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Inelastic Scattering of Dark Matter with Heavy Cosmic Rays

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Research in Astronomy and Astrophysics 2024年第6期24卷 68-80页

作者： Keyu Lu Yue-Lin Sming Tsai Qiang Yuan Le Zhang School of Physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China CSST Science Center for the Guangdong-Hong Kong-Macao Greater Bay Area SYSUZhuhai 519082China Peng Cheng Laboratory Shenzhen 518000China

We investigate the impact of inelastic collisions between dark matter(DM)and heavy cosmic ray(CR)nuclei on CR *** approximate the fragmentation cross-sections for DM-CR collisions using collider-measured proton-nuclei scattering cross-sections,allowing us to assess how these collisions affect the spectra of CR boron and *** derive new CR spectra from DM-CR collisions by incorporating their cross-sections into the source terms and solving the diffusion equation for the complete network of reactions involved in generating secondary *** a specific example with a coupling strength of b_(χ)=0.1 and a DM mass of m_(χ)=0.1 GeV,considering a simplified scenario where DM interacts exclusively with oxygen,a notable modification in the boron-to-carbon spectrum due to the DM-CR interaction is ***,the peak within the spectrum,spanning from 0.1 to 10 GeV,experiences an enhancement of approximately 1.5 ***,in a more realistic scenario where DM particles interact with all CRs,this peak can be amplified to twice its original *** the latest data from AMS-02 and DAMPE on the boron-to-carbon ratio,we estimate a 95%upper limit for the effective inelastic cross-section of DM-proton as a function of DM *** findings reveal that at m_(χ)?2 MeV,the effective inelastic cross-section between DM and protons must be less than O(10^(-32))cm^(2).

关键词： elementary particles nuclear reactions nucleosynthesis abundances scattering astroparticle physics (cosmology:)dark matter

Evolution Toward the Observational Features of a Stripped Envelope TypeⅡb Supernova in a Binary System

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Research in Astronomy and Astrophysics 2022年第5期22卷 146-157页

作者： Gang Long Han-Feng Song Rui-Yu Zhang Ying Qin Liu-Yan Zhao Shi-Tao Qi Fang-Wen Wu College of Physics Guizhou UniversityGuiyang 550025China College of Physics Henan Normal UniversityXinxiang 453007China Department of Physics Anhui Normal UniversityWuhu 241000China

TypeⅡb supernovae(SNeⅡb)that have a thin layer of hydrogen left in their outer envelope have been believed to belong to core collapse *** transfer via Roche lobe overflow can significantly change the nucleosynthesis and surface chemical elements of the progenitors of SNeⅡ*** aim to explore what conditions a close binary can meet with the observational features of SNeⅡ*** find that an observed low mass SNⅡb cannot be produced by a low mass isolated star with M<20,M_(⊙)due to the existence of a thick hydrogen envelope regardless of *** dominate as progenitors in the mass interval(i.e.,M<20 M_(⊙))considered in this *** 16 M_(⊙),primary with a 14 M_(⊙) companion in a binary system with~10 days

关键词： (stars:)binaries(including multiple) close-stars evolution-stars rotation-stars abundances

Spectral analysis of two solar twins and the colors of the Sun

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Science China(Physics,Mechanics & Astronomy) 2010年第8期53卷 579-585页

作者： ZHAO ZhengShi1,2, CHEN YuQin1, ZHAO JingKun1 & ZHAO Gang1 1 National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China 2 Graduate University of Chinese Academy of Sciences, Beijing 100049, China National Astronomical Observatories Chinese Academy of Sciences Beijing China Graduate University of Chinese Academy of Sciences Beijing China

High resolution (R^40,000) and high signal-to-noise ratio (>150) spectra of two solar twins, HD146233 and HD195034, are obtained with the Coude Echelle Spectrograph at the 2.16 m telescope of the National Astronomical Observatories of Chinese Academy of Sciences (Xinglong, China). Based on the detailed spectrum match, comparisons of chemical composition and chromospheric activity, HD146233 and HD195034 are confirmed that they are similar to the Sun except for lithium abundance, which is higher than the solar value. Moreover, among nine solar twin candidates (including HD146233 and HD195034) found in the previous works, we have picked out six good solar twin candidates based on newly-derived homogenous parameters, and collected their colors in the Johnson/Cousins, Tycho, 2MASS and Strmgren system from the literature. The average color are (B-V)⊙=0.644 mag, (V-Ic)⊙=0.707 mag, (BT-VT)⊙=0.725 mag, (J-H)⊙=0.288 mag, (H-K)⊙=0.066 mag, (v-y)⊙=1.028 mag, (v-b)⊙=0.619 mag, (u-v)⊙=0.954 mag and (b-y)⊙=0.409 mag, which represent the solar colors with higher precision than previous works.

