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Meteorologies of brown dwarfs and ex...

Cooper, Curtis Steven.

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Meteorologies of brown dwarfs and extrasolar giant planets.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Meteorologies of brown dwarfs and extrasolar giant planets./
Author:	Cooper, Curtis Steven.
Description:	138 p.
Notes:	Adviser: Adam P. Showman.
Contained By:	Dissertation Abstracts International67-02B.
Subject:	Physics, Astronomy and Astrophysics. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3207854
ISBN:	9780542554001

Meteorologies of brown dwarfs and extrasolar giant planets.
Cooper, Curtis Steven.

Meteorologies of brown dwarfs and extrasolar giant planets. - 138 p.

Adviser: Adam P. Showman.

Thesis (Ph.D.)--The University of Arizona, 2006.

This dissertation explores the consequences of atmospheric dynamics for observations of substellar mass objects (SMOs). Discussed first is the growth of cloud particles of various compositions in brown dwarfs of different surface gravities and effective temperatures. The structure of these objects is calculated with a one-dimensional radiative transfer model. To determine particle sizes, the timescales for microphysical growth processes, including nucleation, coagulation, and coalescence, are compared to the timescale for gravitational sedimentation. The model also allows for sustained uplifting of condensable vapor in convective regions. The results show that particle sizes vary greatly over the range of objects studied. In most cases, clouds on brown dwarfs do not dominate the opacity. Rather, they smooth the emergent spectrum and partially redistribute the radiative energy. The focus then shifts to extrasolar giant planets (EGPs). Results are presented from a three-dimensional model of atmospheric dynamics on the transiting Jupiter-like planet HD 209458b. As a close-in orbiter (known as a "roaster"), HD 209458b is super-heated on its dayside. Due to tidal locking of the interior, the dayside hemisphere faces the star in perpetuity, which leads to very different dynamics than is seen on Jupiter. The flow is characterized by an eastward supersonic jet (u &sim; 4 km s-1) extending from the equator to the mid-latitudes. Temperature contrasts are &sim;500 K at the photosphere. At 220 mbar, winds blow the hottest regions downstream from the substellar point by &sim;60°, with direct implications for the infrared light curve. These simulations are extended to the study of carbon chemistry in HD 209458b's atmosphere by coupling the CO/CH4 reaction kinetics to the dynamics. Disequilibrium results from slow reaction rates at low temperatures and pressures. Effective vertical quenching near the &sim;3 bar level leads to uniformly high concentrations of CO at the photosphere, even in cool regions where CH4 is strongly favored thermodynamically. Observations are underway to detect these signatures of meteorology on HD 209458b and similar planets.

ISBN: 9780542554001Subjects--Topical Terms:

1019521
Physics, Astronomy and Astrophysics.

Meteorologies of brown dwarfs and extrasolar giant planets.
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020 $a 9780542554001
035 $a (UMI)AAI3207854
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040 $a UMI $c UMI
100 1 $a Cooper, Curtis Steven. $3 1271975
245 1 0 $a Meteorologies of brown dwarfs and extrasolar giant planets.
300 $a 138 p.
500 $a Adviser: Adam P. Showman.
500 $a Source: Dissertation Abstracts International, Volume: 67-02, Section: B, page: 0937.
502 $a Thesis (Ph.D.)--The University of Arizona, 2006.
520 $a This dissertation explores the consequences of atmospheric dynamics for observations of substellar mass objects (SMOs). Discussed first is the growth of cloud particles of various compositions in brown dwarfs of different surface gravities and effective temperatures. The structure of these objects is calculated with a one-dimensional radiative transfer model. To determine particle sizes, the timescales for microphysical growth processes, including nucleation, coagulation, and coalescence, are compared to the timescale for gravitational sedimentation. The model also allows for sustained uplifting of condensable vapor in convective regions. The results show that particle sizes vary greatly over the range of objects studied. In most cases, clouds on brown dwarfs do not dominate the opacity. Rather, they smooth the emergent spectrum and partially redistribute the radiative energy. The focus then shifts to extrasolar giant planets (EGPs). Results are presented from a three-dimensional model of atmospheric dynamics on the transiting Jupiter-like planet HD 209458b. As a close-in orbiter (known as a "roaster"), HD 209458b is super-heated on its dayside. Due to tidal locking of the interior, the dayside hemisphere faces the star in perpetuity, which leads to very different dynamics than is seen on Jupiter. The flow is characterized by an eastward supersonic jet (u &sim; 4 km s-1) extending from the equator to the mid-latitudes. Temperature contrasts are &sim;500 K at the photosphere. At 220 mbar, winds blow the hottest regions downstream from the substellar point by &sim;60°, with direct implications for the infrared light curve. These simulations are extended to the study of carbon chemistry in HD 209458b's atmosphere by coupling the CO/CH4 reaction kinetics to the dynamics. Disequilibrium results from slow reaction rates at low temperatures and pressures. Effective vertical quenching near the &sim;3 bar level leads to uniformly high concentrations of CO at the photosphere, even in cool regions where CH4 is strongly favored thermodynamically. Observations are underway to detect these signatures of meteorology on HD 209458b and similar planets.
590 $a School code: 0009.
650 4 $a Physics, Astronomy and Astrophysics. $3 1019521
690 $a 0606
710 2 $a The University of Arizona. $3 1017508
773 0 $t Dissertation Abstracts International $g 67-02B.
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790 1 0 $a Showman, Adam P., $e advisor
791 $a Ph.D.
792 $a 2006
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3207854