Abstract

About 1% of giant stars1 have anomalously high Li abundances (ALi) in their atmospheres, conflicting directly with the prediction of standard stellar evolution models2. This finding makes the production and evolution of Li in the Universe intriguing, not only in the sense of Big Bang nucleosynthesis3,4 or the interstellar medium5, but also for the evolution of stars. Decades of effort have been put into explaining why such extreme objects exist6,7,8, yet the origins of Li-rich giants are still being debated. Here, we report the discovery of the most Li-rich giant known to date, with a very high ALi of 4.51. This rare phenomenon was observed coincidentally with another short-term event: the star is experiencing its luminosity bump on the red giant branch. Such a high ALi indicates that the star might be at the very beginning of its Li-rich phase, which provides a great opportunity to investigate the origin and evolution of Li in the Galaxy. A detailed nuclear simulation is presented with up-to-date reaction rates to recreate the Li enrichment process in this star. Our results provide tight constraints on both observational and theoretical points of view, suggesting that low-mass giants can internally produce Li to a very high level through 7Be transportation during the red giant phase.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Additional information

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

References

  1. 1.

    Brown, J. A., Sneden, C., Lambert, D. L. & Dutchover, E. Jr A search for lithium-rich giant stars. Astrophys. J. Suppl. 71, 293–322 (1989).

  2. 2.

    Iben, I. Jr Stellar evolution. VI. Evolution from the main sequence to the red-giant branch for stars of mass 1 M , 1.25 M , and 1.5 M . Astrophys. J. 147, 624 (1967).

  3. 3.

    Cyburt, R. H., Fields, B. D., Olive, K. A. & Yeh, T.-H. Big bang nucleosynthesis: present status. Rev. Mod. Phys. 88, 015004 (2016).

  4. 4.

    Spite, M. & Spite, F. Lithium abundance at the formation of the Galaxy. Nature 297, 483–485 (1982).

  5. 5.

    Tajitsu, A., Sadakane, K., Naito, H., Arai, A. & Aoki, W. Explosive lithium production in the classical nova V339 Del (Nova Delphini 2013). Nature 518, 381–384 (2015).

  6. 6.

    Sackmann, I.-J. & Boothroyd, A. I. Creation of 7Li and destruction of 3He, 9Be, 10B, and 11B in low-mass red giants, due to deep circulation. Astrophys. J. 510, 217–231 (1999).

  7. 7.

    Denissenkov, P. A. & Herwig, F. Enhanced extra mixing in low-mass red giants: lithium production and thermal stability. Astrophys. J. 612, 1081–1091 (2004).

  8. 8.

    Charbonnel, C. & Lagarde, N. Thermohaline instability and rotation-induced mixing. I. Low- and intermediate-mass solar metallicity stars up to the end of the AGB. Astron. Astrophys. 522, A10 (2010).

  9. 9.

    Wallerstein, G. & Sneden, C. A K giant with an unusually high abundance of lithium—HD 112127. Astrophys. J. 255, 577–584 (1982).

  10. 10.

    Monaco, L. et al. Lithium-rich giants in the Galactic thick disk. Astron. Astrophys. 529, A90 (2011).

  11. 11.

    Kirby, E. N., Fu, X., Guhathakurta, P. & Deng, L. Discovery of super-Li-rich red giants in dwarf spheroidal galaxies. Astrophys. J. 752, L16 (2012).

  12. 12.

    Martell, S. L. & Shetrone, M. D. Lithium-rich field giants in the Sloan Digital Sky Survey. Mon. Not. R. Astron. Soc. 430, 611–620 (2013).

  13. 13.

    Adamów, M., Niedzielski, A., Villaver, E., Wolszczan, A. & Nowak, G. The Penn State-Toruń Centre for Astronomy Planet Search stars. II. Lithium abundance analysis of the Red Giant Clump sample. Astron. Astrophys. 569, A55 (2014).

  14. 14.

    Casey, A. R. et al. The Gaia-ESO survey: revisiting the Li-rich giant problem. Mon. Not. R. Astron. Soc. 461, 3336–3352 (2016).

  15. 15.

