# Summary of K2 Program GO16012

Title: Activity and Planets at the Bottom of the Main-Sequence

PI: Muirhead, Philip Steven (Boston University)
CoIs: Skinner, Julie N

We propose to continue a K2 program to observe a carefully selected sample of ultracool dwarfs (UCDs) with K2 during Campaigns 14, 15, and 16. UCDs occupy the transition from main-sequence stars to brown dwarfs (late-M and later) and are essential to understanding the formation and evolution of the lowest mass objects in the Universe. Historically, photometric monitoring of UCDs for transiting planets and rotational spot modulation has been hampered by their intrinsic faintness and the expected short duration of transit events. The K2 spacecraft provides an excellent opportunity to study these objects in more detail, thanks to the large aperture and near-continuous 80-day photometric coverage of each K2 field. 

Searching for Transiting Planets Orbiting UCDs: The discovery of transiting planets (TRAPPIST-1) orbiting a UCD has had significant implications for the field of exoplanets.  However, the larger population of exoplanets around these small, cool objects remains unprobed and will provide important constraints on planet formation around the smallest dwarfs.  UCDs are small, all roughly the diameter of Jupiter, which implies deep fractional transit signatures. UCDs are also relatively bright in the infrared. A planet that transits a UCD, whether gaseous or rocky, would be an ideal target for near-infrared transit transmission spectroscopy, as has been successfully performed on super Earths orbiting mid-M dwarf stars with the Hubble Space Telescope. Future transit transmission observations with NASAs James Webb Space Telescope may be able to detect biosignatures in the atmospheres of rocky planets, but only for those planets that transit ultra-cool dwarfs. The transits from rocky planets orbiting mid-M and earlier dwarf stars are simply not deep enough to search for biosignatures over the expected lifetime of JWST. Recent studies of short-period planet occurrence around early- and mid-M dwarfs show that lower mass stars have significantly more rocky short-period planets than Sun-like stars. Extrapolating to ultra-cool dwarfs, we expect a large fraction, if not all UCDs to harbor rocky planets with transit probabilities of ~10%. 

Spot morphology at the M/L transition: Studies indicate that over 90% of UCDs show evidence of surface activity in the form of H± emission; however, the nature of the activity is not fully understood. Unlike sun-like stars, UCDs have fully convective interiors and are expected to have magnetic field morphologies markedly different from the Sun. With precise photometric monitoring of UCDs with K2 we will measure the morphology of spots on the surfaces of UCDs via light curve inversion. We will also search for flare events and correlate those flare events to specific spots structures. 

Surface activity in UCDs is related to stellar wind and ultraviolet emission from their chromospheres, both of which affect the photochemistry in the upper atmospheres of orbiting exoplanets. Understanding the nature of surface activity on UCDs is therefore critical for interpreting transit-transmission spectroscopy, as well as inferring the habitability of any detected planets. K2 provides a unique opportunity to study ultra-cool dwarfs in a way never before realized.

