PNV J16484962-4457032 2018 02 06.8628* 16 48 49.62 -44 57 03.2 11.7 U Sco 9 0
2018 02 06.863
Discovered by H. Nishimura, Kakegawa, Shizuoka-ken, Japan, with on 10-s exposure on five frames using Canon EOS 6D digital camera + 200-mm f/3.2 lens under the limiting mag = 14.0, who writes that nothing is visible at this location on three frames taken on 2018 Feb. 3.855, 4.863 and 5.864 UT under limiting mag.= 13s. Thre is a star (mag.= 16.8) at 49s.24 and 01".8.
2018 02 07.33
The star mentioned by Nishimura-san is USNO-A2.0 0450-25608044 (R= 16.8, B= 18.5 mag). Seven VISTA variables (VVV catalog DR2) are located within 6" from the transient's position. The ASAS-SN Sky Patrol (Shappee et al. 2014ApJ...788...48S and Kochanek et al. 2017PASP..129j4502K) observed the transient's position in only one night since solar conjunction: 2018 Feb. 4.38 UT, V~ 15.2 mag (contaminated by nearby stars). No eruptions or outbursts were detected since 2016 March: https://asas-sn.osu.edu/light_curves/1e30e1da-96a9-4523-b07f-dbea266ee738 --- Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)
2018 02 07.7514
PNV J16484962-4457032 is clearly visible at 10.03V matnitude on 2x20s CCD images taken by Robert Fidrich, Hungary on 2018. feb. 07.7514UT with the 0.43m reftractor at the Siding Spring, Australia station of iTelescope network. Preliminary astrometry: 16:48:49.70 -44:57:02.8 https://www.dropbox.com/s/v1sdz8udkdq8i3l/PNV_Sco_18b_crop_1k_x.png?dl=0
2018 02 07.716
Mag. B= 11.1, V= 10.1, R= 9.7, position end figures 49s.64, 03".1 observed by Kaneo, Shizuoka-ken, Japan, using a 0.51-m f/4.4 Siding Spring telescope, remotely.
2018 02 07.7514
Improved astrometry using VaST: 16:48:49.68 -44:57:02.9 (Estimated accuracy of the plate solution: 0.20") -- Robert Fidrich, Budapest, Hungary
2018 02 07.7346
Photometry results were B=12.21, V=10.10, Rc=8.88 and Ic=7.63 with 0.50-m f/4.5 CDK astrograph + FLI PL6303E CCD camera (T30, iTelescope.NET) at Siding Spring Observatory, NSW, Australia. Posoition end figures were R.A.=49.67 and Dec.=3.16. Low resolution spectrum also showed that this PNV was highly reddened. My images are available at http://meineko.sakura.ne.jp/ccd/PNV_J16484962-4457032.jpg and http://meineko.sakura.ne.jp/ccd/PNV_J16484962-4457032-spectrum.jpg. Seiichiro Kiyota (Kamagaya, Japan)
2018 02 07.80
Regarding the positions reported above by R. Fidrich, Kaneo, and S. Kiyota, the closest of the abovementioned VISTA variables is about 0.7" away (VVV J164849.63-445702.43 = VPHASDR2 J164849.6-445702.3; position end figures 49.63s, 02.4"). --- Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)
2018 02 11.7616
Balmer and other emission lines were evolved in spectrum (taken with T17, iTelescope.NET @ SSO, Australia). http://meineko.sakura.ne.jp/ccd/PNV_J16484962-4457032-spectrum-20180211.jpg Seiichiro Kiyota (Kamagaya, Japan)