    Balachandran, S. C., Fekel, F. C., Henry, G. W. & Uitenbroek, H. Two K giants with supermeteoritic lithium abundances: HDE 233517 and HD 9746. Astrophys. J. 542, 978–988 (2000).

  16. 16.

    Reddy, B. E. & Lambert, D. L. Three Li-rich K giants: IRAS 12327-6523, 13539-4153, and 17596-3952. Astron. J. 129, 2831–2835 (2005).

  17. 17.

    Kirby, E. N. et al. Lithium-rich giants in globular clusters. Astrophys. J. 819, 135 (2016).

  18. 18.

    Silva Aguirre, V. et al. Old puzzle, new insights: a lithium-rich giant quietly burning helium in its core. Astrophys. J. 784, L16 (2014).

  19. 19.

    Gaia Collaboration et al. Gaia data release 1. Summary of the astrometric, photometric, and survey properties. Astron. Astrophys. 595, A2 (2016).

  20. 20.

    Alexander, J. B. A possible source of lithium in the atmospheres of some red giants. Observatory 87, 238–240 (1967).

  21. 21.

    Aguilera-Gómez, C., Chanamé, J., Pinsonneault, M. H. & Carlberg, J. K. On lithium-rich red giants: engulfment on the giant branch of Trumpler 20. Astrophys. J. 833, L24 (2016).

  22. 22.

    Cameron, A. G. W. & Fowler, W. A. Lithium and the s-process in red-giant stars. Astrophys. J. 164, 111 (1971).

  23. 23.

    Cyburt, R. H. et al. The JINA Reaclib Database: its recent updates and impact on type-I X-ray bursts. Astrophys. J. Suppl. 189, 240–252 (2010).

  24. 24.

    Busso, M., Wasserburg, G. J., Nollett, K. M. & Calandra, A. Can extra mixing in RGB and AGB stars be attributed to magnetic mechanisms? Astrophys. J. 671, 802–810 (2007).

  25. 25.

    Pfeiffer, M. J., Frank, C., Baumueller, D., Fuhrmann, K. & Gehren, T. FOCES—a fibre optics Cassegrain échelle spectrograph. Astron. Astrophys. Suppl. 130, 381–393 (1998).

  26. 26.

    Takeda, Y., Sato, B., Kambe, E., Sadakane, K. & Ohkubo, M. Spectroscopic determination of stellar atmospheric parameters: application to mid-F through early-K dwarfs and subgiants. Publ. Astron. Soc. Jpn 54, 1041–1056 (2002).

  27. 27.

    Mashonkina, L., Gehren, T., Shi, J.-R., Korn, A. J. & Grupp, F. A non-LTE study of neutral and singly-ionized iron line spectra in 1D models of the Sun and selected late-type stars. Astron. Astrophys. 528, A87 (2011).

  28. 28.

    Carlberg, J. K., Cunha, K., Smith, V. V. & Majewski, S. R. Observable signatures of planet accretion in red giant stars. I. Rapid rotation and light element replenishment. Astrophys. J. 757, 109 (2012).

  29. 29.

    Kurucz, R. L., Furenlid, I., Brault, J. & Testerman, L. Solar flux atlas from 296 to 1300 nm. National Solar Observatory Atlas, 25–33 (National Solar Observatory, Sunspot, NM, 1984).

  30. 30.

    Sitnova, T. et al. Systematic non-LTE study of the −2.6 < [Fe/H] < 0.2 F and G dwarfs in the solar neighborhood. I. Stellar atmosphere parameters. Astrophys. J. 808, 148 (2015).

  31. 31.

    Gustafsson, B. et al. A grid of MARCS model atmospheres for late-type stars. I. Methods and general properties. Astron. Astrophys. 486, 951–970 (2008).

  32. 32.

    Adamów, M. et al. Tracking advanced planetary systems (TAPAS) with HARPS-N II. Super Li-rich giant HD 107028. Astron. Astrophys. 581, A94 (2015).

  33. 33.

    Shi, J. R., Gehren, T., Zhang, H. W., Zeng, J. L. & Zhao, G. Lithium abundances in metal-poor stars. Astron. Astrophys. 465, 587–591 (2007).

  34. 34.

