Astrophysics Brown Bag Lunch Talk 9/27/2021: Speakers: Malena Rice (Yale) And Isobel Romero-Shaw (Monash University, Melbourne)

Monday September 27, 2021 12:00 pm
TBA in person or via Zoom

Speaker: Malena Rice, Yale University          12:00-12:30pm

Origins of Hot Jupiters from the Stellar Obliquity Distribution

Abstract: The obliquity of a star, or the angle between its spin axis and the average orbital plane of its companion planets, provides a unique constraint on that system’s evolutionary history. In contrast with the solar system, where the Sun’s equator is nearly aligned with its companion planets, many hot Jupiter systems have been discovered with large spin-orbit misalignments, hosting planets on polar or retrograde orbits. However, hot Jupiters experience strong tidal interactions with their host stars that can act to realign the systems, distorting their primordial obliquities. We present the first results from the Stellar Obliquities in Long-period Exoplanet Systems (SOLES) survey of Rossiter-McLaughlin measurements, which is extending the sample of stellar obliquity measurements to include systems with wide-orbiting planets that are more representative of the primordial obliquity distribution. We conclude with evidence that high-eccentricity migration and tidal damping are the two primary mechanisms shaping the dynamical evolution of hot Jupiter systems, resulting in the stellar obliquity distribution that is observed today.

Bio: Malena Rice is a PhD candidate at Yale University, where she works with Professor Greg Laughlin to study planetary system evolution. Her research synthesizes the various components of planetary systems through the lens of dynamics, and her interests range from distant solar system studies with TESS to interstellar object origins and hot Jupiter formation. Email:


Speaker: Isobel Romero-Shaw, Monash University          12:30-1:00pm

Eccentricity in Gravitational-Wave Transients

Abstract: LIGO and Virgo have now reported >50 gravitational-wave signals from coalescing compact binaries. The paths that these objects traced around each other just before they merged contain hints about their previous lives. Binary compact objects have two overarching formation channels: isolated, in which the binary evolves without external influence, and dynamical, in which it becomes bound in a populous environment. Isolated binaries are expected to have circular orbits close to merger, but dynamically-formed binaries can retain detectable orbital eccentricity. In this talk, I explain how these different eccentricities arise, present eccentricity measurements for LIGO-Virgo binaries, and discuss their implications for the formation channels of the population.

Bio: Isobel is a PhD student at Monash University in Melbourne, Australia. Her thesis work has centred around binary compact objects with eccentric orbits: their detection via gravitational waves, and their formation (in star clusters or otherwise). She aims to shed light on the formation channels of LIGO-Virgo binaries, and is also interested in what gravitational wave observations can tell us about the properties of compact binary formation environments.


Event Contact

Josh Borrow