A stellar flare−coronal mass ejection event revealed by X-ray plasma motions

Abstract

Coronal mass ejections (CMEs), often associated with flares1,2,3, are the most powerful magnetic phenomena occurring on the Sun. Stars show magnetic activity levels up to ten thousand times higher4, and CME effects on stellar physics and circumstellar environments are predicted to be substantial5,6,7,8,9. However, stellar CMEs remain observationally unexplored. Using time-resolved high-resolution X-ray spectroscopy of a stellar flare on the active star HR 9024 observed with the High Energy Transmission Grating Spectrometer onboard the Chandra X-ray Observatory space telescope, we distinctly detected Doppler shifts in S xvi, Si xiv and Mg xii lines that indicate upward and downward motions of hot plasmas (around 10–25 MK) within the flaring loop, with velocities of 100–400 km s−1, in agreement with a model of a flaring magnetic tube. Most notably, we also detected a later blueshift in the O viii line that reveals an upward motion, with velocity 90 ± 30 km s−1, of cool plasma (about 4 MK), that we ascribe to a CME coupled to the flare. From this evidence we were able to derive a CME mass of \(1\!.\!2_{ - 0.8}^{ + 2.6} \times 10^{21}\) g and a CME kinetic energy of \(5\!.\!2_{ - 3.6}^{ + 27.7} \times 10^{34}\) erg. These values provide clues in the extrapolation of the solar case to higher activity levels in other stars, suggesting that CMEs could indeed be a major cause of mass and angular momentum loss.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Fig. 1: Observed X-ray spectra and light curve of HR 9024.
Fig. 2: Time-resolved line fits.
Fig. 3: Comparison between observed and predicted velocities.
Fig. 4: Extrapolation of the solar flare−CME relation.

Data availability

The Chandra dataset analysed in this work (ObsID 1892) can be accessed from http://cxc.harvard.edu/. The data that support plots and findings of this study are available from the corresponding author upon reasonable request.

References

  1. 1.

    Yashiro, S. & Gopalswamy, N. Statistical relationship between solar flares and coronal mass ejections. In Universal Heliophysical Processes (eds Gopalswamy, N. & Webb, D. F.) Vol. 257, 233–243 (IAU Symp., 2009).

  2. 2.

    Aarnio, A. N., Stassun, K. G., Hughes, W. J. & McGregor, S. L. Solar flares and coronal mass ejections: a statistically determined flare flux−CME mass correlation. Sol. Phys. 268, 195–212 (2011).

    ADS  Article  Google Scholar 

  3. 3.

    Webb, D. F. & Howard, T. A. Coronal mass ejections: observations. Living Rev. Sol. Phys. 9, 3 (2012).

    ADS  Article  Google Scholar 

  4. 4.

    Wright, N. J., Drake, J. J., Mamajek, E. E. & Henry, G. W. The stellar-activity−rotation relationship and the evolution of stellar dynamos. Astrophys. J. 743, 48 (2011).

    ADS  Article  Google Scholar 

  5. 5.

    Khodachenko, M. L. et al. Coronal mass ejection (CME) activity of low mass M stars as an important factor for the habitability of terrestrial exoplanets. I. CME impact on expected magnetospheres of Earth-like exoplanets in close-in habitable zones. Astrobiology 7, 167–184 (2007).

    ADS  Article  Google Scholar 

  6. 6.

    Aarnio, A. N., Matt, S. P. & Stassun, K. G. Mass loss in pre-main-sequence stars via coronal mass ejections and implications for angular momentum loss. Astrophys. J. 760, 9 (2012).

    ADS  Article  Google Scholar 

  7. 7.

    Drake, J. J., Cohen, O., Yashiro, S. & Gopalswamy, N. Implications of mass and energy loss due to coronal mass ejections on magnetically active stars. Astrophys. J. 764, 170 (2013).

    ADS  Article  Google Scholar 

  8. 8.

    Osten, R. A. & Wolk, S. J. Connecting flares and transient mass-loss events in magnetically active stars. Astrophys. J. 809, 79 (2015).

    ADS  Article  Google Scholar 

  9. 9.

    Odert, P., Leitzinger, M., Hanslmeier, A. & Lammer, H. Stellar coronal mass ejections. I. Estimating occurrence frequencies and mass-loss rates. Mon. Not. R. Astron. Soc. 472, 876–890 (2017).

    ADS  Article  Google Scholar 

  10. 10.

