February 21, 2023
AAVSO Forum threads (scroll to the bottom of a thread for latest posts):
- Time Sensitive Alerts: https://www.aavso.org/n-sgr-2023-TCP-J17562787-1714548
- Novae: https://www.aavso.org/n-sgr-2023-TCP-J17562787-1714548-01
Please subscribe to these threads if you are observing this nova so you can be updated as to its behavior and any observing campaigns on it. Join in the discussion or ask questions there!
Event: Nova in Sagittarius: N Sgr 2023 = TCP J17562787-1714548
Discovered independently by:
Yukio Sakurai, Mito, Ibaraki-ken, Japan
Hideo Nishimura, Kakegawa, Shizuoka, Japan
Andrew Pearce, Nedlands, Western Australia
Discovery magnitude:
Sakurai - 9.6 unfiltered, on three frames taken using a Nikon D7100+180-mm f/2.8 lens
Nishimura - mag 10.8 unfiltered, on an image taken using a Canon EOS6D + 200mmf/3 lens
Pearce - 10.5 unfiltered, on three images taken using a Canon 800D camera and 85mm f/1.2 lens
Discovery date:
Sakurai - 2023 February 19.823 UT (reported first to CBAT)
Nishimura - 2023 Feb. 19.8044 UT
Pearce - 2023 February 18.834 UT (reported to CBAT February 19.833)
Coordinates (2000.0): R.A. 17 56 27.90 Decl. -17 14 53.6 (from VSX page for N Sgr 2023)
Spectra: Spectra indicating the object to be a He/N-type classical nova were obtained by K. Taguchi (ATel #15911) on 2023 Feb. 20.8719 UT and on Feb. 20.8738 UT, using the integral field spectrograph mounted on the 3.8-m Seimei telescope at Okayama Observatory of Kyoto University.
Other wavelength observations: Observations obtained by Sokolovsky et al. (ATel #15910) with the Swift/XRT and /UVOT instruments on 2023 Feb. 20.58 UT showed x-ray and ultraviolet emission. They state that "It is somewhat unusual for a nova to show shock-powered X-rays visible to Swift/XRT less than two days after eruption. This may suggest that the transient is a very fast nova and/or a nova embedded in the wind of an evolved donor star."
Observing recommendations: Please observe N Sgr 2023 as it continues to evolve, with observations of all types (visual, CCD/CMOS, DSLR, spectroscopy) and multiple bands as instrumentation permits. Frequency of observation depends on the rate of decline, but Dr. Fred Walter (Stony Brook University) recommends a minimum of one observation per night per band.
For spectroscopy, Dr. Walter recommends spectra in blue to observe He II 4686, H-beta, and the Bowen blend (4640A), in addition to H-alpha. Cadence for spectra depends on how fast the nova continues to evolve, but, he adds, "you can't go wrong with a spectrum every clear night." AAVSO Spectroscopy Section co-leader Lauren Herrington adds: "Slitless spectra would also be valuable; spectra with resolution as low as R=100 are useful to track broad changes in emission as the nova evolves."
Observations reported to the AAVSO:
2023 Feb. 16.839 UT, <11.5 unfiltered DSLR (A. Pearce, Nedlands, W. Australia);
17.816, <12.8 unfiltered DSLR (Y. Sakurai, Mito, Ibaraki-ken, Japan, via TOCP);
17.8492, <15.0: unfiltered DSLR (H. Nishimura, Kakegawa, Shizuoka, Japan, via TOCP);
19.83333, 10.5 (Pearce);
19.834, 11.0: unfiltered DSLR (Pearce);
20.12627, 10.5 (Pearce);
20.36414, 12.066 B +/-0.003 (Pearce, remotely using T72 0.5m f/6.8 reflector + CCD at Rio Hurtado Valley, Chile);
20.36473, 11.390 V +/-0.002 (Pearce, remotely);
20.36659, 11.382 V +/-0.002 (Pearce, remotely);
20.36708, 11.382 V +/-0.004 (Pearce, remotely);
20.36767, 12.081 B +/-0.005 (Pearce, remotely);
20.3575, 11.71 B (S. Kiyota, Kamagaya, Japan, remotely using T72, iTelescope.NET (0.34m F6.8 CDK) + FLI ML-16200 CCD at Deep Sky Chile, Rio Hurtado Valley, Chile, via TOCP);
20.3575, 11.18 V (Kiyota, via TOCP);
20.3575, 9.80 Rc (Kiyota, via TOCP);
20.3575, 9.26 Ic (Kiyota, via TOCP);
20.827, 10.9 unfiltered CCD (T. Noguchi, Katori, Japan, using 0.23-m f/10 Schmidt-Cassegrain + unfiltered CCD (KAF-0261E), via TOCP);
20.84583, 11.5 (Pearce);
21.15972, 11.4 TG +/-0.05 (V. Cseh, Debrecen, Hungary);
21.40207, 12.860 B +/-0.005 (Pearce, remotely using T72 0.5m f/6.8 reflector + CCD at Rio Hurtado Valley, Chile);
21.40293, 12.319 V +/-0.003 (Pearce, remotely);
21.52255, 11.884 V +/-0.002 (F. Romanov, remotely using iTelescope.Net T11 (0.50-m f/6.8 reflector + CCD + f/4.5 focal reducer) in Utah Desert Remote Observatory, Beryl Junction, UT)
21.52360, 12.648 B +/-0.005 (Romanov);
21.52459, 10.715 R +/-0.004 (Romanov);
21.52557, 10.322 I +/-0.009 (Romanov);
21.52660, 11.879 V +/-0.001 (Romanov);
21.52767, 12.625 B +/-0.003 (Romanov);
21.52866, 10.718 R +/-0.003 (Romanov);
21.52963, 10.315 I +/-0.006 (Romanov);
Charts: Charts with comparison stars for N Sgr 2023 may be created using the AAVSO Variable Star Plotter (VSP).
Submit observations: Please submit observations using the name N SGR 2023. When a GCVS name is assigned to this nova, please use it when submitting observations.
- Submit optical observations to the AAVSO International Database using WebObs.
- Submit spectra to the AAVSO Spectroscopy Database (AVSpec).
Notes:
a. Designated TCP J17562787-1714548 when posted to the IAU Central Bureau for Astronomical Telegrams Transient Object Confirmation Page (TOCP).
b. T. Kato (vsnet-alert 27432) identifies the possible progenitor as Gaia DR3 4144602552564272000 (G=18.1, Plx=0.20+/-0.18 mas).
c. Position end figures:
- A. Pearce (2023 02 20.126 UT): 27.90s, 53.7"
- T. Noguchi (2023 02 20.827 UT): 27.91s, 53.5"
d. Images
- H. Nishimura (2023 Feb. 19.8044 UT, discovery image): https://y2.nao.ac.jp/index.php/s/7od8X3zY2PKEA5w
- T. Noguchi (2023 Feb. 20.827 UT): http://park8.wakwak.com/~ngc/images/TCPinSgr_20230220.jpg
- F. Romanov (2023 Feb. 21.5236 UT): https://www.flickr.com/photos/filipp-romanov/52702897703/
Congratulations to Yukio Sakurai, Hideo Nishimura, and Andrew Pearce on their independent discoveries!
This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.
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