Hang Yu
Montana State University, MT·Astronomy & Astrophysics·Early-career
When two stars or a star and a planet orbit each other closely, gravity can stretch them, set their interiors sloshing, and even pull material from one to the other. These tidal effects shape some of the most extreme events in the universe.
- Fields
Astronomy & Astrophysics
Physics
- Topics
binary neutron stars
neutron star mergers
gravitational waves
- Grants
- 3 known grants, through Mar 2031
What they work on
- Model nonlinear tides in binary neutron stars by expanding the stars' fluid motion into eigenmodes (natural vibration patterns), including couplings between modes, and coupling them to gravitational-wave-driven orbital decay.
- Extend tidal calculations to post-Newtonian order, including neutron star spin and orbital eccentricity, to produce gravitational-wave templates comparable with numerical relativity simulations.
- Incorporate nonlinear fluid dynamics, spin precession and orbital eccentricity into relativistic waveform models of binary neutron star inspiral, to better infer neutron star structure and test general relativity.
- Build a first-principles theory of oscillations in the remnant left after a neutron star merger, to explain features in numerical relativity simulations and identify observables sensitive to dense-matter physics.
- Apply a new nonlinear hydrodynamic model to mass transfer in highly eccentric binaries, describing how mass loss reshapes the orbit and donor structure and how nonlinear dissipation acts.
- Test whether eccentric mass-transfer theory explains repeated partial tidal disruption events by massive black holes, and the formation of Hot Jupiters and Hot Neptunes.
More about the research
They range from neutron stars spiraling together while giving off gravitational waves, to stars repeatedly torn apart by giant black holes, to giant planets migrating toward their suns. The common thread is building first-principles theories of tides, fluid motion and mass transfer that can be compared with simulations and observations.
Why it matters
Accurate models of neutron star tides and mergers could help gravitational-wave observatories extract more from each detection. This includes the behavior of matter denser than an atomic nucleus and tests of general relativity. Theory of eccentric mass transfer could help identify the sources of high-energy flares near black holes and probe the star populations in galaxy centers. It could also constrain how close-in exoplanets such as Hot Jupiters and Hot Neptunes form.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
CAREER: Theoretical Models of Neutron Star Matter Effects from Inspiral to Post-Merger
NSF · Apr 2026 – Mar 2031
Collaborative Research: Establishing the theoretical framework for eccentric interacting binaries
NSF · Sep 2026 – Aug 2029
Linear and Nonlinear Tides in Coalescing Binary Neutron Stars
NSF · Jul 2023 – Jun 2027
Closest labs
Rodolfo Barniol Duran
California State University-Sacramento, CA·Astronomy & Astrophysics
Build "meter-to-parsec" numerical simulations that follow neutron star–neutron star and neutron star–black hole mergers from the pre-merger state to the regions where observed light is produced.
Antonios Tsokaros
University of Illinois Urbana-Champaign, IL·Astronomy & Astrophysics
Develop an open-source general relativistic initial data code, based on the COCAL (Compact Object CALculator) code, that lets users set up starting conditions for magnetized neutron stars and black holes, alone or in binaries.
Wolfgang Tichy
Florida Atlantic University, FL·Astronomy & Astrophysics
Simulate binary neutron star mergers containing dark matter across a range of dark matter fractions, particle masses, mass ratios and spins with the BAM code, to set limits on dark matter in neutron stars.
The school
Montana State University: 15 labs on PI Pages, $258M a year on research, 85 research doctorates a year.
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