Head in a Cloud

troposphere and stratosphere meet blogosphere

Head in a Cloud random header image

PATM Workshop 2007

November 14th, 2007 by Hasenkopf · No Comments

Last week, I attended a Planetary Atmospheres Workshop (PATM) in Greenbelt, MD. The conference was only two days long, but the rate of information exchange most definitely surpassed the rate at which I was able to absorb it! This was probably particularly true since I am a laboratory experimentalist, and the focus of the meeting was for planetary atmosphere modelers to convey what sorts of data they need from laboratory experimentalists. If you’re interested in the laundry list of experimental work modelers cited as necessary to improve our current understanding of planetary atmospheres – from Jovian photochemistry to exoplanet atmospheric circulation – go here for some of my (very condensed-don’t worry!) notes from the meeting. Read on for some other thoughts on the meeting.

While at the conference, it struck me that perhaps one of the most useful aspects about attending these sorts of workshops is that it makes you realize how much everyone’s research actually fits together. That’s a fairly obvious statement, however, I know that I, for one, am usually lost in the intricacies and never-ending details of my own very specific, narrowly-focused research, and lose sight of the big picture sometimes. Titan, Earth, Mars, and Venus’ atmospheric dynamics/properties can all be viewed as special cases of scenarios with slightly differing initial conditions. True understanding of planetary atmospheres arises when we understand how tweaking those initial conditions and compositions affect the end-resulting planet. Comparing and contrasting, say, the number of cloud condensation nuclei produced from water-waves breaking on Earth with the number that may be produced by hydrocarbon-waves breaking on the more highly pressurized surface of Titan helps us depict a more general picture of cloud formation on rocky planets with substantial atmospheres (“substantial” meaning that atmospheres consisting of transient gases kicked off from sputtering, sublimation, etc. processes are not counted).

Pushing the bounds of just how general we can conceptualize planetary atmospheres (rocky or gaseous), exoplanet research – dealing with planets outside of our solar system- was a hot topic, and discussed extensively in a presentation by Sarah Seager. Many of the exoplanets that have been found so far are tidally-locked to their parent star. This means that the same hemisphere always faces its parent star. Some of the planets appear to have a huge temperature gradient from light hemisphere to dark hemisphere, while others do not (i.e. extrasolar planet HD 189733bf). One thought as to why some of the planets don’t have a huge temperature gradient is that there are very fast winds, redistributing heat on the planet. This is similar to what occurs on Venus, which has less than 1K diurnal temperature variation and a superrotational atmosphere. However, it is unclear if wind re-distribution can totally account for the lack of temperature difference or if another mechanism is also at play (see Knutson et al., 2007 Nature letter for more info).

Another seemingly off-the-wall conclusion from studying light curves of these planets transiting their parent star is that some of the really hot planets (i.e. HD149026b which has been modeled to have temperatures of ~2100K) may have atmospheres of vaporized titanium oxide (TiO) or vanadium oxide (VO). These highly absorbing compounds may create temperature inversions in the atmosphere, much like Earth’s ozone-containing stratosphere. (To read more about HD149026b, dubbed the hottest planet”, go to this June 2007 Nature letter by Harrington, et al.

That and a lot more was covered at the conference. If you’re interested, check out the other abstracts linked to this page. Also, something to look forward to in the next few days: Mark Seefeldt of CU-Boulder will be posting an article about finding a job in academia after grad school!

Tags: planetary atmospheres

0 responses so far ↓

  • There are no comments yet...Kick things off by filling out the form below.

Leave a Comment