Mohammad Farhat, UC Berkeley
When
Refreshments served at 3:00 pm in the 3rd Floor Atrium
TAP Colloquium
Mohammad Farhat, UC Berkeley
Visit Dates: March 22-25, 2026
Title: Dynamics in Extreme Environments: From Lava to Tatooine Planets
Abstract: Planets in extreme astrophysical regimes are valuable laboratories for building a self-consistent picture of planet formation and evolution, because their orbital, geophysical, and thermodynamic conditions can reveal the governing physics most clearly. In this talk, I focus on two such regimes. // Orbiting at just a few stellar radii, ultra-short-period rocky planets experience intense irradiation and strong tidal interactions. Time-domain observations are beginning to resolve thermal emission patterns that encode coupled interior–surface–atmosphere processes. I will discuss how tidally driven lava waves can excite a sloshing magma ocean, depositing energy into the interior while reshaping surface temperature patterns and the planet’s thermal phase curve. In the second regime, I address the apparent scarcity of circumbinary planets (CBPs). While early expectations suggested that CBPs should be as common as planets around single stars, only 14 transiting CBPs have been identified to date by Kepler and TESS. This dearth becomes a complete desert around the tightest binaries. I will propose a novel mechanism to explain these observed features, in which a non-linear secular resonance encountered over a system’s evolution drives the CBP toward dynamical instability, ejection, or engulfment by the binary. // In the second regime, I address the apparent scarcity of circumbinary planets (CBPs). While early expectations suggested that CBPs should be as common as planets around single stars, only 14 transiting CBPs have been identified to date by Kepler and TESS. This dearth becomes a complete desert around the tightest binaries. I will propose a novel mechanism to explain these observed features, in which a non-linear secular resonance encountered over a system’s evolution drives the CBP toward dynamical instability, ejection, or engulfment by the binary.
Bio: Mohammad Farhat is a Miller Postdoctoral Fellow in the Departments of Astronomy and Earth & Planetary Science at the University of California, Berkeley. He received his B.S. and M.S. in Physics from the American University of Beirut, and then moved to Paris for a Ph.D. in Astrophysics at the Paris Observatory. Mohammad has a broad interest in studying dynamical systems, ranging from the long term evolution of the Earth-Moon system as shaped by geophysical fluid dynamics, to the orbital architecture of exoplanetary systems and disks. His doctoral work on the Earth-Moon system received the IAU PhD Prize and the Astronomy & Astrophysics PhD Thesis Award. More recently, he is especially interested in the interplay between orbital dynamics and planetary geodynamics, and in how this coupling shapes planetary climates.
Links to relevant work:
https://scholar.google.com/citations?user=R9VoZ-oAAAAJ&hl=en
https://www.science.org/content/article/tidal-waves-lava-may-slosh-arou…
https://news.berkeley.edu/2026/01/30/why-are-tatooine-planets-rare-blam…