Effective temperature and luminosity of Li-rich stars (left) and Li abundance and luminosity (right). Our sample are shown by (red) filled circles, whereas data in literature with [Fe/H] ﹩\lt \,-1.7﹩ are shown by open circles for field stars (Roederer et al. 2008, 2014; Ruchti et al. 2011; Martell & Shetrone 2013) and open triangles for cluster stars (Koch et al. 2011; Kirby et al. 2016). The two comparison stars are shown by plus and cross symbols. The evolutionary tracks (Choi et al. 2016; Dotter 2016) for objects with 0.75 M⊙ for two cases of metallicity ([Fe/H] = −1.7 and −2.7) are shown by lines. In the right panel, objects in the globular cluster NGC 6397 (Lind et al. 2009) are shown by small dots. The solid lines show theoretical prediction of Li abundance as a function of luminosity by MIST24 (Choi et al. 2016) for stars with 0.75 M⊙ and [Fe/H] = −2.0 starting from the Spite plateau value ﹩A(\mathrm{Li})=2.2﹩ (the right line), and from A(Li) = 4.5 (left) and 3.5 (middle), the values close to those of J0741+2132 and J0758+4703, respectively. The dashed horizontal lines indicate the luminosity at which Li abundances show significant decreases in globular cluster stars (Lind et al. 2009).