• Home
  • Li in Open Clusters: Cool Dwarfs in the Young, Subsolar-metallicity Cluster M35 (NGC 2168)

Li in Open Clusters: Cool Dwarfs in the Young, Subsolar-metallicity Cluster M35 (NGC 2168)

Hydra spectra of 85 G–K dwarfs in the young cluster M35 near the Li 6708 Å line region are analyzed. From velocities and Gaia astrometry, 78 are likely single-star members that, combined with previous work, produce 108 members with T eff ranging from 6150 to 4000 K as defined by multicolor, broadband photometry, E(BV) = 0.20, and [Fe/H] = −0.15, though there are indications the metallicity may be closer to solar. The Lithium abundance A(Li) follows a well-delineated decline from 3.15 for the hottest stars to upper limits ≤1.0 among the coolest dwarfs. Contrary to earlier work, M35 includes single stars at systematically higher A(Li) than the mean cluster relation. This subset exhibits higher V ROT than the more Li-depleted sample and, from photometric rotation periods, is dominated by stars classed as convective (C); all others are interface (I) stars. The cool, high-Li rapid rotators (RRs) are consistent with models that simultaneously consider rapid rotation and radius inflation; RRs hotter than the Sun exhibit excess Li depletion, as predicted by the models. The A(Li) distribution with color and rotation period, when compared to the Hyades/Praesepe and the Pleiades, is consistent with gyrochronological analysis placing M35's age between the older M34 and younger Pleiades. However, the Pleiades display a more excessive range in A(Li) and rotation period than M35 on the low-Li, slow-rotation side of the distribution, with supposedly younger stars at a given T eff in the Pleiades spinning slower, with A(Li) reduced by more than a factor of four compared to M35.

Astronomical Journal 156, 1, 37 (2018)

Authors: 
Barbara J. Anthony-Twarog*, Constantine P. Deliyannis, Dianne Harmer, Donald B. Lee-Brown*, Aaron Steinhauer, Qinghui Sun, and Bruce A. Twarog* *KU Authors

Department Communications
Newsletters
Paper of the Week

Baldenegro Barrera, Baringer, Bean, Boren, Bowen, Bylinkin, Isidori, Khalil, King, Krintiras, Kropivnitskaya, Lindsey, Majumder, Mcbrayer, Minafra, Murray, Rogan, Royon, Sanders, Schmitz, Tapia Takaki, Wilson & CMS Collaboration

See previous papers

Mr. Bob T-Shirts: Lab Support