# Summary of K2 Program GO14012

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 (155)
EPIC ID, RA (J2000) [deg], Dec (J2000) [deg], magnitude, Investigation IDs
201453319, 163.195914, -0.171523, 18.078, GO14067_LC|GO14012_LC|GO14018_LC
201528766, 162.55199, 0.967564, 18.125, GO14067_LC|GO14012_LC|GO14018_LC
201573260, 163.942365, 1.634359, 18.651, GO14067_LC|GO14012_LC|GO14018_LC
201575762, 162.600189, 1.672161, 18.221, GO14067_LC|GO14012_LC|GO14018_LC
201580841, 162.586993, 1.747867, 17.823, GO14067_LC|GO14012_LC|GO14018_LC
201581268, 163.618597, 1.75426, 18.112, GO14067_LC|GO14012_LC|GO14018_LC
201627847, 166.266582, 2.474101, 17.298, GO14012_LC|GO14005_LC
201640814, 166.372927, 2.675005, 16.948, GO14012_LC
201655944, 166.307752, 2.909826, 17.261, GO14012_LC
201676256, 167.048623, 3.247051, 17.979, GO14012_LC
201693239, 165.436335, 3.525877, 16.553, GO14067_LC|GO14012_LC|GO14018_LC
201705352, 165.354484, 3.729282, 17.714, GO14067_LC|GO14012_LC|GO14018_LC
201744267, 165.007101, 4.384897, 17.488, GO14067_LC|GO14012_LC|GO14018_LC|GO14005_LC
201800829, 163.542809, 5.381282, 17.168, GO14067_LC|GO14012_LC|GO14018_LC
201801587, 164.178972, 5.395744, 18.876, GO14067_LC|GO14012_LC|GO14018_LC
201885041, 164.120109, 7.01454, 11.585, GO14082_LC|GO14025_LC|GO14067_LC|GO14012_LC|GO14072_LC|GO14018_LC|GO14056_LC|GO14030_LC|GO14063_LC|GO14052_LC|GO14005_LC|GO14082_SC|GO14072_SC
248412090, 160.85454, 0.030061, 17.426, GO14067_LC|GO14012_LC|GO14018_LC
248413181, 160.713651, 0.072821, 18.26, GO14067_LC|GO14012_LC|GO14018_LC
248428098, 156.298087, 0.661527, 17.789, GO14012_LC
248433880, 157.63207, 0.875099, 18.709, GO14067_LC|GO14012_LC|GO14018_LC
248440677, 155.780924, 1.131445, 17.03, GO14067_LC|GO14012_LC|GO14018_LC
248442355, 156.227387, 1.194883, 17.219, GO14012_LC
248442470, 162.178379, 1.199465, 14.261, GO14067_LC|GO14012_LC|GO14018_LC|GO14018_SC
248445614, 162.254701, 1.319634, 17.621, GO14067_LC|GO14012_LC|GO14018_LC
248448687, 162.343539, 1.433166, 17.366, GO14067_LC|GO14012_LC|GO14018_LC
248450332, 156.27106, 1.485884, 17.884, GO14067_LC|GO14012_LC|GO14018_LC
248452093, 157.915056, 1.54587, 16.248, GO14067_LC|GO14012_LC|GO14018_LC
248455574, 157.679413, 1.666892, 17.915, GO14067_LC|GO14012_LC|GO14018_LC
248456554, 157.882722, 1.705209, 17.739, GO14067_LC|GO14012_LC|GO14018_LC
248459304, 157.571968, 1.804911, 17.553, GO14067_LC|GO14012_LC|GO14018_LC
248459402, 158.008228, 1.807964, 18.218, GO14012_LC
248463831, 157.682468, 1.952755, 17.049, GO14067_LC|GO14012_LC|GO14018_LC
248464098, 161.031007, 1.961745, 18.132, GO14067_LC|GO14012_LC|GO14018_LC