    Noyes, R. W., Hartmann, L. W., Baliunas, S. L., Duncan, D. K. & Vaughan, A. H. Rotation, convection, and magnetic activity in lower main-sequence stars. Astrophys. J. 279, 763–777 (1984).

    ADS  Article  Google Scholar 

  11. 11.

    Shibata, K. & Magara, T. Solar flares: magnetohydrodynamic processes. Living Rev. Sol. Phys. 8, 6 (2011).

    ADS  Article  Google Scholar 

  12. 12.

    Güdel, M. X-ray astronomy of stellar coronae. Annu. Rev. Astron. Astrophys. 12, 71–237 (2004).

    Google Scholar 

  13. 13.

    Houdebine, E. R., Foing, B. H. & Rodono, M. Dynamics of flares on late-type dMe stars. I. Flare mass ejections and stellar evolution. Astron. Astrophys. 238, 249–255 (1990).

    ADS  Google Scholar 

  14. 14.

    Vida, K. et al. Investigating magnetic activity in very stable stellar magnetic fields. Long-term photometric and spectroscopic study of the fully convective M4 dwarf V374 Pegasi. Astron. Astrophys. 590, A11 (2016).

    Article  Google Scholar 

  15. 15.

    Vida, K. et al. The quest for stellar coronal mass ejections in late-type stars. I. Investigating Balmer-line asymmetries of single stars in virtual observatory data. Astron. Astrophys. 623, A49 (2019).

    Article  Google Scholar 

  16. 16.

    Gunn, A. G., Doyle, J. G., Mathioudakis, M., Houdebine, E. R. & Avgoloupis, S. High-velocity evaporation during a flare on AT Microscopii. Astron. Astrophys. 285, 489–496 (1994).

    ADS  Google Scholar 

  17. 17.

    Berdyugina, S. V., Ilyin, I. & Tuominen, I. The active RS Canum Venaticorum binary II Pegasi. III. Chromospheric emission and flares in 1994–1996. Astron. Astrophys. 349, 863–872 (1999).

    ADS  Google Scholar 

  18. 18.

    Moschou, S.-P., Drake, J. J., Cohen, O., Alvarado-Gomez, J. D. & Garraffo, C. A monster CME obscuring a demon star flare. Astrophys. J. 850, 191 (2017).

    ADS  Article  Google Scholar 

  19. 19.

    Wheatley, P. J. ROSAT observations of V471 Tauri, showing that stellar activity is determined by rotation, not age. Mon. Not. R. Astron. Soc. 297, 1145–1150 (1998).

    ADS  Article  Google Scholar 

  20. 20.

    Mullan, D. J., Sion, E. M., Bruhweiler, F. C. & Carpenter, K. G. Evidence for a cool wind from the K2 dwarf in the detached binary V471 Tauri. Astrophys. J. Lett. 339, L33–L36 (1989).

    ADS  Article  Google Scholar 

  21. 21.

    Testa, P., Reale, F., Garcia-Alvarez, D. & Huenemoerder, D. P. Detailed diagnostics of an X-ray flare in the single giant HR 9024. Astrophys. J. 663, 1232–1243 (2007).

    ADS  Article  Google Scholar 

  22. 22.

    Borisova, A. et al. The different origins of magnetic fields and activity in the Hertzsprung gap stars, OU Andromedae and 31 Comae. Astron. Astrophys. 591, A57 (2016).

    Article  Google Scholar 

  23. 23.

    Strassmeier, K. G., Serkowitsch, E. & Granzer, T. Starspot photometry with robotic telescopes, UBV(RI)C and by light curves of 47 active stars in 1996/97. Astron. Astrophys. Suppl. Ser. 140, 29–53 (1999).

    ADS  Article  Google Scholar 

  24. 24.

    Pizzolato, N., Maggio, A. & Sciortino, S. Evolution of X-ray activity of 1–3 Msun late-type stars in early post-main-sequence phases. Astron. Astrophys. 361, 614–628 (2000).

    ADS  Google Scholar 

  25. 25.

    Testa, P. et al. Geometry diagnostics of a stellar flare from fluorescent X-rays. Astrophys. J. 675, L97 (2008).

    ADS  Article  Google Scholar 

  26. 26.

    Švestka, Z. Speeds of rising post-flare structures. Sol. Phys. 169, 403–413 (1996).

    ADS  Article  Google Scholar 

  27. 27.

