array on
the Rosssi X-ray Timing Explorer on May 27.68 UT.  This error
circle is consistent with the larger region determined with the
RXTE All-Sky Monitor but does not contain the star suggested by
Wagner et al. (IAUC 6920).  The observed 2-10-keV flux of about 110
mCrab indicates a continued brightening of the source.
     M. R. Garcia, J. E. McClintock, P. Berlind, and E. Barton,
Harvard-Smithsonian Center for Astrophysics; and P. Callanan,
University College, Cork, report:  "Spectra and photometry of the
possible counterpart to XTE J2012+381 (Wagner et al., IAUC 6920)
with the Mt. Hopkins 1.5-m and 1.2-m telescopes show that this star
is a heavily reddened M giant.  Photometry on May 28.312-28.469 UT
yields V = 19.7 +/- 0.2, R = 16.3 +/- 0.1, and I = 12.2 +/- 0.1,
with no detected variability.  The apparent brightening described
on IAUC 6920 is most probably an artifact of the extreme red colors
and the mismatch in the bandpasses of the LONEOS images (which used
an unfiltered CCD) and the DSS images.  Neither our photometry nor
that on IAUC 6920 provides any evidence that this star is the
counterpart to XTE J2012+381."

                      (C) Copyright 1998 CBAT
1998 May 29                    (6922)            Daniel W. E. Green

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