Results 91 to 100 of about 425,590 (288)
LAMOST Reveals Long-lived Protoplanetary Disks
The Astronomical JournalWhile both observations and theories demonstrate that protoplanetary disks are not expected to live much longer than ∼10 Myr, several examples of prolonged disks have been observed in the past.
Xiao-Long Wang +4 more
doaj +1 more source
ALMA survey of Class II protoplanetary disks in Corona Australis: a young region with low disk masses [PDF]
Astronomy & Astrophysics, 2019 Context. In recent years, the disk populations in a number of young star-forming regions have been surveyed with the Atacama Large Millimeter/submillimeter Array (ALMA).
P. Cazzoletti +22 more
semanticscholar +1 more source
Gas Evolution in Protoplanetary Disks [PDF]
AIP Conference Proceedings, 2009 This article summarizes a Splinter Session at the Cool Stars XV conference in St. Andrews with 3 review and 4 contributed talks. The speakers have discussed various approaches to understand the structure and evolution of the gas component in protoplanetary disks.
Peter Woitke +12 more
openaire +6 more sources
Meteoritics &Planetary Science, Volume 60, Issue 3, Page 442-463, March 2025.Abstract Cosmic ray exposure (CRE) ages provide information about the parent bodies and source regions of meteorite classes. Cosmogenic noble gases are often used to quantify exposure time scales ranging from tens of ka to hundreds of Ma. The production rate of cosmogenic noble gases is primarily controlled by a meteorite's chemical composition ...
M. Mijjum +5 more
wiley +1 more source
Chemistry of Complex Organic Molecules in the V883 Ori Disk Revealed by ALMA Band 3 Observations
The Astronomical JournalComplex organic molecules (COMs) in protoplanetary disks are key to understanding the origin of volatiles in comets in our solar system, yet the chemistry of COMs in protoplanetary disks remains poorly understood.
Yoshihide Yamato +5 more
doaj +1 more source
Heating and cooling processes in disks*
EPJ Web of Conferences, 2015 This chapter summarises current theoretical concepts and methods to determine the gas temperature structure in protoplanetary disks by balancing all relevant heating and cooling rates.
Woitke Peter
doaj +1 more source
Deep Search for Molecular Oxygen in TW Hya
The Astrophysical Journal, 2023 The dominant form of oxygen in cold molecular clouds is gas-phase carbon monoxide (CO) and ice-phase water (H _2 O). Yet, in planet-forming disks around young stars, gas-phase CO and H _2 O are less abundant relative to their interstellar medium values ...
Becky J. Williams +3 more
doaj +1 more source
Self-Sustained Ionization and Vanishing Dead Zones in Protoplanetary Disks [PDF]
Astrophys.J. 628 (2005) L155-L158, 2005 We analyze the ionization state of the magnetohydrodynamically turbulent protoplanetary disks and propose a new mechanism of sustaining ionization. First, we show that in the quasi-steady state of turbulence driven by magnetorotational instability in a typical protoplanetary disk with dust grains, the amount of energy dissipation should be sufficient ...
arxiv +1 more source
The Nitrogen Carrier in Inner Protoplanetary Disks [PDF]
The Astrophysical Journal, 2019 Abstract The dominant reservoirs of elemental nitrogen in protoplanetary disks have not yet been observationally identified. Likely candidates are HCN, NH3, and N2. The relative abundances of these carriers determine the composition of planetesimals as a function of disk radius due to strong differences in their volatility. A significant
Klaus M. Pontoppidan +6 more
openaire +6 more sources
Meteoritics &Planetary Science, Volume 60, Issue 3, Page 464-483, March 2025.Abstract Xenoliths in carbonaceous chondrites include lithologies that are unrepresented in the meteorite record and so are a rich source of information on asteroid diversity. Cold Bokkeveld is a CM2 regolith breccia that contains both hydrous and anhydrous lithic clasts. Here, we describe a hydrous clast with a fine‐grained rim.
Martin R. Lee +3 more
wiley +1 more source