# Summary of K2 Program GO5069

Title: Exploiting RR Lyrae stars in the C4 and C5 fields of the K2 Mission

PI: Szabo, Robert (Konkoly Observatory of the Hungarian Academy of Sciences)
CoIs: Nemec, James M; Kuehn, Charles August; Plachy, Emese; Molnar, Laszlo; Guggenberger, Elisabeth; Kolenberg, Katrien; Ngeow, Chow-Choong; Jeon, Young-Beom; Moskalik, Pawel A

Space observations of RR Lyrae stars delivered an avalanche of discoveries including new dynamical phenomena that helped to study the internal structure and evolution of horizontal-branch stars. These objects are excellent galactic structure tracers and distance indicators, therefore understanding their dynamics _x0013_ and their optical behavior _x0013_ is of crucial importance to advance our knowledge of galaxy formation and evolution in the Local Group of galaxies and beyond. We plan to study 87 and 90 RR Lyrae stars in the Fields 4&5 with K2's unique capabilities of providing long, uninterrupted, high-precision space photometry. The sample will be used to conduct galactic structure studies and to improve our understanding of dynamical behavior of RR Lyrae stars. Our immediate objectives are: 1. Study the Galactic structure and history by obtaining distances to RR Lyrae stars and determine their spatial distribution (halo streams, over-densities). During the K2 Mission we will build up a unique database from field to field covering different parts of our Galaxy, to yield an unprecedented photometric RR Lyrae sample which will form the base of galactic structure studies and near-field cosmology. 2. Statistical analysis of various dynamical phenomena (double-mode pulsation, Blazhko-modulation, period-doubling, low-dimensional chaos, nonradial modes) and their occurrence rates to better understand their origin and their effect on distance determination. This can only be accomplished with K2. 3. Analyze in detail all RR Lyrae light curves, especially overtone and classical double-mode pulsators. The original Kepler field contained no RRd stars, and only a few RRc. This will aid the investigation of dynamical phenomena (resonances, mode interactions) that may be important in other types of pulsating stars, but can be best studied only in large-amplitude stars and with space photometry. After producing light curves from target pixel data we apply standard time-frequency analysis and study  time-dependent features. State-of-the-art numerical hydrocodes and ground-based follow-up observations will be used to interpret the results. Synthetic galactic models  will be computed to compare the galactic location and number of the observed sample with simulations. The proposed project will provide a unique opportunity to better understand these highly variable classical pulsating stars on the horizontal branch and their role in unraveling the formation of our Galaxy.

