jeudi 12 octobre 2017

V442 And still active

V442 Andromedae was found in emission on the night of august 21st. An outburst occured shortly before that date and is beeing monitored in spectroscopy by a group of astronomers. I have been very lucky with a good weather which allowed myself to acquire lot of spectra of this star:

The spectra show a nice evolution of the double peak emission line since that date:

Here is a daily selection to avoid a too much crowded graph. The emission is still active today even if it is fainter:

Hbeta emission but is now gone:

Measurement of V/R ratio shows this evolution of the Halpha double peak emission with some stable phases and more active/variable ones:

The variations match closely with the photosphere rotation of the star:

A measurement of the HeI 6678 line is by the way showing a nice stellar photosphere rotation period:

The V+R mesurement initially increased, then decreased and is now more stable:

I also measured the distnce between the two peaks. It is now showing a clear increase:

Those measurements are "quick & dirty" ones made automatically using MatLab script. I checked couple of recent measurements as the emission is faint, but it seems to work ok (an offset of 0.75 is substracted on the emission lines):

In summary, I have been very lucky with the weather and the monitoring of V442 And is fun and seems to show some intersting details on this outburst... spectroscopy rocks!

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