Results 51 to 60 of about 2,834 (210)

Hα Variability of AB Aur b with the Hubble Space Telescope: Probing the Nature of a Protoplanet Candidate with Accretion Light Echoes

The Astronomical Journal
Giant planets generate accretion luminosity as they form. Much of this energy is radiated in strong H α line emission, which has motivated direct imaging surveys at optical wavelengths to search for accreting protoplanets.
Brendan P. Bowler, Yifan Zhou, Lauren I. Biddle, Lillian Yushu Jiang, Jaehan Bae, Laird M. Close, Katherine B. Follette, Kyle Franson, Adam L. Kraus, Aniket Sanghi, Quang Tran, Kimberly Ward-Duong, Ya-Lin Wu, Zhaohuan Zhu   +13 more
doaj   +1 more source

On the Evolution and Survival of Protoplanets Embedded in a Protoplanetary Disk

, 2012
We model the evolution of a Jupiter-mass protoplanet formed by the disk instability mechanism at various radial distances accounting for the presence of the disk. Using three different disk models, it is found that a newly-formed Jupiter-mass protoplanet
A. Vazan, Bell, Boley, Boss, Boss, Cai, Cai, D'Alessio, D'Angelo, Durisen, Hartmann, Mayer, R. Helled, Rafikov, Rafikov   +14 more
core   +1 more source

Co-orbital Oligarchy [PDF]

, 2009
We present a systematic examination of the changes in semi-major axis caused by the mutual interactions of a group of massive bodies orbiting a central star in the presence of eccentricity dissipation.
Benjamin F. Collins, Collins, Collins, Ford, Franchi, Goldreich, Halliday, Kenyon, Kokubo, Press, Re'em Sari, Schlichting   +11 more
core   +2 more sources

Protoplanets mission reinstated [PDF]

Eos, Transactions American Geophysical Union, 2006
NASA announced on 27 March that it will go forward with its Dawn mission to Ceres and Vesta, two protoplanets in the solar system.Dawn had been put on hold last fall for a three‐month review, and NASA canceled the mission on 2 March.The agency cited a 20 percent cost overrun (from $373 million to $446 million) and technical issues, including problems ...
openaire   +1 more source

Accretion and Differentiation of Vesta and the Mesosiderite Parent Body Inferred From Ni Stable Isotope Compositions

Geophysical Research Letters, Volume 52, Issue 19, 16 October 2025.
Abstract We present high‐precision Ni stable isotope data for mesosiderites, eucrites, and diogenites to investigate the accretion and differentiation of asteroid 4 Vesta. Ni isotope variations in eucrites and diogenites are dominated by kinetic diffusion and chondritic contamination, rendering them unsuitable for reconstructing Vesta's primitive Ni ...
Ke Zhu, Makiko K. Haba, Qi Chen, Lu Chen
wiley   +1 more source

Deep Paβ Imaging of the Candidate Accreting Protoplanet AB Aur b

The Astronomical Journal
Giant planets grow by accreting gas through circumplanetary disks, but little is known about the timescale and mechanisms involved in the planet-assembly process because few accreting protoplanets have been discovered. Recent visible and infrared imaging
Lauren I. Biddle, Brendan P. Bowler, Yifan Zhou, Kyle Franson, Zhoujian Zhang   +4 more
doaj   +1 more source

Orbital Migration of Protoplanets in a Marginally Gravitationally Unstable Disk. II. Migration, Merging, and Ejection

The Astrophysical Journal, 2023
Protoplanets formed in a marginally gravitationally unstable (MGU) disk by either core accretion or disk instability will be subject to dynamical interactions with massive spiral arms, possibly resulting in inward or outward orbital migration, mergers ...
Alan P. Boss
doaj   +1 more source

Overcoming migration during giant planet formation

, 2007
In the core accretion model, gas giant formation is a race between growth and migration; for a core to become a jovian planet, it must accrete its envelope before it spirals into the host star.
Edward W. Thommes, Leif Nilsson, Lynden-Bell D., Norman Murray   +3 more
core   +1 more source

Electrical Resistivity of Liquid Fe‐16S‐2Si up to 13 GPa With Implications for the Adiabatic Heat Flux Through the Core of Exoplanet TRAPPIST‐1h

Journal of Geophysical Research: Planets, Volume 130, Issue 10, October 2025.
Abstract Thermal convective processes in the liquid cores of terrestrial planetary bodies with the capacity to generate magnetic dynamos may be better characterized by thermal conductivity estimates of core conditions. The composition of the core of asteroid 4 Vesta as determined by geochemical studies of HED meteorites is used as an analog for the ...
E. M. Lenhart, W. Yong, R. A. Secco
wiley   +1 more source

Constraints on the Feasibility of Ferrovolcanism on Asteroid 16 Psyche

Journal of Geophysical Research: Planets, Volume 130, Issue 8, August 2025.
Abstract Asteroid 16 Psyche's surface appears to be highly metallic, but its bulk density suggests a silicate‐rich interior. Ferrovolcanism has been suggested to explain how a silicate‐rich body could develop a metallic surface. This requires trapping of light elements bearing iron‐rich metallic melt in a core solidifying from the outside inwards.
J. J. Jorritsma, W. van Westrenen
wiley   +1 more source