# Summary of K2 Program GO6082

Title: Investigating different populations of RR Lyrae stars with K2

PI: Kolenberg, Katrien (University of Vienna)
CoIs: Szabo, Robert; Molnar, Laszlo; Plachy, Emese; Banyai, Evelin

ABSTRACT:  RR Lyrae stars play a crucial role in astrophysics as standard candles, tracers of galactic history, and touchstones for modelling stellar pulsations. Space data of these crucial objects have led to a giant leap forward in our understanding of their structure and evolution, through the discovery of new dynamical phenomena. Moreover, insight into these stars dynamics is of crucial importance to advance our knowledge of galaxy formation and evolution in the Local Group of galaxies and beyond. In this proposal we plan to study roughly 200-200 RR Lyrae stars in long cadence and 5-5 in short cadence in K2 Fields 6&7. Field 7 contains both galactic RR Lyraes and members of the Sagittarius (Sgr) stream (Cseresnjes 2011, A&A 375, 909), and offers a unique chance to study two distinctly different populations. Moreover, K2's unique long, uninterrupted, high-precision space photometry, allows us conduct galactic structure studies and to improve our understanding of RR Lyrae pulsation and dynamics.

RESEARCH GOALS: 1. Throughout the K2 Mission we are building up a unique database from field to field covering different parts of our Galaxy and beyond (the Sgr dwarf galaxy in Field 7). Such an unprecedented photometric RR Lyrae sample will form the base of galactic structure studies and near-field cosmology. We will study the Galactic structure and history by obtaining distances to RR Lyrae stars and determine their spatial distribution (halo streams, over-densities). 2. The samples of K2 RR Lyrae data allow for a 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. (In the nominal Kepler mission we had around 50 RR Lyrae stars on silicon.) 3. We will perform a detailed analysis of 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 studied in detail only in large-amplitude stars and with space photometry.

METHODS: We produce light curves from target pixel data (PyKE and own software), then apply corrections, trend-filtering, outlier removal, etc. Standard time-frequency analysis (by e.g. Period04) and study of time-dependent features are envisaged. We derive metallicities from empirical relations using the light curve shapes and spectroscopic observations. State-of-the-art numerical hydrocodes (Florida-Budapest, Warsaw) will help to interpret the results. Synthetic galactic models (TRILEGAL) will be used to compare the galactic location and number of the observed sample with simulations. Targets. ~200 RR Lyrae stars will be proposed per field (5-5 for short cadence observations). Due to their distances, RR Lyrae stars are faint, the majority between 15-19 Kepler mag.

EXPERIENCE: Our team consists of members of the Working Group#7 (RR Lyrae and Cepheids) of the Kepler Asteroseismic Science Consortium, who have been working on Kepler data (also preparation and target selection) since the launch of the nominal mission. We have experts on data reduction, pixel photometry, light curve and time-frequency analysis, as well as theorists performing numerical hydrodynamical modeling. We routinely analyzed Kepler data, developed dedicated software to Kepler light curves and published 15+ Kepler RR Lyrae papers in high-impact journals. The group has access to ground-based follow-up (multi-color photometric and spectroscopic) instruments in Taiwan, Korea, and Hungary to complement space-based observations.

