科学研究
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2024.09.18
Unveiling the 70-year mystery of the nature of carbon-deficient red giants
Weak G-band stars, or carbon-deficient red giants (CDGs), characterised by weak or absent G-band absorption of the CH molecule driven by low carbon abundances, have remained mysterious for decades. Here, we present a significant increase in the known CDG population identified through systematic spectroscopic surveys. This expanded sample confirms their rarity (
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2024.09.11
Identifying the Galactic Substructures in 5D Space Using All-sky RR Lyrae Stars in Gaia DR3
Motivated by the vast gap between photometric and spectroscopic data volumes, there is great potential in using 5D kinematic information to identify and study substructures of the Milky Way. We identify substructures in the Galactic halo using 46,575 RR Lyrae stars (RRLs) from Gaia DR3 with the photometric metallicities and distances newly estimated by Li et al. (2023). Assuming a Gaussian prio...
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2024.06.24
Gaia + Bayesian Power: A Deep Dive into Open Cluster Mass Function & Binaries
Open clusters (OCs) are cradles of stars and building blocks of galaxies, offering insights into how stars and galaxies form. It is essential to precisely measure the parameters of OCs, such as age, metallicity, distance, dust extinction, stellar mass function (MF), and binary fraction. I propose a novel Bayesian framework that can identify OC candidates and simultaneously estimate these parame...
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2024.06.17
Granulation in Red Supergiants: The Scaling Relations
Granulations are structures characterized by convection cells reaching the stellar surface and are well-known through observations of the Sun. However, similar granulation structures may also be present on the surfaces of the largest and brightest cool stars in the Universe—the red supergiants (RSGs)—potentially serving as the primary mechanism of their irregular light variations. As predicte...
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2024.06.11
Heating the Super-hot Corona in Solar Active Regions: Insights from RMHD Simulations
What physical mechanisms heat the outer solar or stellar atmosphere to million-kelvin temperatures is a fundamental but long-standing open question. In particular, the solar corona in active-region cores contains an even hotter component reaching 10 MK, manifesting as persistent coronal loops in extreme ultraviolet and soft X-ray images, which imposes a stringent energy budget. Here, we present...
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