Detection of Exomoons & Exorings Orbiting Exoplanets · 2020-02-04 · Detection of Exomoons &...
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Detection of Exomoons & Exorings Orbiting Exoplanets Apurva V. Oza 1* , Sebastien Charnoz 2 , and Robert E. Johnson 3,4 Concept • Rocky exomoons should be abundant in the galaxy, however small, thus activity is needed. • Signatures of activity may already exist in close- in gas giant transmission Na & K spectra. • Outgassing moon models are consistent with plasma-driven Na signatures in several systems. What is an exo-Io? Extrasolar satellites or ring material that are features generally too small to be directly detected at present by nominal searches can in principal be detected using our understanding of solar system observations (e.g., Johnson & Huggins 2006; Charnoz et al 2018; Oza et al. 2019). For instance, like the most active body in the solar system, Io, we describe how alkali gas transmission spectra could be a signature of the geological activity venting from an exo-Io orbiting a hot Jupiter. Analyzing a number of close-in gas giants hosting robust alkaline detections, we confirm that an Io-sized satellite can be stable against orbital decay with the tidal energy driving mass-loss rates order of magnitude higher than Io’s supply to Jupiter’s Na exosphere (Cassidy et al. 2009; Oza et al 2019) and that a debris ring could produce sufficient opacity (Charnoz & Oza in prep). The consequence is that, for instance, potential exo-Io column densities can be more than sufficient to account for the observed equivalent width of an exoplanet transmission spectrum with the high- altitude Na observations at WASP-49b used as an example (Oza et al. 2019). Therefore, comparative planetology, using the solar system observations to infer the presence of satellites or rings, can be critical (e.g, Johnson & Huggins 2006). Abstract Sodium Supply (Physical Process) Mass Loss Rate [kg/s] Column Density [Na cm -2 ] Plasma-Driven Escape (Atmospheric sputtering) 10 4.3 +/- 1.5 10 9.9 +/- 1.5 Thermal Escape (Surface-heating) 10 2.5 +/- 0.1 10 8.1 +/- 0.1 Energy-Limited Escape Moon 10 5.1 +/- 0.3 10 10.7 +/- 0.3 Energy-Limited Escape Planet 10 1.4 +/- 0.3 10 7 +/- 0.3 Stellar and planetary tides keep Io-sized satellites stable against orbital decay and drive extreme volcanism I. Extreme Tidal Heating Extreme volcanism leads to an alkaline atmosphere subject to thermal evaporation and non-thermal mass loss II. Extreme Mass Loss Alkaline mass loss is directly fed to gas giant Hill sphere, in Jupiter’s case dominating the sodium. III. Spectroscopic Signature Jupiter’s Atmospheric Sodium • Incluez les résultats de vos expériences • Résultat 2 • Résultat 3 Proof of concept: WASP 49-b I Observed column density: N Na ~ 10 10.7 Na cm -2 • Bref résumé de ce que vous avez découvert sur la base des résultats • Indiquez et expliquez si les données étayent ou non votre hypothèse QR CODE & REFERENCES • Oza et al. 2019, Sodium and Potassium Signatures of Volcanic Satellites Orbiting Close-in Gas Giant Exoplanets, ApJ. • Charnoz et al. 2018, The Origin of Planetary Ring Systems. In M. Tiscareno & C. Murray (Eds.), Planetary Ring Systems: Properties, Structure, and Evolution. Cambridge: Cambridge University Press. • Johnson & Huggins 2006, Toroidal Atmospheres Around Extrasolar Planets, PASP. • Cassidy et al. 2009, Massive Satellites of Close-in Gas Giant Exoplanets, ApJ 1 Physikalisches Institut, Universität Bern, Bern, Switzerland, 2 IPGP, Sorbonne Universités, Paris, France, 3 Engineering Physics, University of Virginia, Charlottesville, VA 22903, USA, 4 Physics, New York University, 4 Washington Place, NY 10003, USA, Jupiter’s Exospheric Sodium Paper Link: https://tinyurl.com/exoio-paper *[email protected]
Transcript of Detection of Exomoons & Exorings Orbiting Exoplanets · 2020-02-04 · Detection of Exomoons &...