# Targets requested by this program that have been observed (244)
EPIC ID, RA (J2000) [deg], Dec (J2000) [deg], magnitude, Investigation IDs
211397907, 136.907724, 11.608413, 17.589, GO16012_LC
211408907, 131.417345, 11.776784, 18.32, GO16012_LC
211411366, 130.109247, 11.812298, 17.421, GO16012_LC|GO16018_LC
211414589, 134.408558, 11.861, 19.034, GO16012_LC
211422143, 130.04882, 11.97251, 18.08, GO16012_LC
211432983, 131.239125, 12.140487, 16.272, GO16012_LC
211435416, 133.066863, 12.176318, 17.866, GO16012_LC|GO16064_LC
211436280, 131.618951, 12.190227, 18.612, GO16012_LC
211437310, 130.448737, 12.205653, 18.612, GO16012_LC
211439338, 133.995134, 12.235982, 18.875, GO16012_LC|GO16018_LC
211442490, 133.573876, 12.284894, 18.574, GO16012_LC
211444694, 134.112625, 12.318958, 17.754, GO16012_LC
211456689, 131.476007, 12.501563, 18.463, GO16012_LC
211458186, 134.443796, 12.524164, 18.022, GO16012_LC
211458709, 132.643729, 12.533139, 17.127, GO16012_LC|GO16018_LC
211460236, 130.835349, 12.555681, 18.583, GO16012_LC
211460625, 133.417297, 12.561251, 16.814, GO16012_LC|GO16018_LC
211464826, 133.20849, 12.626325, 17.73, GO16012_LC|GO16018_LC
211467731, 134.008805, 12.67086, 18.322, GO16012_LC|GO16018_LC|GO16067_LC
211474473, 129.723676, 12.769217, 18.544, GO16012_LC
211474651, 132.487943, 12.771864, 17.974, GO16012_LC
211478560, 130.870911, 12.829493, 17.664, GO16012_LC|GO16018_LC
211486611, 134.242578, 12.945111, 18.675, GO16012_LC
211493031, 131.375327, 13.039326, 17.924, GO16012_LC|GO16018_LC
211500166, 137.425377, 13.14263, 18.488, GO16012_LC
211502275, 137.208086, 13.171075, 18.001, GO16012_LC
211508921, 137.252294, 13.265213, 18.25, GO16012_LC
211513009, 132.323807, 13.322139, 18.583, GO16012_LC
211516404, 136.04613, 13.370237, 17.802, GO16012_LC
211517510, 134.255658, 13.385764, 19.108, GO16012_LC
211521072, 134.678256, 13.436283, 17.195, GO16012_LC
211539923, 129.688328, 13.700763, 18.099, GO16012_LC
211543734, 130.279843, 13.754382, 17.615, GO16012_LC
211563696, 130.957636, 14.034815, 17.946, GO16012_LC|GO16018_LC
211601751, 133.17966, 14.562194, 18.681, GO16012_LC
211605339, 136.990884, 14.611801, 18.574, GO16012_LC
211616100, 132.912928, 14.759133, 15.628, GO16012_LC|GO16018_LC
211617183, 131.675134, 14.774753, 17.686, GO16012_LC
211620667, 133.933196, 14.823436, 17.682, GO16012_LC
211620839, 138.907759, 14.826074, 18.195, GO16012_LC
211631830, 131.86783, 14.982729, 17.854, GO16012_LC|GO16018_LC
211647239, 136.64745, 15.196592, 17.758, GO16012_LC
211649168, 130.613761, 15.222904, 18.381, GO16012_LC
211661864, 138.956611, 15.397071, 17.423, GO16012_LC
211661978, 138.846964, 15.398704, 17.251, GO16012_LC
211664357, 132.593646, 15.432506, 18.142, GO16012_LC
211674231, 132.365224, 15.566259, 18.311, GO16012_LC
211682079, 138.944638, 15.674762, 18.535, GO16012_LC
211688540, 133.102077, 15.760784, 18.23, GO16012_LC
211693676, 133.830247, 15.830707, 18.928, GO16012_LC
