HR: 1330h
AN: A12A-0074 [PDF]
TI: A Comparative Study of Photochemistry in the Atmospheres of an Extrasolar
AU: Liang, M
EM: mcl@gps.caltech.edu
AF: Caltech, Caltech 150-21
1201 E. California Blvd., Pasadena, CA 91125 United States
AU: Parkinson, C D
EM: cdp@gps.caltech.edu
AF: Caltech, Caltech 150-21
1201 E. California Blvd., Pasadena, CA 91125 United States
AU: Lee, A Y
EM: ytl@gps.caltech.edu
AF: Caltech, Caltech 150-21
1201 E. California Blvd., Pasadena, CA 91125 United States
AU: * Yung, Y
EM: yly@gps.caltech.edu
AF: Caltech, Caltech 150-21
1201 E. California Blvd., Pasadena, CA 91125 United States
AU: Seager, S
EM: seager@dtm.ciw.edu
AF: Carnegie, 5241 Broad Branch Rd., NW Washington, DC 20015 United States
AB:
Since the discovery of the first extrasolar planet 51 Peg b (Mayor \& Queloz 1995), the formation and evolution of planetary
systems have been intensively studied. Most of the known planets have masses similar to the Jupiter and some of them are
orbiting close to the central stars at $< 0.05$ AU. These "hot jupiters" reside in an irradiated environment much more
intense than that for our solar systemÝs giant planets. Using the one-dimensional Caltech/JPL KINETICS model, we have
simulated the atmospheric photochemical processes of a "hot jupiter". Unlike solar jovian planets, OH and O radicals are more
prevalent, driving the chemical reactions in this "hot jupiter". The main results are (a) the atomic hydrogen abundance is
1000 times greater than that of Jupiter and is primarily formed by OH radicals produced in the photolysis of H$_2$O and
subsequent reaction of OH + H$_2$, and (b) hydrocarbon formation is initiated by the downward flux of C atoms produced by the
photolysis of CO in the upper atmosphere, unlike the colder jovian planets which derive their hydrocarbons from
photodissociation of CH$_4$ and subsequent reactions of the products. Hydrocarbon abundances are many orders of magnitude
less than those of Jupiter, implying the haze formation is probably insignificant in affecting the optical spectrum/albedo.
DE: 0317 Chemical kinetic and photochemical properties
DE: 0343 Planetary atmospheres (5405, 5407, 5409, 5704, 5705, 5707)
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting