Results 31 to 40 of about 772 (182)

Molecular catastrophes and the formation of circumstellar dust [PDF]

open access: yesSymposium - International Astronomical Union, 1987
Radiative instabilities due to simple molecules may convert chromospheric material into masering molecules and dust capable of being removed from the star by radiation pressure.
openaire   +2 more sources

Sudden Extreme Obscuration of a Sun-like Main-sequence Star: Evolution of the Circumstellar Dust around ASASSN-21qj

open access: yesThe Astrophysical Journal, 2023
ASASSN-21qj is a distant Sun-like star that recently began an episode of deep dimming events after no prior recorded variability. Here we examine archival and newly obtained optical and near-infrared data of this star.
Jonathan P. Marshall   +8 more
doaj   +1 more source

Dust in circumstellar disks [PDF]

open access: yes, 2006
This thesis presents observational and theoretical studies of the size and spatial distribution of dust particles in circumstellar disks. Using millimetre interferometric observations of optically thick disks around T Tauri stars, I provide conclusive evidence for the presence of millimetre- to centimetre-sized dust aggregates.
openaire   +1 more source

A Coronagraphic Pilot Study of the Circumstellar Environments around Red Supergiants: CD -31°4916’s Dust Morphology

open access: yesThe Astronomical Journal
Many mechanisms have been proposed to contribute to massive-star mass loss, but in general little is known about the physics involved. Studies of circumstellar environments around massive stars might help to determine which mechanisms are the most common.
Jamie R. Lomax   +3 more
doaj   +1 more source

Coagulation–Fragmentation Equilibrium for Charged Dust: Abundance of Submicron Grains Increases Dramatically in Protoplanetary Disks

open access: yesThe Astrophysical Journal, 2023
Dust coagulation in protoplanetary disks is not straightforward and is subject to several slowdown mechanisms, such as bouncing, fragmentation, and radial drift to the star.
Vitaly Akimkin   +4 more
doaj   +1 more source

Discovery and Initial Investigation of a New Low Surface Brightness Planetary Nebula Candidate at High Galactic Latitude

open access: yesAstronomische Nachrichten, Volume 347, Issue 3, March 2026.
ABSTRACT Planetary nebulae represent a late evolutionary phase of low‐ to intermediate‐mass stars. In this article, we present the serendipitous discovery of a previously unknown, faint potential Galactic planetary nebula (PN) in the constellation Camelopardalis, identified during a survey‐inspection, aiming at the detection of dwarf companions of the ...
W. E. Celnik   +12 more
wiley   +1 more source

Circumstellar dust emission models

open access: yesThe Astrophysical Journal, 1994
We present the wavelength-dependent absorption coefficient K(sub lambda) the scattering coefficient o(sub lambda), the albedo w(sub lambda), and the average cosine of the scattering phase function g(sub lambda) between 0.0912 micrometers and 1000 micrometers for four interstellar medium grain models.
Mark G. Wolfire, Ed Churchwell
openaire   +1 more source

Confined Chemistry in Space: Zeolite‐Supported Fe13 Nanoclusters Modulate CS Reactivity

open access: yesSmall Structures, Volume 7, Issue 3, March 2026.
The study explores how an Fe13 cluster confined in chabazite reshapes the reaction of CS and H2 under astrochemical conditions. Confinement promotes C–S bond cleavage over hydrogenation, directing chemistry toward CH4 and H2S formation. Additional CS enables CS2 and C2 species. Microkinetic analysis identifies protoplanetary environments where zeolites
Gerard Pareras, Albert Rimola
wiley   +1 more source

Near-infrared Integral-field Spectroscopy of the Wind Forming Region of CW Leo

open access: yesThe Astronomical Journal
The circumstellar envelope of the carbon star CW Leo exhibited various unexpected changes in recent optical imaging observations. We have performed a follow-up observation using the Near-infrared Integral-Field Spectrograph (NIFS) equipped on the Gemini ...
Hyosun Kim   +3 more
doaj   +1 more source

Satellites and Small Bodies With ALMA: Insights Into Solar System Formation and Evolution

open access: yesAGU Advances, Volume 6, Issue 6, December 2025.
Abstract Our understanding of the formation and evolution of planetary systems has made major advances in the past decade. This progress has been driven in large part by the Atacama Large Millimeter/submillimeter Array (ALMA), which has given us an unprecedented view of solar system bodies themselves, and of the structure and chemistry of forming ...
Katherine de Kleer   +3 more
wiley   +1 more source

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