Results 21 to 30 of about 20,180 (51)
FAST Detection of OH Emission in the Carbon-rich Planetary Nebula NGC 7027
The Astrophysical JournalWe present the first detection of the ground-state OH emission line at 1612 MHz toward the prototypical carbon-rich planetary nebula (PN) NGC 7027, utilizing the newly installed ultrawideband (UWB) receiver of the Five-hundred-meter Aperture Spherical ...
Xu-Jia Ouyang +10 more
doaj +1 more source
Physical properties of Class I methanol masers [PDF]
, 2018 As first realised in the late 1980s, methanol masers come in two varieties, termed Class I and Class II. While Class II masers had observationally been extensively studied in the past, until recently relatively little attention was paid to Class I ...
Leurini, S. +3 more
core +1 more source
Investigating Asymmetry Development from SiO to H2O Maser Regions in VX Sagittarii
The Astronomical JournalSimultaneous very-long-baseline interferometry monitoring observations of H _2 O and SiO masers toward VX Sagittarii were conducted from 2014 February to 2019 January.
Dong-Hwan Yoon +4 more
doaj +1 more source
The Astrophysical JournalWe investigated whether “velocity excess” in circumstellar maser lines can diagnose the earliest evolutionary phases of water fountains (WFs). Here, we define “velocity excess” as maser emission (e.g., H _2 O 22.235 GHz or OH 1665/1667 MHz) detected at ...
Jia-Yong Xie +2 more
doaj +1 more source
Astrometry of the stellar image of U Her amplified by the circumstellar 22 GHz water masers [PDF]
, 2002 The 22 GHz H2O masers in the circumstellar envelope of the Mira variable star U Her have been observed with MERLIN using a phase referencing technique to determine accurate astrometric positions.
W. H. T. Vlemmings +5 more
core +1 more source
Equatorial Enhancement in the Dustiest OH/IR Stars in the Galactic Bulge
The Astrophysical JournalWe have detected the 10 μ m silicate feature and the 11.3 μ m crystalline forsterite feature in absorption in 21 oxygen-rich asymptotic giant branch stars in the Galactic bulge.
Steven R. Goldman +4 more
doaj +1 more source
Considerations on the Origin of IRAS 19312+1950 Based on Long-term Maser Observations
The Astrophysical JournalIRAS 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 +7 more
doaj +1 more source
3D velocity fields from methanol and water masers in an intermediate-mass protostar [PDF]
, 2012 We report multi-epoch VLBI observations of molecular masers towards the high-mass star forming region AFGL 5142, leading to the determination of the 3D velocity field of circumstellar molecular gas at radii 3OH maser emission enabled, for the first time,
MOSCADELLI, Luca +2 more
core +1 more source
Inferences from the kinematic properties of 6.7 GHz methanol masers [PDF]
, 2007 Context. It is now well established that the strong and widespread 6.7 GHz methanol masers are associated with young high mass stars. A still unsolved question is where in the circumstellar environment the masers arise.
Sobolev, A. M. +5 more
core +1 more source
Systematic Search for Water Fountain Candidates Using the Databases of Circumstellar Maser Sources
The Astrophysical Journal Supplement SeriesWater fountains (WFs) are thought to be objects in the morphological evolution of the circumstellar envelopes of low- and intermediate-mass evolved stars, transitioning from spherically symmetric to asymmetric shapes.
Haichen Fan +8 more
doaj +1 more source