# Targets requested by this program that have been observed (206)
EPIC ID, RA (J2000) [deg], Dec (J2000) [deg], magnitude, Investigation IDs
212283691, 206.9730682, -18.028883, 16.747, GO6082_LC
212291374, 207.9161987, -17.7944794, 18.036, GO6082_LC
212291532, 201.9842987, -17.789854, 15.064, GO6082_LC
212304480, 203.3216705, -17.3947906, 14.967, GO6082_LC
212308231, 207.8339539, -17.2856178, 15.642, GO6082_LC
212309712, 204.7882996, -17.241993, 16.749, GO6040_LC|GO6082_LC
212314501, 208.2944641, -17.1011276, 15.722, GO6082_LC
212316775, 205.2556305, -17.0378933, 15.368, GO6040_LC|GO6082_LC
212321981, 206.651825, -16.8898697, 15.119, GO6040_LC|GO6082_LC
212329006, 200.5141296, -16.6933117, 17.246, GO6040_LC|GO6082_LC
212330039, 200.8888702, -16.6660824, 11.47, GO6030_LC|GO6040_LC|GO6082_LC|GO6086_LC
212334136, 208.10495, -16.5545177, 15.421, GO6082_LC
212335761, 206.6337128, -16.5093231, 14.309, GO6082_LC
212335848, 201.229599, -16.5073013, 17.796, GO6040_LC|GO6082_LC
212340130, 204.1108551, -16.3926144, 16.561, GO6040_LC|GO6082_LC
212343739, 205.1958923, -16.2973137, 18.179, GO6040_LC|GO6082_LC
212346963, 201.3938446, -16.2109032, 17.463, GO6082_LC
212347262, 200.5423279, -16.2025509, 17.637, GO6040_LC|GO6082_LC
212350320, 201.4557953, -16.1231976, 15.656, GO6082_LC
212352472, 201.9226685, -16.0655441, 16.318, GO6040_LC|GO6082_LC
212359295, 201.1301117, -15.8918467, 13.68, GO6030_LC|GO6040_LC|GO6082_LC
212367422, 202.4551849, -15.6883087, 15.878, GO6040_LC|GO6082_LC
212379137, 211.3980255, -15.4020433, 14.527, GO6082_LC
212384541, 210.3721466, -15.2719059, 16.112, GO6082_LC
212385200, 211.17099, -15.2552299, 17.888, GO6082_LC
212389345, 211.3885803, -15.1600828, 16.546, GO6082_LC
212390066, 204.6804657, -15.1424942, 15.756, GO6082_LC
212394562, 204.155304, -15.0392027, 17.529, GO6082_LC
212400021, 205.5872955, -14.9137783, 15.992, GO6082_LC
212404864, 204.3618011, -14.8024902, 17.754, GO6040_LC|GO6082_LC
212407078, 202.5437317, -14.7524061, 14.147, GO6082_LC
212409299, 211.1568451, -14.7024469, 14.772, GO6082_LC
212412494, 201.9409027, -14.6298847, 16.359, GO6082_LC
212417417, 202.5108948, -14.5189505, 15.496, GO6040_LC|GO6082_LC
212417452, 203.4745483, -14.5182667, 16.971, GO6082_LC
212419731, 202.1033325, -14.4687948, 14.87, GO6040_LC|GO6082_LC
212421319, 203.4463196, -14.4334145, 16.407, GO6040_LC|GO6082_LC
212425817, 204.7328186, -14.33253, 16.684, GO6040_LC|GO6082_LC
212426424, 202.5080719, -14.3178434, 16.86, GO6040_LC|GO6082_LC
212430801, 210.1286163, -14.2211208, 15.489, GO6082_LC
212441076, 199.454422, -13.9947367, 14.847, GO6040_LC|GO6082_LC
212447818, 210.9787598, -13.8489323, 19.893, GO6082_LC
212448152, 203.9229279, -13.8418694, 17.948, GO6040_LC|GO6082_LC
212449019, 197.4515686, -13.822896, 16.321, GO6082_LC
212450283, 204.9393005, -13.7962847, 15.891, GO6082_LC
212451472, 205.4811554, -13.7710752, 15.761, GO6082_LC
212453596, 205.086853, -13.7246914, 16.109, GO6082_LC
212453656, 204.7658691, -13.7234287, 15.745, GO6082_LC
212455160, 204.4464111, -13.6915226, 17.98, GO6082_LC
212457000, 210.7612305, -13.6500778, 16.808, GO6082_LC
212459957, 205.8011475, -13.5891323, 15.503, GO6082_LC
212462263, 204.2446747, -13.5388203, 17.564, GO6082_LC
212463159, 204.3397369, -13.520896, 16.31, GO6082_LC
212463213, 198.9810486, -13.5198088, 14.966, GO6016_LC|GO6040_LC|GO6082_LC
212466080, 203.6159821, -13.4594698, 17.456, GO6082_LC
212469563, 197.9351501, -13.3849163, 14.847, GO6082_LC
