Emma T. Whelan, Miriam Keppler, Neal J. Turner, Ilaria Pascucci, Erika Hamden, Keri Hoadley and Min Fang
{"title":"Jets from the Upper Scorpius Variable Young Star System 2MASS J16075796-2040087 via KECK/HIRES Spectro-astrometry","authors":"Emma T. Whelan, Miriam Keppler, Neal J. Turner, Ilaria Pascucci, Erika Hamden, Keri Hoadley and Min Fang","doi":"10.3847/1538-4357/ad6c4e","DOIUrl":null,"url":null,"abstract":"2MASS J16075796-2040087 is an ∼5 Myr young star in Upper Sco with evidence for accretion bursts on a timescale of about 15 days and, uncommonly for its age, outflows traced by multicomponent forbidden emission lines (FELs). The accretion bursts may be triggered by a companion at ∼4.6 au. We analyze HIRES spectra optimised for spectro-astrometry to better understand the origin of the several FEL velocity components and determine whether a magnetohydrodynamic (MHD) disk wind is present. The FEL high-velocity component (HVC) traces an asymmetric, bipolar jet ∼700 au long. The jet’s position angle ∼ 277° is not perpendicular to the disk. The lower-velocity emission, classified previously as a disk wind low-velocity component, is found to have more in common with the HVC and overall it is not possible to identify an MHD disk wind component. The spectro-astrometric signal of the low-velocity emission resembles those of jets and its density and ionisation fraction fall into the range of HVCs. We suggest a scenario where the accretion bursts due to the close companion power the jets past the age where such activity ends around most stars. The low-velocity emission here could come from a slow jet launched near the close companion and this emission would be blended with emission from the MHD wind.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"The Astrophysical Journal","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.3847/1538-4357/ad6c4e","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
2MASS J16075796-2040087 is an ∼5 Myr young star in Upper Sco with evidence for accretion bursts on a timescale of about 15 days and, uncommonly for its age, outflows traced by multicomponent forbidden emission lines (FELs). The accretion bursts may be triggered by a companion at ∼4.6 au. We analyze HIRES spectra optimised for spectro-astrometry to better understand the origin of the several FEL velocity components and determine whether a magnetohydrodynamic (MHD) disk wind is present. The FEL high-velocity component (HVC) traces an asymmetric, bipolar jet ∼700 au long. The jet’s position angle ∼ 277° is not perpendicular to the disk. The lower-velocity emission, classified previously as a disk wind low-velocity component, is found to have more in common with the HVC and overall it is not possible to identify an MHD disk wind component. The spectro-astrometric signal of the low-velocity emission resembles those of jets and its density and ionisation fraction fall into the range of HVCs. We suggest a scenario where the accretion bursts due to the close companion power the jets past the age where such activity ends around most stars. The low-velocity emission here could come from a slow jet launched near the close companion and this emission would be blended with emission from the MHD wind.