211694247, 130.370173, 15.838401, 18.178, GO16012_LC
211700511, 137.231219, 15.922774, 18.207, GO16012_LC
211707327, 130.09118, 16.012152, 18.706, GO16012_LC
211707676, 130.22681, 16.016886, 16.786, GO16012_LC|GO16018_LC|GO16022_LC|GO16060_LC
211709984, 130.425618, 16.048288, 18.35, GO16012_LC
211710769, 129.965562, 16.058451, 17.188, GO16012_LC
211727869, 131.505157, 16.294403, 18.323, GO16012_LC
211738457, 130.458106, 16.444883, 18.062, GO16012_LC|GO16018_LC
211740547, 131.627479, 16.474249, 18.285, GO16012_LC
211740609, 129.618772, 16.475046, 18.48, GO16005_LC|GO16012_LC|GO16018_LC
211742071, 130.421667, 16.496342, 17.567, GO16012_LC|GO16018_LC
211742804, 133.793112, 16.506874, 18.13, GO16012_LC
211744621, 129.700708, 16.532249, 17.88, GO16012_LC|GO16060_LC
211749595, 138.676754, 16.602392, 18.424, GO16012_LC
211758584, 133.409548, 16.728647, 16.741, GO16012_LC|GO16018_LC
211759353, 131.189545, 16.739414, 18.9, GO16012_LC|GO16018_LC|GO16031_LC|GO16060_LC
211762382, 130.623998, 16.782818, 17.898, GO16012_LC
211770368, 130.122553, 16.895355, 18.634, GO16012_LC|GO16018_LC
211787250, 138.962152, 17.134682, 17.381, GO16012_LC
211806998, 133.565149, 17.416012, 17.405, GO16012_LC
211809011, 130.322075, 17.443649, 18.448, GO16012_LC
211813916, 129.59527, 17.51387, 17.716, GO16012_LC
211814652, 131.492289, 17.523907, 17.345, GO16012_LC
211839029, 133.848743, 17.86911, 18.275, GO16012_LC
211845911, 133.110979, 17.961969, 18.812, GO16012_LC|GO16018_LC
211847385, 129.804079, 17.981707, 17.353, GO16012_LC|GO16018_LC
211854467, 134.745481, 18.079552, 17.869, GO16012_LC|GO16018_LC|GO16067_LC
211863085, 134.019424, 18.199665, 17.472, GO16012_LC
211865364, 131.342662, 18.230968, 18.471, GO16012_LC
211868028, 132.515251, 18.266577, 18.508, GO16012_LC
211868606, 130.316103, 18.274551, 18.15, GO16012_LC
211869078, 135.680443, 18.280912, 18.486, GO16005_LC|GO16012_LC|GO16018_LC
211869873, 132.817816, 18.291731, 18.112, GO16012_LC|GO16018_LC|GO16067_LC
211873836, 135.891563, 18.348227, 18.147, GO16012_LC
211877438, 130.209518, 18.399841, 18.042, GO16012_LC
211877519, 134.487358, 18.401028, 17.957, GO16012_LC|GO16018_LC
211877657, 130.123962, 18.40255, 12.673, GO16005_LC|GO16012_LC|GO16018_LC|GO16030_LC|GO16052_LC|GO16063_LC
211879285, 129.738332, 18.425844, 15.785, GO16012_LC
211882396, 131.845734, 18.469997, 17.049, GO16012_LC
211892842, 130.530514, 18.621372, 17.886, GO16012_LC|GO16018_LC|GO16060_LC
211896292, 129.820151, 18.672314, 17.504, GO16012_LC
211902245, 134.741065, 18.759565, 18.443, GO16012_LC
211905775, 131.145396, 18.812227, 17.985, GO16012_LC
211908055, 135.574852, 18.846642, 18.716, GO16012_LC
211908599, 133.797382, 18.854534, 19.504, GO16012_LC
211908843, 133.389635, 18.858454, 17.896, GO16012_LC|GO16018_LC
211909496, 129.533504, 18.868223, 16.345, GO16012_LC
211912744, 138.720195, 18.916422, 16.526, GO16012_LC|GO16018_LC
211914136, 133.149885, 18.936193, 18.061, GO16012_LC
