# Summary of K2 Program GO12083

Title: Searching for Extended Exoplanetary Atmospheres Around Active Stars

PI: Jensen, Adam Gabriel (University of Nebraska-Kearney)
CoIs: Cauley, Paul Wilson; Endl, Michael; Redfield, Seth

A key question in studying any planetary atmosphere is what happens at the boundary between the atmosphere and interplanetary space. This unbound, outermost layer of an atmosphere is called its exosphere.  Several observations of extended atmospheres have been made (e.g., Vidal-Madjar et al. 2003, 2004; Linsky et al. 2010; Schlawin et al. 2010; Lecavelier Des Etangs et al. 2010, 2012; Fossati et al. 2010; Jensen et al. 2012; Cauley et al. 2015; Cauley et al. 2016, in preparation) in hydrogen (both ground-state and excited) and various metals.

Our team detected excited, n=2 hydrogen (through hydrogen alpha absorption) in the exosphere of HD 189733b (Jensen et al. 2012), the first such detection in an exoplanet atmosphere. Follow-up observations (Cauley et al. 2015; Cauley et al. 2016, in prep.) confirmed this result by detecting exospheric absorption in hydrogen alpha, hydrogen beta, and hydrogen gamma, and also observed a significant pre-transit signal in these lines.  The pre-transit signal is variable between the two observation sets and the physical interpretation is not clear.  Jensen et al. (2012) hypothesized that the excited hydrogen in the exosphere (the transit signal) may be correlated with chromospheric activity, as HD 189733b, the only planet in that paper's sample of four planets to show H-alpha absorption, was also the most chromospherically active in the sample (as measured by S_HK and log [R'_HK] indices).

In Kepler Guest Observer Cycle 3, we proposed to search for planets around stars which are candidates for chromospheric activity in the Kepler 8 and 10 fields.  We found dozens of suitable targets based on the Radial Velocity Experiment (RAVE) Survey's catalogue of chromospherically active stars (Zerjal et al. 2013).  We now propose to do the same for Kepler Guest Observer Cycle 4 for the Kepler Campaign 11, 12, and 13 fields.  Because the 11 and 12 fields are in the southern celestial hemisphere, these are largely covered by the RAVE survey in particular, whereas the RAVE survey mostly covered field 10.  Therefore, we expect to have roughly double the number of targets for this cycle as we did in the previous cycle, roughly tripling the overall sample.  This will greatly improve the chance of success of the accepted Cycle 3 proposal at minimal cost of targets to the K2 mission.

Looking for planets around active stars with radial velocity methods is often disfavored because the stellar noise limits RV precision.  However, this makes the transit method the more important way to detect planets in these cases. Furthermore, if any of these stars do have a transiting planet, they will be excellent potential candidates for follow-up spectroscopy with the large ground-based telescopes (Keck I, HobbyEberly Telescope) that our team has used in the past to detect exospheric absorption. The goal of follow-up spectroscopic observations would be to search for excited hydrogen absorption from an exosphere, including possible pre-transit signals. As a secondary science product, many of these active stars will have light curves worth studying on their own for stellar astrophysics purposes.

