Nova in Oph: V4371 Oph (N Oph 2025 = TCP J17301230-2753488 = AT 2025wyg)
Abstract:
V4371 Oph (N Oph 2025 = TCP J17301230-2753488 = AT 2025wyg) was discovered by Tadashi Kojima (Tsumagoi, Gunma-ken, Japan) on 2025 Sep. 5.433 UT, magnitude 12.5 unfiltered (Canon EOS 6D CMOS). SPECTROSCOPY by Mitugu Fujii (Okayama, Japan) using the Fujii Kurosaki Observatory 0.4-m telescope + NLS-II spectrograph (res ~1000) on 2025 Sep. 6.423 UT shows a nova; continuum is highly reddened. Spectrum at https://otobs.org/FBO/fko/n/tcp_j1730123-2753488/tcp_j17301230-2753488.htm (via CBET 5603). COORDINATES (J 2000): RA 17 30 12.30 Dec. -27 53 48.8 (VSX). NEARBY STARS: A. Pearce (Nedlands, W. Australia) reports nova is 0.4" from Pan-STARRS DR1 catalogue star 74522625511123781 (mag <20) and 1.4" from Gaia DR3 4061213018095504128 (G magnitude 20.6) (via CBET 5603). PHOTOMETRY: see Justification. LIGHT CURVE: View the light curve via the AAVSO Light Curve Generator (https://www.aavso.org/LCGv2/).
Justification:
The AAVSO requests coverage of this nova with observations of all types (visual, CCD/CMOS, DSLR, spectroscopy) and in all filters as it evolves. All novae are worthy of as good coverage as possible for as long as possible to support research on novae being carried out now and in the future. Spectroscopy is also encouraged where possible. See sections below for cadence and other observing recommendations. NOTE: E. Kazarovets (Inst. of Astronomy, Moscow) reports assignment of the GCVS name V4371 Oph (via CBET 5603, D. W. E. Green, Ed.). PHOTOMETRY (selected from observations submitted to the AAVSO): 2025 Aug. 30.461 UT, <13.0 unfiltered CMOS (T. Kojima, via CBET 5603); Sep. 5.406, 10.9 unfiltered CCD (K. Itagaki, Yamagata, Japan, prediscovery, via CBET 5603); 8.126, 12.85 B (K. Yoshimoto, Yamaguchi, Japan, remotely via Utah Desert Remote Observatory, Beryl Junction, UT, via CBET 5603); 8.126, 10.83 V (Yoshimoto); 8.126, 8.31 I (Yoshimoto); 8.6167, 12.627 B +/-0.012 (A. Pearce, Nedlands, W. Australia); 8.6171, 11.035 V +/-0.004 (Pearce); 8.6175, 9.798 R +/-0.002 (Pearce); 8.6178, 8.598 I +/-0.003 (Pearce); 8.6182, 11.055 V +/-0.005 (Pearce); 8.6186, 12.670 B +/-0.017 (Pearce); 8.6237, 12.611 B +/-0.018 (Pearce); 8.6240, 11.046 V +/-0.004 (Pearce); 8.6243, 9.802 R +/-0.003 (Pearce); 8.6246, 8.639 I +/-0.003 (Pearce). IMAGES: K. Itagaki, Sep. 5.406 UT http://k-itagaki.jp/images/Oph-25-09.jpg; K. Yoshimoto, Sep. 8.126 UT (via CBET 5603) http://orange.zero.jp/k-yoshimoto/TCP_J17301230-2753488_20250908.jpg
Requested Data Types:
Spectroscopy, Photometry
Targets
| Name | Magnitude | Variability Type | Photometry Notes | Spectroscopy Notes |
|---|---|---|---|---|
| V4371 Oph | 10.83 | N |
Cadence: Custom Precision: 100 |
Cadence: Custom Resolution: 250 Desired SNR: 100 |
Spectroscopy Lines:
He II (4686.0 Å), H-beta (4861.0 Å), H-alpha (6563.0 Å)
Photometry Filters:
B (Johnson), V (Johnson), R (Cousins), I (Cousins), g (Sloan), r (Sloan), i (Sloan), z (Sloan), Other (Please Specify)
Comparison Stars:
Finder charts with comparison stars may be created using the AAVSO Variable Star Plotter (VSP, https://apps.aavso.org/vsp/). Field is very crowded.
Co-Authorship
Observers are eligible for co-authorship.
Additional Observer Input:
Additional photometry filters and cadence: also TB, TG, TR. Cadence depends on rate of change and other behavior of the nova, but at least one observation per night is recommended. Additional spectroscopy lines and cadence: Bowen blend (4640 A). 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." Former 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."
Additional Submission Location:
Not provided
Notes:
No public notes