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Title: An improved determination of the lithium depletion boundary age of Blanco 1 and a first look on the effects of magnetic activity

Journal Article · · Astrophysical Journal
;  [1];  [2]
  1. Department of Physics, Fisk University, Nashville, TN 37208 (United States)
  2. Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States)

The lithium depletion boundary (LDB) is a robust method for accurately determining the ages of young clusters, but most pre-main-sequence models used to derive LDB ages do not include the effects of magnetic activity on stellar properties. In light of this, we present results from our spectroscopic study of the very-low-mass members of the southern open cluster Blanco 1 using the Gemini-North Telescope, program IDs: GN-2009B-Q-53 and GN-2010B-Q-96. We obtained Gemini Multi-Object Spectrograph spectra at intermediate resolution for cluster candidate members with I ≈ 13-20 mag. From our sample of 43 spectra, we find 14 probable cluster members by considering proximity to the cluster sequence in an I/I – K {sub s} color-magnitude diagram, agreement with the cluster's systemic radial velocity, and magnetic activity as a youth indicator. We systematically analyze the Hα and Li features and update the LDB age of Blanco 1 to be 126{sub −14}{sup +13} Myr. Our new LDB age for Blanco 1 shows remarkable coevality with the benchmark Pleiades open cluster. Using available empirical activity corrections, we investigate the effects of magnetic activity on the LDB age of Blanco 1. Accounting for activity, we infer a corrected LDB age of 114{sub −10}{sup +9} Myr. This work demonstrates the importance of accounting for magnetic activity on LDB inferred stellar ages, suggesting the need to reinvestigate previous LDB age determinations.

OSTI ID:
22370226
Journal Information:
Astrophysical Journal, Vol. 795, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
Country of Publication:
United States
Language:
English