# Targets requested by this program that have been observed (131)
EPIC ID, RA (J2000) [deg], Dec (J2000) [deg], magnitude, Investigation IDs
206374325, 344.614934, -7.046054, 14.222, GO12019_LC|GO12083_LC|GO12018_LC|GO12123_LC
245924040, 348.263118, -12.010766, 12.093, GO12083_LC|GO12122_LC|GO12071_LC
245928811, 348.209455, -11.775735, 13.31, GO12083_LC|GO12123_LC|GO12049_LC
245931927, 348.175833, -11.619075, 13.908, GO12083_LC|GO12018_LC|GO12123_LC|GO12049_LC
245934992, 348.322736, -11.470071, 13.533, GO12083_LC|GO12123_LC
245938727, 349.784947, -11.285074, 12.003, GO12083_LC|GO12065_LC|GO12122_LC|GO12071_LC
245939392, 352.26313, -11.253427, 11.609, GO12083_LC|GO12122_LC|GO12071_LC|GO12049_LC
245945412, 353.655763, -11.006575, 11.928, GO12083_LC|GO12065_LC|GO12122_LC|GO12071_LC|GO12123_LC|GO12049_LC
245950175, 348.949038, -10.849696, 12.069, GO12083_LC|GO12122_LC|GO12071_LC|GO12049_LC
245951978, 349.914047, -10.793279, 10.499, GO12083_LC|GO12122_LC|GO12071_LC|GO12049_LC
245952459, 349.604937, -10.776796, 10.499, GO12083_LC|GO12024_LC|GO12065_LC|GO12122_LC|GO12071_LC|GO12049_LC
245952632, 349.421767, -10.771697, 12.825, GO12083_LC|GO12071_LC
245954328, 348.284896, -10.718887, 12.731, GO12083_LC|GO12123_LC
245956636, 347.713554, -10.651464, 13.814, GO12083_LC|GO12018_LC|GO12123_LC|GO12049_LC
245957826, 347.24079, -10.616917, 10.921, GO12083_LC|GO12024_LC|GO12122_LC|GO12071_LC|GO12049_LC
245957878, 355.389227, -10.615794, 13.161, GO12083_LC|GO12018_LC|GO12123_LC|GO12049_LC
245959734, 347.368509, -10.564136, 12.868, GO12083_LC
245961194, 348.799771, -10.524179, 10.848, GO12083_LC|GO12122_LC|GO12123_LC
245961509, 347.207116, -10.514294, 14.142, GO12083_LC|GO12123_LC
245976298, 347.575173, -10.107122, 13.628, GO12083_LC|GO12122_LC|GO12018_LC|GO12123_LC|GO12049_LC
246004124, 355.266406, -9.38075, 11.504, GO12083_LC|GO12123_LC
246008095, 346.321941, -9.277825, 14.233, GO12083_LC|GO12123_LC
246010919, 355.489626, -9.206076, 12.427, GO12083_LC|GO12018_LC|GO12123_LC
246011844, 346.345714, -9.181828, 13.961, GO12083_LC|GO12036_LC|GO12002_LC|GO12123_LC|GO12049_LC
246015530, 350.002496, -9.086593, 12.514, GO12083_LC|GO12123_LC
246023568, 347.902967, -8.886915, 14.112, GO12083_LC|GO12048_LC|GO12018_LC|GO12123_LC|GO12049_LC
246032961, 345.844274, -8.647842, 14.297, GO12083_LC|GO12018_LC|GO12123_LC|GO12049_LC
246034726, 348.485602, -8.607397, 10.91, GO12083_LC|GO12122_LC|GO12071_LC|GO12049_LC
246043232, 357.259687, -8.408611, 11.672, GO12019_LC|GO12083_LC|GO12071_LC|GO12123_LC|GO12010_LC
246043993, 352.863683, -8.389921, 12.543, GO12083_LC|GO12018_LC|GO12071_LC|GO12123_LC|GO12049_LC
246044241, 357.297694, -8.384632, 11.936, GO12019_LC|GO12083_LC|GO12018_LC|GO12123_LC
246047096, 351.008875, -8.321636, 13.243, GO12083_LC|GO12122_LC|GO12123_LC|GO12049_LC
246048651, 350.358327, -8.28713, 13.832, GO12083_LC|GO12018_LC|GO12123_LC|GO12049_LC
246048747, 347.523822, -8.28468, 13.052, GO12083_LC|GO12018_LC|GO12123_LC|GO12049_LC
