ALEXIS observation of U Gem

(vsnet-alert 355, Diane Roussel-Dupre)

We have been oberving U Gem with ALEXIS since 0 UT 5 March. We are in a hot time (100% sun lit orbit) which means that we usually turn off the telescopes for the safety of the satellite, but are managing to limp along observing with one telescope pair only without disasterous effects. We did not get on source quickly enough to see the turn on; probably missed it by 0.5 days.

We have been comparing this outburst to the one we observed a year ago and notice a major difference.

April '95 both the 130 and 186 A channels detected U Gem at about the same count rate

March ' 96 only the 130 A channel is detecting U Gem.

Looking at the spectra in the EUVE paper ("EUVE Observations of U Gem", Long, Mauche, Szkody, & Mattei, 1995), we note that there appears to be a type of line feature at the 186 A band, which is consistent with our April, '95 observation. Therefore, based upon the current data, we would conclude that this line is missing at this time.

Because this looks to be a very unusual outburst from this system, we urge continued groundbased observation. If possible, it might be instructive to get groundbased spectra to compare with previous outbursts.

Diane Roussel-Dupre

Diane Roussel-Dupre, NIS-2
Los Alamos National Laboratory
Telephone: (505) 667-8895
FAX: (505) 665-4414

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