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Observations of Extremely Metal-poor O Stars: Weak Winds and Constraints for Evolution Models
McQuinn, Kristen B. W.; Chisholm, John; Berg, Danielle A. +3 more
Metal-poor massive stars drive the evolution of low-mass galaxies, both locally and at high redshift. However, quantifying the feedback they impart to their local surroundings remains uncertain because models of stellar evolution, mass loss, and ionizing spectra are unconstrained by observations below 20% solar metallicity (Z ⊙). We pre…
An optically thin view of the flaring chromosphere: non-thermal widths in a chromospheric condensation during an X-class solar flare
Kowalski, Adam F.; Kerr, Graham S.; Allred, Joel C. +2 more
The bulk of solar flare energy is deposited in the chromosphere. Flare ribbons and footpoints in the chromosphere therefore offer great diagnostic potential of flare energy release and transport processes. High-quality observations from the Interface Region Imaging Spectrograph (IRIS) spacecraft have transformed our view of the Sun's atmospheric r…
X-Shooting ULLYSES: Massive Stars at low metallicity: IX. Empirical constraints on mass-loss rates and clumping parameters for OB supergiants in the Large Magellanic Cloud
van Loon, J. Th.; Crowther, P. A.; Prinja, R. K. +16 more
Context. Current implementations of mass loss for hot, massive stars in stellar evolution models usually include a sharp increase in mass loss when blue supergiants become cooler than Teff ∼ 20 ‑ 22 kK. Such a drastic mass-loss jump has traditionally been motivated by the potential presence of a so-called bistability ionisation effect, …
MCXC-II: Second release of the Meta-Catalogue of X-ray detected Clusters of galaxies
Arnaud, M.; Pratt, G. W.; Melin, J. -B. +2 more
We present the second release of the Meta-catalogue of X-ray detected Clusters of galaxies (hereafter MCXC-II). MCXC-II has been compiled from publicly available ROSAT All Sky Survey-based (NORAS, REFLEX, BCS, SGP, NEP, MACS, CIZA, and RXGCC) and serendipitous (160SD, 400SD, SHARC, WARPS, and EMSS) X-ray cluster catalogues. Redshifts were systemat…
JWST/NIRCam 4–5 µm Imaging of the Giant Planet AF Lep b
Salama, Maïssa; Perrin, Marshall D.; Pueyo, Laurent +23 more
With a dynamical mass of 3 M Jup, the recently discovered giant planet AF Lep b is the lowest-mass imaged planet with a direct mass measurement. Its youth and spectral type near the L/T transition make it a promising target to study the impact of clouds and atmospheric chemistry at low surface gravities. In this work, we present JWST/NI…
Information content of JWST spectra of WASP-39b
Heng, Kevin; Fisher, Chloe; Lueber, Anna +1 more
Context. The era of James Webb Space Telescope (JWST) transmission spectroscopy of exoplanetary atmospheres commenced with the study of the Saturn-mass gas giant WASP-39b as part of the Early Release Science (ERS) program. WASP-39b was observed using several different JWST instrument modes (NIRCam,, NIRISS, NIRSpec G395H and NIRSpec PRISM) and the…
Unveiling MOA-2007-BLG-192: An M Dwarf Hosting a Likely Super-Earth
Lu, Jessica R.; Anderson, Jay; Cole, Andrew A. +15 more
We present an analysis of high-angular-resolution images of the microlensing target MOA-2007-BLG-192 using Keck adaptive optics and the Hubble Space Telescope. The planetary host star is robustly detected as it separates from the background source star in nearly all of the Keck and Hubble data. The amplitude and direction of the lens–source separa…
JOYS+: The link between the ice and gas of complex organic molecules: Comparing JWST and ALMA data of two low-mass protostars
Güdel, M.; Chen, Y.; Henning, Th. +16 more
Context. A rich inventory of complex organic molecules (COMs) has been observed in high abundances in the gas phase toward Class 0 protostars. It has been suggested that these molecules are formed in ices and sublimate in the warm inner envelope close to the protostar. However, only the most abundant COM, methanol (CH3OH), had been firm…
The Pristine Inner Galaxy Survey (PIGS): X. Probing the early chemical evolution of the Sagittarius dwarf galaxy with carbon abundances
Sestito, Federico; Navarro, Julio F.; Martin, Nicolas F. +6 more
We aim to constrain the chemo-dynamical properties of the Sagittarius (Sgr) dwarf galaxy using carbon abundances. At low metal- licities in particular, these properties reveal the early chemical evolution of a system, tracing the contributing supernovae (SNe) and how much of their ejecta eventually made it into the next stellar generation. Our sam…
Identification of the optical emission detected by Gaia with radio structures in parsec-scale active galactic nucleus jets
Lambert, S.; Sol, H.; Pierron, A.
Aims: We investigated the location of the optical emission with respect to the parsec-scale radio structure and attempted to identify whether the optical centroid is coincident with the radio core or a radio component of the jet.
Methods: We used optical Gaia DR3 and 8 GHz ICRF3 positions and a model fitting of 15 GHz imaging by the MOJA…