Gliese 1214 b

The latest from Mr Thomas – Distant Watery Planet Looks Young – is perhaps of some note.

You’ll see why in a minute. First, here’s how he begins:

A new analysis detailing the atmosphere of GJ 1214b—a planet located about 40 light years from earth and one that researchers have studied for about a decade—appeared in the March issue of The Astrophysical Journal. According to Harvard-Smithsonian Center for Astrophysics scientist and lead author Zachory Berta, “GJ1214b is like no planet we know of. A huge fraction of its mass is made up of water.”

You probably heard the news reports. That quote is from this article; B.T.’s other source in this DpSU is The Atmospheric Chemistry of GJ 1214b: Photochemistry and Clouds (the arXiv link is here).

Brian goes on to give a (very) brief explanation of the situation. We have in Gliese 1214 b a planet 7 times more massive than Earth orbiting a red dwarf around a 70th of the distance from it that we do from our Sun. It’s also more than 200 degrees Celsius hotter, and has a rather steamy atmosphere. With that explained we can skip the next two paragraphs in this five paragraph article, right to the punchline:

A 2011 study of the GJ 1214b atmosphere reported that the planet orbits “a relatively bright” red-dwarf.

That’s a rather…odd line, which Thomas goes so far as to source with the only reference to the 2012 study in his article. But that’s not what I’m after – this is:

How long would it take for the solar wind from a bright star to blow away water vapor from such a nearby planet? And how long would it take for the sheer heat of GJ 1214b to eject water vapor from its atmosphere into nearby space, especially considering its fast orbit?

I don’t know Brian – do you? (Do any of my readers know for sure, come to think of it?)

The scientific literature typically does not ask questions like these. If planet GJ 1214b is as watery as astronomers say, then it presents a challenging puzzle for those determined to assign it an evolutionary age of millions or billions of years.

…And that’s it. If Brian does know, he’s not telling. Perhaps it’s time to do some research.

Not much, mind you: the first thing that came up (for me) in a google search of “red dwarf solar wind” was Living with a Red Dwarf from Astrobiology Magazine. As you can probably tell the article is on this very subject and more. To summarise the useful points:

• Red dwarfs are now considered much more hospitable for life than they used to be.
• UV light and Solar Flares can indeed strip off the atmosphere…if nothing is there to protect it.
• But this is largely a feature of younger red dwarfs – after a few short billion years they settle down and will shine constantly for many, many billions of years longer. All you need to do is hold on for that long.
• A magnetic field like ours would be sufficient to do that.
• But if a planet is orbiting a red dwarf anywhere near the habitable zone it’s probably close enough to be tidally locked, meaning its core will rotate slower. Slower rotation will lead to a lesser magnetic field which could even shut off entirely.
• To counter this, the planet in question needs to be bigger/more massive than Earth: a planet 2-10 times more massive than Earth could well be able to maintain a magnetic field big enough, long enough to protect its atmosphere the necessary 3 billion years or so.

Now as I’ve already said, Gliese 1214 b is seven times more massive than Earth. And the Astrobiology article does rather suggest that Brian’s claim that “[t]he scientific literature typically does not ask questions like these” is very much incorrect.

So why is this particular DpSU ‘notable’ in my eyes? Well, we have here fairly strong evidence that B.T. wont even google before he makes statements like this. As such, the hope for me when I write this blog is that when they read them at least some of his readers do.