Apurva V. OZA

I lead research on the escape, outgassing and detection of atmospheres across the solar system and beyond — from Io's volcanoes and Europa's oxygen to evaporating exomoons — combining kinetic theory, 3-D Monte Carlo simulation (SERPENS), and high-resolution spectroscopy with JWST, HST and Europa Clipper.

SERPENS — a 3-D Monte Carlo simulation of an evaporating exomoon transiting its star (Meyer zu Westram, Oza & Galli 2024, JGR): the sputtered particles form a torus and local cloud, visible in evaporative transmission spectroscopy (Gebek & Oza 2020, MNRAS). This is the engine behind our exosphere predictions from Io to the lava worlds.

C'est Quoi une "Exosphère" ? An exosphere is the boundless, external envelope of a gas tenuously extending from a planetary surface or atmosphere. This gas represents the interface between planets and stars as it directly transitions into the interplanetary medium (a.k.a space). What is unique about the gas is: it is, by definition collisionless rendering it unlike any gas one experiences on Earth. This gas would be more similar to a near-vacuum than oxygen itself (प्राणवायु). Understanding, the dynamics of such a physical system are hence quite complex, as the system can behave far from the familiar thermodynamic equilibrium of a gas.

O₂ = O₂ प्राणवायु (Astrobiology, 2026) Molecular oxygen on ocean worlds: radiolytically produced O₂ trapped as bubbles in Europa's water ice, and the downwelling timescales that could deliver this metabolic fuel to the subsurface ocean — the same O₂ that powers life on Earth may power habitability beyond it.

[Exo]Planet-[Exo]moon evolution can occur on rapid (~days) to geological (~Gyr) timescales. Using spacecraft data (JUNO/JIRAM), space observatories (JWST, Hubble Space Telescope) as well as ground-based high-resolution spectrographs (VLT/ESPRESSO; HIRES/KECK) we can capture spectral signatures of this evolution and even question their origin. Surprises include evaporating exomoons and new thermal outgassing mechanisms.

Volcanic SO₂ (Io & exo-Ios) Extraterrestrial & extrasolar volcanism: probing magma oceans through tidally driven SO₂ outgassing on Io — the benchmark for gravitational tidal volcanism — and its infrared spectral signatures at the lava worlds beyond, with JWST.

Titan × Habitable Worlds Observatory Current project: preparing Titan — a world with weather, seas and organic chemistry — as a target for NASA's next flagship, the Habitable Worlds Observatory: N₂/CH₄ escape, photochemistry and the observables that connect atmospheric evolution to habitability.

• Publications
• Google Scholar
• NASA ADS

Planetary Evolution is a fundamental phenomenon largely driven by the physics of atmospheric escape. The applications are far reaching spanning several topics. Here are my current projects in 2026:

  Full research portfolio on my Caltech page →  ·  The Group →

O₂ = O₂: Molecular Oxygen on Ocean Worlds: Oza et al. 2026, Astrobiology — radiolytic O₂ in Europa's ice as metabolic fuel for life beyond Earth.

Volcanic SO₂ & Extrasolar Volcanism: tidally driven SO₂ outgassing on Io and infrared signatures of magma-ocean worlds with JWST.

Titan × Habitable Worlds Observatory: current project — N₂/CH₄ escape, photochemistry and habitability observables for NASA's next flagship.

Alkali Exoplanet-Exomoon Systems Orbiting Nearby Stars: Gebek & Oza 2020, MNRAS; Oza, Johnson, Lellouch et al. 2019, ApJ; Hoeijmakers et al. 2020 (A&A). Full record on NASA ADS.

• 📄 CV (2026)
• 🔒 PCF Intelligence Portal
• 🎵 EuroPaOza — Music

DISHOOM DISHOOM

Desorbing Interiors via Satellite Heating to Observe Outgassing Model. A transparent, semi-analytic model for active [exo]planetary bodies. The model first calculates the heating rate due to tides and/or thermal and plasma irradiation. Subsequently, the mass loss rate, and eventual rate of outgassing is estimated based on the species in question. For Europa, these are water products, and for Ios (and exo-Ios) these are volcanic volatiles. Finally, based on the atmospheric evolution, the observable line-of-sight column density is estimated. Here is the github link for open-access :).

TEACHING

Astrobiology · Planet Formation & Evolution · Radiative Transfer (2027) · Introduction to Planetary Astrophysics — a decade of graduate teaching on three continents. Course details →

For research collaborations, speaking, teaching, or student inquiries — email is best. I respond to serious inquiries within a few days.