Electronic Telegram No. 5346
Central Bureau for Astronomical Telegrams
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V1723 SCORPII = PNV J17261813-3809354 = NOVA SCORPII 2024
     Andrew Pearce, Nedlands, Western Australia, reports his discovery of a
possible nova (mag 7.3) on three frames (limiting mag 12.5) taken on Feb.
9.844 UT with a Canon 800D digital camera (+ 85-mm-f.l. f/1.2 lens).  The
new star is also visible at mag 7.8 on similar images obtained by Pearce on
Feb. 8.827 at mag 7.8, and Pearce confirmed the variable visually on Feb.
9.856 at mag 7.4.  Pearce measured the position of the new variable to be R.A.
= 17h26m18s.13, Decl. = -38d09'35".4 (equinox J2000.0), and the star was given
the designation PNV J17261813-3809354 when he posted it to the Central
Bureau's TOCP webpage.  Pearce adds that nothing is visible at this position
on three images taken on Feb. 7.844 (limiting mag 12.5) with the same
instrumentation.  Pearce also obtained CCD images of PNV J17261813-3809354
remotely on Feb. 10.399 with a 0.50-m f/6.8 reflector located at Rio Hurtado
Valley, Chile, yielding position end figures 18s.06, 36".3; he notes that this
position corresponds to that of a Gaia-survey G-magnitude-19.4 star (Gaia DR3
5974053153713533184).  Approximate magnitudes by Pearce with the Rio Hurtado
reflector:  V = 7.6, B = 9.2, I = 4.3, R = 6.45 at the same time.  Pearce also
obtained magnitudes V = 7.43 and R = 5.65 from CCD images obtained on Feb.
10.791 with a 0.50-m f/6.8 reflector at Siding Spring, NSW, Australia.
     Y. Sakurai, Mito, Japan, informed the Central Bureau (via S. Nakano) of
an independent discovery of this variable at mag 7.1 on three frames taken
with a Nikon 7100 digital camera (+ 180-mm-f.l. f/2.8 lens; limiting mag
11.2) on Feb. 9.836 UT; Sakurai provided position end figures 18s.16, 37".2.
Nothing is visible on three similar frames taken by Sakurai on Feb. 7.836
(limiting mag 11.8).
     Unfiltered images taken with a Canon 6D all-sky camera (8-mm-f.l. f/2.8
lens) on Feb. 10.762 UT by R. H. McNaught, Coonabarabran, NSW, Australia, show
PNV J17261813-3809354 at mag 6.4.  McNaught also found the variable at mag 7.3
on unfiltered images (limiting mag 13.5) taken with a 135-mm f/2.8 lens on
Feb. 9.692.  An unfiltered CCD image obtained by T. Noguchi, Katori, Japan,
using a 0.23-m f/10 Schmidt-Cassegrain reflector on Feb. 10.854 show PNV
J17261813-3809354 at mag 5.8 with position end figures 18s.09, 36".3; (image
posted at URL http://park8.wakwak.com/~ngc/images/PNVinSco_20240210.jpg).
     Additional visual magnitude estimates for PNV J17261813-3809354:  Feb.
10.821 UT, 7.4 (Pearce); 11.25, 7.2 (W. Souza, Atibaia, SP, Brazil); 11.277,
7.5 (A. Amorim, Florianopolis, Brazil); 11.29, 7.3 (J. G. de S. Aguiar, Sao
Paulo, Brazil); 11.32, 6.8 (L. Camargo da Silva, Sao Jose dos Campos, Sao
Paulo, Brazil); 11.34, 6.8 (M. Coronel Rodriguez, Sao Jose dos Campos, Sao
Paulo, Brazil); 12.306, 7.5 (Souza); 12.279, 7.7 (Amorim).
     O. Garde, Chabons, France, reports that the "Southern Spectroscopic
Project Observatory Team" (2SPOT; S. Charbonnel, P. Le Du, L. Mulato, T.
Petit, and Garde) obtained spectroscopy of PNV J17261813-3809354 on Feb.
11.347 UT with the "Deep Sky Chile" 30.5-cm Ritchey-Chretien telescope (+
ATIK460Ex camera + echelle optical-fiber spectrograph; resolution 11000).
Three 1200-s exposures taken just before sunrise) show Balmer lines in
emission with a very red continuum.  Their spectrum is posted at the following
website URL:  http://www.spectro-aras.com/forum/viewtopic.php?t=3113.
     Spectroscopy obtained of PNV J17261813-3809354 by E. Aydi et al. (and
posted at website URL http://www.astronomerstelegram.org/?read=16440) on Feb.
10.4 UT with the 4.1-m Southern Astrophysical Research telescope located at
Cerro Pachon, Chile, show absorption lines and P-Cyg profiles of H Balmer,
Fe II, Na I, and O I, with H_alpha's absorption trough blue-shifted by about
1200 km/s.  Aydi et al. state that their spectra indicate this to be a
classical nova near peak brightness.
     E. Kazarovets writes that the permanent GCVS designation V1723 Sco
has been given to this nova.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2024 CBAT
2024 February 12                 (CBET 5346)              Daniel W. E. Green