The nova Persei 2018 (= V392 Per = TCP J04432130+4721280) is a bright nova in constellation Perseus. The discovery magnitude was 6.2 mag (unfiltered CCD), see [1].
With this brightness it is easy reachable with the Alpy600 spectrograph, but it needs good weather conditions to take a spectrum because of the low altitude in north west direction in the evening sky.
I took two spectra and one RGB image:
At the end of exposure the object had an altitude of 22° (2018-05-05 20:37 UT) and 16° (2018-05-11 21:12 UT).
| Position: | RA 04h 43m 21.38s, DEC +47° 21' 25.9" |
| Progenitor: | V392 Per, see [2] |
| Discovery: | 2018 April 29.474 UT by Yuji Nakamura (Kameyama, Mie, Japan; via CBET 4515) |
| Brightness: | V=6.2 mag (at discovery date), V=8.7 mag (2018-05-06.841 UT), see AAVSO lightcurve of V392 Per outburst |
2018-05-06 19:50 - 20:33 UT, Roof Observatory Kaufering,
Meade 14" ACF telescope on Taurus GM-60 mount, CCD: Moravian G2-8300FW, 3x3 binning, RGB-filter, exposures: R 50x3s, G 50x5s, B 90x10s, B-V calibrated; magnitude measured with Astrometrica: 8.7 mag; click to uncrop image;
For other images see
Here are my spectra of this nova:
2018-05-05 19:59 - 20:37 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: PHD;
Wavelength calibration: Hg lines from energy saving lamp and Ne lines from flicker flame light bulbs,
instrumental response calibration: with reference star SAO 39688, A0 V, data reduction: with
Integrated Spectrographic Innovative Software from Christian Buil;
2018-05-11 20:24 - 21:12 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: PHD;
Wavelength calibration: Hg lines from energy saving lamp and Ne lines from flicker flame light bulbs,
instrumental response calibration: with reference star SAO 39688, A0 V, data reduction: with
Integrated Spectrographic Innovative Software from Christian Buil;
Here is the labeled spectrum from 2018-05-05:
Spectral lines have been identified using [3], [4], [5] and the NIST database.
Very interesting are the shape of Hydrogen and Helium emission lines, they show all a broad base component and narrow lines sitting on top. This emerges rarly in nova outbursts.
According to [3] similar line profiles has been observed in two LMC novae. As a consequence there is evidence, that the ejecta can't be spherical, but axis-symmetric and non uniform (clumpy).
It is unlikely, that this is driven by an accretion disk scenario.
I determined the maximum radial velocity in spectrum from 2018-05-05 with the blueshifted absorption components. This gives for H-Alpha RV = -4000 km/s and for H-Beta
RV = -3500 km/s. In spectrum of 2018-05-11 this feature has vanished. But both values seem to be too high. In a early spectrum (see [4]) RV = -2600 km/s is mentioned.
With FWZI at 10% height from broad H-Alpha lines I get the following results for expansion velocity:
Here is the labeled spectrum from 2018-05-11, only these lines labeled that are not visible in spectrum 2018-05-05:
The Bowen blend consists of lines from N III and C III in the range of 4630 - 4660 Å. The N III lines are the result of
a UV fluorescence process, while the C III lines are due to photo-ionization and subsequent recombination [6]. It seems that the N III lines are stronger
than the C III lines, the same as described in [3] for LMC novae.
Here are the spectra for comparison, the spectrum from 2018-05-11 is shifted in y-direction by 1.5 units for better distinction:
With only two spectra it is difficault to recognize an evolution but changes in spectral features are significant.
The narrow components become more intense, the blueshifted emmission of Hydrogen is more pronounced and additional lines have evolved.
References:
[1] Nova Persei 2018 in AAVSO alert notice 633
[2] Darnley and Starrfield, On the progenitor system of V392 Persei, preprint at arxive.org
[3] Mason and Munari, On the narrow emission line components of the LMC novae 2004 (YY Doradus) and 2009a, A&A 569, A84 (2014)
[4] V392 Per outburst discussion in ARAS spectroscopy forum
[5] ATel #11601
[6] Cornellis et al., An Overview of the Bowen Survey; detecting donor star signatures in Low Mass X-ray Binaries, AIP Conf.Proc.1010:148-152,2008
My other spectroscopic observations: Spektroskopie (German)
[ updated: 2018-06-10 | 
Gregor Krannich
| Gregors astronomy page ]