212472092, 198.776535, -13.3321466, 17.592, GO6082_LC
212476743, 199.6837311, -13.2354412, 16.906, GO6082_LC
212502064, 201.4602661, -12.6905785, 9.671, GO6030_LC|GO6069_LC|GO6082_LC|GO6086_LC|GO6087_LC
212504059, 199.2380066, -12.6481504, 11.601, GO6030_LC|GO6082_LC|GO6087_LC
212507302, 207.1640778, -12.5788679, 17.521, GO6082_LC
212511413, 206.633255, -12.4903374, 18.037, GO6082_LC
212521177, 205.5338745, -12.2842503, 17.753, GO6040_LC|GO6082_LC
212521298, 206.7632141, -12.2816553, 17.844, GO6082_LC
212522016, 206.8797607, -12.266881, 17.498, GO6082_LC
212524664, 206.8722229, -12.2112112, 13.738, GO6030_LC|GO6040_LC|GO6082_LC
212532316, 203.9969635, -12.0455494, 16.228, GO6082_LC
212532428, 202.1935272, -12.0431442, 16.279, GO6040_LC|GO6082_LC
212534342, 205.6269531, -12.0018368, 17.713, GO6082_LC
212535351, 207.8858185, -11.9812384, 16.356, GO6082_LC
212540092, 203.8707581, -11.8856707, 17.92, GO6082_LC
212544488, 201.076889, -11.7928429, 16.978, GO6040_LC|GO6082_LC
212545143, 207.8940125, -11.777832, 17.791, GO6082_LC
212547473, 204.2092743, -11.7283354, 16.16, GO6040_LC|GO6082_LC|GO6082_SC
212555023, 205.7684326, -11.5681448, 16.277, GO6040_LC|GO6082_LC
212562649, 204.7078857, -11.401021, 17.973, GO6040_LC|GO6082_LC
212571112, 204.8252716, -11.2208023, 17.28, GO6082_LC
212571247, 208.9153748, -11.2177839, 16.097, GO6040_LC|GO6082_LC
212575343, 208.7414246, -11.1280489, 13.691, GO6040_LC|GO6082_LC
212575799, 197.9002838, -11.1177912, 15.277, GO6082_LC
212579424, 197.8574066, -11.0425539, 17.443, GO6082_LC
212585135, 204.8157196, -10.9163561, 17.778, GO6040_LC|GO6082_LC
212589131, 209.0255432, -10.8321247, 16.115, GO6040_LC|GO6082_LC
212595129, 199.2252502, -10.6993456, 14.441, GO6040_LC|GO6082_LC
212597328, 204.59021, -10.6499109, 18.187, GO6082_LC
212597399, 206.1784821, -10.6485348, 18.17, GO6082_LC
212597645, 205.033844, -10.6427622, 11.459, GO6030_LC|GO6069_LC|GO6082_LC
212598683, 198.2983856, -10.6180277, 16.096, GO6082_LC
212603999, 202.3020782, -10.4991627, 15.443, GO6082_LC
212606890, 204.7934723, -10.4334078, 15.9, GO6040_LC|GO6082_LC
212607355, 202.1547546, -10.4233522, 17.372, GO6040_LC|GO6082_LC
212612358, 204.9659424, -10.3099184, 15.444, GO6040_LC|GO6082_LC
212613425, 198.5841827, -10.2862654, 16.353, GO6082_LC
212614745, 203.9705963, -10.2558794, 16.672, GO6082_LC
212614766, 199.7694092, -10.2555285, 15.339, GO6040_LC|GO6082_LC
212622156, 211.3177338, -10.0862026, 17.607, GO6082_LC
212626187, 211.0335388, -9.9959087, 15.296, GO6082_LC
212630286, 199.3031921, -9.9009876, 17.726, GO6040_LC|GO6082_LC
212631030, 202.9977417, -9.8841333, 15.377, GO6082_LC
212634341, 208.8648834, -9.8066149, 13.552, GO6032_LC|GO6082_LC
212639395, 201.6233673, -9.690196, 16.928, GO6082_LC
212639932, 199.5865479, -9.6777077, 16.316, GO6082_LC
212640806, 198.3578491, -9.6587791, 15.889, GO6082_LC|GO6082_SC
212643422, 207.8939819, -9.5971174, 16.572, GO6082_LC
212646482, 205.377533, -9.5265102, 15.519, GO6082_LC
212647300, 198.2649078, -9.5070152, 16.7, GO6082_LC
212648408, 211.2419434, -9.481328, 16.558, GO6082_LC
212649058, 206.2090607, -9.4664631, 17.914, GO6082_LC
212652164, 208.9346161, -9.3960762, 17.92, GO6082_LC
212652735, 205.86026, -9.3832827, 18.117, GO6082_LC
212656143, 205.2830353, -9.3048735, 17.871, GO6082_LC
212661557, 210.4731293, -9.178051, 19.762, GO6082_LC
212663528, 203.945755, -9.1314297, 15.278, GO6082_LC
212668141, 208.5868683, -9.0238304, 13.617, GO6030_LC|GO6082_LC
