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IAUC 7486: N LMC 2000

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                                                  Circular No. 7486
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)

     S. N. Shore, Indiana University, South Bend; S. Starrfield,
Arizona State University; H. E. Bond and R. Downes, Space Telescope
Science Institute; P. H. Hauschildt, University of Georgia; R. D.
Gehrz and C. E. Woodward, University of Minnesota; J. Krautter,
Landessternwarte, Heidelberg; and A. N. Evans, Keele University,
write: "We observed this nova (cf. IAUC 7457, 7458) with the Hubble
Space Telescope's Imaging Spectrograph (STIS) on Aug. 19.7 and Aug.
20.9 UT using the medium-resolution echelle gratings (E140M and
E230M).  Three spectra were obtained, centered at 142.5, 197.8, and
270.7 nm with resolutions of about 45 000 (E140M) and 30 000
(E230M).  Weak iron-peak absorption may still be present,
especially from 155.0 to 156.5 nm.  The spectrum strongly resembles
that of V382 Vel obtained 2 months after visual maximum (IAUC 7261)
but with much stronger Ly-alpha and Si III] 189.5-nm and C III]
191.0-nm emission, with Si III]/C III] about 2.  Strong C IV P-Cyg
absorption is seen with a terminal velocity of 2000 km/s, similar
to the FWHM velocity for the emission lines.  The following strong
emission lines have been detected:  C III 107.6-nm, N V 124.0-nm, N
III/O III 126.7-nm, O I 130.4-nm, C II 133.4-nm, Si IV/O IV] 140.0-
nm, C IV 155.0-nm, He II 164.0-nm, O III] 166.7-nm, N III] 175.0-nm,
Si II 181.6-nm, Al III 186.0-nm, Si III] 189.5-nm, C III] 191.0-nm,
N II] 214.5-nm, C II 232.1-nm, Al II 267.2-nm, and Mg II 280.0-nm.
Unusual features of the spectrum are the absence of N IV] at 148.6
and 171.8 nm and the presence of strong Ly-alpha emission at a time
when He II 164.0-nm is also strong, but the Ly-alpha in this nova
is stronger due to lower interstellar absorption.  Most emission
profiles show fine structure consistent with knots of the sort
detected in HST spectra of V1974 Cyg and V382 Vel.  A strong
interstellar absorption line spectrum is present, showing Si II/S
II 126.0-nm, Si IV 140.0-nm, C IV 155.0-nm, Al II 167.1-nm, Al III
186.0-nm, and Fe II 260.0-nm with Galactic and LMC components (+250
km/s) clearly resolved.  The integrated flux from 115.0 to 312.0 nm
was 8.6 x 10**-11 erg cm**-2 s**-1 [or 5.6 x 10**-10 erg cm**-2
s**-1, corrected for LMC reddening with E(B-V) = 0.2].  For a
distance of 50 kpc, this corresponds to 4.1 x 10**4 solar
luminosities.  In view of the similarity of the spectra, these data
yield a probable distance for V382 Vel of 3000 pc, assuming its
reddening is E(B-V) = 0.2.  A further STIS observation is planned
for mid-Nov., and continued groundbased monitoring at all
wavelengths is urged."

                      (C) Copyright 2000 CBAT
2000 September 1               (7486)            Daniel W. E. Green

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