The abundance patterns of r-process-enhanced stars contain key information required to constrain the astrophysical site(s)of r-process nucleosynthesis,and to deepen our understanding of the chemical evolution of our G...The abundance patterns of r-process-enhanced stars contain key information required to constrain the astrophysical site(s)of r-process nucleosynthesis,and to deepen our understanding of the chemical evolution of our Galaxy.To expand the sample of known r-process-enhanced stars,we have developed a method to search for candidates in the LAMOST medium-resolution(R7500)spectroscopic survey by matching the observed spectra to synthetic templates around the EuⅡline at 6645.1 A.We obtain a sample of 13 metal-poor(-2.35<[Fe/H]<-0.91)candidates from 12209 unique stars with 32774 mediumresolution spectra.These candidates will be further studied by high-resolution follow-up observations in the near future.We describe some extensions of this effort to include larger samples of stars,in particular at lower metallicity,using the strength of the BaⅡline at 6496.9 A.展开更多
Spectroscopic observations are a crucial step in driving major discoveries in the era of time-domain surveys.However,the pace of current spectroscopic surveys is increasingly unable to meet the demands of rapidly adva...Spectroscopic observations are a crucial step in driving major discoveries in the era of time-domain surveys.However,the pace of current spectroscopic surveys is increasingly unable to meet the demands of rapidly advancing large-scale time-domain surveys.To address this issue,we propose the"Frog-eyes"system,which employs a pair of narrow-band filters:one positioned near a strong absorption line to capture signals from Doppler shifts,and the other placed on the adj acent continuum to monitor intrinsic variations.The combination of observations from the two filters enables the extraction of radial velocity(RV)curves from a large sample of binary stars,and is particularly efficient for single-lined binaries(SB1),using photometric techniques.Comprehensive mock simulations on SB 1 demonstrate that the binary orbital parameters can be precisely measured from the extracted RV curves for binary systems where the primary star has an effective temperature greater than 6000 K.With a typical ground-based photometric precision of approximately 0.3%,the uncertainties in the derived semi-amplitude K and eccentricity e are less than 10%and 0.1,respectively,for binary systems with K≥30 km s^(-1).These encouraging results are further validated by real observations of the hot subdwarf-white dwarf binary system HD 265435,using a non-specialized"Frog-eyes"system installed on the Chinese 2.16 m telescope.Once this system is properly installed on large-field-of-view survey telescopes,the rate of acquiring RV curves for binaries will approach their detection rate in leading time-domain photometric surveys.展开更多
基金supported by National Key R&D Program of China(Grant No.2019YFA0405502)the Key Research Program of the Chinese Academy of Sciences(Grant No.XDPB09-02)+7 种基金the National Natural Science Foundation of China(Grant Nos.11833006,11473033,11603037,11973049,and 11973052)the international partnership program’s key foreign cooperation project,Bureau of International Cooperation,Chinese Academy of Sciences(Grant No.114A32KYSB20160049)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB34020205)supported by the Astronomical Big Data Joint Research Center,co-founded by the National Astronomical Observatories,Chinese Academy of Sciences and Alibaba Cloudpartial support for this work from grant PHY 14-30152Physics Frontier Center/JINA Center for the Evolution of the Element(JINA-CEE),awarded by the US National Science Foundationpartially supported by the Open Project Program of the Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of SciencesFunding for the project has been provided by the National Development and Reform Commission。
文摘The abundance patterns of r-process-enhanced stars contain key information required to constrain the astrophysical site(s)of r-process nucleosynthesis,and to deepen our understanding of the chemical evolution of our Galaxy.To expand the sample of known r-process-enhanced stars,we have developed a method to search for candidates in the LAMOST medium-resolution(R7500)spectroscopic survey by matching the observed spectra to synthetic templates around the EuⅡline at 6645.1 A.We obtain a sample of 13 metal-poor(-2.35<[Fe/H]<-0.91)candidates from 12209 unique stars with 32774 mediumresolution spectra.These candidates will be further studied by high-resolution follow-up observations in the near future.We describe some extensions of this effort to include larger samples of stars,in particular at lower metallicity,using the strength of the BaⅡline at 6496.9 A.
基金supported by the National Natural Science Foundation of China(Grant Nos.12422303,11988101,11933004,and 12273057)support from the National Key Basic R&D Program of China(Grant No.2023YFA1608303)+11 种基金the China Manned Space Project(Grant No.CMS-CSST-2021-A08)support from the New Cornerstone Science Foundation through the New Cornerstone Investigator Programthe XPLORER PRIZEthe International partnership program of the Chinese Academy of Sciences(Grant No.178GJHZ2022047GC)support from the National Key Basic R&D Program of China(Grant No.2023YFA1607901)partial support for this work(Grant No.PHY 14-30152)the Physics Frontier Center/JINA Center for the Evolution of the Elements(JINA-CEE)the International Research Network for Nuclear Astrophysics(IReNA)awarded by the US National Science Foundation(Grant No.OISE-1927130)support from the National Natural Science Foundation of China(Grant Nos.12090041,and 12090040)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0550100)partially supported by the Open Project Program of the Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences。
文摘Spectroscopic observations are a crucial step in driving major discoveries in the era of time-domain surveys.However,the pace of current spectroscopic surveys is increasingly unable to meet the demands of rapidly advancing large-scale time-domain surveys.To address this issue,we propose the"Frog-eyes"system,which employs a pair of narrow-band filters:one positioned near a strong absorption line to capture signals from Doppler shifts,and the other placed on the adj acent continuum to monitor intrinsic variations.The combination of observations from the two filters enables the extraction of radial velocity(RV)curves from a large sample of binary stars,and is particularly efficient for single-lined binaries(SB1),using photometric techniques.Comprehensive mock simulations on SB 1 demonstrate that the binary orbital parameters can be precisely measured from the extracted RV curves for binary systems where the primary star has an effective temperature greater than 6000 K.With a typical ground-based photometric precision of approximately 0.3%,the uncertainties in the derived semi-amplitude K and eccentricity e are less than 10%and 0.1,respectively,for binary systems with K≥30 km s^(-1).These encouraging results are further validated by real observations of the hot subdwarf-white dwarf binary system HD 265435,using a non-specialized"Frog-eyes"system installed on the Chinese 2.16 m telescope.Once this system is properly installed on large-field-of-view survey telescopes,the rate of acquiring RV curves for binaries will approach their detection rate in leading time-domain photometric surveys.
