Elbereth conference 2025

Session

Session 8

10 avr. 2025, 16:45

Amphithéâtre Evry Schatzman (Observatoire de Paris - Site de Meudon)

85. Space weathering on Mercury: investigation of the spectra of recent impact craters

Michele Lissoni (LIRA, Observatoire de Paris, Université PSL)

10/04/2025 16:45

Astrophysics

Oral presentation

Space weathering is the physical and chemical alteration of planetary surfaces caused by exposure to the space environment and specifically to the solar wind and to micrometeoroid impacts. It is currently the main process affecting the surface of Mercury.

Whereas on most of the surface space weathering appears to have reached saturation, the process is still ongoing in the youngest...

77. M15pc : The search for Giant Planets around M dwarfs with astrometry

Florian Destriez (Observatoire de Paris)

10/04/2025 17:00

Astrophysics

Oral presentation

M-type stars, the most common in the universe, are a major focus for surveys because they are well-suited for detecting low-mass planets in the habitable zone. Despite their importance in the formation and evolution of low-mass planets, little is known about giant planets (GPs) in M star systems. Detecting long period GPs is difficult with transit methods and challenging with radial velocities...

101. Innermost stable circular orbit of comparable-mass compact binaries at the fourth post-Newtonian

Etienne Ligout (APC)

10/04/2025 17:15

Astrophysics

Oral presentation

We compute by means of post-Newtonian (PN) methods the innermost stable circular orbit of comparable-mass compact binaries. Two methods are used with equivalent results: equations of motion in harmonic coordinates and Hamiltonian formalism in ADM coordinates.

97. Investigation of the dominent strahl scattering mechanism near the Sun with PSP

Erwan CHERIER (LIRA - Observatoire de Paris)

10/04/2025 17:30

Astrophysics

Oral presentation

The suprathermal electrons in the solar wind are categorized in two different
populations. The halo is nearly isotropic while the strahl is highly anisotropic.
Following previous studies, we characterize the strahl by its pitch angle width.
We aim at finding correlations between this quantity and local plasma or mag-
netic field parameters, and to compare these correlations with prediction...

63. Diagnostic of the electron density and temperature in the solar wind using the Quasi-Thermal Noise Spectroscopy on Parker Solar Probe

M. Baptiste Verkampt (LIRA - Observatoire de Paris)

10/04/2025 17:45

Oral presentation

The Quasi-Thermal Noise (QTN) spectroscopy is an efficient tool to study, in the frequency domain, the fluctuations due to the thermal motion of the charged particles in a plasma that surrounds a passive antenna. This noise is ubiquitous, and most of the time, is dominant around the electronic plasma frequency. The voltage power spectrum of the electrostatic fluctuations depends on the...