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IAUC 8683: 2006ap; RS Oph

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                                                  Circular No. 8683
Central Bureau for Astronomical Telegrams
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)

SUPERNOVA 2006ap IN NGC 6378
     T. Boles, Coddenham, England, reports the discovery of an
apparent supernova (mag 17.2) on unfiltered CCD images taken on Mar.
2.194 and 3.159 UT with a 0.35-m reflector.  The new object is
located at R.A. = 17h30m41s.19, Decl. = +6o16'33".1 (equinox 2000.0),
which is approximately 11".9 west and 23".0 south of the center of
NGC 6378.  Nothing is visible at this location on Boles' images
from 2005 July 16 and Aug. 29 (limiting mag 19.5) or on Digital Sky
Survey plates from 1997 Apr. 12 (limiting red mag 20.5) and 1990
June 17 (limiting blue mag 21.0).

     J.-U. Ness and S. Starrfield, Arizona State University; J. J.
Drake, Smithsonian Astrophysical Observatory; M. Orio, Istituto
Nazionale di Astrofisica and University of Wisconsin; M. F. Bode,
Liverpool John Moores University; T. J. O'Brien and R. J. Davis,
University of Manchester; J. Osborne and K. L. Page, University of
Leicester; G. Schwarz, West Chester University; J. Krautter,
University of Heidelberg; A. Evans, Keele University; S. P. S.
Eyres, University of Central Lancashire; and R. Gehrz and C.
Woodward, University of Minnesota, report on the first high-
resolution x-ray spectra of the outburst of the recurrent nova RS
Oph (cf. IAUC 8671), obtained on Feb. 26 (two weeks after the
beginning of the outburst).  The Chandra X-ray Observatory High
Energy Transmission Grating and ACIS-S detector observed RS Oph for
10000 s in the wavelength range 0.15-2.5 nm, revealing a rich
emission-line spectrum dominated by resonance lines of He-like and
H-like ions of Fe, S, Si, Mg, and Ne superimposed on a strong
continuum.  The lines seen indicate that a wide range of plasma
temperatures have been observed:  the coolest transition detected
is the O VIII Lyman_alpha doublet at 1.897 nm (emissivity peak at T
= 3 MK), while the hottest is the Fe XXV 1s2p-1s2 resonance line
(emissivity peak at T = 60 MK).  Lines show broadening
corresponding to approximately 2000 km/s at half maximum, with
systematic blueshifts amounting to approximately 500 km/s (Si XIV,
Mg XII, and Ne X) and 1000 km/s (O VIII).
     J. D. West, Mulvane, KS, reports the following infrared
magnitudes of RS Oph obtained with a 0.25-m reflector (+ Optec SSP-4
Photometer):  Feb. 13.4715 UT, J = 2.71 +/- 0.02; 13.4715, H = 2.36
+/- 0.01; 14.4715, J = 3.06 +/- 0.01; 14.4715, H = 2.67 +/- 0.01;
23.4729, J = 4.80 +/- 0.22; 23.4729, H = 4.34 +/- 0.06; 27.5306, H
= 4.74 +/- 0.12.

                      (C) Copyright 2006 CBAT
2006 March 3                   (8683)            Daniel W. E. Green

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