246053081, 346.462833, -8.184615, 13.974, GO12083_LC|GO12018_LC|GO12123_LC|GO12049_LC
246055848, 347.224752, -8.122911, 13.167, GO12083_LC|GO12018_LC|GO12123_LC|GO12049_LC
246069006, 358.052026, -7.822051, 11.329, GO12019_LC|GO12083_LC|GO12122_LC|GO12071_LC
246069493, 347.602978, -7.811996, 7.209, GO12019_LC|GO12083_LC|GO12039_LC|GO12024_LC|GO12002_LC|GO12122_LC|GO12071_LC|GO12012_LC|GO12904_LC|GO12012_SC
246070255, 345.074382, -7.794775, 11.687, GO12083_LC|GO12122_LC
246072555, 358.662786, -7.741892, 12.077, GO12019_LC|GO12083_LC|GO12122_LC|GO12071_LC|GO12049_LC
246073881, 346.28538, -7.711341, 13.305, GO12019_LC|GO12083_LC|GO12123_LC
246081052, 344.998352, -7.551807, 13.974, GO12083_LC|GO12018_LC|GO12123_LC|GO12049_LC
246084817, 345.394591, -7.469835, 11.913, GO12083_LC|GO12122_LC|GO12071_LC|GO12049_LC
246090925, 349.307101, -7.338984, 13.252, GO12083_LC|GO12018_LC|GO12123_LC|GO12049_LC
246093689, 347.104027, -7.277799, 10.641, GO12083_LC|GO12024_LC|GO12122_LC|GO12071_LC
246098711, 346.842674, -7.169054, 13.537, GO12083_LC|GO12123_LC|GO12049_LC
246102818, 344.895249, -7.079678, 13.338, GO12083_LC|GO12006_LC|GO12002_LC|GO12018_LC|GO12123_LC
246104577, 344.895823, -7.03969, 11.372, GO12019_LC|GO12070_LC|GO12050_LC|GO12083_LC|GO12036_LC|GO12024_LC|GO12006_LC|GO12002_LC|GO12122_LC|GO12071_LC|GO12123_LC|GO12049_LC
246110938, 348.771877, -6.899617, 13.537, GO12083_LC|GO12018_LC|GO12123_LC|GO12049_LC
246111400, 352.340265, -6.889855, 11.984, GO12019_LC|GO12083_LC|GO12048_LC|GO12122_LC|GO12071_LC|GO12123_LC
246113903, 352.401436, -6.835755, 8.125, GO12019_LC|GO12083_LC|GO12024_LC|GO12065_LC|GO12122_LC|GO12071_LC|GO12904_LC
246116237, 349.894043, -6.786352, 11.305, GO12083_LC|GO12122_LC|GO12071_LC|GO12123_LC|GO12049_LC
246117528, 350.35823, -6.758232, 14.181, GO12083_LC|GO12123_LC|GO12049_LC
246117697, 346.132114, -6.754365, 13.959, GO12019_LC|GO12083_LC|GO12018_LC|GO12123_LC
246118753, 349.691518, -6.731965, 13.341, GO12083_LC|GO12018_LC|GO12123_LC|GO12049_LC
246123236, 344.749446, -6.635594, 11.013, GO12019_LC|GO12050_LC|GO12083_LC|GO12024_LC|GO12122_LC|GO12071_LC|GO12123_LC|GO12049_LC
246123433, 350.664936, -6.63127, 12.663, GO12083_LC|GO12122_LC|GO12071_LC|GO12123_LC
246124192, 347.970073, -6.615762, 15.379, GO12083_LC|GO12123_LC|GO12049_LC
246125056, 345.86106, -6.596915, 14.276, GO12050_LC|GO12083_LC|GO12123_LC|GO12049_LC
246127251, 346.572923, -6.548811, 13.303, GO12050_LC|GO12083_LC|GO12122_LC|GO12018_LC|GO12123_LC|GO12049_LC
246127614, 345.491692, -6.540604, 14.01, GO12050_LC|GO12083_LC|GO12018_LC|GO12123_LC|GO12049_LC
246134143, 345.007369, -6.400635, 13.834, GO12083_LC|GO12018_LC
246134147, 353.30022, -6.400587, 7.988, GO12019_LC|GO12052_LC|GO12083_LC|GO12039_LC|GO12024_LC|GO12122_LC|GO12071_LC|GO12049_LC|GO12012_LC|GO12904_LC|GO12012_SC
246136275, 349.98775, -6.355487, 13.756, GO12083_LC|GO12123_LC|GO12049_LC
246142765, 344.844513, -6.215228, 13.852, GO12050_LC|GO12083_LC|GO12018_LC|GO12123_LC|GO12049_LC
246147205, 351.52124, -6.122144, 9.885, GO12083_LC|GO12024_LC|GO12122_LC|GO12071_LC|GO12123_LC|GO12049_LC|GO12904_LC