    West, M. J. & Seaton, D. B. SWAP observations of post-flare giant arches in the long-duration 14 October 2014 solar eruption. Astrophys. J. Lett. 801, L6 (2015).

    ADS  Article  Google Scholar 

  28. 28.

    Landi, E., Raymond, J. C., Miralles, M. P. & Hara, H. Physical conditions in a coronal mass ejection from hinode, stereo, and SOHO observations. Astrophys. J. 711, 75–98 (2010).

    ADS  Article  Google Scholar 

  29. 29.

    Drake, J. J., Cohen, O., Garraffo, C. & Kashyap, V. Stellar flares and the dark energy of CMEs. In Solar and Stellar Flares and their Effects on Planets (eds. Kosovichev, A. G., Hawley, S. L. & Heinzel, P.) Vol. 320, 196–201 (IAU Symp., 2016).

  30. 30.

    Alvarado-Gómez, J. D., Drake, J. J., Cohen, O., Moschou, S. P. & Garraffo, C. Suppression of coronal mass ejections in active stars by an overlying large-scale magnetic field: a numerical study. Astrophys. J. 862, 93 (2018).

    ADS  Article  Google Scholar 

  31. 31.

    Huenemoerder, D. P. et al. TGCat: the Chandra transmission grating data catalog and archive. Astron. J. 141, 129 (2011).

    ADS  Article  Google Scholar 

  32. 32.

    Argiroffi, C. et al. Redshifted X-rays from the material accreting onto TW Hydrae: evidence of a low-latitude accretion spot. Astron. Astrophys. 607, A14 (2017).

    Article  Google Scholar 

  33. 33.

    Brickhouse, N. S., Dupree, A. K. & Young, P. R. X-ray Doppler imaging of 44i Bootis with Chandra. Astrophys. J. 562, L75–L78 (2001).

    ADS  Article  Google Scholar 

  34. 34.

    Chung, S. M., Drake, J. J., Kashyap, V. L., Lin, L. W. & Ratzlaff, P. W. Doppler shifts and broadening and the structure of the X-ray emission from Algol. Astrophys. J. 606, 1184–1195 (2004).

    ADS  Article  Google Scholar 

  35. 35.

    Ishibashi, K., Dewey, D., Huenemoerder, D. P. & Testa, P. Chandra/HETGS observations of the Capella system: the primary as a dominating X-ray source. Astrophys. J. 644, L117–L120 (2006).

    ADS  Article  Google Scholar 

  36. 36.

    Smith, R. K., Brickhouse, N. S., Liedahl, D. A. & Raymond, J. C. Collisional plasma models with APEC/APED: emission-line diagnostics of hydrogen-like and helium-like ions. Astrophys. J. 556, L91–L95 (2001).

    ADS  Article  Google Scholar 

  37. 37.

    Singh, K. P., Drake, S. A., White, N. E. & Simon, T. ROSAT observations of five chromospherically active stars. Astron. J. 112, 221 (1996).

    ADS  Article  Google Scholar 

  38. 38.

    Cheng, X., Zhang, J., Saar, S. H. & Ding, M. D. Differential emission measure analysis of multiple structural components of coronal mass ejections in the inner corona. Astrophys. J. 761, 62 (2012).

    ADS  Article  Google Scholar 

  39. 39.

    Landi, E., Miralles, M. P., Raymond, J. C. & Hara, H. Hot plasma associated with a coronal mass ejection. Astrophys. J. 778, 29 (2013).

    ADS  Article  Google Scholar 

Download references

Acknowledgements

We acknowledge a modest financial contribution from the ASI-INAF agreement n.2017-14.H.O.

Author information

Affiliations

Authors

Contributions

C.A., F.R., J.J.D., A.C., P.T., R.B., M.M., S.O. and G.P. contributed to scientific discussion and writing of the text. C.A. and J.J.D. contributed to analysis of observational data. F.R. contributed to the hydrodynamic model development, and C.A. to the synthesis of the model line profile.

Corresponding author

Correspondence to C. Argiroffi.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information: Nature Astronomy thanks Krisztian Vida and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figures 1–2, Supplementary Tables 1–2.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Argiroffi, C., Reale, F., Drake, J.J. et al. A stellar flare−coronal mass ejection event revealed by X-ray plasma motions. Nat Astron 3, 742–748 (2019). https://doi.org/10.1038/s41550-019-0781-4

Download citation

Further reading

Search

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing