# Summary of K2 Program GO16001

Title: Gyrochronology and Magnetic Activity in Wide Binaries with K2

PI: Davenport, James Robert Arthur (Western Washington University)
CoIs: Otani, Tomomi; Buzasi, Derek L; Oswalt, Terry D

We propose to observe approximately 660 wide binary star systems with K2 to simultaneously constrain their rotation periods and flare rates. These systems will allow us to improve calibrations of the age-rotation-activity relationship for field stars across a wide range in age. Flare rates and rotation periods will be measured using previously developed toolkits, and this sample will add to the ongoing analysis of Kepler and K2 wide binary systems.

Stars lose angular momentum as they age, causing their rotation periods to decline at a predictable rate. This "gyrochronology" method provides us with a means to determine stellar ages to within ~10% for Sun-like stars (Barnes 2010 ApJ 722 222). Wide binary systems help to extend the usable mass and age range for gyrochronology, and will be able to test new models of weakened magnetic braking in old field stars (e.g. van Saders et al. 2016 Nature, 529, 181).  A subset of the proposed sample contains white dwarf components whose cooling ages provide a benchmark against which their main sequence companions rotation ages may be compared.

Because slower rotation weakens the internal magnetic dynamo, flare rates are predicted to decline over time. As a result, older stars like the Sun exhibit very few "super flares". The detailed evolution of flare rates for main sequence stars of spectral types G, K, and M is poorly constrained, however, due to the small number of flare stars with known ages. Any wide binary component with a measurable flare rate and rotation age is extremely valuable for such calibrations. These systems will also become important benchmarks for other facets of magnetic activity, such as tracking the evolution of activity cycles and starspot filling factors.