248475980, 158.032505, 2.35839, 18.011, GO14012_LC
248481490, 157.679983, 2.545138, 17.838, GO14012_LC
248484484, 157.815512, 2.644152, 16.898, GO14067_LC|GO14012_LC|GO14018_LC
248498671, 159.012821, 3.10447, 17.469, GO14067_LC|GO14012_LC|GO14018_LC
248519036, 154.176972, 3.716034, 16.654, GO14067_LC|GO14012_LC|GO14018_LC
248519140, 161.439802, 3.719276, 17.772, GO14012_LC
248523311, 158.523511, 3.837911, 16.091, GO14067_LC|GO14012_LC|GO14018_LC
248525204, 154.956809, 3.889558, 17.916, GO14067_LC|GO14012_LC|GO14018_LC
248525367, 154.133897, 3.894437, 17.519, GO14067_LC|GO14012_LC|GO14018_LC
248542664, 160.539914, 4.353959, 17.942, GO14012_LC
248547278, 154.997383, 4.474708, 17.753, GO14067_LC|GO14012_LC|GO14018_LC
248548001, 161.039265, 4.493805, 17.368, GO14067_LC|GO14012_LC|GO14018_LC|GO14063_LC
248551923, 154.272234, 4.596045, 18.359, GO14012_LC|GO14018_LC
248554246, 153.891903, 4.657351, 18.061, GO14012_LC
248559166, 154.4671, 4.792089, 17.926, GO14067_LC|GO14012_LC|GO14018_LC
248559899, 156.847195, 4.813891, 18.433, GO14012_LC
248561247, 154.099069, 4.8515, 18.114, GO14067_LC|GO14012_LC|GO14018_LC
248565564, 153.78974, 4.969107, 18.433, GO14067_LC|GO14012_LC|GO14018_LC
248567554, 158.071098, 5.017558, 14.998, GO14067_LC|GO14012_LC|GO14018_LC
248570548, 160.148889, 5.091599, 18.326, GO14067_LC|GO14012_LC|GO14018_LC
248574498, 154.383663, 5.197497, 17.943, GO14067_LC|GO14012_LC|GO14018_LC
248580531, 155.26159, 5.356202, 17.752, GO14067_LC|GO14012_LC|GO14018_LC
248587338, 156.965133, 5.539516, 17.639, GO14012_LC
248592301, 162.561977, 5.674407, 16.706, GO14067_LC|GO14012_LC|GO14018_LC
248597458, 159.817397, 5.80993, 18.255, GO14067_LC|GO14012_LC|GO14018_LC
248600681, 154.796688, 5.891592, 18.363, GO14067_LC|GO14012_LC|GO14018_LC
248602543, 161.186797, 5.936989, 17.763, GO14067_LC|GO14012_LC|GO14018_LC
248604083, 162.661947, 5.975922, 16.445, GO14067_LC|GO14012_LC|GO14018_LC
248604738, 162.917294, 5.992803, 17.953, GO14067_LC|GO14012_LC|GO14018_LC
248609711, 153.678252, 6.117474, 18.273, GO14067_LC|GO14012_LC|GO14018_LC
248615433, 159.535935, 6.261614, 17.598, GO14067_LC|GO14012_LC|GO14018_LC
248616595, 163.019035, 6.291863, 18.436, GO14012_LC
248621243, 159.492509, 6.410976, 18.017, GO14067_LC|GO14012_LC|GO14018_LC
248622974, 155.68973, 6.453102, 17.818, GO14067_LC|GO14012_LC|GO14018_LC
248623263, 161.80501, 6.460828, 18.841, GO14067_LC|GO14012_LC|GO14018_LC
248624299, 156.940533, 6.486239, 18.173, GO14067_LC|GO14012_LC|GO14018_LC
248631587, 155.437707, 6.670539, 17.344, GO14012_LC
248631849, 155.090307, 6.676745, 17.608, GO14067_LC|GO14012_LC|GO14018_LC
