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AAVSO Alert Notice 616

Nova Scorpii 2018 No. 2 = PNV J16484962-4457032

February 13, 2018

Event: Nova in Scorpius: Nova Sco 2018 No. 2 = PNV J16484962-4457032

Discovered by: Hideo Nishimura (Kakegawa, Shizuoka-ken, Japan, reported by S. Nakano, Sumoto, Japan, via CBET 4488)

Discovery magnitude: unfiltered CCD magnitude 11.7 (on five frames using a Canon EOS 6D digital camera+200-mm-f.l. f/3.2 lens)

Discovery date: 2018 February 6.863 UT
Coordinates (2000.0): R.A. 16 48 49.62  Decl. -44 57 03.2

Spectra: Low-resolution spectroscopy indicating that PNV J16484962-4457032 is a highly reddened nova was obtained by S. Kiyota (Kamagaya, Japan) on 2018 Feb. 7.7 and Feb. 11.76 UT. His spectrograms are posted at and, respectively.

J. Strader et al. report (ATel #11289) that a spectrum obtained with the 4.1-m Southern Astrophysical Research Telescope at Cerro Pachon, Chile, on Feb. 12.39 UT shows PNV J16484962-4457032 to be a classical Fe II type nova.

Observing recommendations: Observations of all types (visual, CCD, DSLR, spectroscopy) and multiple bands as instrumentation permits are strongly encouraged as the nova evolves. Dr. Koji Mukai (NASA Goddard Space Flight Center) recommends that observers use B, V, and I filters if possible to enable studying any color changes.

Observations reported to the AAVSO:
2018 Feb. 07.716 UT, B = 11.1 (observer Kaneo, Shizuoka-ken, Japan, remotely using a 0.51-m f/4.4 telescope at Siding Spring; CBET 4488);
07.716 UT, V = 10.1 (Kaneo);
07.716 UT, R = 9.7 (Kaneo);
07.735, B = 12.21 (S. Kiyota, Kamagaya, Japan, iTelescope with 0.50-m f/4.5 CDK astrograph at Siding Spring Observatory, NSW, Australia; CBET 4488);
07.735, V = 10.10 (Kiyota);
07.735, R_c = 8.88, (Kiyota);
07.735, I_c = 7.63 (Kiyota);
07.7514, 10.026 V +/-0.002 (R. Fidrich, remotely with 0.43-m refractor, iTelescope network, Siding Spring, Australia);  
07.8299 UT, 10.5 (A. Pearce, Nedlands, W. Australia);
08.1875, <9.25 (C. Adib, Porto Alegre, Brazil);
08.3388, 10.0 (L. Camargo da Silva, Santa Catarina, Brazil);
08.7757, 10.1 (Pearce);
09.8215, 9.8 (Pearce);
10.8535, 10.1 (Pearce);
11.7255, 12.12 B +/-0.05 (S. O'Connor, St. George, Bermuda);
11.7262, 10.02 V +/-0.05 (O'Connor);
11.7267, 7.03 I +/-0.17 (O'Connor);
11.74583, 10.4 (C. Wyatt, Walcha, NSW, Australia);
11.81740, 10.3 (Pearce);
12.78960, 10.5 (Pearce);
13.82150, 10.8 (Pearce);

Charts: Charts with a comparison star sequence for Nova Sco 2018 No. 2 may be created using the AAVSO Variable Star Plotter (VSP).

Submit observations: Please submit observations to the AAVSO International Database using the name NOVA SCO 2018 No. 2. Once a GCVS name is announced in an IAU Circular or CBET, please use that name.

Forums: Nova Sco 2018 No. 2 is the topic of the AAVSO Time Sensitive Alerts forum thread and the Novae forum thread

a. Designated PNV J16484962-4457032 when posted to the IAU Central Bureau for Astronomical Telegrams Transient Object Confirmation Page (TOCP). Unless otherwise noted and except for observations reported to the AAVSO, the information in this Alert Notice is taken from IAU CBET 4488. Spectroscopy details are in ATel #11289.

b. Nishimura notes that nothing is visible at this position on three frames taken on 2018 Feb. 3.855, 4.863, and 5.864 UT (limiting mag 13).  

c. Nishimura notes there is a nearby star of mag 16.8 with position end figures 49.24s, 01.8".

d. P. Schmeer (Saarbruecken-Bischmisheim, Germany) notes a VISTA variable (VVV catalog DR2) is located about 0.7" away from the from the discovery position (VVV J164849.63-445702.43 = VPHASDR2 J164849.6-445702.3).

e. Position end figures (J2000.0)
- observer Kaneo (Shizuoka-ken, Japan, 2018 Feb. 07.716 UT): 49.64s, 03.1"
- S. Kiyota (2018 Feb. 07.735 UT): 49.67s, 03.2"
- A. Pearce (2018 Feb. 07.830 UT): 49.63s, 03.0"
- R. Fidrich (2018. Feb. 07.7514 UT): 49.68s, 02.9"

f. Images
- S. Kiyota (2018 Feb. 7.735 UT):

Congratulations to Hideo Nishimura on his latest discovery!

This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.

It’s all about the  standstills, those episodes where the star gets stuck at a mid-point between maximum and minimum. If it doesn’t exhibit standstills it isn’t a Z Cam star.

Data from Catalina Real Time Survey 

Drake et al. 2009, ApJ, 696, 87

Northern CVs brighter than 17th magnitude here.

Southern CV's brighter than 17th magnitude here.


Last updated 09:00 UT on 22 February 2018

New outbursts and unusual activity reported in the last 72 hours


FO Per

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AY Lyr

Current superoutbursts (since ...)
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DM Dra : (20180216)
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IW And (20170812–20170831, 19 days)
OQ Car (20160415–20170826, 498 days)

# indicates a noteworthy or unusual outburst
:  indicates confirmation required
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