Studies of Galactic structure and evolution have benefited enormously from Gaia kinematic information, though additional, intrinsic stellar parameters like age are required to best constrain Galactic models. Asteroseismology is the most precise method of providing such information for field star populations en masse, but existing samples for the most part have been limited to a few narrow fields of view by the CoRoT and Kepler missions. In an effort to provide well-characterized stellar parameters across a wide range in Galactic position, we present the second data release of red giant asteroseismic parameters for the K2 Galactic Archaeology Program (GAP). We provide and based on six independent pipeline analyses; first-ascent red giant branch (RGB) and red clump (RC) evolutionary state classifications from machine learning; and ready-to-use radius and mass coefficients, κ _R and κ _M , which, when appropriately multiplied by a solar-scaled effective temperature factor, yield physical stellar radii and masses. In total, we report 4395 radius and mass coefficients, with typical uncertainties of 3.3% (stat.)1% (syst.) for κ _R and 7.7% (stat.)2% (syst.) for κ _M among RGB stars, and 5.0% (stat.)1% (syst.) for κ _R and 10.5% (stat.)2% (syst.) for κ _M among RC stars. We verify that the sample is nearly complete—except for a dearth of stars with —by comparing to Galactic models and visual inspection. Our asteroseismic radii agree with radii derived from Gaia Data Release 2 parallaxes to within 2.2%0.3% for RGB stars and 2.0%0.6% for RC stars.

银河结构和演化的研究从盖亚运动学信息中获益匪浅，尽管需要额外的内在恒星参数（如年龄）来最好地约束银河模型。星震学是为现场恒星群体提供此类信息的最精确方法，但 CoRoT 和开普勒任务将大部分现有样本限制在几个狭窄的视野范围内。为了在银河位置的广泛范围内提供充分表征的恒星参数，我们为 K2 银河考古计划 (GAP) 提交了第二次发布的红巨星星震参数数据。我们提供和基于六个独立的管道分析；来自机器学习的首次上升红巨星分支 (RGB) 和红丛 (RC) 进化状态分类；和随时可用的半径和质量系数κ _R和κ _M，当适当地乘以太阳标度的有效温度因子时，会产生物理恒星半径和质量。总之，我们报告4395个半径和质量系数，与3.3％（STAT）1％（SYST）典型的不确定性κ _{- [R}和7.7％（STAT）。2％（SYST）为κ_中号RGB分之间，和 5.0% (stat.)1% (syst.) for κ _R and 10.5% (stat.)2% (syst.) for κ _M 在 RC 明星之间。我们通过与银河模型和目视检查进行比较来验证样本几乎是完整的——除了缺乏恒星。我们的星震半径与来自 Gaia Data Release 2 视差的半径一致，RGB 恒星在 2.2%0.3% 以内，RC 恒星在 2.0%0.6% 以内。