地球与行星天体物理
We have initiated a large project on identifying the requirements for developing a realistic and ground-up approach to simulating the formation of terrestrial planets in our solar system. As the first phase of this project, we present here…
Understanding the provenance of CI and CM chondrites, the most primitive materials in our meteorite collections, is critical for shedding light on the Solar System's early evolution and contextualizing findings from recent sample return…
During a hypervelocity impact, both the impactor and target materials evaporate, generating an impact vapor plume with temperatures reaching several thousand K. As the plume cools through adiabatic expansion, chemical reactions are…
As space traffic continues to increase in the cislunar region, accurately determining the trajectories of objects operating within this domain becomes critical. However, due to the combined gravitational influences of the Earth and Moon,…
Evidence suggests the existence of a large planet in the outer Solar System, Planet Nine, with a predicted mass of 6.6 +2.6 / -1.7 Earth masses (Brown et al., 2024). Based on mass radius composition models, planet formation theory, and…
Modeling the internal structure of self-gravitating solid and liquid bodies presents a challenge, as existing approaches are often limited to either overly simplistic constant-density approximations or more complex numerical equations of…
Low-mass, metal-enriched stars were likely present as early as cosmic dawn. In this work, we investigate whether these stars could have hosted planets in their protoplanetary disks. If so, these would have been the first planets to form in…
We obtained 420 high-resolution spectra of Proxima, over 159 nights, using the Near Infra Red Planet Searcher (NIRPS). We derived 149 nightly binned radial velocity measurements with a standard deviation of 1.69 m/s and a median uncertainty…
We determine optimal requirements for the joint detection of habitable-zone planets and cold giant planets with the Habitable Worlds Observatory (HWO). Analysis of 164 nearby stars shows that a coronagraph outer working angle (OWA) of 1440…
We report the discovery of activity emanating from (18916) 2000 OG44 (alternately designated 1977 SD), a minor planet previously reported to be both an extinct comet or an asteroid on a cometary orbit. We observed 2000 OG44 with a thin tail…
With more than a dozen significant detections, the helium triplet has emerged as a key tracer of evaporating exoplanet atmospheres. This near-infrared feature can be observed from the ground and holds great promise, especially with upcoming…
Near-infrared high-resolution echelle spectrographs unlock access to fundamental properties of exoplanets, from their atmospheric escape and composition to their orbital architecture, which can all be studied simultaneously from transit…
Stellar activity variability is one of the main obstacles to the detection of Earth-like planets using the RV method. The aim of this work is to measure the effect of activity in the spectra of M dwarfs and detect activity-sensitive lines…
While stellar metallicity has long been known to correlate with planetary properties, the galactic metallicity gradient alone does not account for the trend. It is therefore possible that there exists some time-dependent component to planet…
Ultra-hot Jupiters showcase extreme atmospheric conditions, including molecular dissociation, ionisation, and significant day-to-night temperature contrasts. Their close proximity to host stars subjects them to intense stellar irradiation,…
We describe the discovery and characterization of TOI-7149~b, a 0.705 $\pm$ 0.075 $M_J$, 1.18 $\pm$ 0.045 $R_J$ gas giant on a $\sim 2.65$ day period orbit transiting an M4V star with a mass of 0.344 $\pm$ 0.030~\solmass{} and an effective…
While planet migration has been extensively studied for classical viscous disks, planet-disk interaction in nearly inviscid disks has mostly been explored with greatly simplified thermodynamics. In such environments, motivated by models of…
Much has been learned about exoplanets and their atmospheres in the last three decades with the help of highly sensitive optical telescopes. Limited observations using X-ray telescopes have revealed the presence of ionospheres with very…
We present the results from the simulations of the atmospheres of hot-Jupiters HD189733b, HD209458b and WASP-39b, assuming the presence of three different types of haze. Using a 3D General Circulation Model, the Unified Model, we capture…
We provide a method to calculate the evolution of an eccentric and inclined orbit under the magnetic effect. Taking the unipolar interaction as an example, we study both coplanar and inclined orbits. We calculate the Lorentz force and then…