248632231, 158.766799, 6.687126, 18.092, GO14012_LC
248634766, 158.100438, 6.750597, 18.146, GO14012_LC
248635824, 163.470624, 6.776567, 18.366, GO14012_LC
248636164, 158.228333, 6.785299, 17.325, GO14012_LC
248638618, 161.225626, 6.846862, 18.268, GO14067_LC|GO14012_LC|GO14018_LC
248648532, 158.108219, 7.088235, 18.564, GO14067_LC|GO14012_LC|GO14018_LC
248651399, 155.102398, 7.15693, 17.349, GO14067_LC|GO14012_LC|GO14018_LC
248653486, 160.831019, 7.209056, 17.635, GO14067_LC|GO14012_LC|GO14018_LC
248655562, 163.819309, 7.258709, 15.263, GO14067_LC|GO14012_LC|GO14018_LC|GO14052_LC
248655628, 153.85461, 7.260646, 17.563, GO14067_LC|GO14012_LC|GO14018_LC
248656132, 154.014349, 7.272909, 18.199, GO14067_LC|GO14012_LC|GO14018_LC
248656573, 163.404629, 7.283172, 17.741, GO14067_LC|GO14012_LC|GO14018_LC
248656932, 162.93829, 7.292343, 18.126, GO14012_LC|GO14018_LC|GO14005_LC
248658559, 158.584494, 7.332827, 17.956, GO14067_LC|GO14012_LC|GO14018_LC
248659481, 154.524064, 7.35573, 18.753, GO14067_LC|GO14012_LC|GO14018_LC
248659647, 162.66375, 7.359687, 17.136, GO14067_LC|GO14012_LC|GO14018_LC|GO14052_LC
248659722, 163.613337, 7.361799, 17.854, GO14067_LC|GO14012_LC|GO14018_LC
248660752, 159.881606, 7.388029, 17.85, GO14067_LC|GO14012_LC|GO14018_LC
248663141, 157.984815, 7.446123, 18.055, GO14067_LC|GO14012_LC|GO14018_LC
248666674, 158.500187, 7.535396, 17.705, GO14067_LC|GO14012_LC|GO14018_LC
248671305, 160.04851, 7.650188, 18.01, GO14067_LC|GO14012_LC|GO14018_LC
248676218, 161.466861, 7.772091, 18.2, GO14067_LC|GO14012_LC|GO14018_LC
248678585, 153.947314, 7.829149, 17.599, GO14012_LC
248680268, 153.823463, 7.870028, 16.969, GO14012_LC|GO14018_LC
248682489, 158.934565, 7.923514, 16.24, GO14067_LC|GO14012_LC|GO14018_LC
248691809, 163.947233, 8.145218, 13.916, GO14012_LC|GO14018_LC|GO14018_SC
248695811, 155.183618, 8.23984, 13.427, GO14067_LC|GO14012_LC|GO14018_LC|GO14063_LC|GO14052_LC
248698441, 154.638263, 8.29919, 17.931, GO14012_LC
248702963, 164.226713, 8.403383, 18.186, GO14012_LC
248718280, 160.758651, 8.753182, 18.402, GO14067_LC|GO14012_LC|GO14018_LC
248724386, 163.716089, 8.896224, 17.765, GO14012_LC
248733548, 157.053115, 9.094399, 17.384, GO14012_LC
248744078, 161.751885, 9.337385, 18.053, GO14067_LC|GO14012_LC|GO14018_LC
248745301, 159.885832, 9.365522, 17.385, GO14067_LC|GO14012_LC|GO14018_LC
248750733, 160.962007, 9.493158, 18.662, GO14067_LC|GO14012_LC|GO14018_LC|GO14005_LC
248751905, 160.632634, 9.520331, 18.333, GO14067_LC|GO14012_LC|GO14018_LC
248754057, 162.204216, 9.570178, 18.139, GO14012_LC
248755514, 164.201294, 9.60446, 16.825, GO14012_LC|GO14018_LC