246149299, 346.101346, -6.076726, 11.605, GO12083_LC|GO12122_LC|GO12071_LC
246150560, 346.155891, -6.049, 11.754, GO12050_LC|GO12083_LC|GO12071_LC|GO12049_LC
246151168, 351.429175, -6.035942, 11.845, GO12083_LC|GO12122_LC|GO12071_LC|GO12123_LC|GO12049_LC
246151755, 347.343461, -6.023205, 11.556, GO12050_LC|GO12083_LC|GO12024_LC|GO12048_LC|GO12122_LC|GO12071_LC|GO12049_LC
246152729, 350.879478, -6.00348, 10.951, GO12083_LC|GO12122_LC|GO12071_LC|GO12123_LC|GO12049_LC|GO12904_LC
246154060, 348.927295, -5.975065, 11.796, GO12083_LC|GO12122_LC|GO12071_LC
246154489, 345.476225, -5.966289, 7.642, GO12019_LC|GO12083_LC|GO12035_LC|GO12048_LC|GO12012_LC|GO12904_LC|GO12012_SC
246157152, 344.527385, -5.910652, 14.127, GO12050_LC|GO12083_LC|GO12123_LC|GO12049_LC
246166368, 349.621567, -5.715988, 11.218, GO12083_LC|GO12024_LC|GO12065_LC|GO12006_LC|GO12122_LC|GO12071_LC|GO12049_LC
246166903, 352.006219, -5.705206, 10.566, GO12083_LC|GO12048_LC|GO12123_LC
246172176, 352.736805, -5.593997, 12.18, GO12083_LC|GO12122_LC|GO12071_LC|GO12049_LC
246172398, 349.468223, -5.589621, 10.923, GO12083_LC|GO12122_LC|GO12071_LC
246178525, 345.925644, -5.46513, 13.087, GO12050_LC|GO12083_LC|GO12018_LC|GO12123_LC|GO12049_LC
246179395, 347.166175, -5.448328, 11.751, GO12083_LC|GO12123_LC
246180128, 348.183435, -5.433394, 13.263, GO12083_LC|GO12123_LC
246190137, 357.807806, -5.224203, 11.592, GO12083_LC|GO12123_LC
246193282, 347.158646, -5.160409, 12.805, GO12083_LC|GO12123_LC
246193370, 347.64795, -5.158833, 10.282, GO12050_LC|GO12083_LC|GO12024_LC|GO12065_LC|GO12122_LC|GO12071_LC|GO12049_LC
246199562, 351.12197, -5.031693, 11.823, GO12083_LC|GO12122_LC|GO12071_LC|GO12049_LC
246203113, 350.488151, -4.958191, 9.955, GO12019_LC|GO12050_LC|GO12083_LC|GO12024_LC|GO12065_LC|GO12122_LC|GO12071_LC|GO12049_LC
246203577, 358.563375, -4.948912, 9.556, GO12019_LC|GO12083_LC|GO12024_LC|GO12065_LC|GO12122_LC|GO12071_LC|GO12049_LC|GO12904_LC
246207098, 348.632958, -4.87855, 11.504, GO12083_LC|GO12122_LC|GO12071_LC
246207483, 345.306182, -4.871615, 13.876, GO12019_LC|GO12083_LC|GO12018_LC|GO12123_LC
246209786, 348.46846, -4.824219, 11.439, GO12050_LC|GO12083_LC|GO12039_LC|GO12071_LC|GO12123_LC|GO12049_LC|GO12904_LC
246213236, 347.96046, -4.753747, 12.277, GO12050_LC|GO12083_LC|GO12122_LC|GO12018_LC|GO12071_LC|GO12123_LC|GO12049_LC
246213922, 347.147415, -4.739902, 11.657, GO12083_LC|GO12122_LC|GO12071_LC
246219683, 348.781324, -4.624779, 12.063, GO12083_LC|GO12065_LC|GO12122_LC|GO12071_LC|GO12049_LC
246225869, 356.93465, -4.507824, 11.767, GO12083_LC|GO12122_LC|GO12071_LC|GO12123_LC|GO12049_LC
246234437, 348.449022, -4.343447, 13.074, GO12050_LC|GO12083_LC|GO12018_LC|GO12123_LC|GO12049_LC
246237099, 352.357085, -4.292856, 12.001, GO12050_LC|GO12083_LC|GO12122_LC|GO12018_LC|GO12071_LC|GO12123_LC|GO12049_LC
246237738, 352.256478, -4.280919, 11.081, GO12083_LC|GO12122_LC|GO12071_LC|GO12903_LC
246238976, 358.346588, -4.257529, 11.667, GO12019_LC|GO12083_LC|GO12122_LC|GO12071_LC|GO12123_LC|GO12049_LC