Detection of Exomoons & Exorings Orbiting Exoplanets
Apurva V. Oza1*, Sebastien Charnoz2, and Robert E. Johnson3,4
Concept
• Rocky exomoons should be abundant in the galaxy, however small, thus activity is needed.
• Signatures of activity may already exist in close-in gas giant transmission Na & K spectra.
• Outgassing moon models are consistent with plasma-driven Na signatures in several systems.
What is an exo-Io?
Extrasolar satellites or ring material that are features generally too small to be directly detected at present by nominal searches can in principal be detected using our understanding of solar system observations (e.g., Johnson & Huggins 2006; Charnoz et al 2018; Oza et al. 2019). For instance, like the most active body in the solar system, Io, we describe how alkali gas transmission spectra could be a signature of the geological activity venting from an exo-Io orbiting a hot Jupiter. Analyzing a number of close-in gas giants hosting robust alkaline detections, we confirm that an Io-sized satellite can be stable against orbital decay with the tidal energy driving mass-loss rates order of magnitude higher than Io’s supply to Jupiter’s Na exosphere (Cassidy et al. 2009; Oza et al 2019) and that a debris ring could produce sufficient opacity (Charnoz & Oza in prep). The consequence is that, for instance, potential exo-Io column densities can be more than sufficient to account for the observed equivalent width of an exoplanet transmission spectrum with the high-altitude Na observations at WASP-49b used as an example (Oza et al. 2019). Therefore, comparative planetology, using the solar system observations to infer the presence of satellites or rings, can be critical (e.g, Johnson & Huggins 2006).
Abstract
Sodium Supply
(Physical Process)Mass Loss Rate
[kg/s]Column Density
[Na cm-2]Plasma-Driven Escape
(Atmospheric sputtering) 104.3 +/- 1.5109.9 +/- 1.5
Thermal Escape
(Surface-heating)102.5 +/- 0.1 108.1 +/- 0.1
Energy-Limited Escape
Moon105.1 +/- 0.3 1010.7 +/- 0.3
Energy-Limited Escape Planet
101.4 +/- 0.3 107 +/- 0.3
Stellar and planetary tides keep Io-sized satellites stable against orbital decay and drive extreme volcanism
I. Extreme Tidal Heating
Extreme volcanism leads to an alkaline atmosphere subject to thermal evaporation and non-thermal mass loss
II. Extreme Mass Loss
Alkaline mass loss is directly fed to gas giant Hill sphere, in Jupiter’s case dominating the sodium.
III. Spectroscopic Signature
Jupiter’s Atmospheric Sodium
• Incluez les résultats de vos expériences • Résultat 2 • Résultat 3
Proof of concept: WASP 49-b I Observed column density: NNa ~ 1010.7 Na cm-2
• Bref résumé de ce que vous avez découvert sur la base des résultats
• Indiquez et expliquez si les données étayent ou non votre hypothèse
QR CODE & REFERENCES
• Oza et al. 2019, Sodium and Potassium Signatures of Volcanic Satellites Orbiting Close-in Gas Giant Exoplanets, ApJ.
• Charnoz et al. 2018, The Origin of Planetary Ring Systems. In M. Tiscareno & C. Murray (Eds.), Planetary Ring Systems: Properties, Structure, and Evolution. Cambridge: Cambridge University Press.
• Johnson & Huggins 2006, Toroidal Atmospheres Around Extrasolar Planets, PASP.
• Cassidy et al. 2009, Massive Satellites of Close-in Gas Giant Exoplanets, ApJ
1Physikalisches Institut, Universität Bern, Bern, Switzerland, 2 IPGP, Sorbonne Universités, Paris, France, 3Engineering Physics, University of Virginia, Charlottesville, VA 22903, USA, 4Physics, New York University, 4 Washington Place, NY 10003, USA,
Jupiter’s Exospheric Sodium
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Paper Link: https://tinyurl.com/exoio-paper *[email protected]
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