248758398, 164.111145, 9.675165, 17.994, GO14012_LC
248759672, 159.136377, 9.706072, 18.727, GO14067_LC|GO14012_LC|GO14018_LC
248766826, 161.467895, 9.876228, 17.751, GO14067_LC|GO14012_LC|GO14018_LC
248767646, 160.811245, 9.895591, 17.7, GO14067_LC|GO14012_LC|GO14018_LC
248775559, 163.78777, 10.089854, 17.849, GO14012_LC
248777799, 154.386846, 10.14621, 18.092, GO14067_LC|GO14012_LC|GO14018_LC
248779449, 159.007869, 10.187454, 18.121, GO14067_LC|GO14012_LC|GO14018_LC
248779451, 154.40185, 10.187463, 18.496, GO14012_LC
248846902, 163.975731, 11.827205, 17.669, GO14012_LC
248846937, 158.98938, 11.828347, 17.623, GO14012_LC
248849283, 159.04222, 11.887527, 18.75, GO14067_LC|GO14012_LC|GO14018_LC
248851357, 157.842591, 11.941511, 17.943, GO14012_LC
248862470, 160.896182, 12.220825, 17.492, GO14067_LC|GO14012_LC|GO14018_LC|GO14063_LC
248863078, 163.673669, 12.235692, 17.149, GO14067_LC|GO14012_LC|GO14018_LC|GO14052_LC
248863697, 159.723165, 12.251317, 18.132, GO14012_LC
248864625, 158.287665, 12.274039, 16.491, GO14067_LC|GO14012_LC|GO14018_LC
248878527, 157.881498, 12.6268, 18.699, GO14012_LC
248881604, 164.82938, 12.711816, 18.211, GO14012_LC
248891072, 158.713228, 12.977992, 17.51, GO14067_LC|GO14012_LC|GO14018_LC
248892238, 162.38689, 13.010339, 17.462, GO14012_LC
248894095, 158.319416, 13.062263, 15.614, GO14012_LC
248904012, 162.437625, 13.36512, 18.239, GO14012_LC
248905059, 161.725128, 13.398472, 17.525, GO14012_LC
248908851, 162.47686, 13.517982, 18.529, GO14067_LC|GO14012_LC|GO14018_LC
251457028, 153.45315, 4.32322, 20.81, GO14012_LC
251457029, 154.08127, 7.51073, 21.985, GO14012_LC
251457030, 157.38511, 9.47071, 21.72, GO14012_LC
251457031, 157.39689, 6.34081, 21.125, GO14012_LC
251457032, 157.74843, 7.39304, 19.97, GO14067_LC|GO14012_LC
251457033, 158.1061, 4.50782, 22.225, GO14012_LC
251457034, 158.15948, 5.22289, 21.655, GO14012_LC
251457035, 158.75519, 6.32228, 21.87, GO14012_LC
251457036, 159.15782, 3.5956, 21.495, GO14012_LC
251457037, 160.12241, 4.52533, 22.02, GO14012_LC
251457038, 160.34705, 4.28657, 20.45, GO14012_LC
251457039, 160.3743, 7.86912, 20.2, GO14012_LC
251457040, 160.37577, 8.99107, 21.575, GO14012_LC
251457041, 160.50598, 12.24626, 21.775, GO14012_LC
251457042, 160.67773, 10.17564, 22.02, GO14012_LC
251457043, 160.71078, 7.37829, 20.25, GO14012_LC
251457044, 160.75131, 6.17754, 20.16, GO14067_LC|GO14012_LC
251457045, 161.27991, 2.99046, 21.585, GO14012_LC
251457046, 162.29467, 10.4701, 19.39, GO14012_LC
251457047, 162.90519, 9.05214, 21.415, GO14012_LC
251457049, 163.49941, -0.40565, 21.7, GO14012_LC
251457050, 165.04861, 9.32913, 21.4, GO14012_LC