4 papers
Infrared SED Modeling of Velocity-Excess Maser Sources: Identifying Incipient Water-Fountain Candidates
Jia-Yong Xie, Jun-ichi Nakashima, Yong Zhang
We investigated whether "velocity excess" in circumstellar maser lines can diagnose the earliest evolutionary phases of Water Fountains (WFs). Here we define "velocity excess" as m…
Gas-phase Molecules in Protoplanetary Nebulae with the 21 μm Emission Feature II. Carbon monosulfide
Jian-Jie Qiu, Yong Zhang, Deng-Rong Lu +7
The carrier of the 21 m emission feature discovered in a handful of protoplanetary nebulae (PPNe) is one of the most intriguing enigmas in circumstellar chemistry. Investigatin…
FAST search for circumstellar atomic hydrogen. III. Planetary nebulae at Galactic latitudes |b|>10degree
Xu-Jia Ouyang, Yong Zhang, Albert Zijlstra +4
The detection of circumstellar atomic hydrogen (\ion{H}{1}) via the 21\,cm line remains a persistent challenge in planetary nebula (PN) studies, primarily due to contamination from…
A molecule-rich torus-like structure in the 21 m source IRAS 23304+6147
Hao-Min Sun, Yong Zhang, Xu-Jia Ouyang +4
A long-standing enigma in observational astronomy is the identification of the so-called 21 m feature in a subset of envelopes of post-asymptotic giant branch (post-AGB) stars.…