    Alexeeva, S. A. & Mashonkina, L. I. Carbon abundances of reference late-type stars from 1D analysis of atomic C I and molecular CH lines. Mon. Not. R. Astron. Soc. 453, 1619–1631 (2015).

  35. 35.

    Mashonkina, L. Astrophysical tests of atomic data important for the stellar Mg abundance determinations. Astron. Astrophys. 550, A28 (2013).

  36. 36.

    Zhang, J., Shi, J., Pan, K., Allende Prieto, C. & Liu, C. NLTE analysis of high-resolution H-band spectra. I. Neutral silicon. Astrophys. J. 833, 137 (2016).

  37. 37.

    Mashonkina, L., Korn, A. J. & Przybilla, N. A non-LTE study of neutral and singly-ionized calcium in late-type stars. Astron. Astrophys. 461, 261–275 (2007).

  38. 38.

    Basu, S., Chaplin, W. J. & Elsworth, Y. Determination of stellar radii from asteroseismic data. Astrophys. J. 710, 1596–1609 (2010).

  39. 39.

    Wu, Y.-Q. et al. Stellar parameters of main sequence turn-off star candidates observed with LAMOST and Kepler. Res. Astron. Astrophys. 17, 5 (2017).

  40. 40.

    Paxton, B. et al. Modules for experiments in stellar astrophysics (MESA). Astrophys. J. Suppl. 192, 3 (2011).

  41. 41.

    Grevesse, N. & Sauval, A. J. Standard solar composition. Space Sci. Rev. 85, 161–174 (1998).

  42. 42.

    Bi, S. L., Li, T. D., Li, L. H. & Yang, W. M. Solar models with revised abundance. Astrophys. J. 731, L42 (2011).

  43. 43.

    Asplund, M., Grevesse, N., Sauval, A. J. & Scott, P. The chemical composition of the Sun. Annu. Rev. Astron. Astrophys. 47, 481–522 (2009).

  44. 44.

    Rogers, F. J. & Nayfonov, A. Updated and expanded OPAL equation-of-state tables: implications for helioseismology. Astrophys. J. 576, 1064–1074 (2002).

  45. 45.

    Ferguson, J. W. et al. Low-temperature opacities. Astrophys. J. 623, 585–596 (2005).

  46. 46.

    Alonso, A., Arribas, S. & Martnez-Roger, C. The effective temperature scale of giant stars (F0-K5). II. Empirical calibration of T eff versus colours and [Fe/H]. Astron. Astrophys. Suppl. 140, 261–277 (1999).

  47. 47.

    Schlafly, E. F. & Finkbeiner, D. P. Measuring reddening with Sloan Digital Sky Survey stellar spectra and recalibrating SFD. Astrophys. J. 737, 103 (2011).

  48. 48.

    Nollett, K. M., Busso, M. & Wasserburg, G. J. Cool bottom processes on the thermally pulsing asymptotic giant branch and the isotopic composition of circumstellar dust grains. Astrophys. J. 582, 1036–1058 (2003).

  49. 49.

    Angulo, C. et al. A compilation of charged-particle induced thermonuclear reaction rates. Nucl. Phys. A 656, 3–183 (1999).

  50. 50.

    Du, X. et al. Determination of astrophysical 7Be(p, γ)8B reaction rates from the 7Li(d, p)8Li reaction. Sci. China Phys. Mech. Astron. 58, 062001 (2015).

  51. 51.

    Bruntt, H. et al. Accurate fundamental parameters for 23 bright solar-type stars. Mon. Not. R. Astron. Soc. 405, 1907 (2015).

  52. 52.

    Hekker, S. & Meléndez, J. Precise radial velocities of giant stars. III. Spectroscopic stellar parameters. Astron. Astrophys. 475, 1003 (2007).

  53. 53.

    Kumar, Y. B., Reddy, B. E. & Lambert, D. L. Origin of lithium enrichment in K giants. Astrophys. J. 730, L12 (2011).

  54. 54.

    De La Reza, R. & da Silva, L. Lithium abundances in strong lithium K giant stars: LTE and non-LTE analyses. Astrophys. J. 439, 917–927 (1995).

  55. 55.

    Kumar, Y. B. & Reddy, B. E. HD 77361: a new case of super Li-rich K giant with anomalous low12C/13C ratio. Astrophys. J. 703, L46–L50 (2009).

