Results 81 to 90 of about 55,496 (241)

Variability in Protoplanetary Nebulae. IX. Evidence for Evolution in a Decade

The Astrophysical Journal, 2022
Abstract We have carried out a new photometric V,R C study of 12 protoplanetary nebulae, objects in the short-lived transition between the asymptotic giant branch and planetary nebula phases of stellar evolution.
Bruce J. Hrivnak, Wenxian Lu, William C. Bakke, Peyton J. Grimm   +3 more
openaire   +2 more sources

Atmospheres of protoplanetary cores: critical mass for nucleated instability [PDF]

Astrophys.J.648:666-682,2006, 2004
We study quasi-static atmospheres of accreting protoplanetary cores for different opacity behaviors and realistic planetesimal accretion rates in various parts of protoplanetary nebula. Atmospheres segregate into those having outer convective zone which smoothly merges with the nebular gas, and those having almost isothermal outer radiative region ...
arxiv   +1 more source

Mid-infrared spectroscopy of protoplanetary and planetary nebulae [PDF]

Monthly Notices of the Royal Astronomical Society, 2002
We present medium-resolution (R ∼600), mid-infrared (7.5-14 μm) spectra of 15 young planetary nebulae. Linestrengths for observed forbidden transitions are presented, and numerous broad emission features from silicates, polyaromatic hydrocarbons (PAHs) and silicon carbide (SiC) are observed.
John C. Wilson, S. A. Rinehart, J. R. Houck, J. D. T. Smith   +3 more
openaire   +2 more sources

The Phases of Water Ice in the Solar Nebula [PDF]

, 2014
Understanding the phases of water ice that were present in the solar nebula has implications for understanding cometary and planetary compositions as well as internal evolution of these bodies. Here we show that amorphous ice formed more readily than previously recognized, with formation at temperatures <70 K being possible under protoplanetary disk ...
arxiv   +1 more source

A far-ultraviolet–driven photoevaporation flow observed in a protoplanetary disk [PDF]

Science
Most low-mass stars form in stellar clusters that also contain massive stars, which are sources of far-ultraviolet (FUV) radiation. Theoretical models predict that this FUV radiation produces photodissociation regions (PDRs) on the surfaces of ...
Olivier Berné, É. Habart, E. Peeters, I. Schroetter, A. Canin, A. Sidhu, R. Chown, E. Bron, T. J. Haworth, Pamela Klaassen, B. Trahin, D. Van De Putte, F. Alarcón, M. Zannese, A. Abergel, Edwin A. Bergin, J. Bernard-Salas, C. Boersma, J. Cami, S. Cuadrado, E. Dartois, Daniel Dicken, M. Elyajouri, Asunción Fuente, J. Goicoechea, Karl D. Gordon, Lina Issa, C. Joblin, O. Kannavou, Baria Khan, O. Lacinbala, D. Languignon, R. Le Gal, A. Maragkoudakis, R. Meshaka, Yoko Okada, T. Onaka, Sofia Pasquini, M. Pound, M. Robberto, M. Röllig, Bethany R. Schefter, T. Schirmer, Thomas Simmer, B. Tabone, A. Tielens, S. Vicente, M. Wolfire   +47 more
semanticscholar   +1 more source

New Paradigms For Asteroid Formation

, 2015
Asteroids and meteorites provide key evidence on the formation of planetesimals in the Solar System. Asteroids are traditionally thought to form in a bottom-up process by coagulation within a population of initially km-scale planetesimals.
Cuzzi, Jeffrey N., Gounelle, Matthieu, Jacquet, Emmanuel, Johansen, Anders, Morbidelli, Alessandro   +4 more
core   +1 more source

Mid‐infrared detection and characterization of refractory inclusions in CM and CO chondrites: A non‐destructive approach for returned space samples

Meteoritics &Planetary Science, Volume 60, Issue 3, Page 544-569, March 2025.
Abstract Refractory inclusions (RIs) in chondrites are widely used as tracers of early solar system formation conditions. In the context of sample‐return missions, a non‐destructive and non‐invasive analytical tool that can rapidly detect and characterize RIs in space samples during their early phase of study is highly needed.
Jean Charlier, Alice Aléon‐Toppani, Rosario Brunetto, Jérôme Aléon, Ferenc Borondics   +4 more
wiley   +1 more source

Material enhancement in protoplanetary nebulae by particle drift through evaporation fronts [PDF]

Astrophys.J. 614 (2004) 490-496, 2004
Solid material in a protoplanetary nebula is subject to vigorous redistribution processes relative to the nebula gas. Meter-sized particles drift rapidly inwards near the nebula midplane, and material evaporates when the particles cross a condensation/evaporation boundary. The material cannot be removed as fast in its vapor form as it is being supplied
arxiv   +1 more source

Volatiles in protoplanetary disks [PDF]

, 2014
Volatiles are compounds with low sublimation temperatures, and they make up most of the condensible mass in typical planet-forming environments. They consist of relatively small, often hydrogenated, molecules based on the abundant elements carbon ...
Bergin, Edwin A., Brittain, Sean, Marty, Bernard, Mousis, Olvier, Oberg, Karin L., Pontoppidan, Klaus M., Salyk, Colette   +6 more
core   +2 more sources

The Formation and Dynamics of Super-Earth Planets

, 2013
Super-Earths, objects slightly larger than Earth and slightly smaller than Uranus, have found a special place in exoplanetary science. As a new class of planetary bodies, these objects have challenged models of planet formation at both ends of the ...
Haghighipour, Nader
core   +1 more source