A map of the day–night contrast of the extrasolar planet HD 189733b

By Heather A. Knutson, D. Charbonneau, Lori E. Allen, Jon Fortney, E. Agol, Nicolas B. Cowan, A. Showman, Curtis S. Cooper, S. Megeath. Nature, 2007

698 citations recorded by the source corpus.

‘Hot Jupiter’ extrasolar planets are expected to be tidally locked because they are close (<0.05 astronomical units, where 1 au is the average Sun–Earth distance) to their parent stars, resulting in permanent daysides and nightsides. By observing systems where the planet and star periodically eclipse each other, several groups have been able to estimate the temperatures of the daysides of these planets. A key question is whether the atmosphere is able to transport the energy incident upon the dayside to the nightside, which will determine the temperature at different points on the planet’s surface. Here we report observations of HD 189733, the closest of these eclipsing planetary systems, over half an orbital period, from which we can construct a ‘map’ of the distribution of temperatures. We detected the increase in brightness as the dayside of the planet rotated into view. We estimate a minimum brightness temperature of 973 ± 33 K and a maximum brightness temperature of 1,212 ± 11 K at a wavelength of 8 μm, indicating that energy from the irradiated dayside is efficiently redistributed throughout the atmosphere, in contrast to a recent claim for another hot Jupiter. Our data indicate that the peak hemisphere-integrated brightness occurs 16 ± 6° before opposition, corresponding to a hotspot shifted east of the substellar point. The secondary eclipse (when the planet moves behind the star) occurs 120 ± 24 s later than predicted, which may indicate a slightly eccentric orbit.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/9125bdeace73ec9a5eb8155a3d305e462d479546

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In Astronomy and Astrophysics

1. Jon Fortney
2. N. Madhusudhan
3. D. Charbonneau
4. A. Showman
5. Sara Seager
6. J. Southworth
7. D. Deming
8. J. Winn

In Instrumentation

1. Jon Fortney
2. N. Madhusudhan
3. J. Southworth
4. D. Charbonneau
5. A. Showman
6. Sara Seager
7. J. Winn
8. H. Knutson