  56. 56.

    Ruchti, G. R. et al. Metal-poor lithium-rich giants in the Radial Velocity Experiment Survey. Astrophys. J. 743, 107 (2011).

  57. 57.

    Carlberg, J. K. et al. The puzzling Li-rich red giant associated with NGC 6819. Astrophys. J. 802, 7 (2015).

  58. 58.

    Lind, K., Asplund, M. & Barklem, P. S. Departures from LTE for neutral Li in late-type stars. Astron. Astrophys. 503, 541–544 (2009).

Download references

Acknowledgements

This research was supported by the National Key Basic Research Program of China (2014CB845700), National Key Research and Development Project of China (2016YFA0400502) and National Natural Science Foundation of China (under grant numbers 11390371, 11603037, 11473033, 11490560, 11505117, 11573032 and 11605097). The Guoshoujing Telescope (LAMOST) is a National Major Scientific Project built by the Chinese Academy of Sciences. Funding for the project has been provided by the National Development and Reform Commission. LAMOST is operated and managed by the National Astronomical Observatories, Chinese Academy of Sciences. This work is supported by the Astronomical Big Data Joint Research Center, co-founded by the National Astronomical Observatories, Chinese Academy of Sciences and Alibaba Cloud. This research uses data obtained through the Telescope Access Program. The authors acknowledge J. Wicker for proofreading the manuscript. We acknowledge the use of Gaia and WISE data, and of the VizieR catalogue access tool.

Author information

Affiliations

  1. Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, China

    • Hong-Liang Yan
    • , Jian-Rong Shi
    • , Yu-Tao Zhou
    • , Qi Gao
    • , Jun-Bo Zhang
    • , Ze-Ming Zhou
    • , Hai-Ning Li
    •  & Gang Zhao
  2. School of Astronomy and Space Science, University of Chinese Academy of Sciences, Beijing, China

    • Hong-Liang Yan
    • , Jian-Rong Shi
    • , Yu-Tao Zhou
    • , Qi Gao
    • , Ze-Ming Zhou
    •  & Gang Zhao
  3. China Institute of Atomic Energy, Beijing, China

    • Yong-Shou Chen
    • , Zhi-Hong Li
    • , Bing Guo
    •  & Wei-Ping Liu
  4. College of Physics and Energy, Shenzhen University, Shenzhen, China

    • Er-Tao Li
  5. College of Physics and Electronics Information, Inner Mongolia University for Nationalities, Tongliao, China

    • Suyalatu Zhang
  6. Department of Astronomy, Beijing Normal University, Beijing, China

    • Shao-Lan Bi
    •  & Ya-Qian Wu

Authors

  1. Search for Hong-Liang Yan in:

  2. Search for Jian-Rong Shi in:

  3. Search for Yu-Tao Zhou in:

  4. Search for Yong-Shou Chen in:

  5. Search for Er-Tao Li in:

  6. Search for Suyalatu Zhang in:

  7. Search for Shao-Lan Bi in:

  8. Search for Ya-Qian Wu in:

  9. Search for Zhi-Hong Li in:

  10. Search for Bing Guo in:

  11. Search for Wei-Ping Liu in:

  12. Search for Qi Gao in:

  13. Search for Jun-Bo Zhang in:

  14. Search for Ze-Ming Zhou in:

  15. Search for Hai-Ning Li in:

  16. Search for Gang Zhao in:

Contributions

H.-L.Y., J.-R.S. and G.Z. proposed and designed the study. H.-L.Y. and J.-R.S. led the data analysis, with contributions from Y.-T.Z., Q.G., J.-B.Z. and Z.-M.Z. Y.-S.C., E.-T.L., S.Z., Z.-H.L., B.G. and W.-P.L. performed the nuclear calculations. S.-L.B. and Y.-Q.W. calculated the evolutionary models and tracks. H.-N.L. carried out the observations. All authors discussed the results and contributed to the writing of the manuscript.

Competing interests

The authors declare no competing interests.

Corresponding author

Correspondence to Jian-Rong Shi.

Supplementary information

  1. Supplementary Information

    Supplementary Figures 1–3, Supplementary Tables 1–2

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/s41550-018-0544-7