Spectrum of Nova Herculis 2021

Nova Herculis 2021 (=V1674 Her = TCP J18573095+1653396) is a bright galactic nova in constellation Hercules. The discovery magnitude was 8.4 mag (Canon EOS 6D digital camera + 200-mm f/3.2 lens with 6-s exposure) [1]. The nova peaked around 12th June with a brightness of V=6.2 mag (see AAVSO light curve). With this brightness it would be easily reachable with the Alpy600 spectrograph, but weather conditions and time limits allowed a spectrum recording at 2021-06-26 at a much dimmer brightness. Up to now I took an image and a spectrum:

2021-06-25 Image, the sky was clear with good transparency, low humidity and avarage seeing, at temperature of 14° C
2021-06-26 Spectrum, the sky was clear with good transparency, low humidity and avarage seeing, at temperature of 17° C

Data about Nova Her 2021

Position:	RA 18h 57m 30.98s, DEC +16° 53' 39.6"
Progenitor:	V1674 Her
Discovery:	2021 June 12.537 UT by Seiji Ueda (Kushiro, Hokkaido, Japan)
Brightness:	V=8.4 mag (at discovery date), V=12.1 mag (2021-06-25.949 UT), see AAVSO light curve of Nova Her 2021

Image and spectra of Nova Her 2021

2021-06-25 22:38 - 22:55 UT, Roof Observatory Kaufering, Meade 14" ACF telescope on Taurus GM-60 mount, CCD: Moravian G2-8300FW, 3x3 binning, L-filter, exposures: 51x15 sec; magnitude measured with Astrometrica: V=11.4 mag; click to uncrop image;

For other images see

Here are my spectra of this nova:

Spectrum of Nova Her 2021, June 25th
2021-06-26 22:53 - 00:42 UT, Roof Observatory Kaufering, Meade 14" ACF telescope on Taurus GM-60 mount, Astro Physics reducer CCDT67, Alpy600 with guiding unit, CCD camera: Atik 428EX, guiding camera: ASI 120 MM; recording software: AstroArt, guiding software: PHD2;
Wavelength calibration: Hg lines from energy saving lamp and Ne lines from flicker flame light bulbs, instrumental response calibration: with reference star HIP 92934 (=HD 175744), B8 pSi, data reduction: with Integrated Spectrographic Innovative Software from Christian Buil;
The spectral type of HIP 92934 may be unprecise in Simbad (character D). I achieved the best fit with a type of B8 V database spectrum.

calibrated spectrum: _nher21_202106262253_cal.fit

Line identification and discussion

Labelled spectrum not done yet!

In ATEL#14718 the flat topped feature is explaied as interaction of different ejecta being shocked [2], see linked spectra. According to ATEL#14723 the type of this nova is a FeII with extreme broad emission lines [3] . In ATEL#14746 it is reported that it is a neon nova in nebular phase (2021-06-30). The [Ne V] at 3426 Å is the second strongest emmission line in optical range after H-Alpha [4].

References:
[1] Nova Her 2021 in AAVSO alert notice 745
[2] Nova Her 2021 in ATel#14718
[3] Nova Her 2021 in ATel#14723
[4] Nova Her 2021 in ATel#14746

My other spectroscopic observations: Spektroskopie (German)

[ updated: 2021-07-17 | Email icon Gregor Krannich | Gregors astronomy page ]