Search Publications
A core in a star-forming disc as evidence of inside-out growth in the early Universe
Chevallard, Jacopo; Maseda, Michael V.; Carniani, Stefano +36 more
The physical processes that establish the morphological evolution and the structural diversity of galaxies are key unknowns in extragalactic astrophysics. Here we report the finding of the morphologically mature galaxy JADES-GS+53.18343−27.79097, which existed within the first 700 million years of the Universe's history. This star-forming galaxy w…
Photometric detection at 7.7 µm of a galaxy beyond redshift 14 with JWST/MIRI
Pérez-González, Pablo G.; Charlot, Stéphane; Chevallard, Jacopo +31 more
The James Webb Space Telescope (JWST) has spectroscopically confirmed numerous galaxies at z > 10. While weak rest-frame ultraviolet emission lines have only been seen in a handful of sources, the stronger rest-frame optical emission lines are highly diagnostic and accessible at mid-infrared wavelengths with the Mid-Infrared Instrument (MIRI) o…
The formation and survival of the Milky Way's oldest stellar disk
Xiang, Maosheng; Huang, Yang; Liu, Jifeng +3 more
It remains a mystery when our Milky Way first formed a stellar disk component that survived and maintained its disk structure from subsequent galaxy mergers. We present a study of the age-dependent structure and star formation rate of the Milky Way's disk using high-α stars with substantial orbital angular momentum that have precise age determinat…
The broken-exponential radial structure and larger size of the Milky Way galaxy
Imig, Julie; Chen, Bingqiu; Wang, Tao +4 more
The radial structure of a galaxy is a fundamental property that reflects its growth and assembly history. Although it is straightforward to measure that of external galaxies, it is challenging for the Milky Way because of our inside perspective. Traditionally, the radial structure of the Milky Way has been assumed to be characterized by a single-e…
An abrupt change in the stellar spin-down law at the fully convective boundary
Angus, Ruth; Amard, Louis; See, Victor +2 more
Unlike partially convective stars such as the Sun, fully convective stars do not possess a radiative core. Whether a star needs this core to generate a solar-like magnetic dynamo is still unclear. Recent studies suggest fully and partially convective stars exhibit very similar period-activity relationships, hinting that dynamos generated by stars …
Enrichment by extragalactic first stars in the Large Magellanic Cloud
Li, Ting S.; Frebel, Anna; Simon, Joshua D. +8 more
The Large Magellanic Cloud (LMC) is the Milky Way's most massive satellite galaxy, which only recently (~2 billion years ago) fell into our Galaxy. As stellar atmospheres preserve the composition of their natal cloud, the LMC's recent infall makes its most ancient, metal-deficient (`low-metallicity') stars unique windows into early star formation …
Insights into star formation and dispersal from the synchronization of stellar clocks
Alves, João; Barrado, David; Burkert, Andreas +3 more
Age is one of the most fundamental parameters of a star, yet it is one of the hardest to determine as it requires modelling various aspects of stellar formation and evolution. When we compare the ages derived from isochronal and dynamical traceback methods for six young stellar associations, we find a systematic discrepancy. Specifically, dynamica…
A seven-Earth-radius helium-burning star inside a 20.5-min detached binary
Filippenko, Alexei V.; Han, Zhanwen; Chen, Xuefei +28 more
Binary evolution theory predicts that the second common envelope ejection can produce low-mass (0.32-0.36 M⊙) subdwarf B (sdB) stars inside ultrashort-orbital-period binary systems, as their helium cores are ignited under nondegenerate conditions. With the orbital decay driven by gravitational-wave (GW) radiation, the minimum orbital pe…
The accretion of a solar mass per day by a 17-billion solar mass black hole
Wolf, Christian; Lai, Samuel; Bian, Fuyan +5 more
Around a million quasars have been catalogued in the Universe by probing deeper and using new methods for discovery. However, the hardest ones to find seem to be the rarest and brightest specimens. Here we study the properties of the most luminous of all quasars found so far. These have been overlooked until recently, which demonstrates that moder…
Detection of an Earth-sized exoplanet orbiting the nearby ultracool dwarf star SPECULOOS-3
Ikuta, Kai; Triaud, Amaury H. M. J.; Tamura, Motohide +82 more
Located at the bottom of the main sequence, ultracool dwarf stars are widespread in the solar neighbourhood. Nevertheless, their extremely low luminosity has left their planetary population largely unexplored, and only one of them, TRAPPIST-1, has so far been found to host a transiting planetary system. In this context, we present the SPECULOOS pr…