TAP Visitor Series

In support of the Planet Formation Initiative, which undertakes the study of theories of the formation and evolution of the Solar System and exoplanet systems, please join us in welcoming –


Friday, January 13, 2023, at 1:00 PM

TITLE: Nitrogen as a Tracer of Planet Formation in the context of Jupiter and Exoplanets


Planetary atmospheres offer important clues to the past planet formation and evolution history. While atmospheric carbon and oxygen have been discussed for tracing past planet formation location, recent studies suggest that atmospheric nitrogen also provides valuable insights on the formation process. In this presentation, Dr. Ohno starts talking about our Solar System Jupiter and then moves to exoplanets regarding the implications of atmospheric nitrogen and related caveats.

One of the remarkable examples can be found in Jupiter: several studies suggested that Jupiter originally formed at >30 AU because Jupiter’s enriched atmospheric nitrogen indicates the accretion of N2 ice, which is condensable at <30 K. However, the Jupiter formation beyond a few tens AU challenges the current planet formation theory. Here, he will first talkabout the importance of the shadows cast by substructures of protoplanetary disk for interpreting atmospheric observations. He will discuss that the disk shadow may be a key to reconciling the Jovian atmospheric compositions with planet formation theory.

The active discussion on Jupiter formation from atmospheric nitrogen motivates us to search for nitrogen in exoplanets. While nitrogen species, such as NH3, will be accessible by JWST for exoplanetary atmospheres, it is not straightforward to constrain the bulk nitrogen abundance, as the nitrogen chemistry is susceptible to disequilibrium processes. In the latter part of the presentation, Dr. Ohno will discuss suitable planetary properties and observational feasibility of nitrogen species in exoplanetary atmospheres based on semi-analytical argument and series of photochemical simulations to suggest strategy and caveats for upcoming JWST observations.



Dr. Ohno is working on planetary science at the University of California Santa Cruz with support from JSPS Overseas Research Fellowships. His primary research interest is theoretical modeling of (exo)planetary atmospheres, including aerosol formation and atmospheric circulation, as well as planet formation in protoplanetary disks. He received hisPh.D. at the Tokyo Instituteof Technology in March 2020 under the supervision of Satoshi Okuzumi andXi Zhang. Dr. Ohno is working with Jonathan Fortney, Xi Zhang, and many other collaborators.



Talk: 1:00 PM MST

Kuiper Space Sciences Building, Room 309

Planetary Theory Tea: 2:00 PM,

Steward Observatory, Room N305

Meet the Speaker:

Contact one of the hosts, Andrew Youdin or Tyler Robinson

or sign up here on the invited speaker schedule.

Viewing Options:

Live stream: Zoom Meeting ID: 861 3028 0268, Passcode: None

Watch later: LPL YouTube Channel