[vsnet-alert 22062] PNV J18040967-1803581: possible nova (11.2 mag) in Sagittarius

Mon Apr 9 05:41:11 JST 2018

PNV J18040967-1803581 (N:)

RA 18h04m09.67s, DEC -18°03'58.1" (J2000.0)
2018 April 8.7229 UT, 11.2 mag (CCD, unfiltered)
Independent discoverers: Tadashi Kojima (Gunma-ken, Japan)
and Hideo Nishimura (Shizuoka-ken, Japan)

2018 04 08.723 UT
Discovered by T. Kojima, Gunma-ken and H. Nishimura, Shizuoka-ken,
independently. Kojima found this star on six frames with five
second exposure using Canon EOS 6D digital camera + 200-mm f/3.2
lens under the limiting mag = 12.5, who writes nothing is visible
at this location on a frames (limit mag = 13.2) taken 2018 March
27.767 UT. Nishimura also found this star (mag.= 11.2) on five
frames taken on 2018 April 8.728 UT with ten second exposure using
Canon EOS 6D digital camera + 200-mm f/3.2 under the limiting
mag.= 14.3, who writes nothing is visible on a frame taken on
Apr. 7.723 UT (limit mag.= 14) and gives the position at end
figures 09s.46, 57".3.

2018 04 08.728 UT
Both images at
http://www.oaa.gr.jp/~oaacs/image/PNVSgr2018K.JPG
http://www.oaa.gr.jp/~oaacs/image/PNVSgr2018N.JPG

2018 04 08.82 UT
The nearest USNO-B1.0 star is 4" away: USNO-B1.0 0719-0746451 at
RA 18h04m09.67s, DEC -18°03'54.4" (J2000.0, R= 18.16 mag,
B= 21.42 mag; G= 18.31 mag in Gaia DR1; r= 19.11, g= 20.95 mag
in Pan-STARRS DR1). No previous outbursts or eruptions were
recorded at the transient's position by the ASAS-SN Sky Patrol
(Shappee et al. 2014ApJ...788...48S and Kochanek et al.
2017PASP..129j4502K) since 2015 February; the latest available
observation is 2018 March 29.605 UT, fainter than mag 16.1 V:
https://asas-sn.osu.edu/light_curves/bec38ad2-4de7-4d4c-8439-4d1230931d53
--- Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)

Follow-up reports:
http://www.cbat.eps.harvard.edu/unconf/followups/J18040967-1803581.html

Spectroscopy, multiband photometry, and precise astrometry are
urgently required.

Clear skies,
Patrick