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Cataclysmic variable

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Daryl's picture
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Joined: 02/07/2015 - 21:35
Cataclysmic variable

Just spotted this report apparently at mag 13.5 it’s 8 magnitudes brighter than normal. Its on the border between Cassiopeia and Perseus

https://www.wis-tns.org/object/2021abog

Robin Leadbeater's picture
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AT 2021abog

Yes I saw that this morning. It is a pity it took 10 hours to report. It was clear here last night so could have grabbed a confirming spectrum.

Robin Leadbeater's picture
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spectrum

I see fellow amateur supernova classifier Claudio Balcon took a spectrum last night and classified as a CV (with a blue continuum and weak Balmer absorption at ~0 redshift)

Daryl's picture
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Cv

Hopefully it will be clear tonight, been clouded out all week 

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It looks to be around 13.7

It looks to be around 13.7 tonight.

Daryl's picture
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cloud

I had hoped to see if I could see it visually but no chance as we had thin high cloud and total cloud by 9:30 last night and with our favourite source of light pollution, the Moon) in the sky for the next week or so I doubt if I would see it visually before it fades.

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Re: CV

VSNET-alert 26333 today announced that early superhumps with a period of 0.05404(4) d and amplitude of 0.055m had been detected (by Tonny Vanmunster), and that the object is a UGWZ type star.   I must say that to me it seems a bit early to give this classification as definite, so probably wait for more data before we all go down the pub to celebrate.   Taichi Kato isn't often wrong in these matters though.

There is a chart and a very limited sequence (two stars so far) available for download from the AAVSO here, using the designation XM78HT or AT 2021ABOG.

Latest magnitude in the AAVSO DB is Vanmunsters showing 13.9-14.0C. (Oct 18.2 UT)

Gary

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XM78HT

AAVSO Chart now has stars down to mag +15.8. Have not seen it yet due to weather but tonight may be the night.

Mel Joslin.

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Re: CV

I've not seen it either due to the weather, and am keen to do so.   Once faded, there is a chance of a rebrightening(s).   It doesn't have to be a UGWZ to do this, as I have seen UGSU's show a rebrightening (In 1996 I once observed a normal outburst in UV Per trigger a superoutburst followed by one rebrightening), but not more than one as UGWZ's are prone to do.

Gary

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XM78HT

Have finally seen XM78HT at 14.8 on 21/10/2021 at 20.11 UT. Has anybody else in the BAA other than Nick James and myself made an observation. The moon being so close made observing so difficult but with our weather you just have to go for it when a chance arrives. Mel Joslin.

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XM78HT

Bit faint for my scope and the sky conditions, last night was clear up to 8:30 when high clouds rolled in and with the moon no chance of doing any VS work. Managed to observe V1405 and TX Psc just before 8pm.