Results 31 to 40 of about 1,478 (224)

Laboratory studies of circumstellar and interstellar materials

, 2009
When the most primitive types of meteorite (chondrites) and interplanetary dust particles (IDPs) formed in the solar protoplanetary disk (solar nebula), all of them incorporated at least two types of presolar material: interstellar organic matter and ...
C.M.O.D. Alexander
core   +1 more source

Rings, Shells, and Arc Structures Around B[e] Supergiants. I. Classical Tools of Nonlinear Hydrodynamics

The Astrophysical Journal
Structures in circumstellar matter reflect both fast processes and quasi-equilibrium states. A geometrical diversity of emitting circumstellar matter is observed around evolved massive stars, in particular around B[e] supergiants.
Dieter H. Nickeler, Michaela Kraus
doaj   +1 more source

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

Small 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

Environmental dependence of Type IIn supernova properties [PDF]

, 2023
Type IIn supernovae occur when stellar explosions are surrounded by dense hydrogen-rich circumstellar matter. The dense circumstellar matter is likely formed by extreme mass loss from their progenitors shortly before they explode.
Hanindyo Kuncarayakti, Joseph P. Anderson, Joseph D. Lyman, Jose L. Prieto, Lluís Galbany, Cristina Jiménez-Palau, Kuncarayakti, Hanindyo, Ping Chen, Thallis Pessi, Lyman, Joseph D., Pessi, Thallis, Takashi J. Moriya, Anderson, Joseph P., Chen, Ping, Moriya, Takashi J., Galbany, Lluís, Jiménez-Palau, Cristina, Dong, Subo, Prieto, Jose L., Kochanek, Christopher S., Christopher S. Kochanek, Subo Dong, Sánchez, Sebastián F., Sebastián F. Sánchez   +23 more
core   +1 more source

Discovery of Volatile Gas in the Giant Impact Disk Around the 150 Myr Old HD 23514

The Astrophysical Journal Letters
We report the discovery of CO _2 gas emission around HD 23514, an F5V star in the ∼150 Myr old Pleiades cluster, hosting one of the rare giant-impact disks with unique mineralogy dominated by silica dust. We show that the dust feature remains stable over
Kate Y. L. Su, Attila Moór, Chengyan Xie, Ilaria Pascucci, George H. Rieke, Ágnes Kóspál, Mark C. Wyatt, Péter Ábrahám, Luca Matrà, Zoe Roumeliotis, D. J. Wilner   +10 more
doaj   +1 more source

The 12CO gas structures of protoplanetary disks in the Upper Scorpius region

Astronomy & Astrophysics
We present measurements of key protoplanetary disk properties inferred from parametric models of ALMA 12CO spectral line visibilities. We derived gas-disk radii, integrated fluxes, optically thick emission layers, and brightness temperature profiles for ...
Zallio Luigi, Rosotti Giovanni P., Vioque Miguel, Miotello Anna, Andrews Sean M., Manara Carlo F., Carpenter John M., Empey Aaron, Kurtovic Nicolás T., Law Charles J., Longarini Cristiano, Paneque-Carreño Teresa, Teague Richard, Villenave Marion, Yen Hsi-Wei, Zagaria Francesco   +15 more
doaj   +1 more source

Diurnal Variability Modulates Episodic Convection in Hothouse Climates Over Ocean and Swamp‐Like Surface Conditions

Journal of Advances in Modeling Earth Systems, Volume 18, Issue 2, February 2026.
Abstract Hot and moist “hothouse” climates occurred in Earth's past and are expected in Earth's far future climate, driven by increasing solar luminosity. In hothouse climate regimes, precipitation transitions from a quasi‐steady state, as in present‐day tropical convection, to an “episodic deluge” or relaxation‐oscillator (RO) regime where ...
Namrah Habib, Guy Dagan, Nathan Steiger
wiley   +1 more source

The Dual-Axis Circumstellar Environment of the Type IIn Supernova 1997eg [PDF]

, 2008
We present multi-epoch spectral and spectropolarimetric observations of the Type IIn supernova (SN) 1997eg that indicate the presence of a flattened disk-like concentration of circumstellar material surrounding nonspherical ejecta, with which the disk is
Hoffman, Jennifer L., Jennifer L. Hoffman, Thomas Matheson, Matheson, Thomas, Chornock, R, Ryan Chornock, Leonard, Douglas C., Douglas C. Leonard, Barth, Aaron J., Alexei V. Filippenko, Aaron J. Barth, Filippenko, Alexei V.   +11 more
core   +1 more source

SN 2020uem: a Possible Thermonuclear Explosion within a Dense Circumstellar Medium (II). The Properties of the CSM from Polarimetry and Light-curve Modeling

The Astrophysical Journal, 2023
Type IIn/Ia-CSM supernovae (SNe IIn/Ia-CSM) are classified by their characteristic spectra, which exhibit narrow hydrogen emission lines originating from strong interaction with a circumstellar medium (CSM) together with broad lines of intermediate-mass ...
Kohki Uno, Takashi Nagao, Keiichi Maeda, Hanindyo Kuncarayakti, Masaomi Tanaka, Koji S. Kawabata, Tatsuya Nakaoka, Miho Kawabata, Masayuki Yamanaka, Kentaro Aoki, Keisuke Isogai, Mao Ogawa, Akito Tajitsu, Ryo Imazawa   +13 more
doaj   +1 more source

Exploring the Effects of Reduced Gravitational Field Impacts on Convective Heat Transfer: A Comprehensive Review

Heat Transfer, Volume 55, Issue 1, Page 764-774, January 2026.
ABSTRACT This review explores the impact of gravitational instability on convective heat transfer, integrating existing research results and theoretical models. Gravitational instability is vital in promoting or hindering convective actions in different systems, such as atmospheric events, ocean currents, and industrial processes.
Hossam A. Nabwey, Muhammad Ashraf, A. M. Rashad, Ali J. Chamkha   +3 more
wiley   +1 more source