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Study of Complex Nitrogen and Oxygen-bearing Molecules toward the High-mass Protostar IRAS 18089–1732

Research in Astronomy and Astrophysics 2024年第6期24卷 81-93页

作者： Arijit Manna Sabyasachi Pal Tapas Baug Sougata Mondal Department of Physics Midnapore City CollegePaschim MedinipurWest Bengal721129India S.N.Bose National Centre for Basic Sciences Block-JDSector-IIISalt Lake CityKolkata700106 India

The observation of oxygen(O)-and nitrogen(N)-bearing molecules gives an idea about the complex prebiotic chemistry in the interstellar *** millimeter and submillimeter wavelength observations have shown the presence of complex O-and N-bearing molecules in the star formation ***,the investigation of those molecules is crucial to understanding the chemical complexity in the star-forming *** this article,we present the identification of the rotational emission lines of N-bearing molecules ethyl cyanide(C_(2)H_(5)CN)and cyanoacetylene(HC_(3)N),and O-bearing molecule methyl formate(CH_(3)OCHO)toward high-mass protostar IRAS18089–1732 using the Atacama Compact *** also detected the emission lines of both the N-and O-bearing molecule formamide(NH_(2)CHO)in the envelope of IRAS 18089–*** have detected the v=0 and 1 state rotational emission lines of CH_(3)*** also detected the two vibrationally excited states of HC_(3)N(v7=1 and v7=2).The estimated fractional abundances of C_(2)H_(5)CN,HC_(3)N(v7=1),HC_(3)N(v7=2),and NH_(2)CHO toward IRAS 18089–1732 are(1.40±0.5)×10^(-10),(7.5±0.7)×10^(-11),(3.1±0.4)×10^(-11),and(6.25±0.82)×10^(-11)***,the estimated fractional abundances of CH_(3)OCHO(v=0)and CH_(3)OCHO(v=1)are(1.90±0.9)×10^(-9)and(8.90±0.8)×10^(-10),*** also created the integrated emission maps of the detected molecules,and the observed molecules may have originated from the extended envelope of the *** show that C_(2)H_(5)CNand HC_(3)N are most probably formed via the subsequential hydrogenation of the CH_(2)CHCNand the reaction between C_(2)H_(2)and CN on the grain surface of IRAS 18089–*** found that NH_(2)CHO is probably produced due to the reaction between NH_(2)and H_(2)CO in the gas ***,CH_(3)OCHO is possibly created via the reaction between radical CH_(3)O and radical HCO on the grain surface of IRAS 18089–1732.

关键词： ism:individual objects(IRA 18089-1732)(except) ism:abundances ism:kinematics and dynamics stars:formation astrochemistry

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Spatial Distribution of HOCN Around Sagittarius B2

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Research in Astronomy and Astrophysics 2022年第3期22卷 61-71页

作者： Si-Qi Zheng Juan Li Jun-Zhi Wang Feng Gao Ya-Jun Wu Shu Liu Shang-Huo Li Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China Key Laboratory of Radio Astronomy Chinese Academy of SciencesNanjing 210033China University of Chinese Academy of Sciences Beijing 100049China Hamburger Sternwarte Universitaet HamburgGojenbergsweg 112D-21029HamburgGermany National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Korea Astronomy and Space Science Institute 776 Daedeokdae-roYuseong-guDaejeon 34055Republic of Korea

HOCN and HNCO abundance ratio in molecular gas can tell us the information of their formation *** performed high-sensitivity mapping observations of HOCN,HNCO,and HNC^(18)O lines around Sagittarius B2(Sgr B2)with the IRAM 30 m telescope at the 3 mm *** 4_(04)-3_(03)and HOCN 4_(04)-3_(03)are used to obtain the abundance ratio of HNCO to *** ratio of HNCO 4_(04)-3_(03)to HNC^(18)O 4;-3;is used to calculate the optical depth of HNCO 4_(04)-3_(03).The abundance ratio of HOCN and HNCO is observed to range from 0.4%to0.7%toward most positions,which agrees well with the gas-grain ***,the relative abundance of HOCN is observed to be enhanced toward the direction of Sgr B2(S),with HOCN to HNCO abundance ratio of~0.9%.The reason for that still needs further *** on the intensity ratio of HNCO and HNC^(18)O lines,we updated the isotopic ratio of;O/;O to be 296±54 in Sgr B2.

