The nature of the lithium enrichment in the most Li-rich giant star

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.

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Fig. 1: Observed spectra and line profile fittings for TYC 429-2097-1.
Fig. 2: Distribution of Li-rich giants.
Fig. 3: Calculated surface abundances and mass fractions of 3He, 7Be and 7Li as functions of the processing time for the mass circulation.

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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  4. 4.

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

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  9. 9.

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

    ADS  Article  Google Scholar 

  10. 10.

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

    Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  17. 17.

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

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  19. 19.

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

    Article  Google Scholar 

  20. 20.

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

    ADS  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  22. 22.

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

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  35. 35.

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

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  38. 38.

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

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  40. 40.

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

    ADS  Article  Google Scholar 

  41. 41.

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

    ADS  Article  Google Scholar 

  42. 42.

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

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  44. 44.

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

    ADS  Article  Google Scholar 

  45. 45.

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

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  49. 49.

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

    ADS  Article  Google Scholar 

  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).

    Google Scholar 

  51. 51.

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

    ADS  Google Scholar 

  52. 52.

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

    ADS  Article  Google Scholar 

  53. 53.

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

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

  56. 56.

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

    ADS  Article  Google Scholar 

  57. 57.

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

    ADS  Article  Google Scholar 

  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).

    ADS  Article  Google Scholar 

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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.

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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.

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Correspondence to Jian-Rong Shi.

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Yan, H., Shi, J., Zhou, Y. et al. The nature of the lithium enrichment in the most Li-rich giant star. Nat Astron 2, 790–795 (2018). https://doi.org/10.1038/s41550-018-0544-7

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