Morphology of Hydrodynamic Winds: A Study of Planetary Winds in Stellar Environments

Abstract

Bathed in intense ionizing radiation, close-in gaseous planets undergo hydrodynamic atmospheric escape, which ejects the upper extent of their atmospheres into the interplanetary medium. Ultraviolet detections of escaping gas around transiting planets corroborate such a framework. Exposed to the stellar environment, the outflow is shaped by its interaction with the stellar wind and by the planet's orbit. We model these effects using Athena to perform 3-D radiative-hydrodynamic simulations of tidally-locked hydrogen atmospheres receiving large amounts of ionizing extreme-ultraviolet flux in various stellar environments for the low-magnetic-field case. Through a step-by-step exploration of orbital and stellar wind effects on the planetary outflow, we find three structurally distinct stellar wind regimes: weak, intermediate, and strong. We perform synthetic Lyman-$\alpha$ observations and find unique observational signatures for each regime. A weak stellar wind$\text{—}$which cannot confine the planetary outflow, leading to a torus of material around the star$\text{—}$has a pre-transit, red-shifted dayside arm and a slightly redward-skewed spectrum during transit. The intermediate regime truncates the dayside outflow at large distances from the planet and causes periodic disruptions of the outflow, producing observational signatures that mimic a double transit. The first of these dips is blue-shifted and precedes the optical transit. Finally, strong stellar winds completely confine the outflow into a cometary tail and accelerate the outflow outwards, producing large blue-shifted signals post-transit. Across all three regimes, large signals occur far outside of transit, offering motivation to continue ultraviolet observations outside of direct transit.

arXiv comment33 pages, 21 figures (7 of which have embedded movies viewable with Adobe Acrobat Pro), Submitted to ApJ

References in corpus (45)

• Atomic Data for Astrophysics. II. New Analytic Fits for Photoionization Cross Sections of Atoms and Ions
• The California-Kepler Survey. III. A Gap in the Radius Distribution of Small Planets
• A Multi-Code Analysis Toolkit for Astrophysical Simulation Data
• Athena: A New Code for Astrophysical MHD
• Kepler planets: a tale of evaporation
• Theoretical Transmission Spectra During Extrasolar Giant Planet Transits
• Atmospheric Escape from Hot Jupiters
• Detection of oxygen and carbon in the hydrodynamically escaping atmosphere of the extrasolar planet HD209458b
• A giant comet-like cloud of hydrogen escaping the warm Neptune-mass exoplanet GJ 436b
• The Role of Core Mass in Controlling Evaporation: the Kepler Radius Distribution and the Kepler-36 Density Dichotomy
• Helium in the eroding atmosphere of an exoplanet
• Evaporation of the planet HD189733b observed in HI Lyman-alpha
• Observations of Mass Loss from the Transiting Exoplanet HD 209458b
• Lyman-$\alpha$ Transit Spectroscopy and the Neutral Hydrogen Tail of the Hot Neptune GJ436b
• A New Window into Escaping Exoplanet Atmospheres: 10830 Å Line of Helium
• Energetic neutral atoms as the explanation for the high velocity hydrogen around HD 209458b
• An evaporating planet in the wind: stellar wind interactions with the radiatively braked exosphere of GJ436 b
• Hint of a transiting extended atmosphere on 55 Cancri b
• Implementation of the Shearing Box Approximation in Athena
• Exoplanet HD 209458b : Evaporation strengthened
• Atmospheric escape from HD 189733b observed in HI Lyman-alpha: detailed analysis of HST/STIS September 2011 observations
• Exoplanet HD209458b: inflated hydrogen atmosphere but no sign of evaporation
• Classification of magnetized star--planet interactions: bow shocks, tails, and inspiraling flows
• On the existence of energetic atoms in the upper atmosphere of exoplanet HD209458b
• New observations of the extended hydrogen exosphere of the extrasolar planet HD209458b
• Magnetically controlled mass loss from extrasolar planets in close orbits
• 3D Gas Dynamic Simulation of the Interaction Between the Exoplanet WASP-12b and Its Host Star
• Magnetohydronamic Evolution of HII Regions in Molecular Clouds: Simulation Methodology, Tests, and Uniform Media
• The long egress of GJ~436b's giant exosphere
• Magnesium in the atmosphere of the planet HD209458b: Observations of the thermosphere-exosphere transition region
• A Detection Of H-alpha In An Exoplanetary Exosphere
• The Dynamics of Stellar Coronae Harboring Hot-jupiters I. A Time-dependent MHD Simulation of the Interplanetary Environment in the HD 189733 Planetary System
• A Second Order Godunov Method for Multidimensional Relativistic Magnetohydrodynamics
• Extended MHD modeling of the steady solar corona and the solar wind
• Colliding Planetary and Stellar Winds: Charge Exchange and Transit Spectroscopy in Neutral Hydrogen
• Magnetohydrodynamic Simulations of Hot Jupiter Upper Atmospheres
• Simulated Photoevaporative Mass Loss from Hot Jupiters in 3D
• Anisotropic winds from close-in extra-solar planets
• The origin of the excess transit absorption in the HD 189733 system: planet or star?
• Exoplanets as probes of the winds of host stars: the case of the M dwarf GJ 436
• Hot planetary winds near a star: dynamics, wind-wind interactions, and observational signatures
• Ultraviolet C II and Si III Transit Spectroscopy and Modeling of the Evaporating Atmosphere of GJ436b
• Characterisation of the HD219134 multi-planet system II. Stellar-wind sputtered exospheres in rocky planets b & c
• Photo-ionization of planetary winds: case study HD209458b
• Photoevaporative Flows From Exoplanet Atmospheres: A 3-D Radiative Hydrodynamic Parameter Study

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