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← First four-exoplanet system imaged

First four-exoplanet system imaged - Comments

Disbelief's Avatar Comment 1 by Disbelief

So how far away is it?

Tue, 14 Dec 2010 13:27:14 UTC | #563085

beanson's Avatar Comment 2 by beanson

Interesting that their relative positions don't seem to have changed in 8 months- I wonder how far out, in conparison with venus, the innermost planet is. I realise that it is hugely bigger than our innermost rocky planets.

Tue, 14 Dec 2010 14:26:28 UTC | #563105

God fearing Atheist's Avatar Comment 3 by God fearing Atheist

Comment 1 by Disbelief :

So how far away is it?

129 light years. Google is your friend.

Tue, 14 Dec 2010 14:34:41 UTC | #563111

God fearing Atheist's Avatar Comment 4 by God fearing Atheist

There are about 208 stars brighter than absolute magnitude 8.5 within 15 parsecs of the Sun ref.

HR 8799 is 39 parsecs away. Thf. approx. 208 * 39 ^ 3 / 15 ^ 3 = 3656 stars can be examined at the same or greater level of detail.

Tue, 14 Dec 2010 14:45:23 UTC | #563122

Alan4discussion's Avatar Comment 5 by Alan4discussion

It's good to see we are starting to get direct imaging of exoplanets,

Comment 2 by beanson

Interesting that their relative positions don't seem to have changed in 8 months- I wonder how far out, in conparison with venus, the innermost planet is. I realise that it is hugely bigger than our innermost rocky planets.

An AU (Astronomical Unit) is the distance fom the Earth to the Sun so this one is 14 and a half Earth orbit radii out from its star. Quite a long way. Bearing in mind that the outer planets in the Solar System take hundreds of years to complete one orbit, you would not expect to see a great deal of movement since 2008.

The new planet, designated HR 8799e, orbits at a distance of 14.5 AU, making it the innermost planet.

:- A young system still building planets by the look of it.

Tue, 14 Dec 2010 14:46:34 UTC | #563123

Alan4discussion's Avatar Comment 6 by Alan4discussion

Daedalus & Icarus: Flyby versus Deceleration

The nominal Daedalus mission profile would accelerate the probe for around 3.8 years with an exhaustive pulse frequency of 250 detonations per second. Assuming no major failure modes occurred during this time the vehicle would then attain its cruise velocity of 0.12c and coast to its target for another 46 years. It would whip through its target system Barnard’s star, 5.9 light years away, in a matter of days.

Damn it! Still too far away!

Tue, 14 Dec 2010 15:04:44 UTC | #563135

Southpaw's Avatar Comment 7 by Southpaw

What's even more interesting is that it's thought we will soon be able to discern the existence of vegetation on such planets.

http://io9.com/5712038/forests-might-be-detectable-on-extrasolar-planets

Tue, 14 Dec 2010 16:03:47 UTC | #563167

mr_rybread's Avatar Comment 8 by mr_rybread

If this is a young system then maybe inner planets form later in the evolution of the solar system--if at all--depending on the stability of the outer planets?

Tue, 14 Dec 2010 19:13:48 UTC | #563267

Disbelief's Avatar Comment 9 by Disbelief

Cheers God Fearing Atheist. A combination of lazyness and a desire to get first post afflicted me.

Wed, 15 Dec 2010 01:47:42 UTC | #563474

Jonathan Dore's Avatar Comment 10 by Jonathan Dore

mr_rybread's Avatar Comment 8 by mr_rybread

If this is a young system then maybe inner planets form later in the evolution of the solar system--if at all--depending on the stability of the outer planets?

No, I'd imagine the inner rocky planets are already there, but current resolution limits on our instruments don't yet allow them to be separated from the start's glare. Hopefully that will change in the near future with space-based scopes working interferometrically.

Wed, 15 Dec 2010 12:49:49 UTC | #563652

wahee's Avatar Comment 11 by wahee

this is great. I always love to see direct images of stars etc. Transit graphs and plots are superb too but it's nice to see a photo

Thu, 16 Dec 2010 17:13:28 UTC | #564219

Schrodinger's Cat's Avatar Comment 12 by Schrodinger's Cat

The angular size of this system is actually quite large.....the outermost planet has an orbit comparable with the maximum size of Mars in the sky...even at a distance of 120 light years.

Thu, 16 Dec 2010 18:12:28 UTC | #564247

Steve Zara's Avatar Comment 13 by Steve Zara

Comment 12 by Schrodinger's Cat

the outermost planet has an orbit comparable with the maximum size of Mars in the sky...

This seemed a bit large, so here is the calculation: the outermost planet has an orbit of radius 100 AU (a rough estimate from the pictures). That's 150 million km. The distance to the star is 120 light years, which is 1,135 trillion km. The angle subtended by the radius of the largest orbit = 0.0015 degrees. The maximum size of Mars in the sky is .0069 degrees. So, it's a reasonable fraction of the size of Mars in the sky. I'm surprised. I had assumed it would be orders of magnitude smaller.

Fri, 17 Dec 2010 01:17:07 UTC | #564432

Reckless Monkey's Avatar Comment 14 by Reckless Monkey

Kepler and Newton would have been pleased to see their formula being used to calculate the orbits and masses of planets outside our own solar system now.

Fri, 17 Dec 2010 11:37:33 UTC | #564561

Hendrix is my gOD's Avatar Comment 15 by Hendrix is my gOD

So are any of the planets in the Goldilocks zone? Ideal conditions for life to occur.

Thu, 30 Dec 2010 16:43:36 UTC | #570888