U Gem in outburst

[Francois Teyssier]

The cataclysmic U Gem has been detected in outburst
It could be still on the rising
Max mag ~ 9
François

[Francois Teyssier]

Tonight spectrum
Broad absorptions for H beta and H gamma

_ugem_20150221_986_fteyssier.png (18.68 KiB) Viewed 10884 times

François Teyssier

[Paolo Berardi]

François, congratulations for your great spectra (I also see the recent Nova Cyg 2014 observation)! During last U Gem outburst, Vmag remained brighter than 10 for about ten days. Unlike in the previous case, this ouburst occurred in a favourable moment to follow the decline phase.

Ciao!
Paolo

[Francois Teyssier]

Thank you Paolo

U Gem is now at its maximum luminosity
The spectrum looks flat at a first on raw images, but ...

clearly the double peak of the disk in rotation

_ugem_20150223_764_fteyssier.png (18.39 KiB) Viewed 10836 times

and a crop on Ha

_ugem_20150223_764_ha.png (12.73 KiB) Viewed 10836 times

with v.sin i ~ 1000 km/s

The disk turns fast !

François

[Francois Teyssier]

Spectre du 24-02
Begening of the decline

_ugem_20150224_759_fteyssier.png (17.51 KiB) Viewed 10781 times

Note the complexe shape of Balmer lines

The V/R ration of H alpha has changed, in comparison to the previous spectrum (rotation of the disk)
A series of several hours should show the V/R evolution ... (for the next outburst)

Cloudy weather tonight, unfortunatly ...

François

[Joan Guarro Flo]

Hi:
Is the U Gem in the 20150225.
J.Guarro.

[Francois Teyssier]

During the decline

Noisy, but interesting shape pf H alpha and H beta

_ugem_20150304_776_fteyssier.png (20.74 KiB) Viewed 10632 times

François Teyssier

[Francois Teyssier]

Tonight spectrum

_ugem_20150305_774_fteyssier.png (21.92 KiB) Viewed 10623 times

François

[Francois Teyssier]

Nive emission from the disk
See also He I (5876 and 6678)

_ugem_20150306_781_fteyssier.png (22.5 KiB) Viewed 10595 times

François

[Peter Somogyi]

Nearly started before Francois's last spectra, a 5 hours exposure (with some technical breaks):

Animated gif of every 2 x 20 minute exposures - except last that was 3 x 20 min:

_ugem_20150306_793_981_psomogyi.gif (80.31 KiB) Viewed 10567 times

Ref. star was: 79-Gem, taken only 4 times (using averages in between).
Interesting to see the continuum temporary rise while Balmer remains almost there, showing other features.