Results 61 to 70 of about 19,742 (238)

The Nitrogen Carrier in Inner Protoplanetary Disks [PDF]

open access: yesThe 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

Sites of Planet Formation in Binary Systems. I. Evidence for Disk−Orbit Alignment in the Close Binary FO Tau

open access: yesThe Astronomical Journal
Close binary systems present challenges to planet formation. As binary separations decrease, so do the occurrence rates of protoplanetary disks in young systems and planets in mature systems.
Benjamin M. Tofflemire   +10 more
doaj   +1 more source

Deep Space Network Radio Science and Ground‐Based Planetary Radar in the Next Decade

open access: yesRadio Science, Volume 60, Issue 7, July 2025.
Abstract The Deep Space Network (DSN) has been a core operational element of NASA's crewed and robotic exploration of the Solar System since the early 1960s. The primary role of the DSN has been to acquire telemetry and navigation data, but over the years, its radiometric and radar capabilities have expanded to form a system for obtaining unique ...
R. S. Park   +13 more
wiley   +1 more source

An ALMA Survey of CO isotopologue emission from Protoplanetary Disks in Chamaeleon I [PDF]

open access: yes, 2017
The mass of a protoplanetary disk limits the formation and future growth of any planet. Masses of protoplanetary disks are usually calculated from measurements of the dust continuum emission by assuming an interstellar gas-to-dust ratio.
Apai, Daniel   +10 more
core   +2 more sources

Chemistry in Externally FUV-irradiated Disks in the Outskirts of the Orion Nebula Cluster

open access: yesThe Astrophysical Journal
Most stars are born in stellar clusters, and their protoplanetary disks, which are the birthplaces of planets, can, therefore, be affected by the radiation of nearby massive stars.
Javiera K. Díaz-Berríos   +6 more
doaj   +1 more source

An overview of the petrography and petrology of particles from aggregate sample from asteroid Bennu

open access: yesMeteoritics &Planetary Science, Volume 60, Issue 5, Page 979-996, May 2025.
Abstract The OSIRIS‐REx mission returned a sample of regolith from the carbonaceous asteroid Bennu in September 2023. We present preliminary in situ investigations of the petrology and petrography of selected particles ranging in size from 0.5 to 3 mm.
Harold C. Connolly Jr   +57 more
wiley   +1 more source

Low EUV Luminosities Impinging on Protoplanetary Disks [PDF]

open access: yes, 2014
The amount of high-energy stellar radiation reaching the surface of protoplanetary disks is essential to determine their chemistry and physical evolution. Here, we use millimetric and centimetric radio data to constrain the EUV luminosity impinging on 14
Brooks, K. J.   +6 more
core   +3 more sources

Zonal Flow and Self-regulating Mechanism in a Hydrodynamic Disk

open access: yesThe Astrophysical Journal
This study addresses key aspects of momentum transport in hydrodynamic disks, which is critical for understanding zonal flow generation and turbulence in compressible hydrodynamic disks.
Chang-Chun Chen   +3 more
doaj   +1 more source

Hydration and dehydration of CM chondrites revealed by X‐ray diffraction combined with textural observations and compositional data

open access: yesMeteoritics &Planetary Science, Volume 60, Issue 5, Page 1194-1215, May 2025.
Abstract The in‐plane rotation method is used to obtain X‐ray random diffraction (XRD) patterns of polished thin sections of 10 CM chondrites. The samples include five intermediately altered CM chondrites with subtypes 2.6–2.3, two heavily altered CM chondrites with subtype 2.0 and three with secondary heating after hydration (Y 980036, Y 980051, and ...
Naoya Imae   +2 more
wiley   +1 more source

PROTOPLANETARY DISK STRUCTURES IN OPHIUCHUS [PDF]

open access: yesThe Astrophysical Journal, 2009
ApJ in press: 51 pages, 13 ...
Sean M. Andrews   +4 more
openaire   +3 more sources

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