Search Publications
Spectral library of age-benchmark low-mass stars and brown dwmarfs
Béjar, V. J. S.; Boudreault, S.; Bonnefoy, M. +3 more
In recent years, some extremely red brown dwarfs have been discovered. They were believed to have a low surface gravity, but many of their spectral characteristics are similar to those of high-surface-gravity brown dwarfs, showing that the spectral characteristics of young brown dwarfs are poorly understood. We aim to test surface-gravity indicato…
Seeds of Life in Space (SOLIS). VIII. SiO isotopic fractionation, and a new insight into the shocks of L1157-B1
Podio, L.; Codella, C.; Ceccarelli, C. +4 more
Context. Contrary to what is expected from models of Galactic chemical evolution, the isotopic fractionation of silicon (Si) in the Galaxy has recently been found to be constant. This finding calls for new observations, also at core scales, to re-evaluate the fractionation of Si.
Aims: L1157-B1 is one of the outflow-shocked regions along the …
Detection of pristine circumstellar material from the Cassiopeia A supernova progenitor
Koo, Bon-Chul; Raymond, John C.; Jaffe, Daniel T. +4 more
Cassiopeia A is a nearby young supernova remnant that provides a unique laboratory for the study of core-collapse supernova explosions1. Cassiopeia A is known to be a type IIb supernova from the optical spectrum of its light echo2, but the immediate progenitor of the supernova remains uncertain3. Here, we report re…
A new trigger mechanism for coronal mass ejections. The role of confined flares and photospheric motions in the formation of hot flux ropes
van Driel-Gesztelyi, L.; Green, L. M.; Valori, G. +1 more
Context. Many previous studies have shown that the magnetic precursor of a coronal mass ejection (CME) takes the form of a magnetic flux rope, and a subset of them have become known as "hot flux ropes" due to their emission signatures in ∼10 MK plasma.
Aims: We seek to identify the processes by which these hot flux ropes form, with a view of …
Power-law energy distributions of small-scale impulsive events on the active Sun: results from IRIS
Ramsay, Gavin; Mathioudakis, Mihalis; Doyle, J. Gerry +2 more
Numerous studies have analysed inferred power-law distributions between frequency and energy of impulsive events in the outer solar atmosphere in an attempt to understand the predominant energy supply mechanism in the corona. Here, we apply a burst detection algorithm to high-resolution imaging data obtained by the Interface Region Imaging Spectro…
Intermediate-mass Stars Become Magnetic White Dwarfs
Caiazzo, Ilaria; Heyl, Jeremy; Richer, Harvey +8 more
When a star exhausts its nuclear fuel, it either explodes as a supernova or more quiescently becomes a white dwarf, an object about half the mass of our Sun with a radius of about that of the Earth. About one-fifth of white dwarfs exhibit the presence of magnetic fields, whose origin has long been debated as either the product of previous stages o…
CO, Water, and Tentative Methanol in η Carinae Approaching Periastron
Corcoran, Michael; Gull, Theodore R.; Damineli, Augusto +12 more
The complex circumstellar environment around the massive binary and luminous blue variable η Carinae is known to harbor numerous light molecules, emitting most strongly in rotational states with upper level energies to ∼300 K. In circumstellar gas, the complex organic molecule methanol (CH3OH) has been found almost exclusively around yo…
SiO maser astrometry of the red transient V838 Monocerotis
Menten, Karl M.; Reid, Mark J.; Ortiz-León, Gisela N. +3 more
We present multiepoch observations with the Very Long Baseline Array of SiO maser emission in the v = 1, J = 1-0 transition at 43 GHz from the remnant of the red nova V838 Mon. We modeled the positions of maser spots to derive a parallax of 0.166 ± 0.060 mas. Combining this parallax with other distance information results in a distance of 5.6 ± 0.…
Discovery of new members of the nearby young stellar association in Cepheus
Montes, D.; Grosso, N.; Guillout, P. +4 more
Context. Young field stars are hardly distinguishable from older ones because their space motion rapidly mixes them with the stellar population of the Galactic plane. Nevertheless, a careful target selection allows for young stars to be spotted throughout the sky.
Aims: We aim to identify additional sources associated with the four young como…
A wide survey for circumstellar disks in the Lupus complex
Alves, J.; Teixeira, P. S.; Scholz, A.
Previous star formation studies have, out of necessity, often defined a population of young stars confined to the proximity of a molecular cloud. Gaia allows us to examine a wider, three-dimensional structure of nearby star forming regions, leading to a new understanding of their history. We present a wide-area survey covering 494 deg2 …