# Summary of K2 Program GO13098

Title: Catch K2-Twos: Finding the Best Planets for Ground-Based Follow Up Spectrophotometry

PI: Mandell, Avi M (NASA GSFC)
CoIs: Morris, Brett M; Angerhausen, Daniel; Huitson, Catherine

Studying extrasolar planets is one of the major frontiers of astronomy today. The field has transformed from simple identification to comprehensive categorization and characterization of exoplanets and exoplanetary systems. Analyses of data provided by the NASA's Kepler mission has revolutionized this field by compiling a statistically significant number of transiting planets and planetary candidates, providing time series data for a large sample of systems that can be utilized in consistent comparative studies (e.g. Angerhausen et al., 2015). 

One promising new way to further characterize some of these transiting systems are methods using ground-based multi-object spectrographs for transit and eclipse spectrophotometry such as GMOS in the optical (e.g. Stevenson et al., 2014; Huitson et al., 2016, in prep.) or MOSFIRE in the infrared (e.g. Crossfield et al., 2013; Morris et al, 2016, in prep.). These emerging ground-based methods allow access to larger apertures and better time-sampling of transit lightcurves than equivalent HST methods. They therefore have the potential to observe transits at the precisions achievable from space but at a fraction of the cost and with the possibility of repeated measurements to further increase reliability. Importantly, ground-based telescopes have access to the full optical wavelength range and so will be highly complementary to JWST.

However, these ground-based methods are constrained by the need for similarly bright comparison stars in close neighborhood to the observed host star of the transiting system. In order to reduce instrumental systematics and optimize the time-sampling at the level needed for high-precision transit atmosphere observations, the comparison stars must be bright, of similar magnitude to the exoplanet host star and be within a few arcmin. 

To identify ideal candidates for ground-based characterization studies, we therefore we propose to use the single, visible wavelength instrument on board of K2 to obtain high-precision long cadence photometry on of the best suited pairs of similarly bright stars (mag < 11.5, separation < 5 arcmin). Assuming an occurrence of well-vetted planet candidates with P d 30 d of about ~2%, we expect to find ~20 planets that will be accessible for spectrophotometric atmospheric characterization from the ground.

The goal of high precision time resolved photometry is to reduce or in the best case remove all noise to achieve photon-noise limited photometry. After years of experience with these data a number of best practices for their handling have emerged: For the reduction and preparation of K2 data as well as for the planet search in the reduced data, we have access to a number of standard procedures that are already widely used in the community (e.g. the PyKe tools, Barclay & Still 2012; K2 specific best practices, Foreman-Mackey et al. 2015; or SIP, Angus et al. 2015). 

Finding these extremely valuable targets will enable us to do exactly the kind of basic research that advances our knowledge by characterization of planets and planetary systems outside of our Solar System in order to determine their compositions, dynamics, energetics, and chemical behaviors. The proposed study will directly support NASAs goal to Discover and study planets around other stars, in order to understand the underlying physical processes of exoplanets and to improve understanding of their origins.
This program already got 478 target masks awarded in K2 cycle 3 (Program GO8066).