211915413, 131.049765, 18.955763, 17.933, GO16012_LC|GO16031_LC
211916047, 134.455912, 18.966202, 17.764, GO16012_LC|GO16018_LC
211917847, 132.932852, 18.992962, 17.687, GO16012_LC|GO16018_LC
211921776, 135.607672, 19.051191, 18.084, GO16012_LC
211925383, 133.858377, 19.104084, 18.134, GO16012_LC
211926110, 134.216154, 19.115366, 18.016, GO16012_LC
211926533, 130.365494, 19.12208, 18.147, GO16012_LC
211928727, 130.289617, 19.155697, 18.699, GO16012_LC|GO16018_LC|GO16031_LC
211934172, 130.245439, 19.237984, 18.705, GO16012_LC|GO16018_LC|GO16022_LC|GO16060_LC
211935805, 137.105393, 19.261974, 18.453, GO16012_LC
211939601, 130.761434, 19.318663, 18.08, GO16012_LC
211943316, 134.704928, 19.374357, 18.202, GO16012_LC
211946370, 131.759328, 19.419514, 18.209, GO16012_LC
211947924, 134.020133, 19.442053, 18.903, GO16012_LC|GO16018_LC
211954124, 137.313711, 19.535667, 18.185, GO16012_LC
211955323, 133.664165, 19.554806, 18.088, GO16012_LC
211964067, 133.569301, 19.687393, 17.446, GO16012_LC|GO16018_LC|GO16060_LC
211969262, 131.797552, 19.765329, 18.392, GO16012_LC|GO16018_LC
211996000, 135.762983, 20.188625, 17.766, GO16012_LC|GO16018_LC
211997634, 138.094968, 20.214989, 16.05, GO16012_LC
212001530, 127.59583, 20.279425, 17.807, GO16012_LC|GO16031_LC
212002604, 134.531745, 20.297375, 18.492, GO16012_LC
212002661, 127.225454, 20.298323, 18.013, GO16012_LC|GO16018_LC|GO16060_LC
212008870, 127.785041, 20.401182, 17.474, GO16012_LC|GO16018_LC
212013999, 134.32405, 20.486818, 18.312, GO16012_LC|GO16018_LC
212015599, 128.871665, 20.513857, 18.138, GO16005_LC|GO16012_LC|GO16018_LC
212017281, 128.008202, 20.541706, 18.164, GO16012_LC|GO16018_LC
212019105, 126.540474, 20.570967, 16.892, GO16012_LC|GO16018_LC
212020426, 134.029013, 20.593599, 18.234, GO16012_LC
212020445, 137.669651, 20.593933, 18.325, GO16012_LC
212021699, 127.868424, 20.615244, 17.885, GO16012_LC|GO16018_LC
212022056, 126.938609, 20.621183, 17.426, GO16012_LC|GO16018_LC
212022763, 126.620861, 20.632746, 18.203, GO16012_LC|GO16018_LC
212027121, 127.989263, 20.705931, 17.847, GO16012_LC|GO16018_LC
212028433, 127.31235, 20.728119, 18.205, GO16012_LC|GO16018_LC
212032430, 135.958587, 20.795139, 19.054, GO16012_LC|GO16018_LC
212041118, 133.9242, 20.945477, 17.775, GO16012_LC
212044515, 128.222709, 21.003181, 17.946, GO16012_LC|GO16018_LC|GO16067_LC
212049526, 136.074919, 21.090063, 17.485, GO16012_LC
212051014, 127.470823, 21.11754, 18.684, GO16012_LC|GO16018_LC|GO16067_LC
212053658, 132.86264, 21.163927, 17.978, GO16012_LC
212059071, 126.643396, 21.258726, 17.839, GO16012_LC|GO16018_LC
212060334, 134.627412, 21.281351, 18.344, GO16012_LC
212066577, 136.765193, 21.393881, 17.673, GO16012_LC|GO16018_LC
212067906, 126.857699, 21.417727, 18.815, GO16012_LC|GO16018_LC
212067916, 128.90187, 21.417801, 18.099, GO16012_LC|GO16018_LC|GO16067_LC
212072712, 127.007957, 21.505678, 17.897, GO16012_LC|GO16018_LC
