Results 91 to 100 of about 301,064 (245)

On Circumstellar Envelope Formation

The Astrophysical Journal, 1997
The origin of magnetic fields observed in circumstellar envelopes and proto-planetary nebulae is investigated theoretically. The build-up region of these fields is likely to be found deep in the progenitor (assumed to be an asymptotic giant branch red giant).
openaire   +1 more source

Clusters Stagnating During Condensation: Metastable Material or a Separate State of Matter?

Annalen der Physik, Volume 537, Issue 10, October 2025.
Condensation stagnation, that is, the existence of a delay between nucleation and growth during the gas‐phase particle formation, is a crucial phenomenon, which manifests itself as the presence of supercritical clusters in resulting particulates. The light emission signature of stagnant clusters is identified in the magnesium particle flame in air, and,
Nicholas R. Jaramillo, Cole A. Ritchie, Michelle L. Pantoya, Igor E. Agranovski, Igor Altman   +4 more
wiley   +1 more source

Early Planet Formation in Embedded Disks (eDisk). XVII. A Compact but Structured Keplerian Disk and Large-scale Streamers Revealed in the Class I Protostellar System IRAS 04169+2702

The Astrophysical Journal
We present high-resolution (∼0 $\mathop{.}\limits^{^{\prime\prime} }$ 05; 8 au) dust continuum and molecular line observations toward the Class I protostellar system IRAS 04169+2702 in the Taurus B213 region, as part of the Atacama Large Millimeter ...
Ilseung Han, Woojin Kwon, Yusuke Aso, Nagayoshi Ohashi, John J. Tobin, Jes K. Jørgensen, Shigehisa Takakuwa, Leslie W. Looney, Yuri Aikawa, Christian Flores, Itziar de Gregorio-Monsalvo, Patrick M. Koch, Chang Won Lee, Jeong-Eun Lee, Zhi-Yun Li, Zhe-Yu Daniel Lin, Jinshi Sai, Travis J. Thieme, Jonathan P. Williams, Sacha Gavino, Miyu Kido, Shih-Ping Lai, Nguyen Thi Phuong, Alejandro Santamaría-Miranda, Hsi-Wei Yen   +24 more
doaj   +1 more source

Formaldehyde in oxygen-rich circumstellar envelopes [PDF]

Monthly Notices of the Royal Astronomical Society, 1993
We test the hypothesis that methane is the source of the carbon observed in carbon-bearing molecules around oxygen-rich stars, by considering the synthesis of formaldehyde which is formed in the reaction between oxygen atoms and methyl radicals. We find that, provided that the parent methane abundance is large enough, millimetre-wave emission lines of ...
T. J. Millar, H. Olofsson
openaire   +1 more source

Infrared spectroscopy and molecules in circumstellar envelopes [PDF]

International Astronomical Union Colloquium, 1994
During the last two decades there has been a tremendous renewal of interest in the circumstellar environment of evolved stars. This renewal has been mainly driven by sensitive microwave observing techniques. Microwave spectroscopy has resulted in a number of fundamental discoveries in circumstellar shells, including the discovery of maser lines and ...
openaire   +1 more source

Linear or Cyclic? Theoretical Investigation of Astrophysically Relevant Magnesium‐Bearing MgCnH Carbon Chains and Related Isomers

Journal of Computational Chemistry, Volume 46, Issue 2, January 15, 2025.
The global minimum energy structure of astrophysically relevant MgCnH systems is linear when n is even, and cyclic when n is odd. ABSTRACT Magnesium‐containing molecules, including MgC2H, MgC4H, and MgC6H, have been detected in the interstellar medium, largely facilitated by their high dipole moments.
A. Karolyna M. S. Gomes, Ricardo R. Oliveira, Thiago M. Cardozo, Felipe Fantuzzi   +3 more
wiley   +1 more source

Excited-state OH Masers in the Water Fountain Source IRAS 18460-0151

The Astrophysical Journal Letters
Water fountain objects are generally defined as evolved stars with low to intermediate initial mass accompanied by high-velocity molecular jets detectable in the 22.235 GHz H _2 O maser line.
Xu-Jia Ouyang, Yong Zhang, Juan Li, Jun-ichi Nakashima, Xi Chen, Hai-Hua Qiao   +5 more
doaj   +1 more source

Properties of the H-alpha-emitting Circumstellar Regions of Be Stars

, 2005
Long-baseline interferometric observations obtained with the Navy Prototype Optical Interferometer of the H-alpha-emitting envelopes of the Be stars eta Tauri and beta Canis Minoris are presented.
Andrillat Y., Arsen R. Hajian, Beeckmans F., Christopher Tycner, Cote J., D. J. Hutter, Fitzgerald M. P., G. C. Gilbreath, Hummel W., J. A. Benson, J. T. Armstrong, John B. Lester, Johnson H. L., N. M. White, Porter J. M., Quirrenbach A., Schild R. E., Schultz G. V., Shao M., Shao M., Stee P., T. A. Pauls, Thom C., Underhill A. B., van Kerkwijk M. H.   +24 more
core   +1 more source

Characterizing AGB stars in Wide-field Infrared Survey Explorer (WISE) bands [PDF]

, 2014
Since asymptotic giant branch (AGB) stars are bright and extended infrared objects, most Galactic AGB stars saturate the Wide-field Infrared Survey Explorer (WISE) detectors and therefore the WISE magnitudes that are restored by applying point-spread ...
Hua, Jinhe, Kong, Xu, Lian, Jianhui, Zhu, Qingfeng   +3 more
core   +1 more source

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

Natural 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, Ghylaine Quitté, Karine Demyk, Christine Joblin   +3 more
wiley   +1 more source