# Targets requested by this program that have been observed (164)
EPIC ID, RA (J2000) [deg], Dec (J2000) [deg], magnitude, Investigation IDs
210580425, 66.859989, 16.677598, 11.378, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC|GO13052_LC
210583619, 66.922952, 16.725037, 10.23, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC
210653579, 67.871133, 17.71866, 11.226, GO13008_LC|GO13049_LC|GO13010_LC|GO13071_LC|GO13018_LC|GO13023_LC|GO13006_LC|GO13098_LC
210656728, 67.904903, 17.760472, 11.418, GO13098_LC
210762111, 67.395304, 19.294784, 10.705, GO13049_LC|GO13123_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13065_LC
210764881, 67.39582, 19.336131, 11.093, GO13049_LC|GO13123_LC|GO13071_LC|GO13122_LC|GO13098_LC
210872806, 65.560945, 20.970178, 11.33, GO13071_LC|GO13122_LC|GO13098_LC|GO13052_LC
210877254, 65.571462, 21.03797, 11.5, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC
210911405, 67.116712, 21.568523, 11.435, GO13071_LC|GO13122_LC|GO13098_LC
210912504, 67.168282, 21.585281, 11.921, GO13071_LC|GO13122_LC|GO13098_LC
210916246, 67.179191, 21.644691, 10.822, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13050_LC|GO13052_LC
246605058, 72.147241, 13.260948, 10.953, GO13071_LC|GO13122_LC|GO13098_LC|GO13065_LC|GO13024_LC
246633807, 72.957156, 13.692363, 11.153, GO13071_LC|GO13122_LC|GO13098_LC
246636039, 72.948764, 13.725222, 10.842, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC|GO13903_LC
246661979, 74.295713, 14.081933, 11.333, GO13098_LC
246667073, 74.253008, 14.148429, 11.155, GO13098_LC
246670346, 74.267138, 14.191468, 10.4, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC|GO13903_LC
246677249, 72.361944, 14.281473, 11.251, GO13071_LC|GO13122_LC|GO13098_LC|GO13065_LC|GO13024_LC
246679251, 72.291799, 14.307432, 11.494, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13903_LC
246686716, 74.314605, 14.403122, 10.255, GO13098_LC
246688973, 74.389129, 14.432124, 11.05, GO13098_LC
246702681, 71.91391, 14.60651, 10.074, GO13071_LC|GO13002_LC|GO13098_LC|GO13065_LC|GO13036_LC
246702818, 71.917879, 14.608431, 10.224, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC|GO13019_LC|GO13903_LC
246726527, 75.876073, 14.901155, 10.811, GO13009_LC|GO13098_LC
246729064, 72.709747, 14.932382, 10.376, GO13123_LC|GO13098_LC
246731017, 75.844701, 14.95541, 10.106, GO13098_LC
246732310, 72.760135, 14.9713, 11.048, GO13008_LC|GO13049_LC|GO13064_LC|GO13010_LC|GO13123_LC|GO13018_LC|GO13023_LC|GO13098_LC|GO13077_LC|GO13090_LC
246744722, 71.707494, 15.117926, 10.111, GO13123_LC|GO13098_LC
246747673, 71.778452, 15.152257, 10.808, GO13123_LC|GO13098_LC
246760202, 76.895352, 15.29804, 11.397, GO13071_LC|GO13122_LC|GO13098_LC
246760737, 76.811189, 15.304827, 11.194, GO13071_LC|GO13122_LC|GO13098_LC
246799660, 75.25157, 15.738451, 11.092, GO13123_LC|GO13009_LC|GO13098_LC
246802056, 75.19517, 15.764015, 11.037, GO13123_LC|GO13098_LC
246803758, 75.145065, 15.781599, 10.661, GO13049_LC|GO13123_LC|GO13071_LC|GO13122_LC|GO13098_LC
246824415, 74.761733, 15.998807, 10.933, GO13123_LC|GO13098_LC
246828453, 74.779987, 16.041785, 11.078, GO13098_LC
246830819, 78.927451, 16.066522, 10.366, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC|GO13052_LC
246832184, 78.953278, 16.079976, 10.794, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC
246836459, 76.597617, 16.124495, 9.105, GO13098_LC
