The theory of brown dwarfs and extrasolar giant planets ● Burrows, A.; Hubbard, W. B.; Lunine, J. I.; Liebert, J. ● The University of Arizona ● Reviews of Modern Physics, July

I. Introduction: A new frontier for stellar and planetary science ● First unimpeachble expample of brown dwarf: Gliese 229B ● The same day, the first extrasolar giant planet discovered: 51 Pegasi b ● 50 Extrasolar planets discovered (417 planets now) ● 150 brown dwarfs known (624 in 2007)

II. An overview of the theory of substellar-mass objects Deuterium-burning limit Distinction between brown dwarfs and planets are based upon mode of formation. Main-sequence edge

II. An overview of the theory of substellar-mass objects

III. The edge of the Main Sequence

IV. Deuterium and Lithium burning

M↑M↑ hydride (FeH, CrH, MgH, CaH) alkali (Na I, K I, Cs I, Rb I) absorption bands H 2 O and CO Absence of H lines TiO and VO Absoption bands CH 4

V. Atmospheric Chemistry and Abundances Iso-T eff Deuterium burning consequence

V. Atmospheric Chemistry and Abundances

NH 3 to N 2 NH 4 to CO

V. Atmospheric Chemistry and Abundances Gliese 229B model Formation of chlorides, hydroxides, and sulfides

V. Atmospheric Chemistry and Abundances ● Photosphere position ―[X alcali Cl]/[X alcali ] = 1 ‐‐‑ [CO]/[CH 4 ] = 1 and [NH 3 ]/[N 2 ] = 1 Others are condensation lines. Clouds: - smooth spectral features - affect the reflection spectra and albedos

VI. Opacities

VII. Brown Dwarf, L Dwarf, and T Dwarf Colors and Spectra

The spikes at Z, J, H, and K are due to the holes the the water absorption spectrum

VII. Brown Dwarf, L Dwarf, and T Dwarf Colors and Spectra ‒‑‐ Black body for T of 290, 190, 160,and 103K Superposed are the sensitivities for many instruments The most sensible are Gemini/SOFIA (light green and solid blue) and NICMOS (black dots)

VII. Brown Dwarf, L Dwarf, and T Dwarf Colors and Spectra - The composition-weighted sum of the absorption cross sections M-Representative – red due to TiO and VO T-Representative – blue due to H 2 O after TiO, VO, and silicates have rained out

VII. Brown Dwarf, L Dwarf, and T Dwarf Colors and Spectra L dwafs: 1300 < Teff < 2100 TiO and VO depletion appearance of FeH and CrH Grow in strength of K, Li, Cs, Rb, and Na

IX. New Worlds: Extrasolar Giant Planets ● Other than radial velocity technics (2003): ● Astrometric techniques ● Nulling interferometry ● Spectral deconvolution ● Photometric deconvolution ● Turn out to be: ● Pulsar timing ● Transit ● Gravitational lensig ● Directly image (infrared and visible)

X. Irradiation, Transits, and Spectra of Close-in Extrasolar Giant Planets I – 0.69M J in isolation A – T eff ~ 1600K B – T eff ~ 1200K C – T eff ~ 1750K, 7 M J D – T eff ~ 1600K, 10M J Observational age-R

XI. The Giant Planets of the Solar System 2 phases He-rich He-poor predicted by Stevenson and Salpeter (1997) Pfaffenzeller (1995) Brown dwarfs in early and advanced ages ‑ ‐ Evolutionary trajectory of its central pressure

XII. Conclusions