Research
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2024.09.27
A Two-Earth-mass Planet Found Orbiting a Dead “Sun”
Images of the area of the microlensing event, indicated by perpendicular white lines two weeks after peak magnification of the background star in 2020, taken by CFHT with seeing of ~ 0.5 arcsec (Left) and in 2023 after its disappearance, obtained by Keck-II with seeing of ~0.08 arcsec (Right). The planetary system with a white dwarf, a two-Earth-mass planet and brown dwarf cannot be seen; the p...
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2024.04.18
JWST and VLT search for the signature of the First Stars
The first stars, known as Population III stars, were born approximately 100 million years after the Big Bang when the universe was less than 1% of its present age. Population III stars are of fundamental importance to the initial mass function (IMF) of stars, which determines how the universe has evolved over time (see Fig. 1). As Population III stars are shortly lived, they rapidly enrich the ...
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2024.04.17
Bridging the Gap between Luminous Red Novae and Common Envelope Evolution
Luminous red novae (LRNe) and common envelope evolution (CEE) are closely related astrophysical phenomena and evolutionary processes that are not well understood. Among them, CEE is a crucial stage in binary stellar evolution. Close compact binaries, Type Ia supernovae, hot sub-dwarfs, and gravitational wave sources may all be the product of CEE. On the other hand, LRNe are bright transients wi...
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2023.08.28
Accreting Planets Leave Chemical Footprints in Protoplanetary Disks
Protoplanetary disks serve as the cradles of planet formation, often revealing captivating features such as bright rings and dark gaps in both dust continuum and gas emission maps. These features have traditionally been attributed planets, which shape the disk by gap-opening and altering its rotation profiles, effects that can potentially be observed.A new study led by Tsinghua Department of As...
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2023.05.05
Direct Imaging of Gas Recycling around a Massive Galaxy 11 Billion Years Ago
Galaxies are the birthplace of most stars and black holes. However, scientists are still debating, how galaxies accrete the fuel to sustain their growth and how they in turn pollute their environment with elements heavier than helium. An international team led by Prof. Zheng Cai at Tsinghua University has now directly observed the neighborhood of a massive galaxy in the early Universe. They fin...
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