246841922, 76.546091, 16.179022, 9.349, GO13098_LC
246867280, 78.439322, 16.434192, 10.471, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC
246867578, 78.354961, 16.437096, 10.383, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC|GO13903_LC
246875826, 77.694496, 16.5166, 9.96, GO13123_LC|GO13009_LC|GO13098_LC
246880365, 77.686186, 16.561738, 9.826, GO13123_LC|GO13098_LC
246883369, 78.053369, 16.591343, 11.118, GO13123_LC|GO13098_LC
246888894, 78.073147, 16.645581, 10.79, GO13053_LC|GO13123_LC|GO13002_LC|GO13098_LC|GO13090_LC
246906494, 71.998053, 16.815519, 11.454, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC
246907781, 77.673602, 16.828571, 10.45, GO13123_LC|GO13098_LC
246911943, 72.012188, 16.868678, 10.858, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC|GO13052_LC
246914508, 77.712808, 16.893367, 11.103, GO13123_LC|GO13071_LC|GO13122_LC|GO13002_LC|GO13098_LC
246914590, 78.310176, 16.894134, 11.404, GO13053_LC|GO13122_LC|GO13098_LC
246918273, 78.297347, 16.930501, 11.052, GO13122_LC|GO13098_LC|GO13038_LC
246920193, 73.9931, 16.949432, 10.916, GO13071_LC|GO13122_LC|GO13098_LC
246921072, 78.583974, 16.957862, 9.977, GO13098_LC
246925732, 78.600262, 17.003728, 9.821, GO13098_LC
246937186, 78.02467, 17.114634, 10.173, GO13123_LC|GO13098_LC
246941795, 78.093733, 17.157947, 10.877, GO13123_LC|GO13098_LC
246944519, 78.171286, 17.183888, 11.484, GO13053_LC|GO13123_LC|GO13098_LC
246952886, 77.367224, 17.264171, 10.666, GO13122_LC|GO13098_LC
246955094, 72.059445, 17.285657, 11.044, GO13123_LC|GO13098_LC
246955287, 77.412523, 17.287519, 11.413, GO13071_LC|GO13122_LC|GO13098_LC
246955698, 72.100706, 17.291628, 10.899, GO13098_LC
246966672, 77.72671, 17.399827, 10.944, GO13122_LC|GO13098_LC
246969289, 77.723335, 17.425158, 11.079, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC
246975459, 78.164928, 17.48525, 10.795, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC
246981318, 78.130071, 17.542411, 11.022, GO13071_LC|GO13122_LC|GO13098_LC
247057664, 72.985053, 18.267726, 10.777, GO13123_LC|GO13098_LC
247057813, 68.30893, 18.26926, 10.96, GO13071_LC|GO13098_LC|GO13082_LC|GO13052_LC
247057906, 73.030042, 18.270142, 10.644, GO13123_LC|GO13098_LC
247062423, 68.360635, 18.312024, 11.079, GO13049_LC|GO13002_LC|GO13098_LC
247130842, 68.290084, 18.964518, 11.506, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC
247135185, 69.605939, 19.005121, 9.637, GO13049_LC|GO13071_LC|GO13002_LC|GO13098_LC|GO13052_LC
247135634, 71.155084, 19.009586, 9.491, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC
247139273, 68.211684, 19.044754, 10.704, GO13098_LC
247140208, 71.130821, 19.053534, 11.123, GO13071_LC|GO13122_LC|GO13098_LC|GO13077_LC
247157963, 70.604378, 19.223551, 11.381, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC
247158298, 70.658015, 19.22665, 11.352, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC
247158617, 80.887091, 19.229859, 11.475, GO13122_LC|GO13098_LC
247159180, 80.843873, 19.235264, 11.382, GO13122_LC|GO13098_LC
247165328, 80.835112, 19.292487, 10.657, GO13071_LC|GO13122_LC|GO13098_LC
247166577, 79.949001, 19.303832, 10.742, GO13071_LC|GO13122_LC|GO13098_LC
247170743, 80.876456, 19.344515, 11.021, GO13071_LC|GO13122_LC|GO13098_LC
247172552, 80.949066, 19.362297, 11.13, GO13071_LC|GO13122_LC|GO13098_LC
247173107, 80.005336, 19.367795, 10.474, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC|GO13903_LC
