CN's+Week+of+October+22

Main Variable Stars Back

//__**Monday, October 22, 2007**__//

I started a new log book today! For everyone to see here on wikispace! :] I hope everyone enjoys it!

Here is my task list for my project. --Review the Variable Stars Power point and update it throughout the year if need be --Look through the AAVSO website and gather information --Add any interesting websites or URL's to the wikispace page as I do my project --Research, through books and websites and find information about Variable Stars (I actually have begun reading a few different books and will update my wikispace with the information I gathered when I'm done.) --Find/schedule observing opportunities at Jordan Hall --Communicate with students from other schools along with Joe Ribaudo and Aaron McNeely --Obtain Email addresses of these people mentioned above. --Figuring out good times to look at Variable Stars, weather conditions, ect. --Find a particular variable star to base my project on (Question- Does it have to be a relatively new variable star? Or can it be a previously researched one?) --Find out information on how to find out variable star brightness, and how to find out light curves --Learn how to do visual magnitude estimations (Compare with a bright and dull star and gain experience)

Tomorrow, I get to go to a variable star meeting at the ND QuarkNet Center. Here I get to meet two students from other schools and maybe Joe R. I'll give you the update tomorrow!! :DD

I have recently added a little something to the Variable Star page. It's only a light curve of Chi Cyg (Cygnus). But it should help give you a somewhat better understanding of what I will be doing in my project on Variable Stars. I will add further details to explain what the light curve is later.

Right now, I'm looking up spectroscopic verification of rotational velocity! It's not going to well, but I've only just begun! So we shall see what I come up with soon!

MY RESEARCH--


 * "Spectroscopy** is the study of the interaction between radiation (electromagnetic radiation, or light, as well as particle radiation) and matter." [|Wikipedia - Spectroscopy]. In astronomy, "the object of study is the spectrum of electromagnetic radiation, including visible light, which radiates from stars and other celestial objects. Spectroscopy can be used to derive many properties of distant stars and galaxies, such as their chemical composition and also their motion, via the Doppler shift." [|Wikipedia - Spectroscopy Astronomy]

The rotational velocity of a star is the rate at which it spins about its axis of rotation. Its units are km/sec. In Astronomy rotational velocity is typically measured from the Doppler broadening of spectral features, which depends also on the inclination of the star's axis relative to the observer's line of sight. This is commonly referred to as V Sin //i//. [|NStED Help]

If you're wondering, because I know I was! :) The Doppler shift is red and blue shifts. "Light from moving objects will appear to have different wavelengths depending on the relative motion of the source and the observer. Observers looking at an object that is moving away from them see light that has a longer wavelength than it had when it was emitted (a redshift), while observers looking at an approaching source see light that is shifted to shorter wavelength (a blueshift)." [|Doppler Shift]



So... now i know what spectroscopy and rotational velocity means! But now I have to figure out how to verify it.. This part isn't going so well for me... :(

__//**Tuesday, October 23, 2007**//__

In class today, I didn't know what it meant about verification yesterday so I asked. KH started to talk to me about spectroscopy and how it verifies rotational velocity. I'll start looking up some more information about that soon! It has something to do with red shifts. I'll try and see if KH can help me learn some more about it tomorrow if there is time.

Dr. L also talked to us about our grades. Nothing really important to state about this, except that I should just put more time into my research so I can keep my grades up! Yay! :] Yup! I sound weird now, don't I?

Today, I got to meet Joe, N, and K (N and K are the students). I got to see around the QuarkNet building and then I had a meeting with Dr. L, Joe, K and N. We were discussing a project proposal to be able to travel to Arizona. I didn't get to hear the whole thing finish out because I had an NHS Halloween Party. (If your curious about that, well then ask me about it.) But when I left, they were discussing about starting a project with I think the star was called.. Cet.. Uh.. I forgot what the first part of it was! Sorry! But I'll give you more information tomorrow after I discuss what's going on with Dr. L! Sorry to leave you out on a limb if you're wondering!

Yay! So I just checked my email and the star is V Cet! I'm about to research some information about it now and I'll have another meeting tomorrow after school around 4 at QuarkNet! I'll get back to you with the meeting and about the star V Cet!

MY RESEARCH--

So V Cet isn't a very popular researched star. I'm having trouble finding information at the moment, but maybe I'll find more! But here's what I obtained from the [|AAVSO] website.

Name -- V Cet Constellation -- Cetus J2000.0 -- 23 57 54.00 -08 57 31.0 (359.47500 -8.95861) B1950.0 -- 23 55 20.10 -09 14 14.0 Var. type -- M (Means the star is red and has molecular bands of titanium oxide noticeable.) Spec. Type -- M3e (I'll see what I can find out about this!) Magnitude Range -- 8.6 - 14.8 V Period -- 257.82 Rise dur. -- 45%


 * __//Wednesday, October 24, 2007//__**

So.. Update on the meeting! We finished the proposal and sent it in! The proposal is "Spectroscopy of V Cet at it's Peak Magnitude." I think that's what it was titled. But yup! Answered some questions! Took about 4 hours but we got pizza! :) If you're curious about the proposal you can ask me about it if you wish! But there isn't that much to more to say because I don't remember the answers to the questions off the top of my head right now!

