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While the nitrile group is by far the most prevalent one among interstellar molecules, the existence of interstellar dinitriles (molecules containing two -CN groups) has recently been proven. Here we report the discovery of two new…

Tracing dust in small dense molecular cores is a powerful tool to study the conditions required for ices to form during the pre-stellar phase. To study these environments, five molecular cores were observed: three with ongoing low-mass star…

星系天体物理 · 物理学 2021-09-08 Laurie E. U. Chu , Klaus W. Hodapp

We have studied four complex organic molecules (COMs), methyl formate ($CH_3OCHO$), dimethyl ether ($CH_3OCH_3$), formamide ($NH_2CHO$), and ethyl cyanide ($C_2H_5CN$), towards a large sample of 39 high-mass star-forming regions…

星系天体物理 · 物理学 2020-09-09 A. Coletta , F. Fontani , V. M. Rivilla , C. Mininni , L. Colzi , Á. Sánchez-Monge , M. T. Beltrán

In an effort to further our interest in understanding basic chemistry of interstellar molecules, we carry out here an extensive investigation of the stabilities of interstellar carbon chains; Cn, H2Cn, HCnN and CnX (X=N, O, Si, S, H, P, H-,…

太阳与恒星天体物理 · 物理学 2016-12-07 Emmanuel E. Etim , Prasanta Gorai , Ankan Das , Sandip K. Chakrabarti , Elangannan Arunan

We present a clear detection of CH2 in absorption towards the molecular cloud complexes Sagittarius B2 and W49 N using the ISO Long Wavelength Spectrometer. These observations represent the first detection of its low excitation rotational…

天体物理学 · 物理学 2009-11-10 E. T. Polehampton , K. M. Menten , S. Bruenken , G. Winnewisser , J. -P. Baluteau

We present high-resolution, high signal to noise absorption-line observations of CN, Ca II, Ca I, CH^+, and CH along twenty lines of sight toward members of the Pleiades. The acquired data enable the most detailed study to date of the…

天体物理学 · 物理学 2010-11-11 A. M. Ritchey , M. Martinez , K. Pan , S. R. Federman , D. L. Lambert

While recent studies of the solar-mass protostar IRAS16293-2422 have focused on its inner arcsecond, the wealth of Herschel/HIFI data has shown that the structure of the outer envelope and of the transition region to the more diffuse ISM is…

太阳与恒星天体物理 · 物理学 2015-06-19 S. Bottinelli , V. Wakelam , E. Caux , C. Vastel , Y. Aikawa , C. Ceccarelli

Aims. Supernovae offer the unique possibility to probe diffuse extra-galactic sightlines via observation of the optical transitions of atoms, molecules and the diffuse interstellar bands (DIBs). Through optical spectroscopy the presence of…

天体物理学 · 物理学 2009-11-13 N. L. J. Cox , F. Patat

We have used archival far-ultraviolet spectra from observations made by HST/STIS and FUSE to determine the column densities and rotational excitation temperatures for CO and H2, respectively, along the lines of sight to 23 Galactic O and B…

天体物理学 · 物理学 2009-01-19 Eric B. Burgh , Kevin France , Stephan R. McCandliss

The wavelength dependences of interstellar extinction and polarization, supplemented by observed elemental abundances and the spectrum of infrared emission from dust heated by starlight, strongly constrain dust models. One dust model that…

星系天体物理 · 物理学 2009-03-11 B. T. Draine

The review contains an analysis of the observed and model curves of the interstellar extinction and polarization. The observations mainly give information on dust in diffuse and translucent interstellar clouds. The features of various dust…

星系天体物理 · 物理学 2015-06-05 N. V. Voshchinnikov

Current measurements indicate that the deuterium abundance in diffuse interstellar gas varies spatially by a factor of ~4 among sightlines extending beyond the Local Bubble. One plausible explanation for the scatter is the variable…

天体物理学 · 物理学 2009-11-10 Jason X. Prochaska , Todd M. Tripp , J. Christopher Howk

Chlorine and molecular hydrogen are known to be tightly linked together in the cold phase of the local interstellar medium through rapid chemical reactions. We present here the first systematic study of this relation at high redshifts using…

We present high S/N measurements of the H I Ly alpha absorption line toward 16 Galactic targets which are at distances between approximately 190 and 2200 pc, all beyond the wall of the Local Bubble. We describe the models used to remove…

星系天体物理 · 物理学 2023-04-05 S. D. Friedman , P. Chayer , E. B. Jenkins , T. M. Tripp , G. M. Williger , G. Hebrard , P. Sonnentrucker

We present high-resolution optical spectra (at ~0.6--1.8 km s-1) of interstellar CN, CH, CH^+, \ion{Ca}{1}, \ion{K}{1}, and \ion{Ca}{2} absorption toward 29 lines of sight in three star-forming regions, \rho Oph, Cep OB2, and Cep OB3. The…

天体物理学 · 物理学 2009-11-10 K. Pan , S. R. Federman , K. Cunha , V. V. Smith , D. E. Welty

We present a theoretical investigation of CN and HCN molecule formation in dense interstellar clouds. We study the gas-phase CN and HCN production efficiencies from the outer photon-dominated regions (PDRs) into the opaque cosmic-ray…

天体物理学 · 物理学 2009-11-13 Gai I. Boger , Amiel Sternberg

A previous article argued that the antagonism between sight-lines with and without a bump at 2200 \AA\ disappears, and that the observed properties of interstellar extinction can be globally understood, if it is accepted that scattered…

星系天体物理 · 物理学 2017-11-08 Frederic Zagury

Column density ratios of complex organic molecules are generally constant across protostellar systems with some low-level scatter. However, the scatter in formamide (NH$_2$CHO) to methanol (CH$_3$OH) column density ratio is one of the…

星系天体物理 · 物理学 2024-07-24 P. Nazari , B. Tabone , G. P. Rosotti , E. F. van Dishoeck

It is commonly assumed that cold and dense Infrared Dark Clouds (IRDCs) likely represent the birth sites massive stars. Therefore, this class of objects gets increasing attention. To enlarge the sample of well-characterised IRDCs in the…

太阳与恒星天体物理 · 物理学 2015-05-13 T. Vasyunina , H. Linz , Th. Henning , B. Stecklum , S. Klose , L. -A. Nyman

We discuss the interstellar absorption from many atomic and molecular species seen in high-resolution $HST$/STIS UV and high-S/N optical spectra of the moderately reddened B3-5~V star HD~62542. This remarkable sight line exhibits both very…

星系天体物理 · 物理学 2020-07-08 Daniel E. Welty , Paule Sonnentrucker , Theodore P. Snow , Donald G. York