247173166, 79.921025, 19.368456, 11.377, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC
247174094, 72.099824, 19.377069, 11.541, GO13071_LC|GO13122_LC|GO13098_LC
247178064, 79.90471, 19.414708, 11.379, GO13071_LC|GO13122_LC|GO13098_LC|GO13038_LC|GO13024_LC
247179825, 78.868383, 19.431151, 9.444, GO13049_LC|GO13071_LC|GO13009_LC|GO13122_LC|GO13098_LC
247179838, 72.108921, 19.431305, 11.623, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC
247187283, 78.85659, 19.502845, 10.038, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13065_LC
247236128, 78.275868, 19.966985, 10.607, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC
247239225, 78.297786, 19.995758, 10.492, GO13071_LC|GO13122_LC|GO13098_LC
247239752, 73.175027, 20.000611, 9.276, GO13008_LC|GO13014_LC|GO13071_LC|GO13002_LC|GO13023_LC|GO13098_LC|GO13024_LC|GO13039_LC|GO13903_LC
247264191, 72.784668, 20.227083, 11.954, GO13071_LC|GO13122_LC|GO13098_LC|GO13903_LC
247272410, 72.810165, 20.302572, 12.002, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC|GO13052_LC|GO13903_LC
247273263, 70.948807, 20.309647, 11.831, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13052_LC
247273504, 71.027874, 20.311848, 11.531, GO13049_LC|GO13071_LC|GO13098_LC|GO13024_LC
247276449, 72.871556, 20.338599, 11.111, GO13071_LC|GO13122_LC|GO13098_LC
247280222, 80.412583, 20.37329, 10.57, GO13122_LC|GO13098_LC
247285694, 80.347368, 20.423273, 10.824, GO13122_LC|GO13098_LC|GO13024_LC
247318677, 78.672936, 20.716272, 10.362, GO13009_LC|GO13098_LC
247323824, 78.747531, 20.761752, 10.713, GO13098_LC
247334633, 70.501586, 20.854973, 11.426, GO13071_LC|GO13122_LC|GO13098_LC|GO13052_LC
247340714, 70.483526, 20.906327, 11.962, GO13071_LC|GO13122_LC|GO13098_LC
247361523, 70.081263, 21.082593, 10.905, GO13071_LC|GO13122_LC|GO13098_LC|GO13052_LC
247365409, 70.122134, 21.115055, 10.194, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC|GO13052_LC
247371116, 72.933102, 21.162378, 10.778, GO13123_LC|GO13098_LC
247373985, 72.946164, 21.185298, 10.565, GO13123_LC|GO13098_LC
247384894, 68.810192, 21.274801, 11.59, GO13071_LC|GO13098_LC
247391465, 68.790259, 21.326902, 11.412, GO13071_LC|GO13098_LC
247392795, 71.507933, 21.337518, 11.168, GO13071_LC|GO13122_LC|GO13098_LC|GO13052_LC
247400955, 71.528179, 21.404218, 11.721, GO13071_LC|GO13122_LC|GO13098_LC
247409600, 76.286814, 21.474622, 11.29, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC
247411406, 74.482164, 21.48894, 11.416, GO13071_LC|GO13122_LC|GO13098_LC
247415759, 76.225023, 21.523949, 10.464, GO13071_LC|GO13122_LC|GO13098_LC|GO13065_LC|GO13024_LC
247416298, 74.447943, 21.527909, 10.776, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13903_LC
247427432, 68.605766, 21.619912, 9.708, GO13071_LC|GO13122_LC|GO13098_LC|GO13052_LC
247427616, 68.651888, 21.621532, 10.198, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13050_LC|GO13052_LC
247428680, 76.37053, 21.629956, 10.857, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13052_LC
247434280, 76.340863, 21.675195, 10.481, GO13071_LC|GO13122_LC|GO13098_LC|GO13052_LC|GO13903_LC
247434831, 69.344769, 21.679594, 9.173, GO13123_LC|GO13098_LC
247441070, 69.403071, 21.73128, 10.036, GO13123_LC|GO13098_LC
247457993, 69.517135, 21.865643, 11.244, GO13049_LC|GO13123_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13050_LC
