Alessandro Alberto Trani

Theoretical and Computational Astrophysics

I am a theoretical astrophysicist interested in the dynamics of collisional systems, which are those systems that evolve primarily via long-range gravitational interactions. This includes star clusters, galactic nuclei, binary stars and planetary systems

My recent research is centered around the gravitational three-body problem and its applications to astrophysical phenomena like gravitational waves and planetary evolution

Three point-masses orbit each other forming a figure-of-eight. This zero-angular-momentum configuration is one of the few stable solutions of the three-body problem

What is the origin of gravitational waves?

My recent work focuses on uncovering the origin of gravitational wave events. Gravitational waves were first detected in 2015, opening a new window on the universe and confirming the existence of black holes.


Often described as “ripples in space-time”, gravitational waves can be generated when two massive objects (such as black holes) orbit each other very closely. As gravitational waves are released, the two objects get closer and closer, spiraling-in until they merge.

Many of the gravitational wave events detected so far come from the coalescence of massive binary black holes. But how such binaries are formed in the Universe? Where do they come from?  What are the mechanims that led to their formation? These are the questions I try to answer in my research

Recent publications

  • A.A.Trani, A.Tanikawa, M.S.Fujii. N.W.C.Leigh, J.Kumamoto, 2021, MNRAS, 504, 910
  • Spin misalignment of black hole binaries from young star clusters: implications for the origin of gravitational waves events

  • A.Tanikawa, H.Susa, T.Yoshida, A.A.Trani, T.Kinugawa, 2021, ApJ, 910, 30
  • Merger Rate Density of Population III Binary Black Holes Below, Above, and in the Pair-instability Mass Gap

  • A.A.Trani, A.S.Hamers, A.Geller, M.Spera, 2020, MNRAS, 499, 4195
  • The ominous fate of exomoons around hot Jupiters in the high-eccentricity migration scenario

  • V.Manwadkar, A.A.Trani, N.W.C.Leigh, 2020, MNRAS, 497, 3694
  • Chaos and Lévy flights in the three-body problem

For a more complete list, check NASA’s astrophysics data system