Central Bureau for Astronomical Telegrams
IAUC 8424: N LMC 2004
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Circular No. 8424
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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NOVA IN THE LARGE MAGELLANIC CLOUD 2004
H. E. Bond, Space Telescope Science Institute; F. Walter,
Stony Brook University; and J. Espinoza, D. Gonzalez, and A. Pasten,
SMARTS Consortium, Cerro Tololo Interamerican Observatory, report
spectroscopic and CCD observations with the 1.5-m and 1.3-m Cerro
Tololo telescopes of the object discovered by Liller (IAUC 8422).
Spectra obtained on Oct. 21.30, 22.33, 23.28, 24.31, and 25.44 UT
(resolution 0.43 nm and range 353-530 nm, except resolution 0.16 nm
and 387-454 nm on Oct. 23.28, and resolution 0.43 and range 600-780
on Oct. 25.44) show strong, triple-peaked Balmer emission lines, as
well as He I and strong N III emission. The Balmer profiles
consist of a sharp core redshifted by 0.4 nm (consistent with the
radial velocity of the LMC) atop a broad, double-horned pedestal.
The two outer peaks forming the horned structure have velocities of
about +/- 2500 km/s. A blueshifted wind absorption feature, whose
velocity on Oct. 21.30 was -3700 km/s, has gradually decreased in
strength. On Oct. 25.33, the H_alpha line had FWZI = 9800 km/s,
with an equivalent width of 120 nm. Astrometry of the CCD frames
using USNO-B1.0 reference stars gives R.A. = 5h56m42s.42, Decl. =
-68o54'34".8 (equinox 2000.0); the faint star mentioned on IAUC
8422 has USNO-B1.0 end figures 42s.40, 34".6, suggesting that it is
likely the quiescent counterpart. A comparison by the undersigned
of a B-band Cerro Tololo image, supplied by Bond, with the
Harvard/Boyden 0.61-m Bruce telescope plate A19851 (a 45-min
exposure taken on the night of 1937 Nov. 23-24 in poor seeing)
shows that the distorted 1937 nova (YY Dor) image coincides in
position with the 2004 nova, though the centroid of the 1937
photographic image may be a bit to the southwest of the centroid of
the 2004 CCD image. (YY Dor would then be only the second
recurrent nova known in the LMC.) Photometry of the 2004 nova from
the CCD frames: Oct. 21.33, V = 12.15, B-V = -0.14; 23.24, 12.79,
-0.25; 24.24, 13.00, -0.30; 25.20, 13.16, -0.23.
E. Mason, A. Ederoclite, M. Stefanon, and T. H. Dall, European
Southern Observatory, Santiago; and M. Della Valle, Istituto
Nazionale di Astrofisica, Arcetri/Firenze, report that a spectrum
of the new nova, obtained on Oct. 25.3 UT with the La Silla 2.2-m
telescope (+ Fiber-fed Extended Range Optical Spectrograph; range
390-900 nm, resolution 48000), is dominated by strong Balmer lines
and O I (4) at 844.6 nm. Emission from He I (11 and 10) was also
detected. The line profiles are very broad. with an average FWHM
of 6600 km/s; such a large velocity is consistent with the typical
spectra of recurrent novae at maximum.
(C) Copyright 2004 CBAT
2004 October 28 (8424) Daniel W. E. Green
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