What types of Stars?

[Racoon]

This is a spin off Jay-qu's how many Stars thread.

I was immensely curious on this subject, and went through much of this Astronomy and Cosmology forum! :xx: :Alien:

S'funny to read some of the older posts and threads!

There is a lot of great information buried in there.

 

Now that I found how many stars have been addressed ; I am up way past my curfew and bedtime thinking about all the Types and Classification of stars! :hyper:

 

How many types or classifications of stars are there??

 

Can anyone tell us, or direct my lazy butt to a good link or two? (lazy because now I'm tired after reading so much)

 

I know Red Giant is one! Betelgeuse was interesting to me. I suppose its a little neurotic to have favorites when it comes to stars. :D

Do you have a "favorite" kind of star? or are you fascinated by certain types of stars?

 

I'll start a list here: so please add what you know,:) thanks.

 

Red Giant >>> really old, big stars

White Dwarf >>> Drip Curl Magic (he added this, not that he is one!:hihi: :D )

[Drip Curl Magic]

It's been a while...

 

But my mom has a degree in astronomy... And I'm sure I've picked up something worth value to this thread.....

 

Gimme a second to rack my brain....

[Jay-qu]

I dont know if there is a certain number of classifications but I know that stars can be placed on a Hertzsprung-Russell Diagram, and that helps classify them :hyper:

 

heres one I found on the web:

from bramboroson.com

[Drip Curl Magic]

k, I'm pretty sure there is a type of star with a name like "white dwarf" or something.

 

White dwarf? (waiting to be corrected or approved)

[Drip Curl Magic]

ahhh, the diagram says I'm right!

[Racoon]

I dont know if there is a certain number of classifications but I know that stars can be placed on a Hertzsprung-Russell Diagram, and that helps classify them :xx:

 

 

from bramboroson.com

 

Thats cool Jay-Qu! :hihi: right on.

 

I didn't see pulsars or quasars on there. Are they stars?

what about binary stars? are those just "regular stars" that are mated through gravity and redshift stuff?

 

I guess I know a few types off the top o' me head, but not enough about them :hyper:

I'm seeing stars like I just got punched. :Alien:

[Jay-qu]

Pulsars are spinning neutron stars that appear to 'pulse' over time. Quasars are quasi stellar objects, they are the most distant objects observable objects in the universe I dont think they are stars, more likely super massive galactic black holes :hyper:

 

binary = 2, double star systems are binary stars.

[Pyrotex]

...I didn't see pulsars or quasars on there. Are they stars?

what about binary stars? are those just "regular stars" that are mated through gravity and redshift stuff?...

"Oh, be a fine girl, kiss me right now."

 

Mister Star Man to the rescue! :hyper: Yes, Pyrotex is none other than Mister Star Man (in a tacky spandex body suit), who took up backyard astronomy as a kid, and drove his family crazy with little jingles as the one above. That jingle is a mnemonic for the main classes of stars: O B A F G K M R N, in order of temperature, with the hottest being first. This classification scheme was invented by the first woman PhD astronomer in America!

 

The Hertsprung Russell diagram is essential in understanding stars. O stars are the really hot blue ones in the upper left corner. They are often found in very young star clusters and are known as "O Associations". B stars are smaller and orange-ish but still huge and hot. When you get down to the G stars, you come to our Sun! R and N stars are the tiny, dim, cool red dwarves in the lower right corner of the HR diagram. The other letters run diagnonally down from upper left to lower right. Here are some other star types:

 

Red Super-giants. These have no letter. They start as O, B or A stars, and when they run out of nuclear fuel at the core, they start burning other elements such as helium and carbon in shells around the core. This puffs them up to huge size, their outer atmospheres get cool and red.

 

Wolf-Rayet stars. Incredibly huge O stars on the verge of going supernova. Very unstable and violent. Rare.

 

Cepheid Variable stars. Rather large orange stars that by chance are just the right size and temp to become unstable in a very regular fashion. They pulse, growing brighter and dimmer in a very regular predictable fashion. They are used to measure distance to other galaxies.

 

White dwarf. They typical end-of-life of normal F, G, K, M stars after they use up their fuel (hydrogen) and shed their outer atmospheres.

