J/A+A/672/A5ivo://CDS.VizieR/J/A+A/672/A5doi:10.26093/cds/vizier.36720005CDSBouvier J.Sousa SPouilly K.Almenara J.M.Donati J.-F.,Alencar S.H.P.Frasca A.Grankin K.Carmona A.Pantolmos G.Zaire B.,Bonfils X.Bayo A.Rebull L.M.Alonso-Santiago J.Gameiro J.F.,Cook N.J.Artigau E. (the Spirou Legacy Survey (SLS) consortium)2024-11-06T20:03:42Z2023-03-23T08:32:00ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frpre-main-sequence-starsphotometryvisible-astronomyYoung stellar systems actively accrete from their circumstellar disk and simultaneously launch outflows. The physical link between accretion and ejection processes remains to be fully understood. We investigate the structure and dynamics of magnetospheric accretion and associated outflows on a scale smaller than 0.1au around the young transitional disk system GM Aur. We devised a coordinated observing campaign to monitor the variability of the system on timescales ranging from days to months, including partly simultaneous high-resolution optical and near-infrared spectroscopy, multiwavelength photometry, and low-resolution near-infrared spectroscopy, over a total duration of six months, covering 30 rotational cycles. We analyzed the photometric and line profile variability to characterize the accretion and ejection processes. The optical and near-infrared light curves indicate that the luminosity of the system is modulated by surface spots at the stellar rotation period of 6.04+/-0.15-days. Part of the Balmer, Paschen, and Brackett hydrogen line profiles as well as the HeI 5876{AA} and HeI 10830{AA} line profiles are modulated on the same period. The Pa{beta} line flux correlates with the photometric excess in the u' band, which suggests that most of the line emission originates from the accretion process. High-velocity redshifted absorptions reaching below the continuum periodically appear in the near-infrared line profiles at the rotational phase in which the veiling and line fluxes are the largest. These are signatures of a stable accretion funnel flow and associated accretion shock at the stellar surface. This large-scale magnetospheric accretion structure appears fairly stable over at least 15 and possibly up to 30 rotational periods. In contrast, outflow signatures randomly appear as blueshifted absorption components in the Balmer and HeI 10830{AA} line profiles. They are not rotationally modulated and disappear on a timescale of a few days. The coexistence of a stable, large-scale accretion pattern and episodic outflows supports magnetospheric ejections as the main process occurring at the star-disk interface. Long-term monitoring of the variability of the GM Aur transitional disk system provides clues to the accretion and ejection structure and dynamics close to the star. Stable magnetospheric accretion and episodic outflows appear to be physically linked on a scale of a few stellar radii, mimicking at the sub-au scale the commonly acknowledged relationship between disk accretion and disk winds on a much larger scale.2023A&A...672A...5Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/672/A5CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/672/A5https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/672/A5http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/672/A5https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/672/A5https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/672/A5http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/672/A5GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/672/A5/umagGM Aur LCOGT u' photometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBand[ugri]instr.bandpasscharJDJulian datedtime.epochdoublemagMagnitude in Bandmagphot.magdoublee_magrms uncertainty on magmagstat.error;phot.magdoubleJ/A+A/672/A5/gmagGM Aur LCOGT g' photometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBand[ugri]instr.bandpasscharJDJulian datedtime.epochdoublemagMagnitude in Bandmagphot.magdoublee_magrms uncertainty on magmagstat.error;phot.magdoubleJ/A+A/672/A5/rmagGM Aur LCOGT r' photometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBand[ugri]instr.bandpasscharJDJulian datedtime.epochdoublemagMagnitude in Bandmagphot.magdoublee_magrms uncertainty on magmagstat.error;phot.magdoubleJ/A+A/672/A5/imagGM Aur LCOGT i' photometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBand[ugri]instr.bandpasscharJDJulian datedtime.epochdoublemagMagnitude in Bandmagphot.magdoublee_magrms uncertainty on magmagstat.error;phot.magdouble