Nova in Sagittarius - V6598 Sgr = N Sgr 2023 No. 3 (= TCP J17525020-2024150)
Abstract:
V6598 Sgr = N Sgr 2023 No. 3 (= TCP J17525020-2024150) was discovered independently by Andrew Pearce (Nedlands, W. Australia) on 2023 July 15.4590 UT at mag 10.3 unfiltered CCD, using Canon 800D digital camera + 85-mm f/1.2 lens, and by Yuji Nakamura (Kameyama, Mie, Japan; reported to CBAT via the National Observatory of Japan) on 2023 July 15.522 UTat mag 9.6: does not give filter, using 135-mm F/4.0 lens +CMOS camera. Spectroscopy indicating the object to be a nova was obtained by: 1) O. Garde et al. (ATel #16135) on 2023 Jul. 15.95 and 16.04 UT using the 2SPOT Alpy600 and eShel spectrographs in Chile. They report that "the source is a classical nova in the early, optically thick stage of expansion." 2) G. Masi, on 2023 Jul. 16.867 UT (low resolution) using a 200 lines/mm grating on the 14” robotic unit part of the Virtual Telescope Project facility in Manciano, Italy (CBET 5278).
Justification:
Observations across multiple bands are requested to study the nova V6598 Sgr as it continues to evolve across various bands and spectrums.
Requested Data Types:
Spectroscopy, Photometry
Targets
| Name | Magnitude | Variability Type | Photometry Notes | Spectroscopy Notes |
|---|---|---|---|---|
| V6598 Sgr | 10.20 | NA |
Cadence: Custom Precision: 100 |
Cadence: Custom Resolution: 250 Desired SNR: 100 |
Spectroscopy Lines:
H-alpha (6563.0 Å)
Photometry Filters:
U (Johnson), B (Johnson), V (Johnson), R (Cousins), I (Cousins), u (Sloan), g (Sloan), r (Sloan), i (Sloan), z (Sloan)
Comparison Stars:
Finder charts with comparison stars may be created using the AAVSO's Variable Star Plotter (VSP; https://apps.aavso.org/vsp/).
Co-Authorship
Observers are not eligible for co-authorship.
Additional Observer Input:
Generally, please observe V6598 Sgr 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, he 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."
Additional Submission Location:
Not provided
Notes:
a) Designated TCP J17525020-2024150 when posted to the IAU Central Bureau for Astronomical Telegrams Transient Object Confirmation Page (TOCP). Designated N Sgr 2023 No. 3 in CBAT Central Bureau Electronic Telegram 5278. b) The progenitor, whose position matches that of the nova, appears to be IGR J17528-2022, an object identified earlier by J. Hare et al. (ApJ, 914, 85 (2021)) as a candidate magnetic cataclysmic variable. c) Images: E. Guido, M. Rocchetto, and A. Valvasori (2023 Jul. 15.6422 UT, CBET 5278): https://tinyurl.com/novasgranim. d) Assigned the permanent GCVS designation V6598 Sgr by E. Kazarovets (CBET 5278).