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IAUC 8948: V5579 Sgr; N Oph 2008

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IAUC number

                                                  Circular No. 8948
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://www.cfa.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)

     R. W. Russell, R. J. Rudy, and D. K. Lynch, The Aerospace
Corporation; C. E. Woodward, University of Minnesota; and H. Marion,
University of Texas and Texas State University, report observations
of V5579 Sgr (cf. IAUC 8937, 8940) on May 9 UT at the Infrared
Telescope Facility (+ SPEX; range 0.8-5.2 microns).  D. Griep, IRTF,
helped to acquire the data.  The nova was at a very early stage of
its spectral development, showing lines of O I, N I, and Ca II, and
exceptionally strong lines of C I.  Lines widths were approximately
1600 km/s at FWHM.  Fe II features were weak, but -- despite that
fact -- this is almost certainly an "Fe II"-type of nova.  Lines of
neutral helium had not yet formed.  The strongest lines in the
infrared spectrum are the O I lines that are fluourescently excited
by Lyman_beta.  These lines indicate a reddening of E(B-V) = 1.2,
some of which may be local to the nova, which has already formed
dust.  In fact, the infrared continuum is dominated by thermal
emission from dust at a single temperature of 1370 K.

     K. Ayani and N. Murakami, Bisei Astronomical Observatory (BAO),
write that low-resolution spectra (range 400-800 nm; resolution 0.5
nm at H_alpha) of the apparent nova announced on IAUC 8947,
obtained with the BAO 1.01-m telescope on May 26.7 UT, confirms
that the object is a nova.  They show H_alpha emission (FWHM about
600 km/s) with a P-Cyg profile, its absorption minimum being blue-
shifted by 730 km/s with respect to the emission peak.  H_beta and
Fe II (multiplet 42) lines also have P-Cyg profiles, although the
absorption component dominates on lines of shorter wavelength.
     Further to IAUC 8947, S. Nakano reports that co-discoverers
K. Nishiyama and F. Kabashima obtained additional unfiltered CCD
frames with a 0.40-m reflector on May 26.562 UT, yielding mag 9.8
for the nova and position R.A. = 17h39m50s.94, Decl. = -23o50'01".0
(equinox 2000.0).  Nakano also forwards an unfiltered CCD
observation by K. Kadota (Ageo, Japan, 0.25-m reflector) on May
26.609 that yielded mag 9.9 and a measured position identical to
that above.
     Visual magnitude estimate of N Oph 2008 by W. Vollmann, Vienna,
Austria:  May 26.969 UT, 10.4.  Photoelectric V magnitudes by L.
Elenin, Lubertsy, Russia, contributed by E. Waagen, AAVSO:  May
26.457, 10.30; 27.380, 10.14.

                      (C) Copyright 2008 CBAT
2008 May 27                    (8948)            Daniel W. E. Green

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