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Studies of Galactic structure and evolution have benefitted 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 $textit{en masse}$, 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 $ u_{mathrm{max}}$ and $Delta u$ 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 & mass coefficients, $kappa_R$ & $kappa_M$, 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 $3.3% mathrm{ (stat.)} pm 1% mathrm{ (syst.)}$ for $kappa_R$ and $7.7% mathrm{ (stat.)} pm 2% mathrm{ (syst.)}$ for $kappa_M$ among RGB stars, and $5.0% mathrm{ (stat.)} pm 1% mathrm{ (syst.)}$ for $kappa_R$ and $10.5% mathrm{ (stat.)} pm 2% mathrm{ (syst.)}$ for $kappa_M$ among RC stars. We verify that the sample is nearly complete -- except for a dearth of stars with $ u_{mathrm{max}} lesssim 10-20mu$Hz -- by comparing to Galactic models and visual inspection. Our asteroseismic radii agree with radii derived from Gaia Data Release 2 parallaxes to within $2.2 pm 0.3%$ for RGB stars and $2.0 pm 0.6%$ for RC stars.
NASAs K2 mission is observing tens of thousands of stars along the ecliptic, providing data suitable for large scale asteroseismic analyses to inform galactic archaeology studies. Its first campaign covered a field near the north galactic cap, a regi
We present the third and final data release of the K2 Galactic Archaeology Program (K2 GAP) for Campaigns C1-C8 and C10-C18. We provide asteroseismic radius and mass coefficients, $kappa_R$ and $kappa_M$, for $sim 19,000$ red giant stars, which trans
Context: After the loss of a second reaction wheel the Kepler mission was redesigned as the K2 mission, pointing towards the ecliptic and delivering data for new fields approximately every 80 days. The steady flow of data obtained with a reduced poin
Context. Although the Gaia catalogue on its own is a very powerful tool, it is the combination of this high-accuracy archive with other archives that will truly open up amazing possibilities for astronomical research. The advanced interoperation of a
The second Gaia data release (Gaia-DR2) contains, beyond the astrometry, three-band photometry for 1.38 billion sources. We have used these three broad bands to infer stellar effective temperatures, Teff, for all sources brighter than G=17 mag with T