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Request for help in monitoring HS 0229+8016

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sfy
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Request for help in monitoring HS 0229+8016

HS 0229+8016 was identified as a cataclysmic variable star during follow-up observations of optically selected CV candidates from the Hamburg Quasar Survey by Aungwerojwit et al. [1].  Its orbital period is 232.550 ± 0.049 min (0.16149 d).

The light curve over the last 12 years appears to show almost continuous low amplitude outbursts of ~0.7 mag for much of the time. Each outburst lasts ~12 - 14 days and the star varies between mag ~13.6 and 14.3. There are two intervals of 100 - 200 days when these appear to reduce or even stop. This is reminiscent of Z Cam behaviour, although this classification is by no means certain. Prof. Boris Gänsicke (University of Warwick, UK) suggests that the low amplitude could mean that only part of the disc takes part in the outbursts, so it may be very close to the borderline of disc stability.

Boris has suggested that intensive observations over a few outburst cycles may shed further light on the behaviour of the system. I would therefore like to request observations of HS 0229+8016 from now and continuing for the next three months (until end Feb 2019). We would like one (or a few) observations per night to define the overall outburst light curve and whether there is a quiescence period between outbursts. CCD observations with a V-filter are preferred, but unfiltered is fine if you don’t have a V-filter. Visual observations are also gratefully received. Continuous photometry is not required at this point.

A chart and sequence for HS 0229+8016 is available from the AAVSO website. Please submit your observations to the BAA VSS or the AAVSO database.

HS 0229+8016 is a far northerly object in Cepheus at RA 02 35 58.23, Dec +80 29 44.2 (J2000.0).

If you have any questions, please contact me at bunburyobservatory AT hotmail.com

Jeremy Shears

[1]. Aungwerojwit A., Gänsicke B.T., Rodríguez-Gil P. et al., A&A, 443, 995-1005 (2005).

sfy
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Brief update on campaign to observe HS 0229+8016

Since launching the campaign, we are getting some very interesting data submitted which so far shows two small outbursts separated by ~9 days. In fact we are now in the third cycle. Far too early to draw any conclusions, but it certainly looks like continuous stunted outbursts or oscillations similar to what has been observed in some nova like and Z Cam stars. The amplitude is ~0.4 mag, between mag 13.9 and 14.3.

Many thanks to Richard Sabo, Gary Poyner, David Boyd, Dave Smith, Ian Miller, David Storey and Sjoerd  Dufoer for your observations. Keep up the good work! 

Other observers would be most welcome to join in.

All the best,
Jeremy Shears

sfy
sfy's picture
Update on January 1

Since the campaign was launched, the star appears to have been systematically varying by ~0.4 mags every ~9 days. A light curve can be seen on the BAA VSS website, which also has a link to further details on the campaign: http://www.britastro.org/vss/

There have been a few gaps in data over the last 2 weeks as poor weather conditions have hit parts of Europe and the US. 
Many thanks to Richard Sabo, Gary Poyner, David Boyd, Dave Smith, Ian Miller, David Storey, Sjoerd Dufoer and Martin Mobberley for their observations. Please do join the campaign if you would like – we need one (or two) measurements per night.

Happy New Year to all and clear skies for 2019!

Jeremy

sfy
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Update on January 21

An updated light curve of this variable covering the first two months of the campaign is shown on the BAA Variable Star Section website.

I’m pleased to say our efforts are paying dividends in revealing an very interesting light curve. So far we have observed 6 of its small oscillations. The 5th looks slightly different from the others in that it’s rise to max was slower.

As ever, more observations would be appreciated. It’s gratifying to see that the intensity of coverage has improved over the last month and it’s good to see new observers joining the campaign.

Very many thanks to everyone who has submitted observations so far: Richard Sabo, Ken Menzies, Gary Poyner, David Boyd, Dave Smith, Ian Miller, David Storey, Sjoerd Dufoer, Martin Mobberley, Jeremy Shears, James Boardman, George Fleming, M. Joslin.

Jeremy

sfy
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Update on Feb 5

An updated light curve covering 2018 Nov 26 to 2019 Feb 4 is shown on the BAA VSS website.

We now have observed 8 oscillations. Many thanks to all observers for keeping this star under their watchful eye: Richard Sabo, Ken Menzies, Gary Poyner, David Boyd, Dave Smith, Ian Miller, David Storey, Sjoerd Dufoer, Martin Mobberley, James Boardman, George Fleming, Mel Joslin,  William Kautter, Erik Schwendeman.

I hope you can be persuaded to continue monitoring. My original intention was to continue until the end of Feb.

All the best,

Jeremy

nekkar
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Need more observations ?

I imaged this object on January 1st but forgot to measure and send it to AAVSO.

Tonight I'll make several observations if you're still interested.

sfy
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Need more observations ?

Yes please!

sfy
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Update Feb 28

I have updated the light curve of this star today and it is available on the VSS website.

In the 3 months of the campaign we have caught 11 of its small outbursts. There is a suggestion that they are stunted outbursts, similar to those seen in some novalike cataclysmic variables, including UU Aqr, in which only a part of the accretion disc goes into outburst.There is also a curious larger-than-normal fade around JD 2458520 (this was present in data from several observers).

Many thanks to all out observers, the list of which has been growing steadily: Richard Sabo, Ken Menzies, Gary Poyner, David Boyd, Dave Smith, Ian Miller, David Storey, Sjoerd Dufoer, Martin Mobberley, James Boardman, George Fleming, Mel Joslin,  William Kautter, Erik Schwendeman, Tamas Tordai and Mario Morales Aimar. Your data have provided a well-sample light curve which I am sure will yield useful results!

The campaign was intended to last 3 months until the end of 2019 Feb, i.e. today. Thus will the campaign is officially ended, observations would also be appreciated after this time. Since this is a circumpolar object and continues to be well positioned for most northern observers. We would like one (or a few) observations per night to define the overall outburst light curve and whether there is a quiescence period between outbursts. In the meantime I will analyse the data received to date.

A summary of what is known about the star and about the campaign is presented in the March edition of the BAA Variable Star Section Circular (page 15) which was issued today.

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