Stable accretion and episodic outflows in the young transition disk system GM Aurigae. A semester-long optical and near-infrared spectrophotometric monitoring campaign
Abstract
Context.Young 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. Aims. We investigate the structure and dynamics of magnetospheric accretion and associated outflows on a scale smaller than 0.1 au around the young transitional disk system GM Aur. Methods. 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. Results. 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 Å and HeI 10830 Å line profiles are modulated on the same period. The Paβ 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 Å 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. Conclusions. 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 in this system.
Additional Information
© The Authors 2023. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This article is published in open access under the Subscribe to Open model. Subscribe to A&A to support open access publication. We thank the referee for a prompt and detailed report. This study is based on observations obtained at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. The observations at the CFHT were performed with care and respect from the summit of Maunakea which is a significant cultural and historic site; based on observations made at Observatoire de Haute Provence (CNRS), France; based on data collected under the ExTrA project at the ESO La Silla Paranal Observatory. ExTrA is a project of Institut de Planétologie et d'Astrophysique de Grenoble (IPAG/CNRS/UGA), funded by the European Research Council under the ERC Grant Agreement n. 337591-ExTrA. We thank Ágnes Kóspál for providing a reduced TESS light curve of GM Aur. Funding for the TESS mission is provided by NASA's Science Mission directorate. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement no. 742095; SPIDI: Star-Planets-Inner Disk-Interactions, http://www.spidi-eu.org). We acknowledge funding from the French National Research Agency (ANR) under contract number ANR-18-CE31-0019 (SPlaSH). SHPA acknowledges financial support from CNPq, CAPES and Fapemig. JFD acknowledges funding from the European Research Council (ERC) under the H2020 research & innovation programme (grant agreement no. 740651 NewWorlds). AF acknowledges support by the PRIN-INAF 2019 STRADE (Spectroscopically TRAcing the Disk dispersal Evolution) and by the Large Grant INAF YODA (YSOs Outflow, Disks and Accretion). JFG was supported by fundação para a Ciência e Tecnologia (FCT) through the research grants UIDB/04434/2020 and UIDP/04434/2020. This work benefited from discussions with the ODYSSEUS (HST AR-16129) and PENELLOPE teams. Some of the plots presented in this paper were built using TOPCAT (Taylor 2005).Attached Files
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Additional details
- Eprint ID
- 122142
- Resolver ID
- CaltechAUTHORS:20230705-470712800.1
- National Research Council of Canada
- Institut national des sciences de l'Univers (INSU)
- University of Hawaii
- Centre National de la Recherche Scientifique (CNRS)
- Institut de Planétologie et d'Astrophysique de Grenoble (IPAG)
- 337591
- European Research Council (ERC)
- 742095
- European Research Council (ERC)
- ANR-18-CE31-0019
- Agence Nationale de la Recherche (ANR)
- Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
- Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
- Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)
- 740651
- European Research Council (ERC)
- Istituto Nazionale di Astrofisica (INAF)
- UIDB/04434/2020
- Fundação para a Ciência e Tecnologia (FCT)
- Fundação para a Ciência e Tecnologia (FCT)
- Created
-
2023-08-18Created from EPrint's datestamp field
- Updated
-
2023-08-18Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)