246247158, 346.176593, -4.103237, 9.805, GO12019_LC|GO12083_LC|GO12024_LC|GO12122_LC|GO12071_LC|GO12123_LC|GO12049_LC|GO12904_LC
246259345, 347.774372, -3.871313, 10.894, GO12083_LC|GO12122_LC|GO12071_LC|GO12123_LC|GO12049_LC
246262053, 347.852729, -3.821165, 12.53, GO12083_LC|GO12122_LC|GO12071_LC|GO12049_LC
246264528, 349.63758, -3.773286, 11.781, GO12083_LC|GO12122_LC|GO12071_LC|GO12123_LC
246266169, 350.330883, -3.742062, 11.282, GO12083_LC|GO12048_LC|GO12123_LC
246278583, 358.283339, -3.492182, 11.452, GO12083_LC|GO12122_LC|GO12071_LC|GO12049_LC|GO12902_LC|GO12903_LC
246286900, 350.374176, -3.329138, 10.417, GO12050_LC|GO12083_LC|GO12122_LC|GO12071_LC|GO12049_LC
246288595, 358.305387, -3.29674, 10.978, GO12083_LC|GO12122_LC|GO12071_LC
246290639, 358.49248, -3.255189, 10.426, GO12083_LC|GO12024_LC|GO12122_LC|GO12071_LC|GO12049_LC|GO12902_LC|GO12903_LC
246291471, 345.740379, -3.238838, 12.0, GO12083_LC|GO12006_LC|GO12122_LC|GO12071_LC|GO12049_LC
246293638, 357.218207, -3.194813, 11.825, GO12083_LC|GO12122_LC|GO12071_LC|GO12049_LC
246294559, 354.823196, -3.177441, 10.405, GO12083_LC|GO12048_LC|GO12123_LC
246301900, 350.545373, -3.028336, 10.807, GO12050_LC|GO12083_LC|GO12122_LC|GO12018_LC|GO12071_LC|GO12123_LC|GO12010_LC|GO12049_LC
246310442, 350.929448, -2.856194, 11.62, GO12050_LC|GO12083_LC|GO12065_LC|GO12122_LC|GO12071_LC|GO12049_LC
246318398, 348.462985, -2.694464, 12.851, GO12083_LC|GO12018_LC|GO12123_LC
246324726, 349.419375, -2.569745, 11.621, GO12083_LC|GO12122_LC|GO12071_LC|GO12123_LC|GO12049_LC
246331130, 350.16122, -2.445158, 11.203, GO12083_LC|GO12048_LC|GO12123_LC
246331757, 347.404685, -2.431998, 10.479, GO12083_LC|GO12103_LC|GO12123_LC|GO12904_LC|GO12103_SC
246335718, 347.53574, -2.352005, 12.606, GO12083_LC|GO12122_LC|GO12071_LC|GO12123_LC|GO12049_LC
246340370, 347.294699, -2.260744, 8.617, GO12085_LC|GO12083_LC|GO12039_LC|GO12062_LC|GO12122_LC|GO12071_LC|GO12049_LC|GO12904_LC
246359551, 348.17551, -1.884707, 11.149, GO12083_LC|GO12123_LC
246364217, 350.240358, -1.793726, 12.436, GO12083_LC|GO12039_LC|GO12002_LC|GO12018_LC|GO12071_LC|GO12123_LC|GO12010_LC
246367712, 349.475494, -1.726963, 10.312, GO12083_LC|GO12002_LC|GO12122_LC|GO12071_LC|GO12049_LC
246369352, 347.098946, -1.694995, 11.431, GO12083_LC|GO12122_LC|GO12071_LC|GO12049_LC
246376831, 350.034159, -1.548312, 12.329, GO12083_LC
246383959, 348.757654, -1.40476, 11.746, GO12083_LC|GO12122_LC|GO12071_LC|GO12049_LC
246385987, 352.048278, -1.362911, 10.809, GO12083_LC|GO12123_LC
246400041, 351.29109, -0.996431, 10.75, GO12083_LC|GO12123_LC
246405404, 347.446235, -0.826307, 9.904, GO12083_LC|GO12036_LC|GO12002_LC|GO12122_LC|GO12071_LC
246410931, 347.088779, -0.657437, 10.861, GO12083_LC|GO12123_LC
246416022, 352.203537, -0.499555, 11.07, GO12083_LC|GO12065_LC
246432069, 347.21024, 0.014658, 10.299, GO12083_LC|GO12082_LC|GO12024_LC|GO12049_LC
246449844, 349.98485, 0.571859, 11.014, GO12083_LC|GO12065_LC|GO12122_LC|GO12071_LC|GO12049_LC