Another Planet!!!

[truestory]

Check it out:
http://www.msnbc.com/news/335007.asp

[This message has been edited by truestory (edited November 23, 1999).]

[Letticia]

This website keeps track of all extrasolar planets found:
http://www.obspm.fr/encycl/catalog.html

[ltcmmdr]

I like to know how can scientists detect planets from distance stars. Even if they got the right equipment it still doesn't make some distant star a planet.

------------------
everything is not what it
appears to be

[Crisp]

Hi ltcmmdr,

Everything we see in the nightsky are stars. We call them stars because they are very bright and very heavy.. Planets do not emit light (well not visible anyway) and they are generally a lot less heavy than their stars.

That's what makes it so difficult to detect a planet around a star, simply because the star itself is so bright, we cannot see the planet revolving around it.

There are different methods thast can be used to detect planets:

A simple and uneffective method:

Planets orbit their stars, so everytime a planet moves in front of side of the star we see the star's brightness fade just this tiny little bit.

If the brigthness is then plotted as a function of the time, you can clearly see the "dimming" of everytime the planet moves in front of the star. That way we can determine the number of hours/days/weeks/.. it takes for the planet to complete one orbit.


The currently used method:

Large planets pull the actual star from its rest position because of gravitational interaction. This causes the star to change from position all the time (since the planet orbits the star, the star is dragged along in a circle). By measuring the doppler shifts in the light we receive from the star, we can tell whether there's something dragging the star or not.

Bye!

Crisp


------------------
"The best thing you can become in life is yourself" -- M. Eyskens.



[This message has been edited by Crisp (edited December 20, 1999).]

[Weitzel]

Based merely on the evidence of periodically-dimming light reaching Earth from the star, how are scientists so certain that this newest finding (the highly-publicized one) is a planet? Could it not be a binary star system, with one star eclipsing the other? Oftentimes one of the stars in such a pair is relatively indistinguishable.

Have they conducted any spectroscopy, etc to confirm that it is indeed a planet?

[Crisp]

Hi Weitzel,

The scientists can determine the mass of the object dragging the main star (this can be calculated by the doppler shifts). Once the mass is known (or can be estimated), you immediatelly know if you've found a planet or a star (since the difference between planets and stars is simply mass).

Bye!

Crisp


------------------
"The best thing you can become in life is yourself" -- M. Eyskens.

[Weitzel]

Okay, thanks Crisp.