LAMOST-MRS-B is one of the sub-surveys of LAMOST medium-resolution(R~7500)spectroscopic survey.It aims at studying the statistical properties(e.g.,binary fraction,orbital period distribution,mass ratio distribution)of...LAMOST-MRS-B is one of the sub-surveys of LAMOST medium-resolution(R~7500)spectroscopic survey.It aims at studying the statistical properties(e.g.,binary fraction,orbital period distribution,mass ratio distribution)of binary stars and exotic stars.We intend to observe about 30000 stars(10 mag≤G<14.5 mag)with at least 10 visits in five years.We first planned to observe 25 plates around the galactic plane in 2018.Then the plates were reduced to 12 in 2019 because of the limitation of observation.At the same time,two new plates located at the high galactic latitude were added to explore binary properties influenced by the different environments.In this survey project,we set the identified exotic and low-metallicity stars with the highest observation priorities.For the rest of the selected stars,we gave the higher priority to the relatively brighter stars in order to obtain high quality spectra as many as possible.Spectra of49129 stars have been obtained in LAMOST-MRS-B field and released in DR8,of which 28828 and 3375 stars have been visited more than twice and ten times with SNR≥10,respectively.Most of the sources are B-,A-,and F-type stars with-0.6<[Fe/H]<0.4 dex.We also obtain 347 identified variable and exotic stars and about 250 stars with[Fe/H]<-1 dex.We measure radial velocities(RVs)by using 892233 spectra of the stars.The uncertainties of RV achieve about 1 km·s^(-1)and 10 km·s^(-1)for 95%of late-and early-type stars,respectively.The datasets presented in this paper are available at http://www.doi.org/10.57760/sciencedb.j00113.00035.展开更多
Multiple stellar populations(MPs) in most star clusters older than 2 Gyr, as seen by lots of spectroscopic and photometric studies, have led to a significant challenge to the traditional view of star formation. In thi...Multiple stellar populations(MPs) in most star clusters older than 2 Gyr, as seen by lots of spectroscopic and photometric studies, have led to a significant challenge to the traditional view of star formation. In this field, spacebased instruments, in particular the Hubble Space Telescope(HST), have made a breakthrough as they significantly improved the efficiency of detecting MPs in crowded stellar fields by images. The China Space Station Telescope(CSST) and the HST are sensitive to a similar wavelength interval, but the CSST covers a field of view which is about 5–8 times wider than that of HST. One of its instruments, the Multi-Channel Imager(MCI),will have multiple filters covering a wide wavelength range from NUV to NIR, making the CSST a potentially powerful tool for studying MPs in clusters. In this work, we evaluate the efficiency of the designed filters for the MCI/CSST in revealing MPs in different color–magnitude diagrams(CMDs). We find that CMDs made with MCI/CSST photometry in appropriate UV filters are powerful tools to disentangle stellar populations with different abundances of He, C, N, O and Mg. On the contrary, the traditional CMDs are blind to multiple populations in globular clusters(GCs). We show that CSST has the potential of being the spearhead instrument for investigating MPs in GCs in the next decades.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12073070,12173081,12090043,11873016,and 12173013)Yunnan Fundamental Research Project(Grant No.202101AV070001)+5 种基金the Science Research Grants from The China Manned Space Project(Grant Nos.CMS-CSST2021-A08,CMS-CSST-2021-A10,and CMS-CSST-2021-B05)CAS‘Light of West China’ProgramGuoshoujing Telescope(the Large Sky Area MultiObject Fiber Spectroscopic Telescope LAMOST)is a National Major Scientific Project built by the Chinese Academy of Sciences.Funding for the project has been provided by the National Development and Reform Commission of ChinaFunding for the DPAC has been provided by national institutions,in particular the institutions participating in the Gaia Multilateral AgreementThe LAMOST fellowship is supported by Special Funding for Advanced Users,budgeted and administrated by Center for Astronomical Mega-Science,Chinese Academy of Sciences(CAMS)supported by Cultivation Project for LAMOST Scientific Payoff and Research Achievement of CAMS-CAS and Special Research Assistant Program of Chinese Academy of Sciences。
文摘LAMOST-MRS-B is one of the sub-surveys of LAMOST medium-resolution(R~7500)spectroscopic survey.It aims at studying the statistical properties(e.g.,binary fraction,orbital period distribution,mass ratio distribution)of binary stars and exotic stars.We intend to observe about 30000 stars(10 mag≤G<14.5 mag)with at least 10 visits in five years.We first planned to observe 25 plates around the galactic plane in 2018.Then the plates were reduced to 12 in 2019 because of the limitation of observation.At the same time,two new plates located at the high galactic latitude were added to explore binary properties influenced by the different environments.In this survey project,we set the identified exotic and low-metallicity stars with the highest observation priorities.For the rest of the selected stars,we gave the higher priority to the relatively brighter stars in order to obtain high quality spectra as many as possible.Spectra of49129 stars have been obtained in LAMOST-MRS-B field and released in DR8,of which 28828 and 3375 stars have been visited more than twice and ten times with SNR≥10,respectively.Most of the sources are B-,A-,and F-type stars with-0.6<[Fe/H]<0.4 dex.We also obtain 347 identified variable and exotic stars and about 250 stars with[Fe/H]<-1 dex.We measure radial velocities(RVs)by using 892233 spectra of the stars.The uncertainties of RV achieve about 1 km·s^(-1)and 10 km·s^(-1)for 95%of late-and early-type stars,respectively.The datasets presented in this paper are available at http://www.doi.org/10.57760/sciencedb.j00113.00035.
基金supported by the National Natural Science Foundation of China (NSFC, Grant No. 12073090)the China Manned Space Project with NO.CMS-CSST-2021-A08,CMS-CSST-2021-B03。
文摘Multiple stellar populations(MPs) in most star clusters older than 2 Gyr, as seen by lots of spectroscopic and photometric studies, have led to a significant challenge to the traditional view of star formation. In this field, spacebased instruments, in particular the Hubble Space Telescope(HST), have made a breakthrough as they significantly improved the efficiency of detecting MPs in crowded stellar fields by images. The China Space Station Telescope(CSST) and the HST are sensitive to a similar wavelength interval, but the CSST covers a field of view which is about 5–8 times wider than that of HST. One of its instruments, the Multi-Channel Imager(MCI),will have multiple filters covering a wide wavelength range from NUV to NIR, making the CSST a potentially powerful tool for studying MPs in clusters. In this work, we evaluate the efficiency of the designed filters for the MCI/CSST in revealing MPs in different color–magnitude diagrams(CMDs). We find that CMDs made with MCI/CSST photometry in appropriate UV filters are powerful tools to disentangle stellar populations with different abundances of He, C, N, O and Mg. On the contrary, the traditional CMDs are blind to multiple populations in globular clusters(GCs). We show that CSST has the potential of being the spearhead instrument for investigating MPs in GCs in the next decades.
