Results 101 to 110 of about 301,064 (245)

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

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

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

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

Effects of Metallicity on Graphite, TiC, and SiC Condensation in Carbon Stars

The Astrophysical Journal
From transmission electron microscopy and other laboratory studies of presolar grains, the implicit condensation sequence of carbon-bearing condensates in circumstellar envelopes of carbon stars is (from first to last) TiC-graphite-SiC.
Gabrielle M. Adams, Katharina Lodders
doaj   +1 more source

High resolution observations of SiO masers: comparing the spatial distribution at 43 and 86 GHz

, 2004
We present sub-milliarcsecond observations of SiO masers in the late-type stars IRC +10011 and Chi Cyg. We have used the NRAO Very Long Baseline Array (VLBA) to map the 43 GHz (v=1, 2 J=1-0) and the 86 GHz (v=1, 2 J=2-1) SiO masers.
Alcolea, Alcolea, Boboltz, Boboltz, Bujarrabal, Bujarrabal, Bujarrabal, Bujarrabal, Bujarrabal, Bujarrabal, Cernicharo, Colomer, Cotton, Danchi, Deguchi, Desmurs, Desmurs, Diamond, Diamond, Doel, Doeleman, Elitzur, F. Colomer, Greenhill, Herman, Herman, Hollis, Humphreys, Humphreys, J. Alcolea, J.-F. Desmurs, K. B. Marvel, Keenan, Kwan, Lockett, Loup, Miyoshi, Olofsson, P. J. Diamond, Pardo, Phillips, Phillips, Pijpers, R. Soria-Ruiz, Rausch, Sánchez Contreras, V. Bujarrabal   +46 more
core   +1 more source

A Molecular Line Survey of the Carbon-Rich Proto-Planetary Nebula AFGL 2688 in the 3mm and 1.3mm Windows [PDF]

, 2013
We present a spectral line survey of the proto-planetary nebula AFGL 2688 in the frequency ranges of 71-111 GHz, 157-160 GHz, and 218-267 GHz using the Arizona Radio Observatory 12m telescope and the Heinrich Hertz Submillimeter Telescope. A total of 143
Chau, Wayne, Dinh-V-Trung, Kwok, Sun, Nakashima, Jun-ichi, Zhang, Yong   +4 more
core   +2 more sources

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

Early Planet Formation in Embedded Disks (eDisk). XIII. Aligned Disks with Nonsettled Dust around the Newly Resolved Class 0 Protobinary R CrA IRAS 32

The Astrophysical Journal
Young protostellar binary systems, with expected ages less than ∼10 ^5 yr, are little modified since birth, providing key clues to binary formation and evolution. We present a first look at the young, Class 0 binary protostellar system R CrA IRAS 32 from
Frankie J. Encalada, Leslie W. Looney, Shigehisa Takakuwa, John J. Tobin, Nagayoshi Ohashi, Jes K. Jørgensen, Zhi-Yun Li, Yuri Aikawa, Yusuke Aso, Patrick M. Koch, Woojin Kwon, Shih-Ping Lai, Chang Won Lee, Zhe-Yu Daniel Lin, Alejandro Santamaría-Miranda, Itziar de Gregorio-Monsalvo, Nguyen Thi Phuong, Adele Plunkett, Jinshi Sai (Insa Choi), Rajeeb Sharma, Hsi-Wei Yen, Ilseung Han   +21 more
doaj   +1 more source

Experimental Phase Function and Degree of Linear Polarization of Light Scattered by Hydrogenated Amorphous Carbon Circumstellar Dust Analogs

The Astrophysical Journal Supplement Series, 2023
Astronomical observations of the polarized intensity of scattered visible light have revealed the presence of dust envelopes around different types of evolved stars.
Juan Carlos Gómez Martín, Olga Muñoz, Julia Martikainen, Daniel Guirado, Isabel Tanarro, Ramón J. Peláez, Belén Maté, Miguel Jiménez-Redondo, Víctor J. Herrero, Marco Peiteado, Teresa Jardiel   +10 more
doaj   +1 more source