PNV J16521887-3754189 (CV:)
Discoverer: Hideo Nishimura (Shizuoka-ken, Japan)
R.A. 16h52m18.87s Decl. -37°54'18.9" (J2000.0)
2017 Feb. 1.862 UT, 11.7 mag (CCD, unfiltered)
Discovered by H. Nishimura, Shizuoka-ken, Japan, on three 10-s frames using 200-mm f/3.2 lens + a Canon digital camera, who writes nothing is visible at this location on his frames taken before 2017 Jan. 25.872 UT, but he found a star (mag.= 12.5) on 2017 Jan. 30.868, mag.= 12.1 on Feb. 2.857 and mag.= 12.7 on Feb. 6.836 UT.
Note a red star within several arc seconds.
Also Kaneko reports mag.= 12.1 (R 11.4, V 13.3, B 15.2) on 2017 Feb. 6.68 UT.
http://www.cbat.eps.harvard.edu/unconf/followups/J16521887-3754189.html
This transient is only 6.7' north of mu2 Scorpii (V= 3.6 mag).
Spectroscopy and time-resolved photometry are urgently required.
Clear skies,
Patrick
https://www.aavso.org/vsx/index.php?view=detail.top&oid=476654
Photometry results were B=14.73, V=14.10, Rc=11.781 and Ic=12.48 with 0.50-m f/4.5 CDK astrograph + FLI PL6303E at iTelescope.NET, Siding Spring Observatory, NSW, Australia. Position end figures were 18.63 and 16.44 in RA and Dec.
http://meineko.sakura.ne.jp/ccd/PNV_16521887-3754189.jpg
Kiyota-san's astrometry places PNV J16521887-3754189 only 0.3" from 2MASS J16521864-3754166 (cf. the discovery report ["Note a red star within several arc seconds."] and Sebastian Otero's VSX remark).
I just do photometry of the star nearest to position reported.. So I do not know whether my identification is correct or not. But that star seems to be brighter than DSS image. What is the type of variability? Spectroscopy are encouraged.
Spectroscopy has not yet been reported.
So it seems that the 2MASS object is the variable star.
The fact that it shows a rather blue color now (B-V= 0.7 or so) compared with the JHK colors in quiescence suggests it might be a YSO. Maybe an EXor or FUor outburst.
So spectroscopy and long-term photometry are needed to confirm this or not.
Hi,
I also observed it the past two nights showing B=14.7, V=14, I=12.
Josch
USNO-B1.0 0520-0568078: R1= 15.04, B2= 18.54, R2= 15.86, I= 12.46
GSC2.3 S8V6023335: F= 16.30, j= 20.16, V= 16.97, N= 13.14
2MASS J16521864-3754166: J= 10.282, H= 9.104, K= 8.596
WISE J165218.64-375416.5: W1= 8.437, W2= 8.399, W3= 7.954, W4= 7.950
Regards,
Patrick
Jay Strader et al. (The Astronomer's Telegram #10071):
We report the spectroscopic classification of the transient PNV J16521887-3754189 as a new Galactic nova.
...
The prominence of He emission lines and the absence of Fe II lines indicates a classification as an He/N nova.
...
http://www.astronomerstelegram.org/?read=10071
Regards,
Patrick
AAVSO Alert Notice 568 reports on the discovery of a nova in Sco - PNV J16521887-3754189. Please see the notice for details and observing instructions.
Many thanks and good observing!
Elizabeth Waagen, AAVSO HQ
V1657 Scorpii = Nova Scorpii 2017 = PNV J16521887-3754189
http://www.cbat.eps.harvard.edu/iauc/09200/09285.html
http://www.cbat.eps.harvard.edu/iau/cbet/004300/CBET004364.txt
Regards,
Patrick