关键词： Sun-colors Star-atmospheres abundances fundamental parameters

A Study of Elemental Abundance Pattern of the r-II Star HD 222925

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Research in Astronomy and Astrophysics 2023年第12期23卷 118-127页

作者： Fang Wen Wan-Qiang Han Wen-Yuan Cui Hong-Jie Li Bo Zhang College of Physics Hebei Normal UniversityShijiazhuang 050024China Department of Physics Shijiazhuang UniversityShijiazhuang 050035China School of Sciences Hebei University of Science and TechnologyShijiazhuang 050018China

HD 222925 is a rare r-process enhanced star in the Milky Way because of its metal abundance([Fe/H]=-1.46±0.10)and Eu abundance([Eu/Fe]=1.32±0.08).Based on the very complete set of elemental abundances of HD 222925,we use the abundance decomposition method to fit the observed abundances of 58elements in the sample star,which is also the largest number of elemental abundances fitted at the same time for a fixed *** analyze the astrophysical origins of elements in HD 222925 by its abundance ratios and component *** is found that the light elements and the iron group elements in HD 222925 mainly originate from the primary process of the TypeⅡsupernovae(SNeⅡ)with the progenitor mass M>10 M_(⊙)and have no contribution from SNe Ia and the first generation of very massive *** contribution of the weak r-process to Ga,Ge,and As is superior to that of the other processes,and its contribution decreases linearly with increasing atomic *** main r-process that is likely derived from a neutron star merger plays a key role in the formation of neutroncapture elements(Z≥38)in HD 222925.

关键词： stars chemically peculiar-stars individual(HD 222925)-nuclear reactions-nucleosynthesis-abundances-stars abundances

Neutrino luminosity of stars with different masses

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Research in Astronomy and Astrophysics 2020年第1期20卷 35-42页

作者： Yang Shi Xun Xue Chun-Hua Zhu Zhao-Jun Wang He-Lei Liu Lin Li Guo-Liang Lü School of Physics and Technology Xinjiang UniversityUrumqi 830046China Department of Physics East China Normal UniversityShanghai 2000062China

Neutrinos play an important role in stellar *** are produced by nuclear reactions or thermal *** the stellar evolution code Modules for Experiments in Stellar Astrophysics(MESA),we study stellar neutrino luminosity with different *** neutrino luminosities of stars with different initial masses at different evolutionary stages are *** find that the neutrino flux of a star with 1 M⊙ mass at an evolutionary age of 4.61×10^9 yr is consistent with that of the *** general,neutrinos are produced by nuclear reactions,and the neutrino luminosity of stars is about one or two magnitudes lower than the photo ***,neutrino luminosity can exceed photo luminosity during the helium flash which can occur for stars with a mass lower than 8 M⊙.Although the helium flash does not produce neutrinos,plasma decay,one of the thermal processes,can efficiently make neutrinos during this *** to the high mass-loss rate,a star with a mass of 9 M⊙ does not undergo the helium *** neutrinos mainly originate from nuclear reactions until the end of the AGB *** the end of the AGB stage,its neutrino luminosity results from plasma decay which is triggered by the gravitational energy release because of the stellar core contracting.

关键词： stars:evolution stars:fundamental parameters nuclear reactions nucleosynthesis abundances

Nucleosynthesis in the accretion disks of Type Ⅱ collapsars

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Research in Astronomy and Astrophysics 2013年第9期13卷 1063-1074页

作者： Indrani Banerjee Banibrata Mukhopadhyay Department of Physics Indian Institute of Science