V Cet infromation from Joe --

The constellation CETUS: -located close to the ecliptic (planets, and more often, asteroids pass through or near the constellation) -lies far from the galactic plane (milky way obstruction is minimal allowing distant galaxies to be visible) -still have no confirmation that kitt peak can observe v cet, but according to wikipedia, the constellation is best viewed in november and can be seen up to +70 deg. combine the fact that kitt peak is at 31 deg. and v cet is 3 deg. higher than the constellation, I think it is doable.

- V CET: -M3e type star, I believe that puts its temperature near 3500 K -varies in magnitude 8.6-14.8 V

OBSERVATIONS: -light curve: -used to track brightness variations which can be the result of a variety of phenomena (this I think we all knew/know) -period of these fluctuations are used as tools to determine distances among other things, also catalogued by aavso for historical significance -shape of light curve can provide insight into conditions and characteristics of the star(s)

-spectra: -magnitude observations are dependent on the wavelength window you use, spectra avoids this selective viewing and can produce information not available from light curves

-wavelength shifts in spectra indicate expansion, contraction, rotation, and/or binary systems -presence of undetected magnetic fields can distort spectra allowing for their discovery -emission and absorption lines are the signatures of stars and provide details of stellar atmospheres and/or gas clouds present in our line of site

-combining spectra and light curves -doing so can result in confirmation of pulsating stars, i.e. expansion and contraction line up with maxima and minima of the light curves.

MY RESEARCH--

Information from http://loke.as.arizona.edu/%7Eckulesa/camp/spectroscopy_intro.html:

What is spectroscopy? --pertains to the dispersion of an object's light into its component colors (i.e. energies). By performing this dissection and analysis of an object's light, astronomers can infer the physical properties of that object (such as temperature, mass, luminosity and composition). --Light acts like a wave -more information coming! sorry ran out of time!


 * //__Thursday, October 25, 2007__//**

MY RESEARCH--

Updating my research from yesterday!

Information from http://loke.as.arizona.edu/%7Eckulesa/camp/spectroscopy_intro.html:

--The //wave speed// of a light wave is simply the speed of light, and //different wavelengths of light manifest themselves as different colors//! The energy of a light wave is inversely-proportional to its wavelength; in other words, **//low-energy waves have long wavelengths, and high-energy light waves have short wavelengths.//**

The Electromagnetic Spectrum
//__**Friday, October 26, 2007**__//

I had a talk with Dr. L about spectroscopy and how we can determine it from a star. I was confused on how this actually worked so he brought up a graph where you can see emissions and light being absorbed. We can determine the spectroscopy of a star by using a black piece of cardboard and a razor so that when the light goes through a telescope it bends in the different waves. You can print these colors on film and you'll have the spectroscopy of the star. Dr. L said he'd probably bring me in this object where you can look through it and be able to see spectroscopy from lights and from around the sun. If we were to go to Arizona, they'd have specific equipment that would helps us get a better spectroscopy of the star V Cet than what we could get. The telescopes there would allow us to receive more photons at one setting than we could get with our telescope. Metaphor to help understand. If it were to rain a kid pool would receive more rain than a wine bottle because of the opening. That's about how the difference in telescopes is. Or so Dr. L told me.

MY RESEARCH--

Information from [|http://zebu.uoregon.edu/~imamura/208/jan18/mk.html]:

Stars are classified in the ordering of O, B, A, F, G, K, M, with O being th hottest and M being the coolest.


 * O; 28,000-50,000 K; ionized atoms, especially helium
 * B; 10,000-28,000 K; neutral helium, some hydrogren
 * A; 7,500-10,000 K; strong hydrogen, some ionized metals
 * F; 6,000-7,500 K; hydrogen and ionized metals, such as calcium and iron
 * G; 5,000-6,000 K; ionized calcium and both neutral and ionized metals
 * K; 3,500-5,000 K; neutral metals
 * M; 2,500-3,500 K; strong molecules, e.g., titanium oxide and some neutral calcium

__//**Sunday, October 27, 2007**//__

I just found out a little more about spectroscopy today. I'm putting up a picture so if people don't understand about absorption or emission, the image will help them to better understand. I also found out some information on what spectroscopy can help us find out about different stars. I also decided to figure out where exactly V Cet is in the constellation Cetus. I have a picture for it, too. I'm not certain if the bottom star is actually V Cet or not, but it has the symbol v or what looks like a v so I'm assuming it is V Cet. I'll try and confirm this with Dr. L tomorrow.

MY RESEARCH--

From this picture, you can tell the difference if the light has been absorbed or if it has released light. A dark line will represent that light has been absorbed, while no color means that light has been released (emission).

Information from http://imagine.gsfc.nasa.gov/docs/science/how_l1/spectra.html:

Spectroscopy is unique to each star (or other objects). From spectral lines you can determine not only the element, but the temperature and density of that element in the star. It also tells us about any magnetic field of the star. The width of the line can tell us how fast the material is moving. We can learn about winds in stars from this. If the lines shift back and forth we can learn that the star may be orbiting another star. We can estimate the mass and size of the star from this. If the lines grow and fade in strength we can learn about the physical changes in the star. Spectral information can also tell us about material around stars. This material may be falling onto the star from a doughnut-shaped disk around the star called an accretion disk. These disks often form around a neutron star or black hole. The light from the stuff between the stars allows astronomers to study the interstellar medium (ISM). The ISM tells us what type of stuff fills the space between the stars. Space is not empty! There is lots of gas and dust between the stars. Spectroscopy is one of the fundamental tools which scientists use to study the Universe.

The constellation Cetus.I'm assuming the bottom star is V Cet, but I'm not fully certain.



Week of October 29