# Summary of K2 Program GO16041

Title: Rotation rates for stars in wide binary systems and a search for hierarchical triples in Kepler K2 campaigns 14-15-16.

PI: Lepine, Sebastien (Georgia State University)
CoIs: 

Wide binary systems are of high interest for both stellar astrophysics and exoplanet research. Because they were born and ejected from the same parent star cluster, they also share the same age and presumably have very similar chemical compositions. At the same time, their large separations mean that they essentially behave like single stars, and can also be observed and studied separately. For stellar astrophysics, these systems represent a unique means of testing stellar evolution models at moderate to old ages (2-12 Gy), complementing data available for younger ages from the study of nearby star clusters or young moving groups. In particular, old wide systems are critical to test the predictions of gyrochronology, which posit a relationship between the age of a low-mass star and its rotation rate, a relationship that may prove critical for dating exoplanet systems discovered by Kepler and other surveys. This gyrochronology hypothesis can be tested by measuring the rotation rates of stars in wide pairs, and verifying that the rotation rates are correlated, which should be true regardless of what their actual ages are. Based on a search of the SUPERBLINK proper motion catalog in the fields to be observed in K2 campaigns 14, 15, and 16, we have identified a total of 194 common proper motion (i.e. co-moving) pairs of stars with angular separations between 4 and 60. Our statistical analysis indicates that >90% of those pairs must be physical binaries in wide orbits (with the rest being chance alignments of unrelated stars). About half the primaries in those wide systems appear to be main-sequence stars of subtypes F-G-K, with the other half consisting of M dwarfs. A majority of the  secondaries, on the other hand, appear to be main-sequence M dwarfs. We propose to use Kepler to observe there stars in wide binary pairs, and measure their rotation rates from an auto-correlation analysis of their light curves. All the pairs should be resolved on the Kepler cameras (4 arcsec pixel size), although some pairs will have overlapping point spread functions and may require pixel-by-pixel analysis. Interestingly, many pairs can be observed in a single Kepler aperture, and thus may only need to be counted as a single target (or may use fewer pixels overall). One prediction of stellar multiplicity models is that very wide companions are often produced by dynamical relaxation in a triple systems, which means that a significant fraction of wide binaries may actually be hierarchical triples, with the inner system having a high probability of being a very tight (spectroscopic or eclipsing) binary star; this prediction will be directly tested with K2, by measuring the detection rate of eclipsing binaries in those pairs.

# Targets requested by this program that have been observed (118)
EPIC ID, RA (J2000) [deg], Dec (J2000) [deg], magnitude, Investigation IDs
211412092, 129.738438, 11.822828, 10.015, GO16001_LC|GO16009_LC|GO16020_LC|GO16021_LC|GO16028_LC|GO16041_LC
211412258, 129.743039, 11.825378, 13.001, GO16005_LC|GO16041_LC|GO16052_LC
211426958, 137.602837, 12.045768, 14.98, GO16005_LC|GO16041_LC|GO16052_LC
211427316, 137.607309, 12.051172, 14.039, GO16005_LC|GO16041_LC|GO16052_LC|GO16056_LC|GO16083_LC
211448668, 136.542947, 12.380227, 16.521, GO16005_LC|GO16041_LC|GO16052_LC
211448699, 136.537572, 12.380786, 15.038, GO16005_LC|GO16041_LC|GO16052_LC|GO16083_LC
211471600, 131.192219, 12.727021, 18.48, GO16041_LC
211471629, 131.193627, 12.727344, 14.885, GO16005_LC|GO16041_LC|GO16052_LC
211495454, 129.790851, 13.075146, 15.975, GO16041_LC
211495551, 129.7897, 13.076518, 11.519, GO16009_LC|GO16020_LC|GO16021_LC|GO16041_LC