We investigate nucleosynthesis inside the gamma-ray burst （GRB） accre- tion disks formed by the Type II collapsars. In these collapsars, the core collapse of massive stars first leads to the formation of a proto-neutron star. After that, an out- ward moving shock triggers a successful supernova. However, the supernova ejecta lacks momentum and within a few seconds the newly formed neutron star gets trans- formed to a stellar mass black hole via massive fallback. The hydrodynamics of such an accretion disk formed from the fallback material of the supernova ejecta has been studied extensively in the past. We use these well-established hydrodynamic models for our accretion disk in order to understand nucleosynthesis, which is mainly ad- vection dominated in the outer regions. Neutrino cooling becomes important in the inner disk where the temperature and density are higher. The higher the accretion rate （M） is, the higher the density and temperature are in the disks. We deal with accre- tion disks with relatively low accretion rates： 0.001 Mo s-1 ~ 3）/~ 0.01 Mo S--1 and hence these disks are predominantly advection dominated. We use He-rich and Si- rich abundances as the initial condition of nucleosynthesis at the outer disk, and being equipped with the disk hydrodynamics and the nuclear network code, we study the abundance evolution as matter inflows and falls into the central object. We investigate the variation in the nucleosynthesis products in the disk with the change in the initial abundance at the outer disk and also with the change in the mass accretion rate. We report the synthesis of several unusual nuclei like 31p, 39K, 43Sc＇ 35C1 and various isotopes of titanium, vanadium, chromium, manganese and copper. We also confirm that isotopes of iron, cobalt, nickel, argon, calcium, sulphur and silicon get synthe- sized in the disk, as shown by previous authors. Much of these heavy elements thus synthesized are ejected from the disk via outflows and hence they should

关键词： accretion accretion disks -- gamma rays: bursts -- black hole physics-- nuclear reactions nucleosynthesis abundances

Atmospheric Parameters and Kinematic Information for the M Giant Stars from LAMOST DR9

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Research in Astronomy and Astrophysics 2023年第5期23卷 78-90页

作者： Dan Qiu Hao Tian Jing Li Chao Liu Lin Long Jian-Rong Shi Ming Yang Bo Zhang Key Laboratory of Space Astronomy and Technology National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences 100049China Institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China School of Physics and Astronomy China West Normal UniversityNanchong 637002China Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China

A catalog of more than 43,000 M giant stars has been selected by Li et *** the ninth data release of *** the data-driven method SLAM,we obtain the stellar parameters(T_(eff),logg,[M/H],[α/M])for all the M giant stars with uncertainties of 57 K,0.25 dex,0.16 dex and 0.06 dex at SNR>100,*** those stellar parameters,we constrain the absolute magnitude in the K-band,which brings distance with relative uncertainties around 25%*** velocities are also calculated by applying cross correlation on the spectra between 8000 and 8950?with synthetic spectra from ATLAS9,which covers the CaⅡ*** between our radial velocities and those from APOGEE DR17 and Gaia DR3 shows that our radial velocities have a system offset and dispersion around 1 and 4.6 km s^(-1),*** the distances and radial velocities combining with the astrometric data from Gaia DR3,we calculate the full 6D position and velocity information,which are able to be used for further chemo-dynamic studies on the disk and substructures in the halo,especially the Sagittarius Stream.

关键词： methods data analysis-stars atmospheres-Galaxy disk-stars abundances

Automatic Normalization and Equivalent-Width Measurement of High-Resolution Stellar Spectra

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Chinese Journal of Astronomy and Astrophysics 2006年第6期6卷 689-696页

作者： Jing-Kun Zhao Gang Zhao Yu-Qin Chen Jian-Rong Shi Yu-Juan Liu Ju-Yong Zhang National Astronomical Observatories Chinese Academy of Sciences Beijing 100012

It is well known that normalization, radial velocity correction and equivalent-width measurement of high-resolution stellar spectra are time-consuming work. In order to improve the efficiency we present an automatic method for these routines. The continuum is determined by fitting the ＇high points＇ in the spectrum. After continuum normalization, the program automatically searches for the position of the Ha line and obtains a rough radial velocity, then computes an accurate radial velocity by cross-correlation between the given spectrum and the solar spectrum. In this method, the equivalent-width is automatically measured using Gaussian fitting. A comparison between our results and those from traditional analysis shows that the typical error for equivalent width is around 3.8% in our method. Developing such automatic routines does not mean to replace the interactive reduction method： it is just for a quick extraction of information from the spectra, especially those obtained in large sky surveys.

关键词： techniques radial velocities - stars abundances

The study of proto-magnetar winds

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Research in Astronomy and Astrophysics 2010年第3期10卷 244-252页

作者： Yan-Jun Chen Ye-Fei Yuan Department of Physics and Electronic Science Changsha University of Science and Technology Changsha Hunan 410114 Center for Astrophysics University of Science and Technology of China Hefei 230026 China

The velocity profiles and properties of proto-magnetar winds are investigated. It is found that the corotation of wind matter with magnetic field lines significantly affects r-process nucleosynthesis and could lead to... 详细信息

关键词： stars: neutron -- stars: winds outflows -- supernovae: general -- stars magnetic fields -- nuclear reactions nucleosynthesis abundances