NEWS: On the Annihilation of Stars that Might Have Been

GEEK: On the Annihilation of Stars that Might Have Been

When I saw that space dot com had an article out called "How to Destroy a Giant Planet," I got really excited in an "I hope no nefarious super-villians are reading this" sort of way. As it turns out, it's coming from an angle not involving dynamite or hordes of zombie minions, but nevertheless it's still quite an informative little essay if you're interested -- not a manual on grand-scale demolition so much, but a study in the structural evolution of gas giants, and the sort of extremes that might have led to these planets' own demise.

The gas giants are apparently something more of a mystery than other bits of our solar system. We have a good handle on how stars are formed, after all, and the concrete inner planets like our own are relatively straightforward, but our colder and more distant satellites are caught somewhere in between. According to a team of researchers at University College London, that very distance is really all that keeps them held together.

In summary, the closer you bring a planet like Jupiter to the actual sun, the more likely it is to no longer exist. Which would be, one would think, pretty much the same response as everything else in the galaxy. The interesting thing is that the researchers say it wouldn't burn up (the bane of all these tiny stars that never ignited) so much as evaporate. Why is that? Loss of atmosphere, they say. It's not happening with our friendly neighbor planets, thanks to distance, but many are watching it happen on aforementioned and ungainly-named HD209485b, which orbits so close to its own sun that a year takes only three and a half days.

The UCL researchers mentioned a magic number, a safe distance of 0.15 Astronomical Units. Anything closer seems to affect the level of hydrogen in the planets' atmosphere, creating something like a hole-in-the-ozone effect -- except that, in this case, air gets sucked out of that hole in the atmosphere like an airplane with a window kicked in.

It's just a little more insight into the way our galaxy works, which is always pretty fascinating. Let's just hope there are no evil scientists reading this: with a few improbable billion dollar planet-moving tools, who knows what sort of malarkey could be done, now that you know how to evaporate a planet.


_DictionaryGirl_ will so call the X-Men on you, so seriously, don't even think about it.

Our universe fascinates me to no end.

Damn Right it is. It's completely mindboggling when considering how expansive our universe is. Most would like to feel as if it stops at some point but It would blow your mind to realize there is no end to our universe. I guess we will never find that restuarant at the end of the universe. I hear it's quite good.

thanks, DG, i'd heard of this before, but not read much on it.
more astronomy pls?!

But Alderaan is a peaceful world...

Yeah, no one was expecting to find all these huge planets near stars - the so called hot-jupiters - but they were the first kind to be discovered. That's becuase the two main methods for planet discovery these days - the doppler or 'wobble' method and the transit of eclipse method - both favor big things near to the star.

But still, it is weird that there are all these big things so near to the stars, and all of planet formation theory has had to be rearranged to accomodate them.

It's a crazy time for planets!

this article caused a serious mid-morning chromatics binge.

I love this article but I'm a little confused.
Wouldn't the distance from it's star be entirely relative to the type of star and it's output.
For instance our Sun is a Yellow dwarf, but what if it were a Blue Giant ? How could 1.5 AU apply ? Are they strictly referring to our Sun and Jupiter here ? They seem to imply this is an applicable benchmark for all gas giant planets. I don't understand how that could be when every star is unique.

I believe it would apply to the first planet that can or does sustain life. 1 au is only a measure of the distance between the sun and earth in our galaxy. If earth were to occupy mars' spot 1 AU would apply to it's relative distance to the sun. I'm sure life in another galaxy regardless of sun type would define 1 AU as the distance between thier sun and them.

Astronomical unit is only a measure of distance between two bodies and therefore it can only be used to guesstimate distance between planets and thier suns. I can imagine what that could change in the math involved.

Um wow.
You are pretty good at talking out of your ass eh ?
How about you go and look that up before you pull a Cliff Claven on me.

Okay, Chainlink, I've tried putting a little thought and research into this post...

AU is an arbitrary measurement; in this case, it is the distance between the Earth and the Sun. As such, distances between other planets and their stars may be compared to the AU to make it a little easier for us to put things into scale.

Regardless of that, the planet mentioned in this article is orbiting a Sun-like star, so the comparison between it and our own solar system is valid.

The photoevaporation effect would most likely prevent a blue giant star from forming planets. Evidence seems to support this idea, as most extrasolar planets have been found orbiting stars similar to our own sun.

How does being precise make it non-arbitrary?

Yr forgiven.

This time.

Thanks !
I appreciate that.
That's a bit more interesting and relevant. It still leaves me with a few questions, but I'm busy at work now. Maybe later I'll get back to this.
Basically it sounds like you are saying, Yes it is relative to the Star, planet and system it is inhabiting and not 1.5 AU.

I appreciate the insult, it goes to show the narrow mindeness that drives the engine. But I forgot that knowledge has nothing to do with having an open mind. How is the speed of light determined? The Speed of sound? All of it is a measure of relative distance, how long it takes to get from one point to another. It's 7th grade phsyics and common sense to define an AU as the distance between the sun(regardless of type) and it's first life supporting planet, hence our AU unit being defined by our distance away from the sun, and used to measure relative distance between other planets and thier sun. I suggest next time you do your homework before insulting others.

HD209458b?

What kind of cruel parent planets name their child HD209458b?

I take it all back.

You aren't even good at talking out your ass. Nor at reading comprehension.
Apparently you failed 7th grade Physics, and spelling, and if they had a class in your seventh grade on common sense I guess you failed that too.
I'm sure when the aliens get back to us about what their arbitrary AU is in their galaxies we can get on with this whole measuring distance thing.

Good luck with all that. I'll have you on ignore until you can pass basic 9th grader stuff.

Ok, I am finding that the AU is a astronomical unit of measurement that has been in use since the 1600's. Our capability to accurately measure the distance between here and the sun has improved greatly and the unit of measurement has changed with the times.
But that said, it seems about as arbitrary as a foot or a yard, an inch, a meter, whatever.
It is a specific and fixed unit of measurement.
Meaning an AU is not any longer or shorter in another galaxy.

Perhaps I didn't phrase that well or chose a poor example. My point was that , lets us say even between Yellow Dwarf stars there is such an enormous amount of variation ( and also I'm thinking of variations within gas giant planets) that 1.5 AH couldn't be the "the significant point of no return" for all gas giant/ yellow dwarf systems. (could it ? )
If the star was a little hotter wouldn't it be 1.8 ? Or if the Planet had more protective H3 in the atmosphere could it be 1.2 ? My confusion and the point of my original question was are they saying 1.5 is the PNR for Jupiter or for HD209458b or are they really postulating that 1.5 AU is the threshold for Gas Giant / Star proximity no matter what the other variables are ? ( that is what seemed absurd to me)

This is interesting, but I still prefer Death Stars as a primary means of destroying planets.

You're quite right, of course. "Arbitrary" might not have been the right word to use, but I meant it in the sense that the Earth-Sun distance was used as the definition for an AU.