Central Bureau for Astronomical Telegrams
IAUC 6322: NOVALIKE Var IN Sgr
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Circular No. 6322
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
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)
Phone 617-495-7244/7440/7444 (for emergency use only)
NOVALIKE VARIABLE IN SAGITTARIUS
S. Nakano, Sumoto, Japan, reports the discovery by Yukio
Sakurai, Otsuka-cho, Mito, Ibaragi-ken, of a possible "slow" nova,
on Fuji G400 film taken with a 300-mm f/2.8 lens, located at R.A. =
17h52m33s.5, Decl. = -17o40'52" (equinox 2000.0); the photograph
taken on Feb. 20.806 UT shows the star as red in color and of mag
11.4. Patrol films taken by Sakurai during 1993-1994 show no
candidate at this location, but the star is visible on films
beginning in 1995 January (when it was of mag 12.5) and continuing
through May, August-October, and again in 1996 January-February --
the star slowly brightening over the past year. M. Hazen, Harvard-
Smithsonian Center for Astrophysics, reports that a search of some
200 plates in the Harvard plate collection, rather evenly
distributed in date of exposure during 1930-1951 and reaching blue
mag 14 (for earlier plates) to 16 (later plates), shows no obvious
variable star at this location. R. H. McNaught, Anglo-Australian
Observatory, reports that a search of Schmidt films reveals "no
strong indication of a red variable that can reach mag 12, but
there are three red excess objects within about 1' of the quoted
position. One is clearly variable but in the range R = 17-20 and
is about 1' west of Sakurai's position. Neither of the other red
stars is obviously variable and are of (very roughly) R = 16 and
18." He notes that a more precise position would be useful.
S. Benetti and H. W. Duerbeck, European Southern Observatory,
report: "E. Cappellaro (Osservatorio Astronomico di Padova)
observed this possible nova with the Dutch 0.9-m telescope at La
Silla (ESO) on Feb. 23.3 UT, finding indeed a new star; preliminary
photometry gives V = 12.8, B-V = +0.6, V-R = +0.6, V-I = +1.0. An
inspection of a fully-reduced CCD spectrogram (range 375-985 nm;
resolution 1.6 nm), taken by B. Leibundgut (ESO) with the ESO 3.6-m
reflector (+ EFOSC1) on Feb. 23.4, reveals that the spectrum is
consistent with a reddened early G-type star of high luminosity; no
emission lines are visible. H-beta is in absorption at 485.7 nm,
while H-alpha could be present in absorption, blended with another
absorption feature (at 657.75 nm). Na I D lines are the strongest
absorption feature of the spectrum (measured at 588.7 nm). The
probable pre-outburst counterpart is visible as a star of mJ = 21,
mR = 20.5 on the ESO/SRC sky survey films. While the outburst
amplitude and lightcurve suggest a slow or symbiotic nova, the lack
of obvious emission lines one year after brightening is very unusual."
(C) Copyright 1996 CBAT
1996 February 23 (6322) Daniel W. E. Green
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