Results 31 to 40 of about 4,364 (222)

Temperature Distributions in Circumstellar Dust Shells [PDF]

Symposium - International Astronomical Union, 1987
The knowledge of the temperature distribution in circumstellar dust shells (CDS) is needed for both the calculation of the emergent IR spectrum and the modelling of physical processes, e.g. dust formation.
Th. Henning, J. Gürtler
openaire   +1 more source

Kinetics of the tautomerization of thioimidic acids R−C(SH)NH → R−C(S)NH2: For R = H, F, HO, CN, NC, H2N, HC(O), HC(S), HC≡ C, CH3, CF3, H2C=CH, HOCH2, H2NCH2,CH3C(O), C2H5, (CH3)2CH, C6H5

International Journal of Chemical Kinetics, Volume 55, Issue 11, Page 731-742, November 2023., 2023
Abstract The kinetics of the tautomerization of thio‐imidic acids RC(SH)NH were determined at low (50–300 K) and high (500–1500 K) temperatures as R was varied to encompass mono‐ and diatomic species H, F, HO, NC, CN through H2N, HC(O), HC(S), HC≡ C, H3C, F3C, HOCH2, H2C=CH, CH3C(O), H2NCH2 and including ethyl, isopropyl and phenyl groups. The presence
Judith Würmel, John M. Simmie
wiley   +1 more source

Evaluating the GeoSnap 13‐μ$$ \mu $$m cutoff HgCdTe detector for mid‐IR ground‐based astronomy

Astronomische Nachrichten, Volume 344, Issue 8-9, October-November 2023., 2023
Abstract New mid‐infrared HgCdTe (MCT) detector arrays developed in collaboration with Teledyne Imaging Sensors (TIS) have paved the way for improved 10‐μ$$ \mu $$m sensors for space‐ and ground‐based observatories. Building on the successful development of longwave HAWAII‐2RGs for space missions such as NEO Surveyor, we characterize the first 13‐μ ...
Jarron M. Leisenring, Dani Atkinson, Rory Bowens, Vincent Douence, William F. Hoffmann, Michael R. Meyer, John Auyeung, James Beletic, Mario S. Cabrera, Alexandra Z. Greenbaum, Philip Hinz, Derek Ives, William J. Forrest, Craig W. McMurtry, Judith L. Pipher, Eric Viges   +15 more
wiley   +1 more source

Substituent effects in the tautomerization of imidic acids R−C(OH)=NH → R−C(O)NH2: Kinetic implications for the formation of peptide bonds in the interstellar medium

International Journal of Chemical Kinetics, Volume 55, Issue 7, Page 381-391, July 2023., 2023
Abstract A number of amides, RC(O)NH2, have been detected spectroscopically in the space between the stars. Naturally the study of how these are formed is an important question on the path of chemical evolution from the elements C, H, N, O, P, … to life because the so‐called peptide‐bond −C(O)−NH− is a key linkage in poly‐amino acids or proteins.
Judith Würmel, John M. Simmie
wiley   +1 more source

Modeling extinction and reddening effects by circumstellar dust in the Betelgeuse envelope in the presence of radiative torque disruption [PDF]

, 2022
Circumstellar dust is formed and evolved within the envelope of evolved stars, including Asymptotic Giant Branch (AGB) and Red Supergiant (RSG). The extinction of stellar light by circumstellar dust is vital for interpreting RSG/AGB observations and ...
Nguyen, Dieu D., Hoang, Thiem, Nguyen, Dieu, Giang, Nguyen Chau, Fuda, Nguyen, Bui, Tuan Van, Hoang, Thuong, Diep, Pham Ngoc, Ngoc, Nguyen Bich, Van Bui, Tuan, Hoang, Thuong D., Phan, Hien, Tram, Le Ngoc, Truong, Bao, Phuong, Nguyen Thi   +14 more
core   +2 more sources

RR Tel: Determination of Dust Properties During Minimum Obscuration

Open Astronomy, 2012
the ISO infrared spectra and the SAAO long-term JHKL photometry of RR Tel in the epochs during minimum obscuration are studied in order to construct a circumstellar dust model.
Jurkić T., Kotnik-Karuza D.
doaj   +1 more source

Dust Echoes from Luminous Fast Blue Optical Transients

The Astrophysical Journal, 2023
Luminous fast blue optical transients (LFBOTs) such as AT2018cow form a rare class of engine-powered explosions of uncertain origin. A hallmark feature of these events is radio/millimeter synchrotron emission powered by the interaction of fast ≳0.1 c ...
Brian D. Metzger, Daniel A. Perley
doaj   +1 more source

Dust distribution in circumstellar shells [PDF]

Proceedings of the International Astronomical Union, 2011
AbstractWe present numerical simulations of the hydrodynamical interactions that produce circumstellar shells. These simulations include several scenarios, such as wind-wind interaction and wind-ISM collisions. In our calculations we have taken into account the presence of dust in the stellar wind. Our results show that, while small dust grains tend to
van Marle, Allard Jan, Meliani, Zakaria, Keppens, Rony, Decin, Leen   +3 more
openaire   +2 more sources

Circumstellar Dust Shells [PDF]

Symposium - International Astronomical Union, 1975
The optical properties of circumstellar graphite particle shells are considered. In the case of the optically thin shell (e.g. the shell of a RCB star after minimum), the temperature of the grains is calculated. It is shown that the dust shell always has a sharp inner border. The RCB phenomenon may be considered as a sudden moving of this border toward
openaire   +1 more source

The Effects of Circumstellar Dust Scattering on the Light Curves and Polarizations of Type Ia Supernovae [PDF]

, 2022
Observational signatures of the circumstellar material (CSM) around Type Ia supernovae (SNe Ia) provide a unique perspective on their progenitor systems.
Hu, Maokai, Wang, Lifan, Wang, Xiaofeng
core   +2 more sources