Results 11 to 20 of about 3,849,349 (342)
Excited Hydroxyl Outflow in the High-mass Star-forming Region G34.26 + 0.15
The Astrophysical Journal, 2023 G34.26 + 0.15 is a region of high-mass star formation that contains a broad range of young stellar objects in different stages of evolution, including a hot molecular core, hypercompact H ii regions, and a prototypical cometary ultracompact H ii region ...
Wei Siang Tan +6 more
doaj +1 more source
Comparing Complex Chemistry in Neighboring Hot Cores: NOEMA Studies of W3(H2O) and W3(OH)
The Astrophysical Journal, 2023 Presented here are NOEMA interferometric observations of the neighboring hot cores W3(H _2 O) and W3(OH). The presence of two star-forming cores at different evolutionary stages within the same parent cloud presents a unique opportunity to study how the ...
Will E. Thompson +3 more
doaj +1 more source
Mapping Physical Conditions in Neighboring Hot Cores: NOEMA Studies of W3(H2O) and W3(OH)
The Astrophysical Journal, 2023 The complex chemistry that occurs in star-forming regions can provide insight into the formation of prebiotic molecules at various evolutionary stages of star formation.
Morgan M. Giese +3 more
doaj +1 more source
Surveying the Giant H ii Regions of the Milky Way with SOFIA: V. DR7 and K3-50
The Astrophysical Journal, 2023 We present our fifth set of results from our mid-infrared imaging survey of Milky Way Giant H ii (GH ii ) regions with our detailed analysis of DR7 and K3-50.
James M. De Buizer +3 more
doaj +1 more source
A population of hypercompact H II regions identified from young H II regions [PDF]
Astronomy & Astrophysics, 2021 Context. The derived physical parameters for young H II regions are normally determined assuming the emission region to be optically thin. However, this assumption is unlikely to hold for young H II regions such as hyper-compact H II (HC H II) and ultra-compact H II (UC H II) regions and leads to underestimation of their properties.
Yang, AY +10 more
openaire +6 more sources
Symposium - International Astronomical Union, 1973 The observed far infrared flux of H II regions is interpreted as evidence for the presence of internal dust absorbing a fraction of Lyman continuum photons. The effect of this dust on the required number of ionizing photons and on the helium to hydrogen line intensity ratios are discussed and analytic formulae describing these effects are presented for
openaire +1 more source
PHANGS–JWST First Results: Destruction of the PAH Molecules in H ii Regions Probed by JWST and MUSE
The Astrophysical Journal Letters, 2023 Polycyclic aromatic hydrocarbons (PAHs) play a critical role in the reprocessing of stellar radiation and balancing the heating and cooling processes in the interstellar medium but appear to be destroyed in H ii regions.
Oleg V. Egorov +32 more
doaj +1 more source
Properties of H II Regions in the Centers of Nearby Galaxies [PDF]
, 1997 As part of an optical spectroscopic survey of nearby, bright galaxies, we have identified a sample of over 200 emission-line nuclei having optical spectra resembling those of giant extragalactic H II regions. Such "H II nuclei," powered by young, massive
Alexei V. Filippenko +15 more
core +2 more sources
Chlorine and Sulfur in Nearby Planetary Nebulae and H II Regions [PDF]
, 2011 We derive the chlorine abundances in a sample of nearby planetary nebulae (PNe) and H II regions that have some of the best available spectra. We use a nearly homogeneous procedure to derive the abundance in each object and find that the Cl/H abundance ...
Gloria Delgado-Inglada +4 more
core +1 more source
The Chocolate Chip Cookie Model: Dust-to-metal Ratio of H ii Regions
The Astrophysical Journal Letters, 2023 Using a sample of face-on star-forming galaxies selected from the Sloan Digital Sky Survey, we statistically derive the typical optical depth τ _cl of individual H ii regions based on the “Chocolate Chip Cookie” model of Lu et al. (2022).
Jiafeng Lu +3 more
doaj +1 more source