# Targets requested by this program that have been observed (82)
EPIC ID, RA (J2000) [deg], Dec (J2000) [deg], magnitude, Investigation IDs
200200357, , , , GO16001|GO16003|GO16021|GO16063|ALPHA_CANCRI-LC-BRIGHT_STAR_DISC
211400219, 135.52923, 11.643649, 13.702, GO16001_LC|GO16005_LC|GO16052_LC|GO16056_LC|GO16083_LC
211402742, 133.252532, 11.683366, 10.227, GO16001_LC|GO16052_LC
211405388, 133.07787, 11.723501, 12.629, GO16001_LC|GO16021_LC|GO16031_LC|GO16064_LC
211405649, 131.732452, 11.727347, 10.749, GO16001_LC|GO16009_LC|GO16021_LC|GO16083_LC
211411632, 133.815867, 11.816198, 13.01, GO16001_LC|GO16021_LC|GO16052_LC
211412092, 129.738438, 11.822828, 10.015, GO16001_LC|GO16009_LC|GO16020_LC|GO16021_LC|GO16028_LC|GO16041_LC
211426841, 132.668226, 12.044022, 13.873, GO16001_LC|GO16031_LC|GO16064_LC
211429166, 132.965596, 12.079666, 13.38, GO16001_LC|GO16021_LC|GO16031_LC|GO16064_LC
211430866, 133.136292, 12.106943, 12.561, GO16001_LC|GO16009_LC|GO16021_LC|GO16031_LC|GO16064_LC
211432167, 132.863806, 12.127919, 8.55, GO16001_LC|GO16021_LC|GO16028_LC|GO16065_LC
211432806, 134.663061, 12.137539, 11.673, GO16001_LC|GO16009_LC|GO16021_LC|GO16083_LC
211435038, 132.391049, 12.170734, 8.319, GO16001_LC|GO16021_LC|GO16028_LC
211435372, 130.421878, 12.175715, 9.45, GO16001_LC|GO16004_LC|GO16052_LC
211443351, 133.043918, 12.298292, 9.856, GO16001_LC|GO16009_LC|GO16021_LC|GO16028_LC|GO16065_LC
211444688, 133.639745, 12.31887, 10.604, GO16001_LC|GO16004_LC|GO16052_LC
211451249, 130.860286, 12.419062, 10.815, GO16001_LC|GO16009_LC|GO16020_LC|GO16021_LC|GO16028_LC|GO16083_LC
211452150, 135.599187, 12.432932, 12.524, GO16001_LC|GO16009_LC|GO16020_LC|GO16021_LC|GO16052_LC|GO16083_LC
211461322, 133.094109, 12.572371, 11.964, GO16001_LC|GO16021_LC
211466875, 133.578911, 12.658047, 11.368, GO16001_LC|GO16065_LC
211482640, 135.290348, 12.888177, 12.222, GO16001_LC|GO16009_LC|GO16021_LC
211508636, 131.328728, 13.261418, 9.323, GO16001_LC|GO16052_LC
211514184, 133.267053, 13.338783, 10.562, GO16001_LC|GO16009_LC|GO16021_LC|GO16028_LC
211515573, 130.086541, 13.358313, 10.659, GO16001_LC|GO16009_LC|GO16021_LC|GO16028_LC
211527014, 131.265884, 13.520806, 11.859, GO16001_LC|GO16009_LC|GO16020_LC|GO16021_LC|GO16041_LC|GO16052_LC
211528401, 134.067756, 13.540569, 12.528, GO16001_LC|GO16005_LC|GO16009_LC|GO16052_LC|GO16083_LC
211529184, 130.611416, 13.551621, 9.839, GO16001_LC|GO16009_LC|GO16021_LC|GO16028_LC|GO16041_LC|GO16052_LC
211557955, 131.016357, 13.953349, 10.664, GO16001_LC|GO16021_LC|GO16028_LC
211612202, 131.569877, 14.704022, 11.101, GO16001_LC|GO16009_LC|GO16020_LC|GO16021_LC|GO16028_LC|GO16074_LC|GO16083_LC
211621378, 132.482696, 14.833385, 7.558, GO16001_LC|GO16003_LC|GO16021_LC|GO16028_LC
211650470, 137.310034, 15.241044, 8.354, GO16001_LC|GO16021_LC|GO16028_LC
211657909, 137.212627, 15.342437, 10.578, GO16001_LC|GO16052_LC
211672981, 136.757995, 15.549171, 10.499, GO16001_LC|GO16009_LC|GO16021_LC|GO16028_LC|GO16083_LC
211680876, 130.142609, 15.65851, 12.036, GO16001_LC|GO16009_LC
211691978, 131.575703, 15.807889, 10.873, GO16001_LC|GO16021_LC|GO16083_LC
211715985, 138.608419, 16.130567, 9.434, GO16001_LC|GO16009_LC|GO16021_LC|GO16028_LC
211721876, 133.811207, 16.211643, 8.715, GO16001_LC|GO16021_LC
211736487, 133.243353, 16.416777, 9.72, GO16001_LC|GO16021_LC|GO16033_LC|GO16071_LC
211736551, 137.205327, 16.417652, 9.276, GO16001_LC|GO16009_LC|GO16021_LC|GO16028_LC|GO16063_LC
211738518, 135.622605, 16.445604, 10.172, GO16001_LC|GO16021_LC|GO16033_LC
211765775, 132.471564, 16.830502, 11.298, GO16001_LC|GO16015_LC|GO16041_LC|GO16052_LC|GO16015_SC
211839462, 132.505921, 17.874565, 10.037, GO16001_LC|GO16009_LC|GO16021_LC|GO16065_LC
