Search Publications
Gravitational instability in a planet-forming disk
Dong, Ruobing; Tang, Ya-Wen; Teague, Richard +7 more
The canonical theory for planet formation in circumstellar disks proposes that planets are grown from initially much smaller seeds1–5. The long-considered alternative theory proposes that giant protoplanets can be formed directly from collapsing fragments of vast spiral arms6–11 induced by gravitational instability12–14<…
The POKEMON Speckle Survey of Nearby M Dwarfs. II. Observations of 1125 Targets
Hartman, Zachary D.; Ciardi, David R.; Lund, Michael B. +7 more
Stellar multiplicity is correlated with many stellar properties, yet multiplicity measurements have proven difficult for the M dwarfs—the most common type of star in our galaxy—due to their faintness and the fact that a reasonably complete inventory of later M dwarfs did not exist until recently. We have therefore carried out the Pervasive Overvie…
Chemical abundances along the quasar main sequence
Marziani, P.; del Olmo, A.; Czerny, B. +5 more
Context. The main sequence of quasars has emerged as a powerful tool for organizing the observational and physical characteristics of type-1 active galactic nuclei (AGNs). Aims. In this study, we present a comprehensive analysis of the metallicity of the gas in the broad-line region, incorporating both new data and previously published findings, t…
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…
ALMA-IMF: XV. Core mass function in the high-mass star formation regime
Galván-Madrid, R.; Cunningham, N.; Braine, J. +38 more
The stellar initial mass function (IMF) is critical to our understanding of star formation and the effects of young stars on their environment. On large scales, it enables us to use tracers such as UV or Hα emission to estimate the star formation rate of a system and interpret unresolved star clusters across the Universe. So far, there is little f…
Evidence for non-zero turbulence in the protoplanetary disc around IM Lup
Hughes, A. Meredith; Wilner, David J.; Kóspál, Ágnes +6 more
The amount of turbulence in protoplanetary discs around young stars is critical for determining the efficiency, timeline, and outcomes of planet formation. It is also difficult to measure. Observations are still limited, but direct measurements of the non-thermal, turbulent gas motion are possible with the Atacama Large Millimeter/submillimeter Ar…
JWST's PEARLS: 119 multiply imaged galaxies behind MACS0416, lensing properties of caustic crossing galaxies, and the relation between halo mass and number of globular clusters at z = 0.4
Grogin, Norman A.; Koekemoer, Anton M.; Pirzkal, Nor +26 more
We present a new lens model for the ɀ = 0.396 galaxy cluster MACS J0416.1 –2403 based on a previously known set of 77 spectroscop-ically confirmed, multiply imaged galaxies plus an additional set of 42 candidate multiply imaged galaxies from past HST and new JWST data. The new galaxies lack spectroscopic redshifts but have geometric and/or photome…
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…
PROJECT-J: JWST Observations of HH46 IRS and Its Outflow. Overview and First Results
Hartigan, Patrick; Codella, Claudio; Alcalá, Juan M. +23 more
We present the first results of the JWST program PROJECT-J (PROtostellar JEts Cradle Tested with JWST), designed to study the Class I source HH46 IRS and its outflow through NIRSpec and MIRI spectroscopy (1.66–28 µm). The data provide line images (∼6.″6 in length with NIRSpec, and up to ∼20″ with MIRI) revealing unprecedented details within …
Dissecting the Crab Nebula with JWST: Pulsar Wind, Dusty Filaments, and Ni/Fe Abundance Constraints on the Explosion Mechanism
Temim, Tea; Drissen, Laurent; Rest, Armin +19 more
We present JWST observations of the Crab Nebula, the iconic remnant of the historical SN 1054. The observations include NIRCam and MIRI imaging mosaics plus MIRI/MRS spectra that probe two select locations within the ejecta filaments. We derive a high-resolution map of dust emission and show that the grains are concentrated in the innermost, high-…