I tried to plot the data in excel and because I only got 4 readings it produces a jagged line graph instead of a nice curve..
Rob,did your estimates change every hour you observed it and if it did what instumentation were you using?
Thanks
Cheers Orestis
Orestis,
You will need more than 4 points.
Initially, I would just plot whatever you get on a grid on paper. You can add extra points at the corresponding phase times from different nights to confirm the cycle. You are really just trying to confirm the cycle not construct the whole thing from scratch.
My estimates were just visual and they did change every hour around the primary eclipse time.
No, 4 points nowhere near enough. Try to get as many points as you can. In a night, you should get at least 6-10 points. But that means pulling an all-nighter. However, you can get some idea if you do what Rob said. Take a number of points each night, for consecutive nights. Try to get some both at minimum and maximum light. That way, you get points at the top and bottom of your lightcurve and you can then extrapolate a curve from these. Don't forget to get points at either side of the eclipse as well. Excel isn't the best for extrapolating curves with and the less points you have the more jagged and wonky your curve will look.
I have plotted the points I have now corresponding to the phase times.Time is the x axis with 0 hours to 16 hours written and the the y axis is the mags with 6.1 up the top to 7.1 down the bottom.
So far I have 6 points constructing a nice secondary eclipse dip but not a primary yet.I have 6.1 at 4 hours a 6.2 and 6.3 inbetween that and a 6.4 at 8 hours and then 6.2 at approx 12 hours maybe 13.then a 6.5 at 14 hours.
So if i get the data for the primary minimum i can produce 3/4 of the light curve.
Thanks for alll the help guys
Cheers Orestis
ps-I got one reading yesterday at 6.3 mag but then clouded up before being able to observe the primary minimum.I hope to get a reading soon.
Now you're making some progress.
To help you get more points, especially around the primary eclipse, here is an extension of phase times through to next weekend.
You will notice that the phase P shifts by about 50% every 24 hours as 1.5P=1.5x16=24 hours. Also times at a particular point in a phase are very similar every 48 hours (2 days) as 3P=3x16=48 hours. Every now and then the times are shift by a half hour. This is a correction due to the phase being 15.874hours long and not exactly 16 hours.
Thats just what i needed as it clouded up on sunday and i didn't have more predictions,i thought of adding 16 hours to the latest minimum,but as you mentioned the period is not exactly 16 hours.
Thanks a lot Rob,
I will tell you how I go soon,the weather is very bad at the moment,but hopefully it will clear over the coming week.
The last week was very cloudy and I didn't get any results but it cleared up yesterday for a successful observation of the primary eclipse.
I decided to do some half hour intervals and have even noticed change between such short amounts of time,I have plotted all my data corresponding to phase times and have attached it.
I can pretty much confirm this star has the charachteristics of a beta- lyrae eclipsing binary star showing a primary eclipse and secondary eclipse.
Thanks Guys for the tremoundous help.
ps-sorry about the quality of the graph
However, you now have to show the proof to your assumption that the star is a typical beta-Lyrae variable. How does the light curve that you've generated compare to the typical light curve of a beta Lyrae variable. What does the journal literature tell you and how can you fit what you've found into the accepted theory and observations.
This is what you have to write down in your report. This is how you show that you've done the work and followed it up with the study of the literature in order to prove the assumptions about the star that you've made. Preferably, a scientist would've done some previous reading on the subject before they did their observations, but you wouldn't be in a position to know or do that. I think though you'll be able to produce a very good report on what you have done
I shall provide some comparison light curves to show the similarity between them.
I did do some previous reading on this subject of EB variable stars but as you have hinted this is an incredibly complex subject and way beyond my level of understanding.
I can pretty much confirm this star has the charachteristics of a beta- lyrae eclipsing binary star showing a primary eclipse and secondary eclipse.
Thanks Guys for the tremoundous help.
ps-sorry about the quality of the graph
Hi Orestis,
Some great visual observations there. Well done!
Carl has offered some good advice.
You seem to be on the right track in your statement i.e. your observations do not prove it is a beta-Lyrae eclipsing binary but they can confirm it is an eclipsing binary with a short period, a characteristic of a beta-Lyrae eclipsing binary.
There are 2 charachteristics that this star shares with a beta-lyrae EB star that I can confirm that is that it has short period and each star periodically eclipses one another.
Also from the data I have gathered can i assume that one star is bigger than the other to produce different sized minimums.But i don't know that each star is the same brightness so i think i can't assume there different sizes.right?
The are several ways you can tell which star is the bigger and/or brighter of the two, but most are beyond the scope of your study. The main one is using spectroscopy to look at the spectral lines and their intensity. You can tell from this whether the star is a MS, giant or supergiant (therefore how bright it is), what spectral class it is and even how rapid the orbit of the two stars is. You can then use stellar theory to determine the size of each star.
You can also identify the EB type from the shape and timing of the light curve. beta-Lyrae variables have a rather gradual slip into the eclipse cycle on both the secondary and the primary eclipse as one (or both) of the star is extended and it's hard to pin down where the eclipse starts. Algol type EB's have a relatively easy to define eclipse start as both stars have distinct stellar limb boundaries....the timing is reasonably sharp.
There are a number of papers specifically about the star which will help you with your report. You want to download them and read them. If you have any difficulties with the science, let me know and I'll explain what's being said
Remember Carl I have switched to V1010 OPH as my star but no worries I found it in SIMBAD.
This is very interesting stuff,just wondering how do they determine which is the primary and secondary components?
As Robh said in the beta lyrae system the primary is bigger than the secondary.I always thought the primary star was bigger or is it determined on other basis such as luminosity or mass?
Mass, luminosity, spectral class, orbital characteristics etc etc. Depends on each system and what type of EB it is. In most cases, the primary will be the larger star. But in some, the secondary will be larger due to its advanced evolutionary stage, but it won't be as massive or not necessarily more luminous. Though in some cases it can be more luminous.
This is very interesting stuff,just wondering how do they determine which is the primary and secondary components?
Orestis,
For any double star, the primary is the brighter of the two stars. The apparent brightness of the stars will depend on their luminosity and distance. Generally, for a main sequence star luminosity is proportional to mass i.e. the larger the mass the higher the luminosity and the hotter the star. However, if a double star is a chance alignment, it is possible that the secondary is inherently more massive and luminous but appears less bright because it is much further way.
In the case of binary systems, the two stars are essentially the same distance from the Earth. If they are both main sequence stars then the brighter and more luminous star should also be the most massive. However, with these extremely close binaries I guess the stars are not "normal" and involve mass transfers and accretion disks etc. Thus, in the beta Lyrae system, the more luminous primary is less massive.
A Very Big thanks to Everyone that helped,Especially Robh(Couldn't have done this without you),Carl and Rob_K.
I Recieved full marks for it which I am very happy about.At our school we run the science fair which has most of the science classes experiments on display,Our whole class submitted ours and I recieved First in Show award,with $50 as a bonus( pays off one of EP'S).
Thanks so much for the help and I will be looking forward to doing more science for Astronomy.
A Very Big thanks to Everyone that helped,Especially Robh(Couldn't have done this without you),Carl and Rob_K.
I Recieved full marks for it which I am very happy about.At our school we run the science fair which has most of the science classes experiments on display,Our whole class submitted ours and I recieved First in Show award,with $50 as a bonus( pays off one of EP'S).
Thanks so much for the help and I will be looking forward to doing more science for Astronomy.
Regards Orestis
That's great to hear that you won 1st prize at the science fair!!!. Congratulations It's also great to hear that you achieved full marks for your project. Keep up the good work
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