Accurate surface rotation measurements are crucial to estimate stellar ages and improve our understanding of stellar rotational evolution.
K2
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, PLATO, Press Release
Exoplanet Exploration In The Context Of The PLATO Mission: From Detection To Population Studies
This thesis constitutes an observational effort to advance our understanding of planet formation and evolution across different regimes.
Posted inAstronomy & Telescopes, Exoplanets, -moons, -comets, Status Report
Comparing The Architectures Of Multiplanet Systems From Kepler, K2, And TESS Data
Exoplanet surveys like Kepler, TESS, and K2 have shown that planetary systems are common in our galaxy.
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report
An Eccentric Sub-Neptune Moving Into the Evaporation Desert
Though missions such as Kepler, K2, and TESS have discovered >2,000 sub-Neptune and Neptunian planets, there is a dearth of such planets at close-in (P≲3 days) orbits.
Posted inAstronomy & Telescopes, Exoplanets, -moons, -comets, Status Report
Statistical Reevaluation of the USP Classification Boundary: Smaller Planets Within 1 Day, Larger Period Ratios Below 2 Days
Terrestrial worlds with P<1 day, known as ultra-short period planets (USPs), comprise a physically distinct population whose origins may be attributed to various possible formation channels within multi-planet systems.
![Relations between mutual inclination and stellar metallicity and stellar mass after sample control. Left: stellar metallicity vs. mutual inclination plot for a subsample of 78 systems selected to minimize the influence of stellar mass. Right: stellar mass vs. mutual inclination plot for a subsample of 81 systems selected to minimize the influence of stellar metallicity. Unlike [Fe/H] vs. ∆i, the correlation between stellar mass and ∆i is not statistically significant in our sample, although we cannot completely rule out such a correlation. See Section 5 for more details. -- astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2025/02/Short-Period-Small-Planets.png?resize=1200%2C720&ssl=1)
Posted inAstrogeology, Exoplanets, -moons, -comets, Status Report, Stellar Cartography
Short-Period Small Planets with High Mutual Inclinations are more Common around Metal-Rich Stars
We present a correlation between the stellar metallicities and the mutual inclinations of multi-planet systems hosting short-period small planets (a/Rs<12, Rp<4Re). We analyzed 89 multi-planet systems discovered by Kepler, K2, […]
Posted inExoplanets, -moons, -comets, Press Release
Ultra-dense Super-Earth With An Outer Companion Offers Clues About Its Formation
An international team led by researchers in Japan and Europe has discovered a new multi-planet system around a Sun-like star, including an ultra-short period planet with one of the highest […]
Posted inAstronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Stellar Cartography
Stellar Cartography: Small And Close-In Planets Are Uncommon Around A-type Stars
The Kepler and K2 missions enabled robust calculations of planet occurrence rates around FGKM-type stars. However, these missions observed too few stars with earlier spectral types to tightly constrain the […]
![Super-Earth occurrence for Kepler (black circles) and K2 (gray circles), TESS data assuming all candidates are real (teal square), and 99.7% confidence intervals to calculate the upper limits for TESS data assuming all candidates are false positives (teal triangles) as a function of metallicity. The [-0.25,-0.5] bin occurrence rates are offset horizontally for visual clarity. The best-fit power-law trend line for the Kepler and K2 data (yellow) is displayed and extrapolated to [Fe/H]= -0.75 showing the 1-σ uncertainties (Zink et al. 2023). We show the combined best-fit exponential trend line for Kepler, K2, and TESS (purple) (eq. 6) including the 1-σ uncertainties. Each metallicity bin is indicated by gray dashed lines. Within the [-0.75,-1] bin, there is insufficient data to further constrain the super-Earth occurrence rate as a function of metallicity (denoted by the gray hatched region). -- astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2024/07/The-First-Evidence-of-a-Host.png?resize=1200%2C720&ssl=1)
Posted inAstrochemistry, Astrogeology, Exoplanets, -moons, -comets, Press Release
The First Evidence of a Host Star Metallicity Cut-off In The Formation of Super-Earth Planets
Planet formation is expected to be severely limited in disks of low metallicity, owing to both the small solid mass reservoir and the low opacity accelerating the disk gas dissipation.
![Mass–radius diagram of confirmed exoplanets with mass and radius precision better than 3σ and 10σ, respectively. Planetary parameters (black dots) are taken from the NASA Exoplanet Archive (https://exoplanetarchive.ipac.caltech.edu), and updated to October 2023. HD 73344b is represented by the red dot. The red arrow represents the upper 10σ limit on its mass. Composition models calculated from Aguichine et al. (2021) with a core mass fraction of 30% and various H2O mass fraction (from 10% to 80%) are represented by coloured lines (see text). Composition models calculated from Lopez & Fortney (2014) for a 1 Gyr-old system, Teq,b ∼ 900 K, and an envelope mass fraction fenv = [1, 2, 3, 4, 5] % are shown in gray. For comparison, the relation for an Earth-like composition (32.5% core, 67.5% mantle) from Brugger et al. (2017) is shown by the green dashed curve, and some solar system planets (Venus, the Earth, Uranus and Neptune) are displayed. -- astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2024/05/A-Low-mass-Sub-Neptune-Planet.png?resize=1200%2C719&ssl=1)
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy, Status Report
A Low-mass Sub-Neptune Planet Transiting The Bright Active Star HD 73344
Context. Planets with radii of between 2-4 RE closely orbiting solar-type stars are of significant importance for studying the transition from rocky to giant planets.