关键词： ism:abundances ism:interstellar clouds ism:interstellar molecules

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Optical Properties of C-rich(12C,SiC and FeC)Dust Layered Structure of Massive Stars

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Research in Astronomy and Astrophysics 2022年第3期22卷 133-142页

作者： Rui-Qing Wu Meng-Qiu Long Xiao-Jiao Zhang Yun-Peng Wang Meng-Li Yao Ming-Ming Li Chun-Hua Zhu Guo-Liang Lü Zhao-Jun Wang Ju-Jia Zhang Zhao Wang Wu-Jin Chen School of Physics and Electronics Central South UniversityChangsha 410083China School of Physical Science and Technology Xinjiang UniversityUrumqi 830046China Yunnan Observatories(YNAO) Chinese Academy of SciencesKunming 650216China School of Chemistry and Chemical Engineering Guangxi UniversityNanning 530004China School of Medicine Xinjiang Medical UniversityUrumqi 830011China

The composition and structure of interstellar dust are important and complex for the study of the evolution of stars and the interstellar medium(ism).However,there is a lack of corresponding experimental data and model *** theoretical calculations based on ab-initio method,we have predicted and geometry optimized the structures of Carbon-rich(C-rich)dusts,carbon(^(12)C),iron carbide(Fe C),silicon carbide(Si C),even silicon(^(28)Si),iron(^(56)Fe),and investigated the optical absorption coefficients and emission coefficients of these materials in 0D(zero-dimensional),1D,and 2D *** the nebular spectra of the supernovae(SN)with the coefficient of dust,we find that the optical absorption coefficient of the 2D^(12)C,^(28)Si,^(56)Fe,Si C and Fe C structure corresponds to the absorption peak displayed in the infrared band(5–8)μm of the spectrum at 7554 days after the SN1987A *** also corresponds to the spectrum of 535 days after the explosion of SN2018bsz,when the wavelength was in the range of(0.2–0.8)and(3–10)μ***,2D Si C and Fe C correspond to the spectrum of 844 days after the explosion of SN2010jl,when the wavelength is within(0.08–10)μ***,Fe C and Si C may be the second type of dust in SN1987A corresponding to infrared band(5–8)μm of dust and may be in the ejecta of SN2010jl and *** nano-scale C-rich dust size is~0.1 nm in SN2018bsz,which is 3 orders of magnitude lower than the value of 0.1μ*** addition,due to the ionization reaction in the supernova remnant(SNR),we also calculated the Infrared Radiation(IR)spectrum of dust *** find that the cation of the 2D layered(Si C)^(2+)has a higher IR spectrum than those of the cation(Si C)^(1+)and neutral(Si C)^(0+).

关键词： stars:carbon (ism:)dust extinction ism:abundances

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GGCHEMPY: A Pure Python-based Gas-grain Chemical Code for Efficient Simulation of Interstellar Chemistry

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Research in Astronomy and Astrophysics 2022年第1期22卷 30-45页

作者： Jixing Ge Chinese Academy of Sciences South America Center for Astronomy National Astronomical ObservatoriesCASBeijing 100101China

In this paper,we present a new gas-grain chemical code for interstellar clouds written in pure Python(GGCHEMPY(GGCHEMPY is available on https://***/JixingGE/GGCHEMPY)).By combining with the high-performance Python compiler Numba,GGCHEMPY is as efficient as the Fortran-based *** the Python features,flexible computational workflows and extensions become *** a showcase,GGCHEMPY is applied to study the general effects of three-dimensional projection on molecular distributions using a two-core system which can be easily extended for more complex *** comparing the molecular distribution differences between two overlapping cores and two merging cores,we summarized the typical chemical differences such as N2 H+,HC3 N,C2 S,H2 CO,HCN and C2 H,which can be used to interpret 3 D structures in molecular clouds.