211845396, 137.763418, 17.955075, 11.87, GO16001_LC|GO16020_LC|GO16052_LC|GO16083_LC
211879192, 134.594194, 18.424573, 12.962, GO16001_LC|GO16005_LC|GO16009_LC|GO16020_LC|GO16021_LC|GO16052_LC|GO16074_LC|GO16083_LC
211906132, 131.373281, 18.817486, 8.056, GO16001_LC|GO16021_LC|GO16028_LC|GO16063_LC
211909987, 131.335545, 18.875395, 8.859, GO16001_LC|GO16021_LC|GO16031_LC|GO16060_LC
211910977, 131.32504, 18.890366, 9.561, GO16001_LC|GO16021_LC|GO16022_LC|GO16028_LC|GO16031_LC|GO16060_LC|GO16065_LC
211914045, 129.797676, 18.934938, 11.132, GO16001_LC|GO16009_LC|GO16020_LC|GO16021_LC|GO16052_LC
211918335, 130.007101, 18.999848, 10.042, GO16001_LC|GO16009_LC|GO16010_LC|GO16021_LC|GO16022_LC|GO16028_LC|GO16031_LC|GO16060_LC|GO16065_LC
211920612, 130.9839, 19.034175, 8.433, GO16001_LC|GO16009_LC|GO16021_LC|GO16038_LC|GO16044_LC|GO16065_LC|GO16038_SC
211933891, 131.669218, 19.233635, 10.387, GO16001_LC|GO16021_LC
211935518, 130.476516, 19.257418, 11.181, GO16001_LC|GO16009_LC|GO16021_LC|GO16022_LC|GO16031_LC|GO16060_LC|GO16065_LC|GO16071_LC
211954451, 129.961314, 19.540814, 6.409, GO16001_LC|GO16003_LC|GO16031_LC
211955190, 129.985399, 19.552991, 7.337, GO16001_LC|GO16006_LC|GO16021_LC|GO16031_LC
211957527, 137.042131, 19.58805, 13.16, GO16001_LC|GO16005_LC|GO16021_LC|GO16052_LC
211962912, 130.092028, 19.669939, 6.236, GO16001_LC|GO16003_LC|GO16031_LC
211964025, 130.086448, 19.686737, 7.605, GO16001_LC|GO16006_LC|GO16010_LC|GO16021_LC|GO16031_LC
212015356, 136.678861, 20.509862, 8.36, GO16001_LC|GO16041_LC|GO16052_LC|GO16065_LC
212019900, 134.099021, 20.584477, 10.837, GO16001_LC|GO16021_LC
212038083, 132.837738, 20.890027, 10.284, GO16001_LC|GO16021_LC|GO16028_LC
212070276, 126.889398, 21.460888, 9.118, GO16001_LC|GO16009_LC|GO16021_LC|GO16028_LC
212159393, 136.307008, 23.240375, 12.199, GO16001_LC|GO16009_LC|GO16020_LC|GO16021_LC|GO16052_LC|GO16083_LC
212160907, 131.334047, 23.273798, 12.329, GO16001_LC|GO16009_LC|GO16021_LC
212161918, 134.312559, 23.296435, 12.495, GO16001_LC|GO16052_LC
212165121, 133.03864, 23.372946, 11.545, GO16001_LC|GO16009_LC
212168289, 134.108029, 23.446228, 12.259, GO16001_LC|GO16009_LC|GO16021_LC
212181661, 135.205252, 23.780045, 8.95, GO16001_LC|GO16009_LC|GO16010_LC|GO16021_LC|GO16028_LC|GO16034_LC|GO16041_LC|GO16063_LC
212181684, 130.737351, 23.780693, 11.418, GO16001_LC|GO16021_LC|GO16028_LC
212182310, 130.491859, 23.798885, 8.758, GO16001_LC|GO16004_LC
212188298, 131.727452, 23.958291, 12.121, GO16001_LC|GO16009_LC|GO16021_LC|GO16052_LC|GO16083_LC
212188653, 133.250399, 23.967364, 11.114, GO16001_LC|GO16009_LC|GO16021_LC|GO16028_LC
212194110, 130.500117, 24.11669, 12.819, GO16001_LC|GO16009_LC|GO16020_LC|GO16021_LC
212194811, 130.761487, 24.137161, 9.84, GO16001_LC|GO16010_LC|GO16020_LC|GO16037_LC|GO16052_LC|GO16063_LC
212205954, 134.496897, 24.472923, 11.785, GO16001_LC|GO16009_LC|GO16039_LC|GO16065_LC|GO16083_LC
212207080, 130.368344, 24.509085, 11.159, GO16001_LC|GO16021_LC|GO16028_LC|GO16083_LC
251287671, 139.640812, 15.270736, 12.967, GO16001_LC|GO16005_LC|GO16009_LC|GO16041_LC|GO16052_LC|GO16083_LC
251317129, 139.952961, 18.270408, 9.84, GO16001_LC|GO16009_LC|GO16020_LC|GO16021_LC|GO16028_LC
251322682, 140.446311, 18.746338, 8.436, GO16001_LC|GO16009_LC|GO16021_LC|GO16028_LC|GO16063_LC
251327508, 140.772478, 19.157679, 11.42, GO16001_LC|GO16005_LC|GO16009_LC|GO16020_LC|GO16021_LC|GO16028_LC|GO16031_LC|GO16041_LC|GO16052_LC|GO16083_LC
251379331, 137.197791, 23.405202, 12.892, GO16001_LC|GO16009_LC|GO16021_LC
251387264, 136.372091, 23.95915, 11.371, GO16001_LC|GO16052_LC
251408086, 137.089344, 25.252952, 11.762, GO16001_LC|GO16021_LC|GO16083_LC