Results 61 to 70 of about 55,649 (206)

Infrared interferometry of circumstellar envelopes [PDF]

Symposium - International Astronomical Union, 1999
This paper will review the technical progress of interferometric infrared observing techniques from the first 2-element interferometer 25 years ago to the 3+ element arrays now coming into service. To date, only the Infrared Spatial Interferometer (ISI) has published separate-element interferometric data on circumstellar dust shells in the infrared and
openaire   +2 more sources

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

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

H2O masers in circumstellar envelopes

The Astrophysical Journal, 1987
The spatial structure of H/sub 2/O maser emission at 22.235 GHz for 12-late-type variable stars has been measured with a resolution of 0.07 arcsec. The H/sub 2/O maser regions of Mira variables range from 9 or less to 108 AU in total extent, while those of supergiant long-period variables are 300-720 AU in extent.
Adair P. Lane, K. J. Johnston, J. H. Spencer, P. F. Bowers, P. J. Diamond   +4 more
openaire   +1 more source

The circumstellar envelope of AFGL 4106

Astronomy & Astrophysics, 1999
10 pages, 11 figures.
van Loon, J.T., Molster, F.J., van Winckel, H., Waters, L.B.F.M.   +3 more
openaire   +3 more sources

The deep eclipses of RW Aur revisited by long‐term photometric and spectroscopic monitoring

Astronomische Nachrichten, Volume 345, Issue 4, May 2024.
Abstract RW Aurigae is a young stellar system containing a classical T Tauri star as the primary component. It shows deep, irregular dimmings, first detected in 2010. At the University Observatory Jena, we carried out optical follow‐up observations. We performed multiband (BVRI) photometry of the system with the Cassegrain‐Teleskop‐Kamera II and the ...
Oliver Lux, Markus Mugrauer, Richard Bischoff   +2 more
wiley   +1 more source

Gas-phase Molecules in Protoplanetary Nebulae with the 21 μm Emission Feature

The Astronomical Journal
It has been more than 30 years since the enigmatic 21 μ m emission feature was first discovered in protoplanetary nebulae (PPNs). Although dozens of different dust carrier candidates have been proposed, there is as yet no widely accepted one.
Jian-Jie Qiu, Yong Zhang, Jun-ichi Nakashima, Jiang-Shui Zhang, Fei Li, Deng-Rong Lu, Xin-Di Tang, Xiao-Ling Yu, Lan-Wei Jia   +8 more
doaj   +1 more source

Limitations of the modified blackbody fit method for determining molecular cloud properties

Astronomische Nachrichten, Volume 345, Issue 4, May 2024.
Abstract Achieving a comprehensive understanding of the star and planet formation process is one of the fundamental tasks of astrophysics, requiring detailed knowledge of the physical conditions during the different phases of this process. During the earliest stages, that is, concerning physical processes in molecular clouds and filaments, the column ...
Niko Zielinski, Sebastian Wolf
wiley   +1 more source

Considerations on the Origin of IRAS 19312+1950 Based on Long-term Maser Observations

The Astrophysical Journal
IRAS source 19312+1950 (hereafter I19312) is an infrared point source with maser emissions of SiO, H _2 O, and OH molecules. Although initial observations suggested that I19312 might be an evolved star, its characteristics are not fully consistent with ...
Huan-Xue Feng, Jun-ichi Nakashima, D. Engels, S. Etoka, Jaeheon Kim, Yong Zhang, Jia-Yong Xie, Jian-Jie Qiu   +7 more
doaj   +1 more source

A spectral-line survey of CIT 6 between 30 and 50 GHz with the eQ receiver at NRO 45 m

Astronomy & Astrophysics
Context. At the end of the long H-burning phase (main sequence), low-mass to intermediate-mass stars evolve into asymptotic giant branch (AGB) stars that can have carbon-rich envelopes depending on the initial C/O ratio. In their circumstellar envelopes (
Nguyen-Luong Quang, Nakamura Fumitaka, Taniguchi Kotomi, Dinh-V-Trung, Liu Sheng-Yuan, Shimoikura Tomomi, Chiong Chau-Ching, Dobashi Kazuhito, Hirano Naomi, Yonekura Yoshinori, Nishimura Atsushi, Ogawa Hideo, Chien Chen, Ho Chin-Ting, Hwang Yuh-Jing, Yeh You-Ting, Lai Shih-Ping, Fujii Yasunori, Yamasaki Yasumasa, Kawabe Ryohei, Nolan Adam, Dung Pham Viet   +21 more
doaj   +1 more source