Citations in the corpus

• A Unified Theory for the Atmospheres of the Hot and Very Hot Jupiters: Two Classes of Irradiated Atmospheres (2007, methodology): “Very recently Knutson et al. (2007a) observed the secondary eclipse of HD 209458b in all four InfraRed Array Camera (IRAC) bands.”
• Observations of Transiting Exoplanets with the James Webb Space Telescope (JWST) (2014, background): “The amplitude of the phase curve can be compared to the depth of the secondary eclipse in order to determine how much heat transfer is occurring (Knutson et al. 2007).”
• THE FLAT TRANSMISSION SPECTRUM OF THE SUPER-EARTH GJ1214b FROM WIDE FIELD CAMERA 3 ON THE HUBBLE SPACE TELESCOPE (2011, background): “These ramps are reminiscent of those seen in highcadence Spitzer light curves at 8 and 16 µm (e.g. Deming et al. 2006; Knutson et al. 2007a; Charbonneau et al. 2008) which Agol et al. (2010) recently proposed may be due to “charge trapping” within the detector pixels.”
• STABILIZING CLOUD FEEDBACK DRAMATICALLY EXPANDS THE HABITABLE ZONE OF TIDALLY LOCKED PLANETS (2013, background): “If convective clouds occur on hot Jupiters, the interpretation of their thermal phase variations (e.g., Knutson et al. 2007) will have to be revisited.”
• THERMAL PHASE VARIATIONS OF WASP-12b: DEFYING PREDICTIONS (2011, positive): “…for non-transiting short-period planets (Cowan et al. 2007; Crossfield et al. 2010), but are most potent when combined with transit and eclipse observations for edge-on systems, because of the additional knowledge of the planet’s inclination, mass, and radius (Knutson et al. 2007, 2009a, 2009b).”
• starry: Analytic Occultation Light Curves (2018, methodology): “…map corresponding to the maximum likelihood model is plotted at the top right, showing a statistically significant eastward offset in the location of the hotspot in agreement with previous studies (Knutson et al. 2007; Agol et al. 2010; de Wit et al. 2012; Majeau et al. 2012; Rauscher et al. 2018).”
• INFRARED TRANSMISSION SPECTROSCOPY OF THE EXOPLANETS HD 209458b AND XO-1b USING THE WIDE FIELD CAMERA-3 ON THE HUBBLE SPACE TELESCOPE (2013, methodology): “For this Figure, band depth is defined as the average transit depth from 1.36-1.44µm minus the average depth from 1.27-1.30µm. squares are our reanalysis of the STIS bands defined by Knutson et al. (2007a), and the diamond is the narrow sodium band absorption from Charbonneau et al. (2002).”
• THE CLIMATE OF HD 189733b FROM FOURTEEN TRANSITS AND ECLIPSES MEASURED BY SPITZER (2010, methodology): “This measured correlation allows us to derive a better correction for the stellar variation during the observation of Knutson et al. (2007), giving us a better measurement of the planet’s phase function.”
• Stellar activity of planetary host star HD 189 733 (2008, background): “Nevertheless, Knutson et al. (2007) discussed the possibility of a weak eccentricitye cosω = 0.0010 ± 0.0002, whereω is the longitude of pericenter for HD 189733b, to explain a time delay of 150± 24 s in the photometric observations of the secondary transit.”
• Homogeneous studies of transiting extrasolar planets – I. Light-curve analyses (2008, methodology): “The method has been used before on several TEPs (e.g. Bouchy et al. 2005a; Pont et al. 2005; Gillon et al. 2007a; Knutson et al. 2007a).”
• High-precision photometry by telescope defocussing. I. The transiting planetary system WASP-5 (2009, background): “The high equilibrium temperature of WASP-5b makes the system a good candidate for detecting the secondary eclipse at phase 0.5 (e.g. Deming et al. 2005; Harrington et al. 2007; Knutson et al. 2007), which would help our understanding of the physics of the atmospheres of gas giants.”
• Exoplanet Atmospheres: Physical Processes (2010, methodology): “These properties led to the concept (Knutson et al. 2007a) that the ramp is due to charge trapping in the detector.”
• On the radiative equilibrium of irradiated planetary atmospheres (2010, background): “Both were verified by observations in the infrared (Harrington et al. 2006; Knutson et al. 2007a).”
• Transit spectrophotometry of the exoplanet HD189733b. I. Searching for water but finding haze with HST NICMOS (2009, background): “Spitzer antitransit measurements have shown efficient heat redistribution, measuring the planet’s temperature profile from orbital phase curves (Knutson et al. 2007, 2009) and a definitive detection of atmospheric water from emission spectra (Grillmair et al. 2008).”
• Hubble Space Telescope transmission spectroscopy of the exoplanet HD 189733b: high‐altitude atmospheric haze in the optical and near‐ultraviolet with STIS (2011, background): “Finally, orbital phase curves can probe the global temperature distribution and study atmospheric circulation (Knutson et al. 2007a).”
• TRANSITIONS IN THE CLOUD COMPOSITION OF HOT JUPITERS (2016, background): “Fast eastward winds and planetary scale waves shift the temperatures eastward: west of the substellar point the atmosphere is cooler than east of it (Showman & Guillot 2002; Knutson et al. 2007).”
• DISEQUILIBRIUM CARBON, OXYGEN, AND NITROGEN CHEMISTRY IN THE ATMOSPHERES OF HD 189733b AND HD 209458b (2011, methodology): “…for inferring properties of both the planet and its host star (e.g., Charbonneau et al. 2000, 2002, 2005; Henry et al. 2000; Seager & Sasselov 2000; Brown 2001; Brown et al. 2001; Burrows et al. 2001; Hubbard et al. 2001; Deming et al. 2005b; Knutson et al. 2007, 2009; Madhusudhan & Seager 2009).”
• Optimal estimation retrievals of the atmospheric structure and composition of HD 189733b from secondary eclipse spectroscopy (2011, methodology): “…(∼1100 K) of the dayside hemisphere at pressure levels above the troposphere (100 mbar) is possibly maintained by efficient energy re-distribution throughout the whole planetsystem as suggested by the observations in theSpitzer IRAC channels (Knutson et al. 2007; Charbonneau et al. 2008).”
• MULTIWAVELENGTH CONSTRAINTS ON THE DAY–NIGHT CIRCULATION PATTERNS OF HD 189733b (2008, methodology): “This planet has a mass of 1.14±0.06 MJup (Bouchy et al. 2005; Torres et al. 2008) and a radius of 1.138±0.027RJup (Bakos et al. 2006b; Winn et al. 2007a; Knutson et al. 2007; Pont et al. 2007, 2008; Torres et al. 2008), and orbits a K0V primary with a V -band magnitude of 7.67 (Bouchy et al. 2005).”