Results 41 to 50 of about 13,043 (174)

A Comprehensive Model of Morphologically Realistic Cosmic Dust Particles: An Application to Mimic the Unusual Polarization Properties of the Interstellar Comet 2I/Borisov

open access: yesThe Astrophysical Journal, 2023
The cosmic dust particles found in space are mainly porous aggregates of smaller grains. Theoretically, these aggregates are replicated using fractal geometry, assuming a cluster of spheres.
Prithish Halder, Sujan Sengupta
doaj   +1 more source

A search for diffuse bands in the circumstellar envelopes of post-AGB stars

open access: yes, 2007
In this work we present the results of a systematic search for diffuse bands (DBs, hereafter) in the circumstellar envelopes of a carefully selected sample of post-AGB stars.
Allamandola   +106 more
core   +2 more sources

Dust evolution and satellitesimal formation in circumplanetary disks [PDF]

open access: yes, 2018
It is believed that satellites of giant planets form in circumplanetary disks. Many of the previous contributions assumed that their formation process proceeds similarly to rocky planet formation, via accretion of the satellite seeds, called ...
Drazkowska, Joanna, Szulágyi, Judit
core   +1 more source

Insights Into the Gas‐Phase Structure and Internal Dynamics of Diphenylsilane: A Broadband Rotational Spectroscopy Study

open access: yesChemPhysChem, Volume 26, Issue 2, January 14, 2025.
The structure of diphenylsilane could be determined from the rotational spectra of all its singly substituted heavy atom isotopologues. A comparison with its oxygen analogue diphenylether revealed some interesting differences in the internal dynamics as well as in the gas‐phase structure.
Gayatri Batra, Melanie Schnell
wiley   +1 more source

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

open access: yesThe 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   +10 more
doaj   +1 more source

The Low Velocity Wind from the Circumstellar Matter Around the B9V Star sigma Herculis

open access: yes, 2002
We have obtained FUSE spectra of sigma Her, a nearby binary system, with a main sequence primary, that has a Vega-like infrared excess. We observe absorption in the excited fine structure lines C II* at 1037 A, N II* at 1085 A, and N II** at 1086 A that ...
Abgrall H.   +10 more
core   +1 more source

Silicate Emission Profiles from Low-Mass Protostellar Disks in the Orion Nebula: Evidence for Growth and Thermal Processing of Grains [PDF]

open access: yes, 2006
We present 8--13 micron low resolution spectra (R~100) of 8 low-mass protostellar objects ("proplyds") in the Orion Nebula using the Long Wavelength Spectrometer (LWS) at the W. M. Keck Observatory.
Bally, John   +4 more
core   +2 more sources

First direct detection of large polycyclic aromatic hydrocarbons on asteroid (162173) Ryugu samples: An interstellar heritage

open access: yesNatural Sciences, Volume 4, Issue 4, October 2024.
Large free aromatic species, with up to 61 carbon atoms, were detected in grains of the Ryugu carbonaceous asteroid using ultra‐sensitive two‐step laser mass spectrometry. This discovery confirms the presence of large polycyclic aromatic hydrocarbons in the interstellar medium and provides new information on the formation and evolution of organic ...
Hassan Sabbah   +3 more
wiley   +1 more source

Near-infrared Integral-field Spectroscopy of the Wind Forming Region of CW Leo

open access: yesThe Astronomical Journal
The circumstellar envelope of the carbon star CW Leo exhibited various unexpected changes in recent optical imaging observations. We have performed a follow-up observation using the Near-infrared Integral-Field Spectrograph (NIFS) equipped on the Gemini ...
Hyosun Kim   +3 more
doaj   +1 more source

The Ionization Energies of Dust-Forming Metal Oxide Clusters

open access: yesUniverse, 2021
Stellar dust grains are predominantly composed of mineralic, anorganic material forming in the circumstellar envelopes of oxygen-rich AGB stars. However, the initial stage of the dust synthesis, or its nucleation, is not well understood.
David Gobrecht   +3 more
doaj   +1 more source

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