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ageorge95
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I'm a yr 12 student doing a full year research assignment and i have decided to find the age of the star, Sirius. I have access to a pretty good telescope and equipment but I am not sure where to start. Suggestions anyone?
ageorge95 said:I'm a yr 12 student doing a full year research assignment and i have decided to find the age of the star, Sirius. I have access to a pretty good telescope and equipment but I am not sure where to start. Suggestions anyone?
e^(i Pi)+1=0 said:Couldn't you get a good approximation by its spectra? The more heavy elements, the older the star.
e^(i Pi)+1=0 said:Couldn't you get a good approximation by its spectra? The more heavy elements, the older the star.
ageorge95 said:I was hoping to do just that and use the Hertzsprung-Russell diagram which requires the luminosity and colour of a star to determine the age of the star. How would I do get this information using a telescope?
A new method is helping scientists assess the ages of isolated stars, including all stars known to have planets...A star's rotation slows with time, research shows, giving scientists a clock to understand its age.
The research is published in May 20 issue of The Astrophysical Journal Letters.
http://news.discovery.com/space/star-age-exoplanet-110523.html
Radrook said:This method [a new one presently limited to certain types of stars] is based on how fast the star is spinning.
Gyrochronology
http://www.google.com/search?source...ox&ie=UTF-8&oe=UTF-8&rlz=1I7ACAW_enUS378US378
ageorge95 said:Thanks for the suggestion Radrook. Do you think that I can measure stellar rotation with a 10" LX200 SCHMIDT CASSEGRAIN TELESCOPE. It looks like this:
http://www.google.com.au/imgres?q=10%22+LX200+SCHMIDT+CASSEGRAIN+TELESCOPE&um=1&hl=en&sa=N&biw=1366&bih=705&tbm=isch&tbnid=3W30xEqYlfT3xM:&imgrefurl=http://www.skiesunlimited.net/index.php%3FProductID%3D845&docid=gJdFDfre6zLVdM&imgurl=http://www.skiesunlimited.net/images/products/845_main.jpg&w=300&h=474&ei=4_o9T4OoGKTLmAWkzvXOBw&zoom=1&iact=hc&vpx=341&vpy=312&dur=117&hovh=282&hovw=179&tx=116&ty=259&sig=112911186707980595689&page=1&tbnh=152&tbnw=96&start=0&ndsp=20&ved=0CIEBEK0DMA8
In a four year preparatory study conducted with specially designed instrument (Hectochelle) mounted on the MMT telescope on Mt. Hopkins in southern Arizona, Meibom and his colleagues sorted out information in nearly 7000 individual stars and used Kepler data to determine how fast those stars were spinning.
http://www.universetoday.com/85901/a-new-spin-on-stellar-age/
Hectospec & Hectochelle
A Brief Description:
http://mmto.org/node/55
MMT Obervatory
http://en.wikipedia.org/wiki/MMT_Observatory
Keppler Data Archive
The data from the Kepler Mission are processed and archived in the Multimission Archive at Space Telescope Science Institute (STScI). The public Kepler Planet Candidates are there as well.
http://kepler.nasa.gov/Science/ForScientists/dataarchive/
Instruction Manual
8", 10", 12", 14", 16" LX200GPS Schmidt-Cassegrain Telescopes
7" LX200GPS Maksutov-Cassegrain Telescope
with Autostar II Hand Controller
http://www.cgtp.duke.edu/~plesser/observatory/LX200GPS_manual.pdf
...the rotation periods of stars older than about half a billion years can't be measured from the ground where Earth's atmosphere interferes. Fortunately, this is not a problem for the Kepler spacecraft .
http://www.sciencenewsline.com/space/2011052512580000.html
Drakkith said:Nice! Never heard of that before, thanks Radrook.
ageorge95 said:Since I cannot find the age of a star individually how would I find the age of a star cluster?
Thanks Cepheid. So you're saying all I need to do is find the luminosity and colour and apply this to the HR diagram. I only have two questions.cepheid said:This is something you would use a Hertzsprung-Russell Diagram for. The idea is that for stars on the main sequence, the ones that are bluer, hotter, and more luminous don't "live" for as long as the stars that are redder, cooler, and dimmer. The reason for this is that the hotter and more luminous stars have a larger mass. More mass means a higher central core temperature. A higher core temperature means a higher rate of nuclear fusion. Now, the "lifetime" of a star is defined as the amount of time it spends on the main sequence. The main sequence is defined as the portion of the stellar life cycle during which stars produce energy by nuclear fusion of hydrogen into helium in their cores. If the hotter and more luminous stars have a higher fusion rate, then they will run out of their nuclear fuel (hydrogen) in their cores sooner than the dimmer stars. Therefore, the hotter and brighter stars will spend less time on the main sequence. Once they run out of core hydrogen and fusion ceases, the stellar radii and surface temperatures change. This causes those stars to move off the main sequence on the H-R diagram. They move up and to the right onto the red giant branch (corresponding to becoming brighter and having cooler surface temperatures).
