VSX J012426.9+084154 Update

9 years 5 months ago #87718 by dmcdona
VSX J012426.9+084154 Update was created by dmcdona
Folks - I managed to get a couple more nights worth of data and finally nailed VSX J012426.9+084154. The AAVSO VSX data is currently being reviewed but should be live in the next 24 hours or so. You saw it here first :-)

The period is 0.48720 days (11.7 hours) with minima of 0.2 and 0.4 mags.

Here is a plot showing the data. Note that there are two cycles shown and the data has been binned to make the plot clearer.




Enjoy!
Dave

p.s. original material etc here: www.irishastronomy.org/index.php?option=...ew&catid=11&id=86864

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9 years 5 months ago #87719 by dmcdona

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9 years 5 months ago #87720 by DaveGrennan
Replied by DaveGrennan on topic Re:VSX J012426.9+084154 Update
WOW Great stuff Dave,

Question: The data looks very symmetrical on both sides of the dip. Is there another smaller dip in between the main one and if so is this again due to eclipse/transit of the orbiting binary.

Congrats on this excellent work.

Regards and Clear Skies,

Dave.
J41 - Raheny Observatory.
www.webtreatz.com
Equipment List here

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9 years 5 months ago #87721 by dmcdona
Replied by dmcdona on topic Re:VSX J012426.9+084154 Update
Not quite sure what you mean Dave but, starting from the left hand side of the plot:

The data starts off at the first (deepest) minima (i.e. mid-eclipse). This is a dip of about 0.4 to 0.5 mags.

The binary system then brightens again and as the two starts rotate about each other, the second minima starts and reaches a dip of about 0.15 mag.

We then see the start of the first minima in its totality.

Looking at the chart, the data to the right of large V dip in the centre of the plot is simply a repeat of the data on the left hand side. VSO's prefer to see two cycles on the same plot.

So, we have the first minima of 0.4 mags followed by a second minima of 0.1 mag.

In terms of time, each minima is about 2.4 hours each and the entire period is about 11.7 hours. This length od period is what reulted in data having to be collected over such a long time (well, weather conditions too!).

Hope that explains things a bit better.

Here's a YouTube video that also explains he basic principles: goo.gl/4R2NS

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9 years 5 months ago #87722 by mjc
Replied by mjc on topic Re:VSX J012426.9+084154 Update
That's really good stuff there Dave.
The Youtube video helps and I can see why there is a second dip.

By phased I assume you mean you combine data from different observing sessions and combine them "in phase" - but I am not sure what you mean by "binned". It could be really obvious - but I'm not seeing it.

Really excellent work.

Mark C.

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9 years 5 months ago #87723 by dmcdona
Replied by dmcdona on topic Re:VSX J012426.9+084154 Update
Mark - a phase plot attempts to determine the "period" of an object - asteroid, variable, exoplanet etc. The observations made over many days would normally be called "sessions". After all that processing, I could do with a good session... :-)

Each session is added into the mix then the software takes over and using various algorithms, comes up with a period that fits the data. That final period found is then plotted onto a "phased" plot. Not sure if I just confused you more...

Binning just means averaging out adjacent points. If I bin by two, I get the average point of 2 adjacent points. In this case, I binned by five. So each point on the plot is in fact an average of five data points. It makes the chart clearer - there is in fact five times more data in it than you can see.

Glad you like the work though :-)

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9 years 5 months ago #87724 by DaveGrennan
Replied by DaveGrennan on topic Re:VSX J012426.9+084154 Update
Dave,

I'm referring to the dips indicated by the yellow arrows here;



I think what i'm referring to is the secondary minima. BTW did you take this data all in one session or over a few nights?

Regards and Clear Skies,

Dave.
J41 - Raheny Observatory.
www.webtreatz.com
Equipment List here

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9 years 5 months ago #87726 by dmcdona
Replied by dmcdona on topic Re:VSX J012426.9+084154 Update
OK - now I see what you're talking about.

From left to right, the first red arrow is the second half of the primary minimum (~0.4 mag). The next (yellow) arrow is the secondary minimum (~0.1 mag). The next dip (not marked by you) is the primary minimum in its entirety. The next yellow arrow is the secondary minimum in its entirety and the final red arrow is the first half of the primary minimum.

Essentially, the plot is actually the same data repeated twice to show two full phases of the eclipse. That is the way AAVSO wants it plotted.

The single phase plot looks like this:


The gap betweeen the primary and secondary minima is simply a lack of data points, not an artificially generated gap... As you can see, the phased plot with two cycles (the plot you arrowed) starts at the bottom of the primary minimum and is then repeated twice.

The data was taken over 8 nights (8 sessions). The dates go from 17 October last year to 09 January this year. The period of close to 12 hours didn't help matters - parts of the curves were imaged a good few times. It was only the January data that really nailed the final period.

By the way, all the data (including full size plots) is publicly available on the AAVSO VSX website here: www.aavso.org/vsx/index.php?view=detail.top&oid=249715

Look to the bottom of the page - the additional data is clickable.

Hope that explains things a bit better...

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9 years 5 months ago #87727 by DaveGrennan
Replied by DaveGrennan on topic Re:VSX J012426.9+084154 Update
Absolutely stunning work McDonald, David J. I understand now, I'm a bit slow on the uptake sometimes. Jeex 8 nights of data. With the way the weather has been thats some doing.

Blown away by this, well done mate.

Regards and Clear Skies,

Dave.
J41 - Raheny Observatory.
www.webtreatz.com
Equipment List here

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9 years 5 months ago #87730 by mjc
Replied by mjc on topic Re:VSX J012426.9+084154 Update
Thanks Dave

Thats fine - understood.

Mark

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