Published October 20, 2023 | Version Published
Journal Article Open

Twenty-five Years of Accretion onto the Classical T Tauri Star TW Hya

  • 1. ROR icon Peking University
  • 2. ROR icon California Institute of Technology
  • 3. ROR icon University of California, Davis
  • 4. ROR icon Federal University of Toulouse Midi-Pyrénées
  • 5. ROR icon Harvard-Smithsonian Center for Astrophysics
  • 6. ROR icon Stony Brook University
  • 7. ROR icon Rice University
  • 8. ROR icon European Southern Observatory
  • 9. ROR icon Massachusetts Institute of Technology
  • 10. ROR icon Purple Mountain Observatory
  • 11. ROR icon University of Science and Technology of China
  • 12. ROR icon Universität Hamburg
  • 13. ROR icon Space Telescope Science Institute
  • 14. ROR icon Universidade Federal de Minas Gerais
  • 15. ROR icon Search for Extraterrestrial Intelligence
  • 16. ROR icon Astronomical Observatory of Capodimonte
  • 17. ROR icon Osservatorio Astrofisico di Catania
  • 18. ROR icon Joint Institute for Laboratory Astrophysics
  • 19. ROR icon Institut de Planétologie et d'Astrophysique de Grenoble
  • 20. ROR icon University of Michigan–Ann Arbor
  • 21. ROR icon Boston University
  • 22. ROR icon Atacama Large Millimeter Submillimeter Array
  • 23. ROR icon Max Planck Institute for Astrophysics
  • 24. ROR icon Hunter College
  • 25. ROR icon The Graduate Center, CUNY
  • 26. ROR icon American Museum of Natural History
  • 27. ROR icon NOIRLab
  • 28. ROR icon Thüringer Landessternwarte Tautenburg
  • 29. ROR icon Smith College
  • 30. ROR icon University of Valparaíso
  • 31. ROR icon University of Hertfordshire
  • 32. ROR icon Federico Santa María Technical University
  • 33. ROR icon Max Planck Institute for Astronomy
  • 34. ROR icon Indian Institute of Science Education and Research, Tirupati
  • 35. ROR icon Rochester Institute of Technology
  • 36. ROR icon Amherst College
  • 37. ROR icon National Autonomous University of Mexico
  • 38. ROR icon Konkoly Observatory
  • 39. CSFK, MTA Centre of Excellence, Budapest, Konkoly Thege Miklós út 15-17, H-1121, Hungary
  • 40. ROR icon Osaka University

Abstract

Accretion plays a central role in the physics that governs the evolution and dispersal of protoplanetary disks. The primary goal of this paper is to analyze the stability over time of the mass accretion rate onto TW Hya, the nearest accreting solar-mass young star. We measure veiling across the optical spectrum in 1169 archival high-resolution spectra of TW Hya, obtained from 1998–2022. The veiling is then converted to accretion rate using 26 flux-calibrated spectra that cover the Balmer jump. The accretion rate measured from the excess continuum has an average of 2.51 × 10−9M yr−1 and a Gaussian distribution with an FWHM of 0.22 dex. This accretion rate may be underestimated by a factor of up to 1.5 because of uncertainty in the bolometric correction and another factor of 1.7 because of excluding the fraction of accretion energy that escapes in lines, especially Lyα. The accretion luminosities are well correlated with He line luminosities but poorly correlated with Hα and Hβ luminosity. The accretion rate is always flickering over hours but on longer timescales has been stable over 25 years. This level of variability is consistent with previous measurements for most, but not all, accreting young stars.

Copyright and License

© 2023. The Author(s). Published by the American Astronomical Society.

Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

Acknowledgement

We thank the referee for a careful read and comments, which saved us from publishing a significant error and misinterpretation of possible periods in the veiling. We thank the many people who have contributed time and effort into obtaining this data at the telescope, reducing the data, and developing archives to make the data available. This list includes Ilaria Pascucci, Feng Long, and Claudio Melo. We also thank Kevin France for discussions of Lyα emission. This work benefited from discussions with the ODYSSEUS team (HST AR-16129; Espaillat et al. 2022https://sites.bu.edu/odysseus/).

