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HT Cas in outburst

SXN's picture
SXN
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Joined: 2010-03-12

The outburst of the eclipsing UGSU HT Cas has been confirmed. Arto Oksanen had it at 13.27V most recently.

Superoutbursts of this one can get as bright as 12th magnitude. Will this be the one?

It has a period of about 105 minutes. Time series and snapshot observations are recommended. 

Mike Simonsen
AAVSO

Likeliness of superoutburst
weo's picture
weo
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Joined: 2010-03-25

It looks like HT Cas is more likely coming down, not brightening more, based on CCY's visual observation of 13.1 18 hours before OAR's V observations (which are 13.3 and fainter) and based on the 1985 superoutburst pattern.

There are two definite superoutbursts (1985, 2010) and one possible superoutburst (1963) of HT Cas recorded in the AAVSO International Database since it was added to the observing program in 1961, and since about 1975 there has been very solid coverage, so I don't think we have missed any superoutbursts that would have occurred during the observing season. We have the rise time only for the 1985 one (~1.5 days from <15.6 to 13.2, another 24 hours to 10.7). Following this pattern, it seems OAR's obs would have been considerably brighter if a superoutburst were underway. Also, I know the outburst frequency of HT Cas has increased greatly over the last 15 years (and so the superoutburst behavior might have changed, too). But, even with the increased frequency there has only been one superoutburst and that occurred relatively recently, in 2010, so it seems the odds are pretty high against the current outburst being a superoutburst.

That being said, good coverage of every outburst of HT Cas is important precisely because it has changed its behavior in the past 15 years, so visual and CCD observers, please follow it as long as you can, and thank you for your efforts and your observations!

Good observing,  Elizabeth Waagen

AAVSO 49 Bay State Rd. Cambridge, MA 02138 aavso@aavso.org 617-354-0484