关键词： astrochemistry (ism:)evolution ism:molecules ism:abundances methods:numerical

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Heavy element contributions of rotating massive stars to interstellar medium

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Research in Astronomy and Astrophysics 2021年第5期21卷 287-295页

作者： Rui-Qing Wu Chun-Hua Zhu Guo-Liang Lv Zhao-Jun Wang He-Lei Liu School of Physical Science and Technology Xinjiang UniversityUrumqi 830046China

Employing the stellar evolution code Modules for Experiments in Stellar Astrophysics(MESA),we calculate yields of heavy elements from massive stars via stellar wind and core−collapse supernova(CCSN)ejecta to the interstellar medium(ism).In our models,the initial masses(Mini)of massive stars are taken from 13 to 80 M⊙,their initial rotational velocities(V)are 0,300 and 500 km s^(−1),and their metallicities are[Fe/H]=−3,−2,−1 and *** yields of heavy elements coming from stellar winds are mainly affected by stellar rotation which changes the chemical abundances of stellar surfaces via chemically homogeneous evolution,and enhances mass-loss *** estimate that the stellar wind can produce heavy element yields of about 10^(−2)(for low metallicity models)to a mass of severalM⊙(for low metallicity and rapid rotation models).The yields of heavy elements produced by CCSN ejecta also depend on the large amount of remnantmass which is mainly determined by the mass of the *** models calculate that the yields of heavy elements produced by CCSN ejecta can get up to several M⊙.Compared with stellar wind,CCSN ejecta has a greater contribution to the heavy elements in *** also compare the 56Ni yields calculated in this work with the observational *** models only explain the 56Ni masses produced by faint SNe or normal SNe with progenitor mass lower than about 25 M⊙,and greatly underestimate the 56Ni masses produced by stars with masses higher than about 30M⊙.

关键词： Stars:massive rotation ism:abundances

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Detection of hydroxyacetone in protostar IRAS 16293–2422 B

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Research in Astronomy and Astrophysics 2020年第8期20卷 217-229页

作者： Yan Zhou Dong Hui Quan Xia Zhang Sheng-Li Qin Department of Astronomy Yunnan Universityand Key Laboratory of Astroparticle Physics of Yunnan ProvinceKunming 650091China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Department of Chemistry Eastern Kentucky UniversityRichmondKY 40475USA

Hydroxy acetone(CH3 COCH2 OH)is one of the smallest molecules that contain both hydroxyl and carbonyl group on neighboring carbon *** steric configuration is characteristic of saccharides and determines their biochemical *** attempt to search for hydroxy acetone toward the massive star formation region Sagittarius B2(N)was *** we report the first detection of CH3 COCH2 OH in the solar-type protostar IRAS 16293-2422 B,using the Atacama Large Millimeter Array science verification data at Band *** a total of 11 unblended transitions of CH3 COCH2 OH with upper level energies ranging from 86 to 246 K are *** our local thermodynamic equilibrium analysis,we derived that the rotational temperature of CH3 COCH2 OH is 160±21 K and the column density is(1.2±1.0)×10^16 cm^-2,which results in a fractional abundance of 7×10^-10 with respect to molecular *** this work,we present the identification of CH3 COCH2 OH in IRAS 16293-2422 B and propose a simple formation *** unambiguous identification of hydroxyacetone may provide the basis for future study of the origin and evolution of saccharides in the interstellar medium.

关键词： ism:abundances ism:individual(IRAS 16293–2422 B) ism:molecules

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A new data structure for accelerating kinetic Monte Carlo method

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Research in Astronomy and Astrophysics 2019年第12期19卷 235-244页

作者： Xu-Li Zheng Dong-Hui Quan Hai-Long Zhang Xiao-Hu Li Qiang Chang Olli Sipila Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Department of Chemistry Eastern Kentucky UniversityRichmondKYUSA Max-Planck-Institute for Extraterrestrial Physics(MPE) Giessenbachstr.185748 GarchingGermany School of Astronomy and Space Science University of Chinese Academy of SciancesBeijing 100049China

The kinetic Monte Carlo simulation is a rigorous numerical approach to study the chemistry on dust grains in cold dense interstellar clouds. By tracking every single reaction in chemical networks step by step, this approach produces more precise results than other approaches but takes too much computing time. Here we present a method of a new data structure, which is applicable to any physical conditions and chemical networks, to save computing time for the Monte Carlo algorithm. Using the improved structure,the calculating time is reduced by 80 percent compared with the linear structure when applied to the osu-2008 chemical network at 10K. We investigate the effect of the encounter desorption in cold cores using the kinetic Monte Carlo model with an accelerating data structure. We found that the encounter desorption remarkably decreases the abundance of grain-surface H2 but slightly influences the abundances of other species on the grain.

关键词： astrochemistry molecular processes methods:numerical ism:molecules ism:abundances

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