Results 81 to 90 of about 1,259 (182)

The Abundance of Mg in the Interstellar Medium

, 1997
An empirical determination of the f-values of the far-UV Mg II lines at 1239 A and 1240 A is reported. The strong near-UV Mg II lines at 2796 A and 2803 A are generally highly saturated along most interstellar sightlines outside the local ISM and usually yield extremely uncertain estimates of Mg II column densities in interstellar gas.
openaire   +2 more sources

Laboratory Rotational Spectroscopy Leads to the First Interstellar Detection of Singly Deuterated Methyl Mercaptan (CH2DSH)

The Astrophysical Journal Letters
We report an extensive rotational spectroscopic analysis of singly deuterated methyl mercaptan (CH _2 DSH) using both millimeter and far-infrared synchrotron spectra to achieve a global torsional analysis of the three lowest torsional substates ( e _0 ...
Hayley A. Bunn, Silvia Spezzano, Laurent H. Coudert, Jean-Claude Guillemin, Yuxin Lin, Christian P. Endres, Brant Billinghurst, Olivier Pirali, Jes Jørgensen, Valerio Lattanzi, Paola Caselli   +10 more
doaj   +1 more source

The Impact of Hydrogen Atom Tunneling on Aromatic Chemistry in TMC-1

The Astrophysical Journal
Hydrogen atom tunneling likely plays a substantial role in the gas-phase chemistry of astrochemical environments. To determine the potential effect that it has on the chemical modeling of aromatic molecules, we screened both the kida.uva.2024 network and
Reace H. J. Willis, Thomas H. Speak, Alex N. Byrne, Christopher N. Shingledecker, Ilsa R. Cooke   +4 more
doaj   +1 more source

High-resolution Mid-infrared Spectroscopy of SVS13-A with EXES/SOFIA: The Surprisingly High CH3OH/H2O Ratio in the Planet-forming Zone of a Solar Mass Protostar

The Astrophysical Journal Letters
Water and methanol are key components of interstellar ices and gas in star- and planet-forming regions, but direct observations of water in low-mass protostars are challenging due to atmospheric absorption.
Curtis DeWitt, Marta De Simone, Eleonora Bianchi, Cecilia Ceccarelli, Claudio Codella, Sarah Nickerson, Keeyoon Sung, Albert Rimola, Vittorio Bariosco, Piero Uliengo, Naseem Rangwala   +10 more
doaj   +1 more source

Interstellar Abundance of the Hydrogen Molecule.

The Astronomical Journal, 1962
Abstract : Contents: Mechanisms for the formulation of molecular hydrogen Dissociative processes for a static interstellar medium Dissociative effects of clouds motions Summary Appendix A: Photodissociation and photoionization Appendix B: Velocity distribution of H I clouds Appendix C: Stromgren spheres Appendix D: Problem in Brownian ...
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Element Nucleosynthetic Origins from Abundance Spatial Distributions beyond the Milky Way

The Astrophysical Journal Letters
An element’s astrophysical origin should be reflected in the spatial distribution of its abundance, yielding measurably different spatial distributions for elements with different nucleosynthetic sites.
Zefeng Li, Mark R. Krumholz, Anna F. McLeod, A. Mark Swinbank, Emily Wisnioski, J. Trevor Mendel, Francesco Belfiore, Giovanni Cresci, Giacomo Venturi, Jia-Lai Kang   +9 more
doaj   +1 more source

Potential Nitrogen Enrichment via Direct-collapse Wolf–Rayet Stars in a z = 4.7 Star-forming Galaxy

The Astrophysical Journal
We present analyses of a nitrogen-enriched star-forming galaxy, ID60001, at z = 4.6928 based on James Webb Space Telescope/NIRSpec Multi-Object Spectroscopy and NIRCam photometry. From rest-frame optical emission lines we derive the nitrogen-to-oxygen (N/
Yechi Zhang, Takahiro Morishita, Massimo Stiavelli   +2 more
doaj   +1 more source

The LBT Yp Project. II. MODS Spectra, Physical Conditions, and Oxygen Abundances in Local Metal-poor Nebulae

The Astrophysical Journal
Empirically measuring the primordial He mass fraction, Y _p , requires a significant number of low-metallicity nebulae with direct constraints on He/H and O/H abundances.
Noah S. J. Rogers, Evan D. Skillman, Richard W. Pogge, Erik Aver, Miqaela K. Weller, Danielle A. Berg, John J. Salzer, John H. Miller Jr., Jayde Speigel, Allison L. Strom   +9 more
doaj   +1 more source

Investigating Enols Chemistry in the Interstellar Medium: Rotational Spectroscopy and Interstellar Search of (E)-1-Propenol

The Astrophysical Journal
Enols represent highly reactive intermediates toward the synthesis of complex organic molecules in the interstellar medium (ISM) and serve as key tracers of nonequilibrium chemistry driven by Galactic cosmic rays.
Michela Nonne, Mattia Melosso, Francesca Tonolo, Luca Bizzocchi, Silvia Alessandrini, Jean-Claude Guillemin, Amavi Kpoezoun, Gnon Baba, Víctor M. Rivilla, Izaskun Jiménez-Serra, Cristina Puzzarini   +10 more
doaj   +1 more source

On the Abundance of Interstellar Beryllium.

The Astrophysical Journal, 1955
Lyman, Jr. Spitzer, George B. Field
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