Search Publications
No surviving non-compact stellar companion to Cassiopeia A
Justham, Stephen; Do, Tuan; Milisavljevic, Dan +7 more
Massive stars in binaries can give rise to extreme phenomena such as X-ray binaries and gravitational wave sources after one or both stars end their lives as core-collapse supernovae. Stars in close orbit around a stellar or compact companion are expected to explode as "stripped-envelope supernovae", showing no (Type Ib/c) or little (Type IIb) sig…
A new radio molecular line survey of planetary nebulae. HNC/HCN as a diagnostic of ultraviolet irradiation
Kastner, J. H.; Alcolea, J.; Santander-García, M. +3 more
Certain planetary nebulae (PNe) contain shells, filaments, or globules of cold gas and dust whose heating and chemistry are likely driven by UV and X-ray emission from their central stars and from wind-collision-generated shocks. We present the results of a survey of molecular line emission in the 88-236 GHz range from nine nearby (<1.5 kpc) pl…
The Gaia-ESO Survey: Age spread in the star forming region NGC 6530 from the HR diagram and gravity indicators
Gilmore, G.; Franciosini, E.; Randich, S. +33 more
Context. In very young clusters, stellar age distribution is empirical proof of the duration of star cluster formation and thus it gives indications of the physical mechanisms involved in the star formation process. Determining the amount of interstellar extinction and the correct reddening law are crucial steps to derive fundamental stellar param…
Superflares on AB Doradus observed with TESS
Schmitt, J. H. M. M.; Czesla, S.; Robrade, J. +2 more
We present short-cadence data of the ultra-active star AB Dor measured by the Transiting Exoplanet Survey Satellite (TESS). In the TESS light curves of AB Dor, we found numerous flare events in addition to time-variable rotational modulation with an amplitude of up to 7%. We identified eight superflares (releasing more than 1034 erg) an…
Study of CS, SiO, and SiS abundances in carbon star envelopes: assessing their role as gas-phase precursors of dust
Cernicharo, J.; Agúndez, M.; Massalkhi, S.
Aims: We aim to determine the abundances of CS, SiO, and SiS in a large sample of carbon star envelopes covering a wide range of mass loss rates to investigate the potential role that these molecules could play in the formation of dust in the surroundings of the central AGB star.
Methods: We surveyed a sample of 25 carbon-rich AGB stars …
Thermal emission from bow shocks. I. 2D hydrodynamic models of the Bubble Nebula
Green, Samuel; Mackey, Jonathan; Haworth, Thomas J. +2 more
The Bubble Nebula (or NGC 7635) is a parsec-scale seemingly spherical wind-blown bubble around the relatively unevolved O star BD+60°2522. The young dynamical age of the nebula and significant space velocity of the star suggest that the Bubble Nebula might be a bow shock. We ran 2D hydrodynamic simulations to model the interaction of the wind of t…
Particle acceleration in a nearby galaxy cluster pair: the role of cluster dynamics
Brunetti, G.; Rossetti, M.; Shimwell, T. W. +17 more
Context. Diffuse radio emission associated with the intracluster medium (ICM) is observed in a number of merging galaxy clusters. It is currently believed that a fraction of the kinetic energy in mergers is channeled into nonthermal components, such as turbulence, cosmic rays, and magnetic fields, which may lead to the formation of giant synchrotr…
VLTI/PIONIER survey of disks around post-AGB binaries. Dust sublimation physics rules
Min, M.; Van Winckel, H.; Kamath, D. +4 more
Context. Post-asymptotic giant branch (AGB) binaries are surrounded by circumbinary disks of gas and dust that are similar to protoplanetary disks found around young stars.
Aims: We aim to understand the structure of these disks and identify the physical phenomena at play in their very inner regions. We want to understand the disk-binary inte…
Discovery of a 21 Myr old stellar population in the Orion complex⋆
Lewis, Geraint F.; Buder, Sven; Ness, Melissa K. +12 more
Context. The Orion complex is arguably the most studied star-forming region in the Galaxy. While stars are still being born in the Orion nebula, the oldest part was believed to be no more than 13 Myr old.
Aims: In order to study the full hierarchy of star formation across the Orion complex, we perform a clustering analysis of the Ori OB1a reg…
Properties of small meteoroids studied by meteor video observations
Vojáček, V.; Borovička, J.; Koten, P. +2 more
Aims: The complex study of millimetre-sized meteoroids can reveal more about the structure and origin of population of these meteoroids.
Methods: Double-station video observations, paired with spectroscopic video observations, were used to study small meteoroids. In total 152 sporadic and shower meteors of maximum brightness between magn…