212075399, 133.145402, 21.555073, 17.342, GO16012_LC|GO16018_LC
212077206, 133.948754, 21.588945, 16.608, GO16012_LC|GO16018_LC
212078253, 134.920836, 21.607233, 18.188, GO16012_LC|GO16018_LC
212080001, 128.490226, 21.641556, 17.6, GO16012_LC|GO16018_LC|GO16067_LC
212081772, 137.683159, 21.67293, 18.031, GO16012_LC|GO16018_LC
212083796, 128.843313, 21.711617, 17.726, GO16012_LC|GO16018_LC|GO16067_LC
212089454, 128.58998, 21.816275, 18.135, GO16012_LC|GO16018_LC|GO16067_LC
212090931, 136.993378, 21.846096, 17.868, GO16012_LC
212092449, 135.623948, 21.875914, 18.5, GO16012_LC
212093472, 136.49553, 21.895918, 17.908, GO16012_LC
212097518, 136.713279, 21.972763, 18.096, GO16012_LC
212098179, 137.371309, 21.985786, 18.084, GO16012_LC|GO16018_LC
212102189, 127.613506, 22.062668, 17.133, GO16012_LC|GO16018_LC
212104352, 134.622681, 22.105198, 18.364, GO16012_LC
212106355, 136.281481, 22.146194, 18.038, GO16012_LC|GO16018_LC
212111539, 135.042086, 22.249088, 18.0, GO16012_LC|GO16018_LC
212111554, 134.522912, 22.249502, 16.67, GO16012_LC|GO16018_LC
212117165, 136.544114, 22.360041, 18.211, GO16012_LC|GO16018_LC
212117236, 128.617605, 22.3615, 17.953, GO16012_LC|GO16018_LC
212119590, 128.939067, 22.408632, 17.211, GO16012_LC|GO16018_LC|GO16067_LC
212127137, 133.496552, 22.560087, 17.818, GO16012_LC|GO16018_LC
212130922, 127.505853, 22.636833, 18.613, GO16012_LC|GO16018_LC
212155930, 132.643829, 23.163855, 17.985, GO16012_LC|GO16018_LC
212156288, 134.43698, 23.171358, 17.758, GO16012_LC|GO16018_LC
212158934, 130.157506, 23.230766, 17.689, GO16012_LC|GO16018_LC
212162176, 133.609702, 23.30221, 18.96, GO16012_LC|GO16018_LC
212162270, 129.80406, 23.304527, 17.522, GO16012_LC
212162487, 129.868619, 23.310183, 18.09, GO16012_LC|GO16018_LC
212164721, 136.204619, 23.363379, 17.6, GO16012_LC
212166246, 135.070213, 23.399033, 18.104, GO16012_LC
212170651, 129.774803, 23.502945, 18.857, GO16012_LC|GO16018_LC
212183917, 133.13587, 23.842665, 18.268, GO16012_LC|GO16018_LC
212183961, 133.382993, 23.843685, 17.101, GO16012_LC|GO16018_LC|GO16067_LC
212184948, 132.894454, 23.870983, 16.939, GO16012_LC|GO16018_LC|GO16067_LC
212196866, 133.069497, 24.195242, 18.259, GO16012_LC|GO16018_LC|GO16067_LC
212216110, 129.872439, 24.807875, 17.034, GO16012_LC|GO16018_LC|GO16067_LC
251287438, 139.600382, 15.242834, 16.627, GO16012_LC|GO16018_LC
251291235, 139.448854, 15.667943, 17.5, GO16012_LC
251292472, 139.497705, 15.804727, 17.822, GO16012_LC
251292563, 139.405571, 15.815097, 16.159, GO16012_LC
251294456, 139.704881, 16.024231, 17.904, GO16012_LC
251295651, 140.277854, 16.151838, 17.671, GO16012_LC
251296062, 139.67989, 16.195328, 18.204, GO16012_LC
251297477, 139.31847, 16.343321, 18.057, GO16012_LC
251309259, 139.134376, 17.556393, 18.25, GO16012_LC
251311389, 139.364805, 17.753531, 17.551, GO16012_LC
251311486, 139.836927, 17.763405, 17.781, GO16012_LC
251314012, 140.822831, 17.996485, 18.907, GO16012_LC|GO16018_LC
