Albedo, internal heat, and energy balance of Jupiter: Preliminary results of the Voyager Infrared Investigation

Hanel, Rudolf; Conrath, B. J.; Herath, L.; Kunde, V. G.; Pirraglia, J. A.

doi:10.1029/ja086ia10p08705

Cited by 133 publications

(116 citation statements)

References 29 publications

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“…In addition, for the case of planets in our own solar system, the gap between them and brown dwarfs is substantial. Jupiter (124 K; Hanel et al 1981) is much cooler than the coldest known brown dwarf WISE J085510.83−071442.5 (≈250 K; Luhman 2014), which is itself much cooler than the next coolest known brown dwarfs at ≈350-400 K (Luhman et al 2012;Dupuy & Kraus 2013). This range of effective temperature corresponds to a factor of ∼100 in luminosity.…”

Section: Introductionmentioning

confidence: 99%

The Hawaii Infrared Parallax Program. Ii. Young Ultracool Field Dwarfs* †

Liu

Dupuy

Allers

2016

ApJ

233

320

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We present a large, uniform analysis of young (≈10-150 Myr) ultracool dwarfs, based on new high-precision infrared (IR) parallaxes for 68 objects. We find that low-gravity (vl-g) late-M and L dwarfs form a continuous sequence in IR color-magnitude diagrams, separate from the field population and from current theoretical models. These vl-g objects also appear distinct from young substellar (brown dwarf and exoplanet) companions, suggesting the two populations may have a different range of physical properties. In contrast, at the L/T transition, young, old, and spectrally peculiar objects all span a relatively narrow range in near-IR absolute magnitudes. At a given spectral type, the IR absolute magnitudes of young objects can be offset from ordinary field dwarfs, with the largest offsets occurring in the Y and J bands for late-M dwarfs (brighter than the field) and mid/late-L dwarfs (fainter than the field). Overall, low-gravity (vl-g) objects have the most uniform photometric behavior while intermediate-gravity (int-g) objects are more diverse, suggesting a third governing parameter beyond spectral type 1 This work is largely based on observations obtained with WIRCam, a joint project of CFHT, Taiwan, Korea, Canada, France, and the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.2 Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. -2 -and gravity class. We examine the moving group membership for all young ultracool dwarfs with parallaxes, changing the status of 23 objects (including 8 previously identified planetary-mass candidates) and fortifying the status of another 28 objects. We use our resulting age-calibrated sample to establish empirical young isochrones and show a declining frequency of vl-g objects relative to int-g objects with increasing age. Notable individual objects in our sample include high-velocity ( 100 km s −1 ) int-g objects; very red late-L dwarfs with high surface gravities; candidate disk-bearing members of the MBM20 cloud and β Pic moving group; and very young distant interlopers. Finally, we provide a comprehensive summary of the absolute magnitudes and spectral classifications of young ultracool dwarfs, using a combined sample of 102 objects found in the field and as substellar companions to young stars.Subject headings: brown dwarfs -proper motions -parallaxes -solar neighborhood IntroductionObservational studies of brown dwarfs have been inspired by two complementary perspectives. One has been the desire to expand the parameter space of classical stellar astrophysics. Brown dwarfs are t...

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Section: Introductionmentioning

confidence: 99%

The Hawaii Infrared Parallax Program. Ii. Young Ultracool Field Dwarfs* †

Liu

Dupuy

Allers

2016

ApJ

233

320

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“…The Galileo probe measured.wind speeds of 170 m/s down to -o125 km beneath the cloud tops [Atkinson et al, 1998]. Since the surface heat loss is nearly twice that received from solar insolation [Hanel et al, 1981;1983], convective heat transfer is important in the deep atmosphere of each planet [Stevenson, 1982].…”

Section: Introductionmentioning

confidence: 99%

Strong zonal winds from thermal convection in a rotating spherical shell

Aurnou

Olson

2001

Geophysical Research Letters

104

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“…The spectrum of a planet is composed mainly of reflected stellar light and thermal emission from the planet; the measurement of the energy balance is an essential parameter in quantifying the energy source of dynamical activity of the planet (stellar versus internal sources). The Voyager observations of the Giant Planets in the Solar System have allowed an accurate determination of the energy budget by measuring the Bond albedo of the planets (Jupiter: [78]; Saturn: [79]; Uranus: [123]; Neptune: [124]). EChO extends these methods to exoplanets: the reliable determination of the spectrum in reflected versus thermal range will provide a powerful tool for classifying the dynamical activity of exoplanets.…”

Section: Energy Budget: Heating and Cooling Processesmentioning

confidence: 99%

The EChO science case

et al. 2015

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The discovery of almost two thousand exoplanets has revealed an unexpectedly diverse planet population. We see gas giants in few-day orbits, whole multi-planet systems within the orbit of Mercury, and new populations of planets with masses between that of the Earth and Neptune-all unknown in the Solar System. Observations to date have shown that our Solar System is certainly not representative of the general population of planets in our Milky Way. The key science questions that urgently need addressing are therefore: What are exoplanets made of? Why are planets as they are? How do planetary systems work and what causes the exceptional diversity observed as compared to the Solar System? The EChO (Exoplanet Characterisation Observatory) space mission was conceived to take up the challenge to explain this diversity in terms of formation, evolution, internal structure and planet and atmospheric composition. This requires in-depth spectroscopic knowledge of the atmospheres of a large and well-defined planet sample for which precise physical, chemical and dynamical information can be obtained. In order to fulfil this ambitious scientific program, EChO was designed as a dedicated survey mission for transit and eclipse spectroscopy capable of observing a large, diverse and well-defined planet sample within its 4-year mission lifetime. The transit and eclipse spectroscopy method, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allows us to measure atmospheric signals from the planet at levels of at least 10 −4 relative to the star. This can only be achieved in conjunction with a carefully designed stable payload and satellite platform. It is also necessary to provide broad instantaneous wavelength coverage to detect as many molecular species as possible, to probe the thermal structure of the planetary atmospheres and to correct for the contaminating effects of the stellar photosphere. This requires wavelength coverage of at least 0.55 to 11 μm with a goal of covering from 0.4 to 16 μm. Only modest spectral resolving power is needed, with R~300 for wavelengths less than 5 μm and R~30 for wavelengths greater than this. spectroscopy technique means that no spatial resolution is required. A telescope collecting area of about 1 m 2 is sufficiently large to achieve the necessary spectro-photometric precision: for the Phase A study a 1.13 m 2 telescope, diffraction limited at 3 μm has been adopted. Placing the satellite at L2 provides a cold and stable thermal environment as well as a large field of regard to allow efficient time-critical observation of targets randomly distributed over the sky. EChO has been conceived to achieve a single goal: exoplanet spectroscopy. The spectral coverage and signal-to-noise to be achieved by EChO, thanks to its high stability and dedicated design, would be a game changer by allowing atmospheric composition to be measured with unparalleled exactness: at least a factor 10 more precise and a factor 10 to 1000 more accurate tha...

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Albedo, internal heat, and energy balance of Jupiter: Preliminary results of the Voyager Infrared Investigation

Cited by 133 publications

References 29 publications

The Hawaii Infrared Parallax Program. Ii. Young Ultracool Field Dwarfs* †

The Hawaii Infrared Parallax Program. Ii. Young Ultracool Field Dwarfs* †

Strong zonal winds from thermal convection in a rotating spherical shell

The EChO science case

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