Stellar nova V1405 Cas (low resolution spectrum) (Remco Kemperman)

Stellar nova V1405 Cas (low resolution spectrum)

On 18-3-2021 a nova was discovered in Cassiopeia by a japenese amateur astronomer. I captured a spectrum of it on 23-3-2021 with a staranalyzer diffraction grating.

What you can clearly see are hydrogen emission lines, but also helium emission lines. Normal stars don't have that. This is about the mother of all hydrogen bombs. The accumulated hydrogen that the white dwarf steals from the companion red giant star suddenly fuses when the pressure gets too high. Part of it is fused and the rest is thrown into space and heated. That is the reason for the strong emission lines. The white dwarf remains intact and happily continues to snip off gas from the companion star until the next bang.

Now, after calibration, the blue shift of the emission lines can also be seen. This is due to the glowing gases coming our way at a significant speed and the emission lines shift towards the blue due to the doppler effect.

In the spectrum of this nova the many P-Cygni profiles can be seen, both in the hydrogen Balmer lines and in the helium lines.

A P-Cygni profile is an absorption valley that precedes an emission peak. The absorption valley is caused by the absorption of the light from the star, by the gas ejected in our viewing direction.

The fact that the absorption valley has shifted blue has to do with the speed of the ejected gas coming in our direction. The width of the absorption valley is a measure of the speed at which the gas is ejected.

The hot gas, perpendicular to our viewing direction, radiates and is responsible for the emission peak.

the gas therefore consists mainly of hydrogen and helium.

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Status	Basic failed
Started	...
Astrometry.net job	4346016
PixInsight job	n/a
PixInsight queue size	n/a
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