Exoplanet albedo spectra and colors as a function of planet phase, separation, and metallicity

Details Exoplanet albedo spectra and colors as a function of planet phase, separation, and metallicity Exoplanet albedo spectra and colors as a function of planet phase, separation, and metallicity

2010-09-16

arxiv.org/abs/1009.3071v1

Astronomy and Astrophysics

Astrophysics

Earth and Planetary Astrophysics

62 pages, 19 figures, 6 tables Accepted for publication in ApJ

Scientific paper

First generation optical coronagraphic telescopes will obtain images of cool gas and ice giant exoplanets around nearby stars. The albedo spectra of exoplanets at planet-star separations larger than about 1 AU are dominated by reflected light to beyond 1 {\mu}m and are punctuated by molecular absorption features. We consider how exoplanet albedo spectra and colors vary as a function of planet-star separation, metallicity, mass, and observed phase for Jupiter and Neptune analogs from 0.35 to 1 {\mu}m. We model Jupiter analogs with 1x and 3x the solar abundance of heavy elements, and Neptune analogs with 10x and 30x. Our model planets orbit a solar analog parent star at separations of 0.8 AU, 2 AU, 5 AU, and 10 AU. We use a radiative-convective model to compute temperature-pressure profiles. The giant exoplanets are cloud-free at 0.8 AU, have H2O clouds at 2 AU, and have both NH3 and H2O clouds at 5 AU and 10 AU. For each model planet we compute moderate resolution spectra as a function of phase. The presence and structure of clouds strongly influence the spectra. Since the planet images will be unresolved, their phase may not be obvious, and multiple observations will be needed to discriminate between the effects of planet-star separation, metallicity, and phase. We consider the range of these combined effects on spectra and colors. For example, we find that the spectral influence of clouds depends more on planet-star separation and hence temperature than metallicity, and it is easier to discriminate between cloudy 1x and 3x Jupiters than between 10x and 30x Neptunes. In addition to alkalis and methane, our Jupiter models show H2O absorption features near 0.94 {\mu}m. We also predict that giant exoplanets receiving greater insolation than Jupiter will exhibit higher equator to pole temperature gradients than are found on Jupiter and thus may have differing atmospheric dynamics.

Affiliated with

Also associated with

No associations

Rating

Exoplanet albedo spectra and colors as a function of planet phase, separation, and metallicity does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Exoplanet albedo spectra and colors as a function of planet phase, separation, and metallicity, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Exoplanet albedo spectra and colors as a function of planet phase, separation, and metallicity will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-27043