Photometric Light Curves and Polarization of Close-in Extrasolar Giant Planets

By Sara Seager, B. Whitney, D. I. F. A. Study, Space Telescope Science Institute, Harvard University. 2000

278 citations recorded by the source corpus.

The close-in extrasolar giant planets (CEGPs), ≲0.05 AU from their parent stars, may have a large component of optically reflected light. We present theoretical optical photometric light curves and polarization curves for the CEGP systems from reflected planetary light. Different particle sizes of three condensates are considered. In the most reflective case, the variability is ≈100 μmag, which will be easily detectable by the upcoming satellite missions Microvariability and Oscillations of Stars (MOST), COROT, and Measuring Oscillations in Nearby Stars (MONS), and possibly from the ground in the near future. The least reflective case is caused by small, highly absorbing grains such as solid Fe, with variation of much less than 1 μmag. Polarization for all cases is lower than current detectability limits. We also discuss the temperature-pressure profiles and resulting emergent spectra of the CEGP atmospheres. We discuss the observational results of τ Boo b by Cameron et al. and Charbonneau et al. in context of our model results. The predictions—the shape and magnitude of the light curves and polarization curves—are highly dependent on the sizes and types of condensates present in the planetary atmosphere.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/6a4e3005556de2aa3813d356df225dd8d2ddae50

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. Jon Fortney
2. N. Madhusudhan
3. A. Showman
4. M. Marley
5. Sara Seager
6. H. Knutson
7. D. Deming
8. V. Parmentier

Citations in the corpus

• A Unified Theory for the Atmospheres of the Hot and Very Hot Jupiters: Two Classes of Irradiated Atmospheres (2007, background): “While Na and K lead to strong absorption in optical wavelengths, causing extremely dark atmospheres in the optical (Sudarsky et al. 2000; Seager et al. 2000), at 0.45 and 4.4 mbar, respectively, 4 and 1.5 times more incident stellar is actually absorbed by H2O than by alkalis.”
• Irradiated planets (2001, methodology): “Recent works include models of 51 Peg B (Goukenleuque et al. 2000), HD209458a (Seager & Sasselov 2000) and a study of EGP photometric and polarization properties (Seager et al. 2000).”
• Periodic Flux Variability of Stars due to the Reflex Doppler Effect Induced by Planetary Companions (2003, background): “…sphere scattering represents the upper limit to the amount of reflected light for a wide range of reasonable models, although larger scattered light signals are possible near zero phase angle (when the planet is at superior conjunction) due to, e.g. strong back-scattering (Seager et al. 2000).”
• DISEQUILIBRIUM CARBON, OXYGEN, AND NITROGEN CHEMISTRY IN THE ATMOSPHERES OF HD 189733b AND HD 209458b (2011, background): “Thermochemical equilibrium is assumed for most models (e.g., Burrows & Sharp 1999; Seager et al. 2000; Lodders & Fegley 2002; Sharp & Burrows 2007; Burrows et al. 2007, 2008; Fortney et al. 2008a; Visscher et al. 2010a), although potential departures from equilibrium are sometimes explored through…”
• THE ATMOSPHERIC SIGNATURES OF SUPER-EARTHS: HOW TO DISTINGUISH BETWEEN HYDROGEN-RICH AND HYDROGEN-POOR ATMOSPHERES (2008, methodology): “We determine molecular opacities following the procedure outlined in Seager et al. (2000) for wavelengths ranging from 0.1 to 100 µm.”
• Magnetic activity in the photosphere of CoRoT-Exo-2a. Active longitudes and short-term spot cycle in (2008, methodology): “The light reflected by the planet reaches 1.0 × 10−4 in relative flux units if we adopt a geometric albedo of 13 percent, that is quite high in view of the hot Jupiter atmospheric models computed by, e.g., Sudarsky et al. (2000), Seager et al. (2000), Burrows et al. (2008).”
• Exoplanet Atmospheres: Physical Processes (2010, background): “A tantalizing claimed detection of polarization from the hot Jupiter HD189733b (Berdygunia et al. 2008) reported polarization levels that exceeded theoretical expectations (Seager et al. 2000) by an uncomfortable margin.”
• INFERENCE OF INHOMOGENEOUS CLOUDS IN AN EXOPLANET ATMOSPHERE (2013, background): “…long suggested that clouds would also play a strong role in shaping the spectra of exoplanets in general (Barman et al. 2001; Marley et al. 2013), and hot Jupiters in particular (Marley et al. 1999; Seager et al. 2000; Sudarsky et al. 2000) before having been actually reported (Evans et al. 2013).”
• Aeronomy of extra-solar giant planets at small orbital distances (2003, background): “Yet, the skin temperature of an EGP at 0.05 AU expected to be approximately 750 K(Goukenleuque et al. 2000; Seager et al., 2000; Sudarsky et al., 2003)and the gravitational acceleration of HD209458b is∼ 900 cm s−2, implying a scale height of∼ 700 km, a value far too sma to explain the observed H…”
• THE STATISTICS OF ALBEDO AND HEAT RECIRCULATION ON HOT EXOPLANETS (2009, background): “For a planet whose albedo is dominated by clouds (as opposed to Rayleigh scattering) the albedo depends on the composition and size of cloud particles (Seager et al. 2000).”
• EXOPLANET ALBEDO SPECTRA AND COLORS AS A FUNCTION OF PLANET PHASE, SEPARATION, AND METALLICITY (2010, methodology): “We build on prior work (Marley et al. 1999a; Sudarsky et al. 2000; Seager et al. 2000; Ford et al. 2001; Burrows et al. 2004; Burrows 2005; Dyudina et al. 2005; Sudarsky et al. 2003, 2005) by developing additional model capabilities for generating albedo spectra at different phases and by examining…”
• Analytic Light Curves for Planetary Transit Searches (2002, background): “For treatment of subtler effects during planetary transitsee Seager et al. (2000); Seager & Sasselov (2000); Hubbard et al. (2001); Hui & Seager (2002).”
• The Changing Face of the Extrasolar Giant Planet HD 209458b (2002, background): “Similarly, condensates, such as MgSiO3 (enstatite), may also be found inside the diffuse hot spots, where temperatures may be high enough (Sudarsky, Burrows, & Pinto 2000; Seager et al. 2000).”