251317744, 139.340166, 18.324823, 18.912, GO16012_LC|GO16018_LC
251318965, 140.787128, 18.431873, 18.462, GO16012_LC
251339342, 138.779269, 20.203949, 18.856, GO16012_LC
251340073, 139.979267, 20.260275, 17.973, GO16012_LC
251340486, 139.44123, 20.293373, 17.874, GO16012_LC|GO16018_LC
251343403, 141.022671, 20.524809, 18.107, GO16012_LC
251343822, 140.294724, 20.557823, 18.282, GO16012_LC
251345293, 140.303302, 20.680042, 19.089, GO16012_LC
251347715, 141.079466, 20.886778, 18.238, GO16012_LC|GO16018_LC
251347931, 139.134891, 20.905138, 19.171, GO16012_LC
251352135, 139.729167, 21.258148, 18.224, GO16012_LC
251353494, 139.809454, 21.372665, 19.309, GO16012_LC
251353841, 140.925753, 21.400368, 18.213, GO16012_LC
251355936, 139.658989, 21.568283, 17.133, GO16012_LC|GO16018_LC
251356321, 141.213659, 21.600428, 17.728, GO16012_LC
251357067, 139.062698, 21.664244, 14.55, GO16012_LC|GO16018_LC|GO16067_LC|GO16018_SC
251357246, 139.152134, 21.678967, 18.671, GO16012_LC
251358654, 140.489818, 21.806606, 17.816, GO16012_LC|GO16018_LC
251358731, 139.493098, 21.812864, 17.914, GO16012_LC
251359579, 139.845627, 21.88203, 18.511, GO16012_LC|GO16018_LC
251362266, 140.546173, 22.098789, 18.215, GO16012_LC
251362678, 139.34167, 22.129421, 18.126, GO16012_LC|GO16018_LC
251363006, 141.054084, 22.154423, 18.12, GO16012_LC
251363073, 139.821567, 22.160566, 18.326, GO16012_LC
251364084, 138.064998, 22.238585, 17.253, GO16012_LC|GO16018_LC
251364457, 137.935179, 22.264774, 17.949, GO16012_LC
251365679, 137.269758, 22.357634, 17.56, GO16012_LC|GO16018_LC
251376611, 137.295898, 23.198843, 17.962, GO16012_LC
251382784, 136.761114, 23.653938, 17.399, GO16012_LC
251385331, 137.54245, 23.829952, 15.747, GO16012_LC|GO16018_LC
251394129, 137.229502, 24.425194, 18.907, GO16012_LC|GO16018_LC|GO16067_LC
251394211, 138.188497, 24.430386, 18.365, GO16012_LC|GO16018_LC|GO16067_LC
251394456, 135.018806, 24.44656, 18.282, GO16012_LC
251394863, 136.489489, 24.471724, 18.194, GO16012_LC|GO16018_LC|GO16067_LC
251395427, 137.144694, 24.507771, 18.017, GO16012_LC|GO16018_LC|GO16067_LC
251396437, 134.912393, 24.57391, 17.444, GO16012_LC|GO16018_LC
251397724, 138.166891, 24.650553, 16.964, GO16012_LC|GO16018_LC|GO16067_LC
251402226, 136.922652, 24.916964, 17.954, GO16012_LC|GO16018_LC
251403541, 138.396684, 24.994251, 17.979, GO16012_LC|GO16018_LC|GO16067_LC
251403618, 137.36527, 24.999182, 19.389, GO16012_LC
251404208, 137.707351, 25.03162, 17.721, GO16012_LC|GO16018_LC|GO16067_LC
251405376, 135.862108, 25.097836, 17.689, GO16012_LC|GO16018_LC|GO16067_LC
251406926, 134.901977, 25.185841, 18.135, GO16012_LC|GO16018_LC|GO16067_LC
251407310, 136.602592, 25.210575, 17.824, GO16012_LC|GO16018_LC|GO16067_LC
251408963, 133.298608, 25.30171, 17.827, GO16012_LC|GO16018_LC|GO16067_LC
251809145, , , , GO16012_LC
251809146, , , , GO16012_LC
251809147, , , , GO16012_LC
251809149, , , , GO16012_LC
251809150, , , , GO16012_LC