Search Publications
JWST unveils the brown dwarf sequence of 47 Tucanæ
Bedin, L. R.; Nardiello, D.; Griggio, M.
We have developed a technique to restore scientific usage in compromised (publicly available) images collected with the JWST of the Galactic globular cluster NGC 104 (47 Tucanæ). In spite of the degradation and limited data, we were able to recover photometry and astrometry for the coolest stellar objects ever observed within a globular cluster, p…
Investigating 16 Open Clusters in the Kepler/K2-Gaia DR3 Field. I. Membership, Binary Systems, and Rotation
Bi, Shaolan; Ge, Zhishuai; Li, Tanda +9 more
Using data from Gaia Data Release 3 and Kepler/K2, we present a catalog of 16 open clusters with ages ranging from 4-4000 Myr that provides detailed information on membership, binary systems, and rotation. We assess the memberships in 5D phase space, and estimate the basic parameters of each cluster. Among the 20,160 members, there are 4381 stars …
Red horizontal branch stars: An asteroseismic perspective
Tailo, Marco; Stokholm, Amalie; Valentini, Marica +7 more
Robust age estimates of red giant stars are now possible thanks to the precise inference of their mass based on asteroseismic constraints. However, there are cases where such age estimates can be highly precise yet very inaccurate. An example is giants that have undergone mass loss or mass transfer events that have significantly altered their mass…
Exploring the chemodynamics of metal-poor stellar populations
Smiljanic, R.; da Silva, A. R.
Context. Metal-poor stars are key for studying the formation and evolution of the Galaxy. Evidence of the early mergers that built up the Galaxy remains in the distributions of abundances, kinematics, and orbital parameters of its stars. Several substructures resulting from these mergers have been tentatively identified in the literature.
Aim…
Observing Atmospheric Escape in Sub-Jovian Worlds with JWST
Alam, Munazza K.; Espinoza, Néstor; Dos Santos, Leonardo A. +1 more
Hydrodynamic atmospheric escape is considered an important process that shapes the evolution of sub-Jovian exoplanets, particularly those with short orbital periods. The metastable He line in the near-infrared at 1.083 µm is a reliable tracer of atmospheric escape in hot exoplanets, with the advantage of being observable from the ground. How…
Precise masses and ages of 1 million RGB and RC stars observed by LAMOST
Huang, Yang; Zhang, Huawei; Wang, Chun +1 more
We construct a catalogue of stellar masses and ages for 696 680 red giant branch (RGB) stars, 180 436 primary red clump (RC) stars, and 120 907 secondary RC stars selected from the LAMOSTDR8. The RGBs, primary RCs, and secondary RCs are identified with the large frequency spacing (∆ν) and period spacing (∆P) estimated from the LAMOST spectra with …
The outburst of the changing-look AGN IRAS 23226-3843 in 2019
Schartel, N.; Komossa, S.; Kollatschny, W. +8 more
Aims: IRAS 23226-3843 has previously been classified as a changing-look active galactic nucleus (AGN) based on observations taken in the 1990s in comparison to X-ray data (Swift, XMM-Newton, and NuSTAR) and optical spectra taken after a very strong X-ray decline in 2017. In 2019, Swift observations revealed a strong rebrightening in X-ray and…
Water Vapor Vertical Distribution on Mars During Perihelion Season of MY 34 and MY 35 With ExoMars-TGO/NOMAD Observations
Aoki, S.; Vandaele, A. C.; Daerden, F. +18 more
The water vapor in the Martian atmosphere plays a significant role in the planet's climate, being crucial in most of the chemical and radiative transfer processes. Despite its importance, the vertical distribution of H2O in the atmosphere has not still been characterized precisely enough. The recent ExoMars Trace Gas Orbiter mission, wi…
Backstreaming ions at a high Mach number interplanetary shock. Solar Orbiter measurements during the nominal mission phase
Vainio, R.; Owen, C. J.; Wimmer-Schweingruber, R. F. +9 more
Context. Solar Orbiter, a mission developed by the European Space Agency, explores in situ plasma across the inner heliosphere while providing remote-sensing observations of the Sun. The mission aims to study the solar wind, but also transient structures such as interplanetary coronal mass ejections and stream interaction regions. These structures…
Surface structure of 45 Hercules: an otherwise unremarkable Ap star with a surprisingly weak magnetic field
Petit, P.; Amarsi, A. M.; Kochukhov, O. +3 more
The origin of magnetic fields and their role in chemical spot formation on magnetic Ap stars is currently not understood. Here, we contribute to solving this problem with a detailed observational characterization of the surface structure of 45 Her, a weak-field Ap star. We find this object to be a long-period, single-lined spectroscopic binary and…