Gravity sucks.

[Mikey]

A "suicidal" planet is discovered.

[stitch626]

Cool. Glad I'm not there.

[Tsukiyumi]

The title is very punny.

Nice work, Mikey.

[Teaos]

While these hot jupiters are cool (or hot) I wish they were capable of finding more rocky planets.

[Tsukiyumi]

While these hot jupiters are cool (or hot) I wish they were capable of finding more rocky planets.

Same here.

I wonder if it's a question of us not having the capability to find them, or whether they're just rare.

[Teaos]

We just cant find them yet. The two main ways we use to find planets rely on them being big and close to the star.

[Tyyr]

Exactly. The first way we find planets is by detecting regular dips in a star's brightness. Essentially the planet passes in front of the star, part of its obscured, its not as bright. Well, to determine that's a planet you need to see the same dip in a regular pattern. Since we can't stare at a stars for years on end that method relies on the planets being very close to the star so their orbital period is measured in days. In order to get a detectable dimming in the star the planet also needs to be big to occlude as much of the star as possible.

The other way we detect them is by watching a star and looking for it to wobble slightly. You see stars aren't perfectly stationary. Just like a star's gravity pulls on the planets the planets also pull on the star. Our sun isn't stationary, it actually has its own very weird, very small orbit. This orbit can make a distant star appear to wobble. By determining the size of the star and the size of the wobble you can figure out the size of the planet. The downside, you need a lot of wobble to detect which means you need very big planets in relation to the size of their star. It also helps that they have short orbital periods so the wobble is quick and regular enough to catch.

[Mikey]

There's another factor in the seeming rarity of rocky planets - their actual rarity. I'm extrapolating on my own here, and I'm no astrpohysicist by any stretch - but it would seem to me that a star has to be in a an almost perfect position on the Main Sequence in order to develop with enough heavy elements to throw off a ring of a protoplanets that would include metallic cores. It's far easier fro a protostar to form with the raw materials for the seeds of gas planets.

[Teaos]

Not to mention about the hot jupiters that fall into the middle of the system sucking uo any smaller planets on their way down.

[IanKennedy]

We should be starting to find them in the next year or so. We've just put a satellite up that will be able to resolve distortions on the surface of remote stars (we've been able to do that for quite some time, it how we know about the makeup of the centre of the star). This new device can see to much higher resolutions and should allow us to see the disturbances caused by smaller rocky planets. It's taken 20 years to get the money together to build and launch the machine but it should give some interesting results.

How I know this? One of the team of astronomers was on the cruise we went on and did three lectures during our days at sea. The last one of these was on his own topic 'Asteroseismology' and was fascinating.

[Mikey]

I may be wrong, but isn't that how the WASP worked (albeit to lower resolution?)

[Tyyr]

My wife would have killed me. Going on a cruise and my idea of fun would have been to sit in the hall listening to those lectures.

[IanKennedy]

I may be wrong, but isn't that how the WASP worked (albeit to lower resolution?)

No, WASP looks for planets crossing in front of the star and thus altering the observed brightness. This only really works if you obscure a significant proportion of the star. The other method was to look for wobble in the position of the star caused by the gravitational pull of the orbiting planet. This one looks at the picture of the surface of the star and looks at resonance patterns in the brightness of the surface. By using Fourier transforms on the patterns they see they can detect the minute gravity pulls on smaller planets.

[Mikey]

So, measuring starquakes, then, or tides in the star's surface?

[IanKennedy]

My wife would have killed me. Going on a cruise and my idea of fun would have been to sit in the hall listening to those lectures.

These were days at sea, you can't get off so you find things to do on the ship. She would go to the Spa and have a massage while I would listen to the astronomer.