A giant planet embedded in the magnetosphere of its star [ tau Bootis ]

SpaceRef ^ | Thursday, November 30, 2006 | Canada-France-Hawaii Telescope

[SunkenCiv]

[A]n international team of researchers, led by two French astronomers... has just discovered a magnetic field on tau Bootis, a star orbited by a giant planet on a close-in orbit... Up to now, only indirect clues pointed to the presence of magnetic fields on stars hosting giant extra-solar planets. This result opens major prospects, in particular the study of the interaction between the planet and the magnetosphere of its star... [A]lthough indirect effects of magnetic fields have already been detected on stars hosting giant extrasolar planets, no direct measurement had ever been done until now... They detected the magnetic field of tau Bootis, a one billion year old star, having a mass of one and a half solar masses and located at nearly 50 light years from the Earth... orbited by a giant planet with 4.4 Jupiter masses on a very close-in orbit at 0.049 AU... possesses a magnetic field of a few gauss, just a little more than the Sun's, but showing a more complex structure. Moreover, astronomers have also measured the level of differential rotation of the star, a crucial parameter in the generation of magnetic fields. In the present case, the matter located at the equator rotates 18% faster than that located at the poles, leading by one full turn in approximately 15 days. By comparing the differential rotation of the star with the revolution of the giant extrasolar planet, astronomers have noticed that the planet is synchronized with stellar material located at about 45 degrees. This observation suggests very complex interactions between the magnetosphere of the star and its companion, perhaps similar to the interaction of the magnetosphere of Jupiter with its satellite Io, giving rise to the so-called "Io torus".

[SunkenCiv]

[SunkenCiv]

[SunkenCiv]

I know how we all love Hot Jupiters... pass the marshmallows...

---

· Catastrophism ping list · join · view topics · view or post blog · bookmark ·

---

[SunkenCiv]

• Space Daily
• Astrobiology Magazine
• Space Daily
• The Planetary Society

[Jedi Master Pikachu]

Why doesn't the gas giant boil away? Or is its mass sufficient to keep itself together? Or is the star cold (relative to the Sun)?

[Jedi Master Pikachu]

And how do you use bazooka type in your posts? What is the html code for that?

[Lurker]

>font="<

L

[SunkenCiv]

here's the code for changing the font, in this case, Comic Sans MS, a controversial font that I've liked since I saw Hankster (Hank Zevallos) use it on The Globe, a now-defunct forum system that was also one of those Internet bubble millionaire stocks. :') Anyway:

<font face="comic sans ms"></font>

regarding this:

Why doesn't the gas giant boil away? Or is its mass sufficient to keep itself together? Or is the star cold (relative to the Sun)?

The star is thought to be colder (that was in the article above, but I may have edited that out), however the answer to the question is, either the planet is a relatively new acquisition (captured from an encounter), or is a blob of crap that came up out of the star, or it's been migrating inward for a long while due to various possibilities, including retrograde motion around the parent star.

Due to frame dragging (a predicted phenomenon derived from Einstein's Fear of Relatives), the planet's time frame may be different, but even if valid, this wouldn't help these "hot Jupiters" because the effect is very small.

In any case, it was fortuitously discovered near its terminal point. It may be that these types of planets about to be gulped down are not very common, and are overrepresented in the extrasolar planets discovered so far, simply because they are easier to spot. That is probably correct IMHO.

[SunkenCiv]

http://freerepublic.com/focus/f-chat/1481572/posts?page=15#15

[AndrewC]

A giant planet embedded in the magnetosphere of its star [ tau Bootis ]"

"Tall Booty" is spelled wrong.

[SunkenCiv]

:')