# Targets requested by this program that have been observed (88)
EPIC ID, RA (J2000) [deg], Dec (J2000) [deg], magnitude, Investigation IDs
211307207, 132.503886, 9.996456, 14.769, GO5069_LC
211310837, 133.971127, 10.069017, 13.225, GO5057_LC|GO5069_LC
211348419, 132.615319, 10.785189, 16.408, GO5069_LC
211398225, 132.013772, 11.613536, 16.333, GO5069_LC
211398788, 134.06181, 11.622377, 14.637, GO5069_LC
211410664, 126.286908, 11.802441, 14.28, GO5069_SC|GO5069_LC
211412103, 133.989809, 11.823017, 17.465, GO5069_LC
211484212, 135.81143, 12.910256, 16.047, GO5069_LC
211492294, 126.647965, 13.028224, 18.741, GO5069_LC
211496026, 126.29002, 13.083488, 17.274, GO5069_LC
211503714, 128.22992, 13.191244, 11.722, GO5069_SC|GO5007_LC|GO5033_LC|GO5057_LC|GO5069_LC|GO5104_LC
211516905, 130.704667, 13.376936, 17.063, GO5069_LC
211517741, 125.192877, 13.388874, 15.21, GO5069_LC
211523969, 123.189622, 13.47725, 15.37, GO5069_LC|GO5101_LC
211532246, 125.216513, 13.594366, 19.677, GO5069_LC
211553019, 129.616364, 13.883045, 17.369, GO5069_LC
211565461, 123.489114, 14.060074, 17.127, GO5069_LC
211573254, 135.55878, 14.167763, 16.471, GO5069_LC
211580649, 124.278589, 14.272635, 14.776, GO5069_LC
211598885, 123.743219, 14.524615, 17.133, GO5069_LC
211612680, 136.845371, 14.711094, 16.083, GO5069_LC
211620065, 123.515526, 14.815416, 16.395, GO5069_LC
211690919, 133.215443, 15.792722, 19.106, GO5069_LC
211691308, 124.904513, 15.798516, 15.473, GO5069_LC
211694449, 126.20299, 15.841135, 18.175, GO5069_LC
211700735, 132.465803, 15.925779, 16.204, GO5006_LC|GO5069_LC
211701322, 129.206529, 15.933356, 16.429, GO5069_LC
211728918, 132.70562, 16.310424, 14.399, GO5069_LC
211779259, 124.823828, 17.022502, 16.153, GO5069_LC
211779577, 129.832844, 17.027141, 15.858, GO5069_LC
211781167, 126.338311, 17.048983, 17.148, GO5069_LC
211783365, 132.724464, 17.080158, 18.966, GO5069_LC
211792469, 131.100596, 17.209303, 19.4, GO5069_LC
211820288, 133.705015, 17.604445, 16.241, GO5034_LC|GO5069_LC
211826447, 129.329082, 17.691877, 16.015, GO5069_LC
211842208, 127.047876, 17.911518, 16.96, GO5069_LC
211879654, 136.66732, 18.430836, 17.159, GO5069_LC
211884856, 135.040218, 18.506365, 17.731, GO5069_LC
211888680, 135.592859, 18.561109, 18.828, GO5069_LC
211889811, 126.924956, 18.577093, 19.318, GO5069_LC
211891454, 128.314488, 18.600625, 16.029, GO5069_LC
211891936, 135.028211, 18.607945, 15.292, GO5069_LC
211898723, 126.109491, 18.707973, 17.486, GO5069_SC|GO5069_LC
211913888, 129.278364, 18.932351, 16.174, GO5057_LC|GO5069_LC
211917094, 130.299796, 18.981897, 18.522, GO5069_LC
211918301, 125.318282, 18.999469, 16.075, GO5069_LC
211933496, 132.014886, 19.22796, 15.414, GO5069_LC
211934548, 135.485598, 19.243553, 17.586, GO5069_LC
211966067, 136.798251, 19.717249, 17.397, GO5069_LC
211968795, 133.89877, 19.757556, 19.554, GO5069_LC
211971021, 123.41208, 19.792278, 16.76, GO5069_LC
211988670, 123.733947, 20.071161, 17.206, GO5069_LC
212010186, 133.010155, 20.423592, 15.505, GO5069_LC
212029063, 124.318119, 20.738879, 19.835, GO5069_LC
212066778, 128.354265, 21.397469, 16.976, GO5069_LC
212074806, 127.358473, 21.544224, 17.953, GO5069_LC
212083439, 134.335153, 21.704798, 17.823, GO5069_LC
212099502, 130.481684, 22.011319, 15.868, GO5069_LC
212106005, 127.887032, 22.13912, 18.025, GO5069_LC
212106539, 131.062579, 22.149725, 17.701, GO5069_LC
212130982, 134.508809, 22.638194, 13.501, GO5069_LC
212133146, 126.718154, 22.681678, 15.386, GO5069_LC
212143308, 132.13856, 22.890562, 16.395, GO5069_LC
212143841, 130.512413, 22.901846, 17.248, GO5069_LC
212144370, 126.651216, 22.913041, 19.071, GO5069_LC
212160442, 130.161762, 23.26397, 11.628, GO5069_SC|GO5033_LC|GO5057_LC|GO5069_LC|GO5060_LC
212168575, 128.286685, 23.452719, 14.033, GO5069_LC
228682496, 127.9628677, 13.8716402, 19.15, GO5069_LC
228682497, 125.8879013, 21.5707798, 20.17, GO5069_LC
228682498, 127.3170929, 22.1871109, 17.98, GO5069_LC
228682499, 133.4813538, 19.0416203, 18.08, GO5069_LC
228682500, 124.9187927, 17.6254196, 18.87, GO5069_LC
228682501, 135.3500061, 19.2611103, 19.89, GO5069_LC
228682502, 136.0469818, 18.3621807, 19.94, GO5069_LC
228682503, 133.0038147, 16.9683609, 20.01, GO5069_LC
228682504, 123.8872681, 19.4362202, 20.11, GO5069_LC
228682505, 135.351593, 19.2610607, 20.13, GO5069_LC
228682506, 127.9470901, 19.4159107, 20.18, GO5069_LC
228682507, 129.7155609, 22.2782707, 20.18, GO5069_LC
228682508, 126.5645523, 17.1967201, 20.22, GO5069_LC
228682509, 126.1568985, 21.4959393, 20.22, GO5069_LC
228682510, 132.1858978, 20.4085407, 20.25, GO5069_LC
228682511, 132.3443451, 19.9701405, 20.29, GO5069_LC
228682512, 127.3123627, 18.9354305, 20.31, GO5069_LC
228682513, 129.1518707, 20.1652508, 20.36, GO5069_LC
228682514, 123.4091492, 19.2470398, 20.43, GO5069_LC
228682515, 126.2561111, 21.5693302, 20.46, GO5069_LC
228682516, 123.1126404, 19.2214298, 20.81, GO5069_LC