Skip to main content Accessibility help
×
Home

7Li in Metal-Poor Stars: The Spread of the Li Plateau

  • Sean G. Ryan (a1)

Abstract

A highly homogeneous study of 23 halo field dwarf stars has achieved a Li abundance accuracy of 0.033 dex per star. The work shows that the intrinsic spread of the Li abundances of these stars at a given metallicity is < 0.02 dex, and consistent with zero. That is, the Spite Li plateau for halo field dwarfs is incredibly thin. The thinness rules out depletion by more than 0.1 dex by a rotational-induced extra-mixing mechanism. Despite the thinness of the plateau, an increase of Li with [Fe/H] is seen, interpreted as evidence of Galactic chemical evolution (GCE) of Li, primarily due to Galactic cosmic ray (GCR) spallation reactions in the era of halo formation. The rate of Li evolution is concordant with: (1) observations of spallative 6Li in halo dwarfs; (2) GCE models; and (3) data on Li in higher metallicity halo stars. New data have also revealed four new ultra-Li-deficient halo dwarfs, doubling the number known. Based on their propensity to cluster at the halo main sequence turnoff and also to exist redward of the turnoff, we hypothesise that they are the products of binary mergers that ultimately will become blue stragglers. We explain their low Li abundances by normal pre-main-sequence (and possibly main-sequence) destruction in the low mass stars prior to their merging. If this explanation is correct, then such stars need no longer be considered an embarrassment to the existence of negligible Li destruction in the majority of field halo dwarfs.

    • Send article to Kindle

      To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      7Li in Metal-Poor Stars: The Spread of the Li Plateau
      Available formats
      ×

      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      7Li in Metal-Poor Stars: The Spread of the Li Plateau
      Available formats
      ×

      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      7Li in Metal-Poor Stars: The Spread of the Li Plateau
      Available formats
      ×

Copyright

References

Hide All
Alonso, A., Arribas, S., & Martínez-Roger, C. 1996, A&AS, 117, 227
Bell, R. A. & Oke, J. B. 1986, ApJ, 307, 253
Boesgaard, A. M., Deliyannis, C. P., Stephens, A., & King, J. R. 1998, ApJ, 493, 206
Boesgaard, A. M. & Steigman, G. 1985, ARAA, 23, 319
Boesgaard, A. M. & Tripicco, M. J. 1986a, ApJ, 302, L49
Boesgaard, A. M. & Tripicco, M. J. 1986b, ApJ, 303, 724
Bonifacio, P. & Molaro, P. 1997, MNRAS, 285, 847
Cayrel, R., Spite, M., Spite, F., Vangioni-Flam, E., Cassé, M., & Audouze, J. 1999, A&A, 343, 923
Deliyannis, C. P., Demarque, P., & Kawaler, S. D. 1990, ApJS, 73, 21
Deliyannis, C. P., Pinsonneault, M. H., & Duncan, D. K. 1993, ApJ, 414, 740
Deliyannis, C. P. & Ryan, S. G. 2000, in prep
Fields, B. D. & Olive, K. A. 1999, New Astronomy, 4, 255
Fields, B. D. & Olive, K. A. 1999, ApJ, 516, 797
Hanson, R. B., Sneden, C., Kraft, R. P., & Fulbright, J. 1998, AJ, 116, 1286
Hobbs, L. M., & Thorburn, J. A. 1994, ApJ, 428, L25L28
Hobbs, L. M., Welty, D. E., & Thorburn, J. A. 1991, ApJ, 373, L47
Magain, P. 1987, A&A, 181, 323
Hobbs, L. M. & Thorburn, J. A. 1997, ApJ, 491, 772
Lambert, D. L., Heath, J. E., & Edvardsson, B. 1991, MNRAS, 253, 610
Norris, J. E., Ryan, S. G., & Stringfellow, G. S. 1994, ApJ, 423, 386
Norris, J. E., Ryan, S. G., Beers, T. C., & Deliyannis, C. P. 1997, ApJ, 485, 370
Pinsonneault, M. H., Deliyannis, C. P., and Demarque, P. 1992, ApJS, 78, 179
Pinsonneault, M. H., Walker, T. P., Steigman, G., & Narayanan, V. K. 1999, ApJ, 527, 180
Rebolo, R., Molaro, P., & Beckman, J. E. 1988, A&A, 192, 192
Romano, D., Matteucci, F., Molaro, P., & Bonifacio, P. 1999, A&A, in press
Ryan, S. G., Beers, T. C., Deliyannis, C. P., & Thorburn, J. A. 1996, ApJ, 458, 543
Ryan, S. G., Beers, T. C., Olive, K. A., Fields, B. D., & Norris, J. E. 2000a, ApJL, in press
Ryan, S. G., Beers, T. C., Kajino, T., & Rosolankova, K. 2000c, in prep
Ryan, S. G., Kajino, T., Beers, T. C., Suzuki, T., Rosolankova, K., & Romano, D. 2000b, in prep
Ryan, S. G., Norris, J. E., & Beers, T. C. 1998, ApJ, 506, 892
Ryan, S. G., Norris, J. E., & Beers, T. C. 1999, ApJ, 523, 654
Smith, V. V., Lambert, D. L., & Nissen, P.-E. 1993, ApJ, 408, 262
Smith, V. V., Lambert, D. L., & Nissen, P. E. 1998, ApJ, 506, 405
Spite, F. & Spite, M. 1982, A&A, 115, 357
Spite, F. & Spite, M. 1993, A&A, 279, L9
Spite, M., Molaro, P., Francois, P., & Spite, F. 1993, A&A, 271, L1
Spite, M., & Spite, F. 1981, IAU Coll. 68, Astrophysical Parameters for Globular Clusters, David Phillip, A. G. & Haynes, D. S. eds (Kluwer, Dordrecht)
Thorburn, J. A. 1992, ApJ, 399, L83
Thorburn, J. A. 1994, ApJ, 421, 318

Related content

Powered by UNSILO

7Li in Metal-Poor Stars: The Spread of the Li Plateau

  • Sean G. Ryan (a1)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.