211499253, 130.865228, 13.129664, 10.846, GO16021_LC|GO16041_LC|GO16052_LC
211499385, 130.865403, 13.13174, 10.846, GO16005_LC|GO16020_LC|GO16041_LC
211524148, 133.793199, 13.479762, 15.135, GO16005_LC|GO16041_LC|GO16052_LC
211524515, 133.796469, 13.485007, 13.748, GO16005_LC|GO16041_LC|GO16052_LC|GO16083_LC
211526901, 131.271461, 13.518927, 16.304, GO16005_LC|GO16041_LC|GO16052_LC
211527014, 131.265884, 13.520806, 11.859, GO16001_LC|GO16009_LC|GO16020_LC|GO16021_LC|GO16041_LC|GO16052_LC
211529184, 130.611416, 13.551621, 9.839, GO16001_LC|GO16009_LC|GO16021_LC|GO16028_LC|GO16041_LC|GO16052_LC
211529603, 130.609197, 13.557181, 12.828, GO16005_LC|GO16009_LC|GO16041_LC|GO16052_LC|GO16056_LC
211545368, 136.834683, 13.777637, 11.277, GO16009_LC|GO16020_LC|GO16021_LC|GO16041_LC|GO16052_LC
211546159, 136.834189, 13.788966, 15.168, GO16005_LC|GO16041_LC|GO16052_LC
211589263, 137.611577, 14.393997, 15.015, GO16005_LC|GO16041_LC|GO16052_LC
211589414, 137.617816, 14.395756, 15.634, GO16005_LC|GO16041_LC|GO16052_LC
211626033, 131.263387, 14.901062, 16.384, GO16041_LC
211626683, 131.269004, 14.910258, 18.038, GO16039_LC|GO16041_LC
211631180, 130.427359, 14.973185, 19.111, GO16041_LC
211631231, 130.428475, 14.97416, 17.356, GO16005_LC|GO16041_LC
211640715, 130.14421, 15.107574, 18.913, GO16041_LC
211641201, 130.138644, 15.11412, 13.939, GO16005_LC|GO16041_LC|GO16052_LC
211658648, 136.103001, 15.353178, 16.363, GO16005_LC|GO16041_LC|GO16052_LC
211658713, 136.104079, 15.354003, 16.673, GO16005_LC|GO16041_LC
211688447, 137.293777, 15.759475, 15.881, GO16005_LC|GO16041_LC
211688473, 137.291156, 15.759841, 11.858, GO16009_LC|GO16021_LC|GO16041_LC
211703362, 129.700358, 15.959713, 11.488, GO16009_LC|GO16020_LC|GO16021_LC|GO16041_LC|GO16052_LC
211703497, 129.700619, 15.961385, 14.013, GO16005_LC|GO16041_LC
211736643, 130.096246, 16.419203, 11.186, GO16009_LC|GO16020_LC|GO16021_LC|GO16028_LC|GO16041_LC
211736739, 130.095864, 16.420359, 14.578, GO16041_LC
211765775, 132.471564, 16.830502, 11.298, GO16001_LC|GO16015_LC|GO16041_LC|GO16052_LC|GO16015_SC
211765962, 132.46737, 16.833119, 12.637, GO16005_LC|GO16009_LC|GO16041_LC|GO16052_LC|GO16056_LC
211839986, 134.018509, 17.881572, 12.937, GO16005_LC|GO16009_LC|GO16020_LC|GO16021_LC|GO16041_LC|GO16052_LC
211840203, 134.028534, 17.884501, 16.524, GO16005_LC|GO16041_LC
211842885, 131.298357, 17.921051, 13.873, GO16005_LC|GO16041_LC|GO16052_LC
211843075, 131.299726, 17.92334, 16.085, GO16041_LC
211847425, 136.315815, 17.982241, 17.157, GO16041_LC
211847478, 136.314273, 17.983023, 16.493, GO16041_LC
211849901, 129.924474, 18.016665, 15.352, GO16005_LC|GO16041_LC|GO16052_LC
211850431, 129.928123, 18.023753, 13.687, GO16005_LC|GO16041_LC|GO16052_LC|GO16083_LC
211856195, 138.689117, 18.103544, 18.807, GO16041_LC
211856298, 138.68607, 18.104676, 14.905, GO16005_LC|GO16041_LC|GO16052_LC|GO16083_LC
211899552, 130.584444, 18.720072, 17.188, GO16041_LC
211900075, 129.967808, 18.727873, 17.314, GO16041_LC
211900703, 129.963259, 18.736683, 17.993, GO16041_LC
211900813, 130.578655, 18.738537, 17.341, GO16041_LC
211911514, 132.573449, 18.898312, 14.762, GO16041_LC
211911623, 132.573993, 18.899808, 12.778, GO16009_LC|GO16020_LC|GO16021_LC|GO16041_LC|GO16052_LC
211935903, 137.089425, 19.263411, 12.748, GO16005_LC|GO16009_LC|GO16020_LC|GO16021_LC|GO16041_LC|GO16052_LC
211936038, 137.090787, 19.265421, 18.289, GO16041_LC
212005131, 126.988891, 20.340252, 14.268, GO16005_LC|GO16041_LC|GO16052_LC
212005512, 126.978288, 20.346737, 12.98, GO16009_LC|GO16020_LC|GO16021_LC|GO16041_LC
212012534, 133.455511, 20.461379, 14.256, GO16005_LC|GO16041_LC|GO16052_LC
212012682, 133.45418, 20.463806, 14.256, GO16041_LC|GO16052_LC
212014507, 136.660405, 20.494998, 16.309, GO16039_LC|GO16041_LC
212015356, 136.678861, 20.509862, 8.36, GO16001_LC|GO16041_LC|GO16052_LC|GO16065_LC
212018921, 134.377495, 20.568141, 14.748, GO16005_LC|GO16041_LC
