Astrophysics

Astrophysics is an area concerning various physical ranging from planetary sized systems, to galactic scale systems and beyond, that intersects various disciplines such as Newtonian dynamics, relativistic physics and particle physics processes.

For our latest developments/activities in this area, please see the listing below at the end of this article.

Exoplanets

An exoplanet is a planet outside the Solar System. In the Milky Way galaxy, it is expected that there are many billions of planets (at least one planet, on average, orbiting around each star, resulting in 100–400 billion exoplanets), with many more free-floating planetary-mass bodies orbiting the galaxy directly.

We study the long-term dynamics of known multi-planet systems. This allow us to test the accuracy of the orbital parameters' determinations, as well as to understand how these systems evolved. We also look for the stable zones in the gaps between already-known planets in order to determine where is it possible to locate Earth-like planets.

See here a movie made by the PhD Animation on "Exoplanets Explained", for a review on the main observational methods used to detect exoplanets.


Latest Astrophysics Publications

First Sagittarius A* Event Horizon Telescope Results. VII. Polarization of the Ring, The Event Horizon Telescope Collaboration (w/ H. Olivares); ApJL 964 (2024) L25.

Publication type
Regular Articles
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First Sagittarius A* Event Horizon Telescope Results. VIII. Physical Interpretation of the Polarized Ring, The Event Horizon Telescope Collaboration (w/ H. Olivares); ApJL 964 (2024) L26.

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Regular Articles
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The imitation game reloaded: effective shadows of dynamically robust spinning Proca stars, I. Sengo, P. V. P. Cunha, C. A. R. Herdeiro, E. Radu; arXiv:2402.14919 [gr-qc].

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Regular Articles
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Ordered magnetic fields around the 3C 84 central black hole, G. F. Paraschos et al. (w/ H. Olivares); Astron. Astrophys. 682 (2024) L3, arXiv:2402.00927 [gr-qc].

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Regular Articles
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Fundamental Physics Opportunities with the Next-Generation Event Horizon Telescope, D. Ayzenberg et al. (w/ P. V P. Cunha and H. Olivares); arXiv:2312.02130 [astro-ph.HE].

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Regular Articles
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Latest Astrophysics News & Events

The optical appearance of some regular compact objects

Gr@v Seminars - Banner
Speaker
Mercè Guerrero (CIDMA, University of Aveiro)
Event date
Venue
On-site: Sala Sousa Pinto
Event type
The significance of multi-ring images in the optical appearance of spherically symmetric compact objects is discussed. Such images are produced by an optically and geometrically thin accretion disk illuminating the object.

Young brown dwarfs and rogue planets in the Milky Way

Gr@v Seminars - Banner
Speaker
Koraljka Muzic (IA, University of Lisbon)
Event date
Venue
Hybrid: Sala Sousa Pinto and Zoom
Event type

There are at least 100 billion brown dwarfs and planetary-mass objects in our Galaxy - objects that are not orbiting a star and have masses between that of Jupiter and of the lowest mass stars (~80 MJup). Several theories for their formation have been proposed, and could all as well be at work, but their relative importance is not known and is expected to vary with mass and environment.

Numerical evolution of well-posed field theories with anisotropic scaling

Gr@v Seminars - Banner
Speaker
Marcelo Rubio (SISSA, Trieste)
Event date
Venue
On-site: Room TBD
Event type
Dynamical equations exhibiting an anisotropic scaling between space 
and time admit a dispersive nature, as they contain higher-order spatial derivatives, 
but remain second order in time.

Discussion of the paper "Accretion within the innermost stable circular orbit: analytical thermodynamic solutions in the adiabatic limit", by A. Mummery and S. Balbus

Speaker
Héctor Olivares (U. Aveiro)
Event date
Venue
Hybrid: Room Sousa Pinto and Zoom
Ends on
Event type

Accretion within the innermost stable circular orbit: analytical thermodynamic solutions in the adiabatic limit

A. Mummery, and S. Balbus

arXiv:2302.14437 [astro-ph.HE]