A Planet Literally Boils Under the Heat of Its Star

The Bad Astronomer writes "Astronomers have found what appears to be a planet so hot it's literally vaporizing, boiling away from the heat of its star. KIC 12557548b was found using the transit method, periodically blocking some light from its star as it orbits around. But the amount of light blocked changes every transit. Given it's less than a million miles from the surface of the star, astronomers interpret this (PDF) as the planet itself turning to vapor, and the expanding cloud of rock-laden gas is what's blocking the starlight. The planet is most likely somewhat bigger than Mercury, but losing 100,000 tons of matter every second it'll only be around another few hundred million years."

100,000 tons

[SJHillman]

"but losing 100,000 tons of matter every second it'll only be around another few hundred million years."

Is that 100,000 tons at Earth-normal gravity or at this much smaller planet's (although possibly denser?) gravity?

Holy cow ...

[gstoddart]

but losing 100,000 tons of matter every second it'll only be around another few hundred million years

It's numbers like this that really make my head spin.

Yes, I get that planets are big items, and space is big and vast ... but I can't even begin to imagine the sheer amount of material we're talking about in even just a few hours, let alone the next "few hundred million years".

Anybody got a car analogy or something which might put these numbers into a little better perspective for those of us who don't work on scales like this?

I can't even begin to wrap my head around it ... a google search for one of the biggest things I could think of says that a Nimitz [wikipedia.org] class aircraft carrier is about 101,000 tons. I saw one once, and it was utterly huge.

The idea of something that big boiling off every second for a few hundred million years makes my head hurt.

Re:This Doesn't Make Sense

[Anonymous Coward]

Losing mass does not change the orbit unless the process of losing mass applies a net force on the planet. And it would only cause it to spiral inward if that net force was in the correct direction.

Re:100,000 tons

[david.given]

I'd actually written up a long pedanttastic post on how a ton is defined in terms of pounds and is therefore a unit of weight, while a tonne is defined in terms of kilograms and is therefore a unit of mass; but it looks like they've sneakily redefined the pound (in both the UK and the US) to be a unit of mass. The cads!

But as ton can be either 1000kg, 907kg, 1016kg, or even one of about five volumes, depending who you ask, I'd strongly recommend the metric spelling for clarity...

(It is not true I'm a card-carrying member of the Pedant's Society. It's actually made out of plastic.)