212018980, 134.378716, 20.569206, 17.863, GO16005_LC|GO16041_LC
212021116, 132.922181, 20.605688, 16.278, GO16041_LC
212021192, 132.925435, 20.606934, 16.738, GO16041_LC
212029966, 127.839514, 20.753395, 16.81, GO16005_LC|GO16041_LC
212030041, 127.840696, 20.754848, 16.026, GO16005_LC|GO16041_LC|GO16052_LC
212034471, 134.455303, 20.828151, 8.89, GO16009_LC|GO16021_LC|GO16028_LC|GO16041_LC
212074750, 137.511717, 21.543283, 16.848, GO16005_LC|GO16041_LC
212075118, 137.512852, 21.549964, 14.917, GO16005_LC|GO16041_LC|GO16052_LC|GO16074_LC
212112419, 137.050005, 22.266403, 10.466, GO16009_LC|GO16021_LC|GO16028_LC|GO16041_LC|GO16083_LC
212113541, 134.089371, 22.288877, 17.792, GO16041_LC
212113552, 134.087804, 22.289125, 17.393, GO16041_LC
212114321, 136.291562, 22.304569, 17.336, GO16041_LC
212114469, 136.304698, 22.307527, 13.373, GO16021_LC|GO16041_LC|GO16052_LC|GO16083_LC
212120283, 132.811931, 22.421972, 15.733, GO16005_LC|GO16041_LC
212120399, 132.810434, 22.424227, 17.595, GO16041_LC
212120603, 134.445909, 22.42782, 18.158, GO16041_LC
212120610, 134.450049, 22.427925, 15.184, GO16005_LC|GO16041_LC|GO16052_LC
212154899, 135.701752, 23.140525, 11.365, GO16009_LC|GO16020_LC|GO16021_LC|GO16041_LC|GO16052_LC|GO16083_LC
212154963, 135.702961, 23.14176, 13.979, GO16005_LC|GO16041_LC
212181661, 135.205252, 23.780045, 8.95, GO16001_LC|GO16009_LC|GO16010_LC|GO16021_LC|GO16028_LC|GO16034_LC|GO16041_LC|GO16063_LC
212181772, 135.221801, 23.782888, 14.195, GO16005_LC|GO16041_LC|GO16052_LC|GO16056_LC
212191199, 131.606552, 24.034779, 16.246, GO16005_LC|GO16041_LC|GO16052_LC
212191269, 131.600247, 24.036816, 15.367, GO16005_LC|GO16041_LC|GO16052_LC|GO16074_LC
212216791, 133.464846, 24.831914, 12.82, GO16009_LC|GO16020_LC|GO16041_LC
212216954, 133.458049, 24.83729, 17.344, GO16039_LC|GO16041_LC
212217220, 132.141168, 24.845732, 12.431, GO16021_LC|GO16041_LC|GO16052_LC|GO16074_LC
212217433, 132.148668, 24.853117, 11.055, GO16009_LC|GO16020_LC|GO16021_LC|GO16041_LC|GO16052_LC|GO16074_LC|GO16083_LC
251285608, 139.588981, 15.040853, 14.734, GO16005_LC|GO16041_LC|GO16052_LC|GO16083_LC
251285643, 139.584332, 15.044466, 15.725, GO16005_LC|GO16041_LC
251287671, 139.640812, 15.270736, 12.967, GO16001_LC|GO16005_LC|GO16009_LC|GO16041_LC|GO16052_LC|GO16083_LC
251287693, 139.64033, 15.273174, 16.119, GO16005_LC|GO16041_LC
251293202, 139.470229, 15.889526, 19.165, GO16041_LC
251293204, 139.473247, 15.8896, 16.785, GO16005_LC|GO16041_LC
251327505, 140.76253, 19.157288, 14.0, GO16005_LC|GO16041_LC|GO16052_LC|GO16056_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
251329354, 139.976388, 19.321841, 15.112, GO16005_LC|GO16041_LC|GO16052_LC
251329448, 139.980899, 19.329714, 17.954, GO16041_LC
251340268, 141.034701, 20.275705, 16.859, GO16039_LC|GO16041_LC
251340295, 141.033819, 20.277512, 19.07, GO16039_LC|GO16041_LC
251341201, 140.070227, 20.351518, 14.958, GO16005_LC|GO16041_LC|GO16052_LC|GO16083_LC
251341220, 140.072162, 20.352972, 17.215, GO16005_LC|GO16041_LC
251346035, 139.802427, 20.741522, 14.979, GO16005_LC|GO16041_LC|GO16052_LC|GO16083_LC
251346053, 139.802034, 20.743188, 14.979, GO16005_LC|GO16041_LC|GO16052_LC|GO16083_LC
251365170, 139.005134, 22.317767, 13.313, GO16041_LC|GO16056_LC
251365173, 139.006315, 22.318146, 13.563, GO16041_LC
251387104, 137.972455, 23.948527, 14.22, GO16004_LC|GO16041_LC|GO16052_LC|GO16083_LC
251387146, 137.976278, 23.951725, 15.477, GO16005_LC|GO16041_LC|GO16052_LC
251394492, 137.950407, 24.449055, 16.258, GO16041_LC
251394638, 137.950005, 24.458242, 13.287, GO16005_LC|GO16021_LC|GO16041_LC|GO16052_LC|GO16083_LC
251394753, 138.40338, 24.465452, 16.773, GO16005_LC|GO16041_LC
251394770, 138.395513, 24.466257, 15.734, GO16005_LC|GO16041_LC
251399701, 137.876797, 24.768637, 18.444, GO16041_LC
251399746, 137.875998, 24.770515, 18.486, GO16041_LC
251809255, , , , GO16041_LC
251809256, , , , GO16041_LC