Lightest Known Exoplanet Discovered: Gliese 581 e, 1.9 Earth-masses

[2552]

http://www.space.com/scienceastronomy/090421-lightest-exoplanet.html

n.

 

[the.punk]

Mmm.
How might live there?

 

[ryan]

Why dont we name these planets properly, mythical names or something, not Planet N22074 or something. Or would naming all these planets be too big for someone to handle at NASA, cos theres alot out there.

 

[Michkov]

We´d run out of names sooner or later. Just let the aliens there name it:lol:

 

[eveningsky339]

Ah, I remember the days when we could only find planets that were the size of Neptune, bare minimum.

 

[ryan]

Ah, I remember the days when we could only find planets that were the size of Neptune, bare minimum.

Ahhh, those were the days, the day when spaceflight was a day dream, and i would probaply be wearing a top hat.

 

[TMac3000]

Now that we have found four planets in the Gleise system, I suggest at least giving them proper designations, such as Gleise IV. Actual names would be even better. Greek and Roman are starting to run low, so how about Egyptian? Gleise IV should be called Abydos, after the planet they found in Stargate.

Gleise I: Osiris

Gleise II: Isis

Gleise III: Anubis

 

[Hartmann]

Now that we have found four planets in the Gleise system, I suggest at least giving them proper designations, such as Gleise IV. Actual names would be even better. Greek and Roman are starting to run low, so how about Egyptian? Gleise IV should be called Abydos, after the planet they found in Stargate.

Gleise I: Osiris

Gleise II: Isis

Gleise III: Anubis

Another idea could be use names from Sci movies or games, there are a lot and they are very nice.

igneus, helion prime, crematoria , coruscan...

 

[Ark]

crematoria

What we should have called Mercury.

 

[RisingFury]

Ah, I remember the days when we could only find planets that were the size of Neptune, bare minimum.

I haven't read the article yet, but I'm guessing the planet they found orbits very close to it's star and the star is small... it's year is probably within a couple of days... and it's likely that that star has a lower mass too.


We can accurately measure the mass of a planet by the wobble it causes on it's star. Just as the planets fly around the star in an orbit, so does the their star. However, the orbit of the star has a very small radius and it's likely that the barycenter is within the star itself.

As the star wobbles, it gets closer and further away from us periodically. That causes shift of it's light towards red and blue part of the spectrum. We can determine the planet's "year" by timing how long a shift from red to blue and back to red lasts.

The more massive the planet is and the closer it is, the more it will move it's star around.

HARPS is currently our most accurate spectrometer and is capable of detecting a velocity of around 0.9 m/s, which is damn good, given that the speed of light is just under 300 000 000 m/s.

Even with such accuracy, a planet as small as Earth will only barely move it's star around. If I remember correctly, the velocity with which Earth moves our Sun is only 0.25 km/h, which translates to 0.07 m/s. So we're going to have to increase our accuracy 10 times before we can find planets the mass of Earth by the wobble they cause on their star... however, such a spectrograph would better be located in an Earth trailing orbit around the Sun to kill the effects of the atmosphere.