G.J.H. and J.T. are supported by the National Key R&D program of China 2022YFA1603102 from the Ministry of Science and Technology (MOST) of China and by general grant 12173003 from the National Natural Science Foundation of China. Z.G. acknowledges support from FONDECYT Postdoctoral 3220029. Z.G. acknowledges support by ANID Millennium Science Initiative Program NCN19_171. Support for this HMG was provided by the National Aeronautics and Space Administration through Chandra Award Number GO1-22007X issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060. A.F. and J.A. acknowledge 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). This work has been funded by the European Union under the European Union Horizon Europe Research & Innovation Program 101039452 (WANDA). This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program under grant agreement No 716155 (SACCRED). J.F.D. acknowledges funding from the European Research Council (ERC) under the H2020 research and innovation program (grant 740651, NewWorlds). SHPA acknowledges financial support from CNPq, CAPES, and Fapemig. J.H.K. is supported by NASA XRP grant 80NSSC19K0292 and NASA ADAP grant 80NSSC22K0625 to RIT.

This work is based in part on observations obtained at the Canada–France–Hawaii Telescope (CFHT), which is operated by the National Research Council of Canada, the Institut National des Sciences de lUnivers of the Center National de la Recherche Scientique of France, and the University of Hawaii. The CFHT observations were obtained in programs 08AF11, 10AP11, 12Ap12, 14AP18, and 16AP18 (PI Donati) and 15BE97 (PI Malo).

This work is also based in part on observations collected at the European Southern Observatory under ESO programs 106.20Z8 (PI Manara), 074.A-9021 (PI Setiawan), 089-A-9007, 090.A.9013, 092.A-9007 (PI Mohler), 093.A-9029 (PI Gredel), 099.A-9010 (PI Sarkis), 099.A-9008 (PI Mueller), 0101.A-9012 (PI Launhardt), 075.C-0202 (PI Gunther), 081.C-0778, 082.C-0390 (PI Weise), 082.C-0427 (PI Doellinger), 082.C-0218 (PI Melo), 089.C-0299 (PI Pascucci), 085.C-0238 (PI Alcala), 085.C-0764 (PI Güenther), 103.200T (PI Günther), and 60.A-9036 and 60.A-9022 (engineering runs, no PI listed).

This research is based on observations made with the NASA/ESA Hubble Space Telescope obtained from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs GO-8041 (PI Linsky), GO-9093 (PI Johns-Krull), 11608 (PI Calvet), and 13775 (PI Espaillat) and can be accessed via DOI:10.17909/0v8a-vq31.

Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. This research has made use of the Keck Observatory Archive (KOA), which is operated by the W. M. Keck Observatory and the NASA Exoplanet Science Institute (NExScI), under contract with the National Aeronautics and Space Administration. The Keck data were obtained in programs C199LA (PI Herczeg), C247Hr (PI Carpenter), C252Hr (PI Hillenbrand), C186Hr (PI Hillenbrand), C199Hb (PI Herczeg), and C269Hr (PI Dahm).

Observing time with SMARTS/Chiron obtained by PI Walter was made possible by a Research Support grant from Stony Brook University. We thank Wei-Chun Jao, Leonardo Paredes, and Todd Henry for managing the Chiron spectrograph and their prompt scheduling of the requested observations.

The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.

Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them.

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Additional details

Related works

Is new version of
Discussion Paper: arXiv:2308.14590 (arXiv)
Is supplemented by
Dataset: 10.17909/0v8a-vq31 (DOI)

Funding

National Key R&D program of China
2022YFA1603102
National Natural Science Foundation of China
12173003
Fondo Nacional de Desarrollo Científico y Tecnológico
3220029
National Aeronautics and Space Administration
GO1-22007X
National Aeronautics and Space Administration
NAS8-03060
National Institute for Astrophysics
2019 STRADE
National Institute for Astrophysics
INAF YODA
European Union
101039452
European Research Council
716155
European Research Council
740651
National Council for Scientific and Technological Development
Coordenação de Aperfeicoamento de Pessoal de Nível Superior
Fundação de Amparo à Pesquisa do Estado de Minas Gerais
National Aeronautics and Space Administration
80NSSC19K0292
National Aeronautics and Space Administration
80NSSC22K0625
Space Telescope Science Institute
National Aeronautics and Space Administration
NAS 5-26555
W. M. Keck Foundation
Stony Brook University

Dates

Accepted
2023-08-14
Accepted
Available
2023-10-12
Published

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Published