 

Planetary nebula. What white dwarf stars are called while their outer atmospheres are still being shed. Very beautiful. A dying star.

 

Black dwarf. Theoretically what a white dwarf becomes after it cools off--which takes a billion years.

 

Brown dwarf. A "star" smaller than an N class red dwarf, that doesn't quite have enough mass to trigger fusion at its core. It glows in infrared because it is hot, but not hot enough to glow red.

 

Red dwarf. M, R, N stars. The most common type in the universe. Also the longest lived.

 

Variable star. Any star whose brightness changes over times shorter than a human life. Cepheids make up only one sub-class of variables. Reasons for variability change from sub-class to sub-class. Sometimes a star will "burp" when a new fuel starts being burned; it will expand getting brighter, than slowly collapse getting dimmer, and bounce between the two extremes for millions of years before settling down.

 

Supernova. Type II. O, B and large A stars are so massive that when they run out of fuel (hydrogen) they don't just shrink to a white dwarf. They keep shrinking, rapidly! The shock waves detonate the core and 90% of the star goes blasting out into space. Secondary shock waves smash the remaining 10% so small that all atoms, protons and electrons are compressed into pure neutrons. This leaves a...

 

Neutron star.

 

Pulsar. A neutron star that spins rapidly. Its super powerful magnetic field causes twin beams of radio (and sometimes light) to beam out like search lights on a merry-go-round.

 

Supernova. Type I. A neutron star can be in a binary system. (two stars orbiting each other). Somehow, the parner does survive the supernova that produced the neutron star. Amazing. Then the neutron star pulls gas off of the partner and it accumulates on the surface of the neutron star. When it gets about a centimeter deep, the intense gravity of the neutron star's surface compresses the gas enough for it to fuse, like a giant hydrogen bomb. All the gas detonates, and the buildup starts over again.

 

Supernova. Type Ia. If the neutron star is massive enough, the detonation of accumulated gases somehow causes the detonation of the neutron star itself, producing one of the biggest explosions in the universe. Nothing is left behind--all trace vanishes.

 

Quasar. Not a star. Short for Quasi Stellar Object (QSO). An object that "looks" like a star, but is in reality the core of a galaxy more than half way across the universe--a galaxy with a super-massive black hole at its core.

[Racoon]

Hell Yes Pyrotex! :confused:

 

Thats what I was looking for! You Da' Man! :D

You will get repped again, once I spread some around.

 

Thank you for taking the time Star Man

I'll see you in a comic book eh? :eek2:

[coldcreation]

Hi hi hi hi

[Jay-qu]

So I just had a lecture on this today, figures! Learnt about the H-R diagram, and the O B A F G K M (R N apparently not important enough to be included :D ) we then also got told about the size designation, from Luminous supergiants down to dwarfs.

 

Our sun is a G2 V fairly ordinary star..

[Harry Costas]

Hello Jay

You said

"Quasars are quasi stellar objects, they are the most distant objects observable objects in the universe I dont think they are stars, more likely super massive galactic black holes"

quarsars are usually defined wrong.

 

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http://www.phys.vt.edu/~jhs/faq/quasars.html

quote:

"They are

 

What is your definition of a quasar?

This is best answered with history. When radio telescopes were first turned on the heavens, point sources of radio waves were discovered (along with spread-out regions of emission along our Milky Way). Astronomers using ordinary visible-light telescopes turned toward these radio points and looked to see what was there. In some cases a supernova remnant was found, in others, a large star-birth region, in others a distant galaxy. But in some places where point sources of radio waves were found, no visible source other than a stellar-looking object was found (it looked like a point of like --- like a star does). These objects were called the "qausi-stellar radio sources", or "quasars" for short. Later, it was found these sources could not be stars in our galaxy, but must be very far away --- as far as any of the distant galaxies seen. We now think these objects are the very bright centers of some distant galaxies, where some sort of energetic action is occurring, most probably due to the presence of a supermassive black hole at the center of that galaxy (supermassive = made up from a mass of about a billion solar masses).

What do quasars have to do with black holes?