The net effect of this is that if you assume that all the stars in the cluster were roughly born at the same time, then there will be certain point on the main sequence to the left of which stars simply don't exist (i.e. that portion of the main sequence is missing). The reason is because the lifetimes of stars bluer than this are shorter than the age of the cluster. So stars of those spectral types have already "veered" off the main sequence and onto the giant branch. We call this point on the H-R diagram at which the main sequence cuts off the "main sequence turn-off point." The older a cluster is, the farther to the right the main sequence turn-off point will be (because in an older cluster even the cooler, dimmer, and more longer-lived stars have "died" i.e. evolved off the main sequence).
So, you can age a cluster simply by looking at where the main sequence turn-off point occurs. The age of the cluster is equal to the main sequence lifetime of the stars at the turn-off point.
ageorge95 said:Thanks Cepheid. So you're saying all I need to do is find the luminosity and colour and apply this to the HR diagram. I only have two questions.
1. How do I measure luminosity and colour using a telescope?
2. How do I convert the point on the HR diagram to the age of the cluster?
Sorry for asking basic questions but there is little information on the internet on how to do this.
Thanks Drakkith. I attended a session for astrophotography last year and there is an expert at the school. So I don't think I will have a problem taking photos. I'm just not sure how to extract this information from the photo. Also can anyone answer my second question from my last post. How do you convert the turn off point on the HR diagram to the age of the cluster?Drakkith said:What you are asking about is pretty much astrophotography. Head over to cloudynights.com and hit up the forums there, as that site is dedicated to the hobby. If you can't find the information on their forum, just post a thread asking about it and I'm sure someone can give you some links. The basics of astrophotography are required for your project, so even if it seems like some of it doesn't apply to you, it probably does. But be warned, this is probably not something you can learn to do in just a few weeks or even months. Getting used to using a telescope and the associated equipment, along with the night sky, is probably going to take upwards of a year or so. (Based on my personal experience in the hobby) If you have someone who can be there to show you everything would make things go much faster, but if you don't, then it's going to take a while probably.
As Chronos suggested, getting the values directly from a listing would probably be the quickest and easiest way.
ageorge95 said:Also can anyone answer my second question from my last post. How do you convert the turn off point on the HR diagram to the age of the cluster?
cepheid said:So, you can age a cluster simply by looking at where the main sequence turn-off point occurs. The age of the cluster is equal to the main sequence lifetime of the stars at the turn-off point.
ageorge95 said:If I have understood this correctly. (The length from start to turnoff/ the length from start to finish) * lifespan of star class = age of cluster.
Assuming this is right, why can't i do the same with an individual star?Also this is a website that showed how to determine colour;
http://www.astronomynotes.com/starprop/s5.htm
This requires measuring the flux which this website says can be easily done with a CCD camera;
http://curious.astro.cornell.edu/question.php?number=37 [Broken]
ageorge95 said:Okay can someone give me a clear step by step procedure as to what to do because I am very confused.
vociferous said:That is a pretty impressive order of magnitude calculation and comes pretty close to the "true" lifespan. Sirius will fuse hydrogen for about 10^9 years.
Large stars do not have very good convection (the ability to transport materials from outside the core) so they actually start fusing Helium long before they come close to exhausting their supply of hydrogen, so the lifespan of the star is less than you calculate.
Because of poor convection, these massive stars cannot transport things such as helium (which forms a shell around the core) to the surface of the sun where the change might be observed by spectroscopy. The plasmas we observe are more or less in the same ratio as when the star first formed.
However, as I mentioned before, we can estimate a star's age from the ratio of hydrogen and helium to metals (everything heavier). The more metals, the younger the gas the star formed from, because stars release metals into the galaxy when they form white dwarfs or explode in a supernova, so they have slowly been building up in the Milky Way.
Scientists determine the age of a star by looking at its color, luminosity, and composition. They can also use the star's position in the Hertzsprung-Russell diagram, which plots a star's luminosity against its temperature, to estimate its age.
Yes, scientists can accurately determine the age of a star using various methods and observations. However, the accuracy may vary depending on the available data and the complexity of the star's evolution.
The most common method used to determine the age of a star is through its spectral analysis. This involves studying the elements present in the star's atmosphere and using their abundance to estimate its age.
A star's mass plays a crucial role in determining its age. High-mass stars have shorter lifetimes compared to low-mass stars, as they burn through their fuel at a faster rate. Therefore, a star's mass is an essential factor in estimating its age.
No, the age of a star cannot be determined through direct observation as it takes millions or billions of years for a star to evolve. Scientists use indirect methods and observations to estimate a star's age, such as studying its properties and comparing them to theoretical models.