1、2023-1-21ContentsvYoung active starvWith SONGvWith mini-SONGvWhen SONG +mini-SONGWhy young active star vThe past of our SunvThe evolution history of Milky Way vGood targets for extrasolar planets searchvDistinguish between variation in frequency caused by oscillation and activities 2023-1-212023-1-2
2、1PTTSCTTSWTTSZAMSEarly evolution of solar-like stars（Neuhuser 1997）2023-1-21vM2.5M （Late spectral type）vEarly phase of evolution(t central area of Taurus-Auriga (Neuheauser et al 1995;Wichmann et al 2000)vObservational research of our groupXinglong groupXinglong group：Li&Hu 1998Li&Hu 1998ROSAT brigh
3、tROSAT bright source catalog source catalog&Tycho&Tycho catalog catalog sample sample of young solar type starsof young solar type starscriterioncriterion：logC+0.4VlogC+0.4V(Lx 10(Lx 1030 30 erg serg s-1-1)Monitoring observation on Monitoring observation on 60 cm telescope60 cm telescope at at Xingl
4、ong observation stationXinglong observation stationWTTS candidates most distributed in theWTTS candidates most distributed in the outside region outside region of Taurusof TaurusAurigaAuriga2023-1-21Why high resolution?Identify these YSS candidatesStudy the relationship between them and the nearby y
5、oung groupsResearch the relationship between the EW of Li and the rotation periodHigh resolution observations are necessary.（Wichmann 1996;Martin 1998）2023-1-21Research methodvSampleV=SampleSample：63 stars63 stars（167spectra167spectra）Spectroscopic observation log2023-1-212023-1-21Histogram of EW(Li
6、)2023-1-212023-1-21WTTW+PTTSWTTW+PTTS21 stars 21 stars 33%33%ZAMSZAMS20stars 32%20stars 32%MSMS22 stars22 stars 35%35%About 2/3 are young stars2023-1-21Young active starvBackgroundvIdentification of a sample of young solar-type star candidatesvIdentification of an active spectroscopic binary:HD14687
7、5vResearch of two young solar-type stars within 20pcvsummary2023-1-21Young low-mass binaryvOpportunity to derive precise measurements of the fundamental stellar parameters of their constituent stars(stellar mass&radius)vDerive calibrations of young-star evolutionary modelsvDetermine the unbiased mas
8、s-ratio and orbital-period distributionvThe sample of well-studied young low-mass binaries remains smallvHigh resolution spectroscopic observation (powerful technique)Identify binaryObtain accurate parameters(mass&mass ratio)2023-1-21HD146875HD146875vBright X-ray source(Schwope 2000)vV8.81 magvNone
9、hight resolution spectroscopic observations before thenv2005.04.25：show double linesv2006.02.17&06.09：show shift between linesvtill 2008.03.25：totally 45 spectra2023-1-212023-1-21Radial velocity curve2023-1-212023-1-21Spectral DisentanglingvKOREL code (Hadrava 1995)2023-1-212023-1-21Photometic varib
10、ilityv2008.02.15-04.14 vAmplitude:0.057magvCased by spots on the primary,but not ellipsoidal distortionva synchronous system(spots face us/pri-)2023-1-21Age method 12023-1-21Age method 2v Age 100 150Myr2023-1-21Subtracted profileChromospheric activityObserved spectrumModelG9G9K0K0v Strong chromosphe
11、ric activity on the primaryEmission originates in plage-like regions2023-1-21Young active starvBackgroundvIdentification of a sample of young solar-type star candidatesvIdentification of an active spectroscopic binary:HD146875vResearch of two young solar-type stars within 20pcvsummary2023-1-21vTW Hy
12、a Association(TWA)TW Hya 20Myr，56.4PC The nearest star formation region.（Zuckerman b.et al 2001，2004）Nearby young groups2023-1-21v11 stars in our sample:EW(Li)100 m D 50 PCvSo close&so young early evolution of the sun understand the structure and the evolution history of the Milky Way perfect sample
13、 for exoplanet survey2023-1-212 stars D20PC（Wang&Wei,2009,RAA,9,315）2023-1-21HIP54446843Age(Myr)100-80030-1002023-1-21Young active starvBackgroundvIdentification of a sample of young solar-type star candidatesvIdentification of an active spectroscopic binary:HD146875vResearch of two young solar-type
14、 stars within 20pcvsummary2023-1-21SummaryvFinish the identification of a sample comprising 63 stars,and 2/3 of them are young solar-type stars(YSS)vIdentify a ZAMS active double lined spectroscopic binary：HD 146875vSpectroscopic study of two YSS(HIP 544&HIP 46843)within 20 pc of the sunShortage of
15、these observationsvSingle site,single telescopevTime gap is big vWe need network&continuous observations 2023-1-21SONGWith SONG-spectroscopyvStellar Observations Network Group(SONG)vEight telescopes(3/8 in progress)vFilling the time gap(avoid aliasing frequencies)vAstroseismic research of pulsating
16、starsvAstroseismic research of Other objects including young active stars2023-1-21Astroseismology,C.Aerts,J.Christensen Dalsgaard,D.W.Kurtz2023-1-21With mini-SONGv Photometryv Multicolorv SimultaneousvDistinguish variation caused by planets and stellar activitiesvLow frequency oscillation of starsvP
17、rimary parameters of stars2023-1-21When SONG+mini-SONGvPrecise spectroscopy+multicolor photometryv Simultaneous!vDistinguish between variation in frequency caused by oscillation and activities vOscillation evolution of solar like stars along the evolution trackv2023-1-21What can we do?vFor our SONG&mini-SONGvCooperate shoulder to shouldervResearch,site Lets enjoy it!2023-1-212023-1-21