See the above answer. It is thought the infall of matter into the supermassive black hole can result in very hot regions where huge energies are released, powering the quasar (i.e., producing the emitted light, etc.).

link on quarsar"

 

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Link on stars

Indicate the different types

 

http://www-astronomy.mps.ohio-state.edu/~pogge/Ast162/Unit2/himass.html

 

 

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[Pyrotex]

So I just had a lecture on this today, figures! Learnt about the H-R diagram, and the O B A F G K M (R N apparently not important enough to be included ;) ) we then also got told about the size designation, from Luminous supergiants down to dwarfs....

JQ,

I am truly impressed to discover that you are so young, and that you are studying to be an astro-physicist. Heavy duty!

 

That was what I wanted to be, and still have regrets that I did not pursue. I discovered the stars on a cool late August night in north Alabama, at the tender age of 12, when my parents allowed me and my brothers to camp out in the back yard overnight. I kept waking up to see the stars, discovered that they moved, found the Milky Way, and as the dawn was breaking, feverishly memorized the pattern of the brightest stars. The next day I drew a "map" of these dozen or so stars. Years later, I found them again in an atlas: Cygnus, Aquila & Lyra, the so-called "Summer Triangle".

 

I built my own reflecting telescopes when I was 15 to 17. I majored in Physics because that was the prerequisite for getting into Astronomy. But, alas, my father could not afford the "big" colleges that gave PhD degrees in Astronomy. So, I subscribed to Sky and Telescope magazine instead. {sigh} And followed my second choice career, computer science.

 

I envy you and wish you the very best in your pursuit of career. Good luck.

[Jay-qu]

Thanks Pyrotex, I hope to complete a PhD in Astronomy or astophysics eventually - The next 8 years should be interesting, I dont seem to be daunted by the fact I will still be in school when im 26 :evil:

[Harry Costas]

Hello All

 

For those who want links to different types of stars.

 

BBC - Science & Nature - Space - Star Types.htm

CategoryStar types - Wikipedia, the free encyclopedia.htm

Neutron stars and pulsars.htm

Principle Star Types Based on Temperature.htm

Science Astronomy Stars and Constellations Star Types - Open.htm

Star Classification - Zoom Astronomy.htm

star types.htm

Star Types.htm

 

you may have to go through google that where I got them from

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[Nootropic]

Let us not forget about those lovely violents known as magnetars. Picture: One of these babies within ten light years of the Earth going off. Mass extinction anyone? These objects are of interest mostly becaue I find that they are of a possible explanation for those mysterious gamma ray bursts that seem to occur "randomly."

 

http://www.space.com/scienceastronomy/bright_flash_050218.html

[Harry Costas]

Hello All

 

More magnetars

 

http://antwrp.gsfc.nasa.gov/apod/ap050221.html

http://antwrp.gsfc.nasa.gov/apod/ap041126.html

http://antwrp.gsfc.nasa.gov/apod/ap040306.html

http://antwrp.gsfc.nasa.gov/apod/ap030704.html

http://antwrp.gsfc.nasa.gov/apod/ap010901.html

http://antwrp.gsfc.nasa.gov/apod/ap980903.html

 

 

http://antwrp.gsfc.nasa.gov/apod/ap980527.html

Quote:

"What do you call a neutron star with a super-strong magnetic field? You guessed it ... a Magnetar. Imagine a star with more mass than the sun, the density of a neutron, and a magnetic field about a thousand trillion (a one followed by 15 zeroes) times stronger than Earth's. It sounds exotic and theoretical, but strong evidence for the existence of magnetars has recently been announced based on data from orbiting X-ray and Gamma-ray observatories. Neutron stars are formed in the violent crucibles of stellar explosions. Some become pulsars with relatively weak magnetic fields, spinning and emitting pulses of electromagnetic radiation as their rotation slows. However, astronomers now believe that some become magnetars, with magnetic fields so intense that the solid neutron star crust buckles and shifts under its influence. The resulting star quakes could repeatedly generate brief flashes of hard X-rays and soft gamma-rays giving rise to the rare but mysterious "soft gamma repeaters" (not to be confused with " gamma-ray bursters"!). This still frame from an animation illustrating a spinning, flashing magnetar emphasizes the looping magnetic field lines embedded in the X-ray hot neutron star surface"