247460925, 75.046254, 21.889718, 11.46, GO13123_LC|GO13098_LC
247461699, 74.965213, 21.895992, 10.676, GO13123_LC|GO13098_LC
247466699, 69.543662, 21.93631, 11.463, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13050_LC
247480142, 69.265164, 22.041527, 10.646, GO13071_LC|GO13122_LC|GO13098_LC|GO13903_LC
247484019, 69.305134, 22.071095, 11.23, GO13071_LC|GO13122_LC|GO13098_LC
247488100, 67.730056, 22.10227, 10.423, GO13098_LC
247491545, 76.426494, 22.128814, 11.156, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13050_LC
247492010, 76.383204, 22.132282, 11.471, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13050_LC
247497941, 67.725955, 22.179168, 10.398, GO13098_LC
247507113, 70.993326, 22.249884, 12.114, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13050_LC
247509076, 69.902303, 22.264882, 11.555, GO13122_LC|GO13098_LC
247509655, 70.949971, 22.269376, 11.664, GO13049_LC|GO13071_LC|GO13122_LC|GO13002_LC|GO13098_LC|GO13065_LC|GO13050_LC
247510486, 76.261733, 22.276034, 10.598, GO13071_LC|GO13122_LC|GO13098_LC|GO13065_LC|GO13903_LC
247511742, 76.184147, 22.285674, 10.709, GO13049_LC|GO13097_LC|GO13071_LC|GO13122_LC|GO13002_LC|GO13098_LC|GO13095_LC|GO13050_LC|GO13052_LC|GO13097_SC
247512118, 76.268463, 22.288932, 11.492, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC
247513351, 69.899045, 22.298315, 11.415, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13050_LC
247529791, 75.542461, 22.423291, 11.079, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC
247538906, 69.585561, 22.492735, 11.464, GO13071_LC|GO13122_LC|GO13098_LC|GO13050_LC
247542126, 69.642966, 22.51726, 10.845, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13050_LC
247625811, 76.360684, 23.161379, 11.42, GO13098_LC
247667941, 72.585002, 23.476881, 10.624, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13050_LC|GO13052_LC
247671012, 72.619309, 23.500198, 11.429, GO13071_LC|GO13122_LC|GO13098_LC
247697398, 72.020687, 23.694338, 11.053, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC|GO13052_LC
247699916, 75.602022, 23.711863, 11.548, GO13098_LC
247707090, 72.065262, 23.763228, 10.039, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC|GO13015_LC|GO13903_LC
247707722, 75.579561, 23.767491, 11.541, GO13098_LC
247717055, 75.621693, 23.833364, 10.364, GO13071_LC|GO13122_LC|GO13098_LC|GO13052_LC
247719695, 75.4965, 23.852272, 11.528, GO13123_LC|GO13098_LC
247721080, 75.435828, 23.861749, 11.285, GO13123_LC|GO13098_LC
247725551, 75.650718, 23.892409, 9.792, GO13071_LC|GO13122_LC|GO13098_LC|GO13024_LC|GO13052_LC
247727224, 72.415551, 23.903713, 10.76, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC
247728956, 75.665241, 23.915404, 11.521, GO13049_LC|GO13098_LC
247729521, 75.598615, 23.919208, 11.669, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC
247733099, 72.478415, 23.943183, 10.719, GO13071_LC|GO13122_LC|GO13098_LC
247761998, 75.837172, 24.146119, 10.941, GO13098_LC
247765548, 75.924772, 24.171068, 11.066, GO13098_LC
247771437, 75.850279, 24.21159, 11.325, GO13098_LC
248093972, 71.17297, 26.532549, 10.734, GO13009_LC|GO13098_LC
248099508, 71.384922, 26.578284, 10.297, GO13049_LC|GO13071_LC|GO13122_LC|GO13098_LC|GO13052_LC
248101101, 71.163232, 26.591708, 9.992, GO13123_LC|GO13098_LC
248107860, 71.42096, 26.648837, 10.621, GO13071_LC|GO13122_LC|GO13098_LC|GO13903_LC