212676020, 201.9743958, -8.8371506, 17.563, GO6040_LC|GO6082_LC
212678942, 201.5572205, -8.7685308, 16.006, GO6040_LC|GO6082_LC
212681681, 208.2313538, -8.7041626, 16.118, GO6040_LC|GO6082_LC
212684145, 200.2303162, -8.646925, 13.644, GO6030_LC|GO6040_LC|GO6082_LC|GO6082_SC
212688460, 201.1383057, -8.542635, 15.237, GO6082_LC
212692525, 208.4310455, -8.4445276, 17.007, GO6082_LC
212693014, 209.0383148, -8.4320288, 17.1, GO6082_LC
212698817, 205.2377625, -8.2894964, 16.087, GO6082_LC
212699568, 210.39328, -8.2714663, 17.86, GO6082_LC
212699845, 206.3618164, -8.2640924, 17.389, GO6082_LC
212707714, 209.3441467, -8.0693293, 15.041, GO6082_LC
212712239, 199.2264709, -7.9583211, 17.657, GO6082_LC
212717166, 202.2771606, -7.8354921, 16.262, GO6082_LC
212719863, 199.1981049, -7.768507, 17.418, GO6082_LC
212724347, 198.8944855, -7.6526341, 15.458, GO6040_LC|GO6082_LC
212725898, 200.3707123, -7.6133161, 18.002, GO6082_LC
212725978, 202.0682983, -7.6113968, 15.089, GO6040_LC|GO6082_LC
212726491, 204.5612946, -7.598743, 18.101, GO6082_LC
212727382, 203.619278, -7.5753512, 15.782, GO6082_LC
212733673, 202.5197906, -7.4160762, 15.876, GO6082_LC
212734072, 204.3340302, -7.4059691, 18.069, GO6082_LC
212746631, 209.2340546, -7.0710878, 18.233, GO6082_LC
212753920, 201.7888031, -6.8711748, 18.154, GO6082_LC
212755221, 207.3382416, -6.8336349, 14.681, GO6082_LC
212763021, 205.964325, -6.6147642, 16.236, GO6082_LC
212763847, 209.1501465, -6.5915842, 19.366, GO6082_LC
212765214, 209.022644, -6.552536, 17.884, GO6082_LC
212766147, 199.3987274, -6.525506, 17.422, GO6082_LC
212767731, 203.7511139, -6.4816499, 18.265, GO6040_LC|GO6082_LC
212773156, 203.2146912, -6.3271441, 16.0, GO6040_LC|GO6082_LC
212775050, 205.1661072, -6.2699409, 16.256, GO6082_LC
212780441, 206.5960541, -6.1116791, 17.076, GO6082_LC
212784103, 208.0542603, -6.0040278, 17.474, GO6082_LC
212785152, 207.6932831, -5.975338, 15.295, GO6082_LC
212788477, 202.3436737, -5.883142, 11.761, GO6030_LC|GO6040_LC|GO6054_LC|GO6082_LC|GO6086_LC|GO6082_SC
212788540, 205.4754028, -5.8815622, 17.071, GO6082_LC
212789652, 205.1361542, -5.8500309, 13.764, GO6030_LC|GO6082_LC
212789806, 209.0077057, -5.8454041, 17.775, GO6082_LC
212791383, 203.0880127, -5.8003221, 15.933, GO6082_LC
212795516, 207.7886963, -5.6773829, 17.724, GO6082_LC
212801866, 209.0554352, -5.4838238, 15.74, GO6082_LC
212802166, 207.3288422, -5.47539, 17.139, GO6082_LC
212808200, 202.0995026, -5.2857828, 13.259, GO6030_LC|GO6040_LC|GO6082_LC|GO6082_SC
212809223, 208.9995117, -5.2540712, 16.551, GO6082_LC
212814000, 208.0185852, -5.103137, 14.807, GO6082_LC
212814577, 207.3954468, -5.0843568, 19.123, GO6082_LC
212817187, 206.8277435, -5.000391, 18.798, GO6082_LC
212817671, 202.4692688, -4.9842062, 16.302, GO6082_LC
212821726, 203.4610748, -4.852562, 17.193, GO6082_LC
212821891, 208.1152191, -4.8472352, 14.94, GO6082_LC
212824246, 204.93396, -4.7664452, 14.077, GO6082_LC
212827898, 201.8995209, -4.6434808, 14.427, GO6082_LC
212831202, 204.870224, -4.531858, 16.095, GO6082_LC
212832929, 203.3832092, -4.4685488, 18.193, GO6082_LC
212833339, 204.0895844, -4.4541311, 13.8, GO6032_LC|GO6082_LC
229228086, 201.0461, -10.51462, 17.36, GO6082_LC
229228087, 200.61754, -6.914, 17.63, GO6082_LC
229228088, 200.33333, -15.334167, 17.67, GO6082_LC
229228089, 208.51797, -10.91143, 17.68, GO6082_LC
229228090, 198.98183, -14.21586, 18.14, GO6082_LC
229228091, 203.98717, -13.87589, 18.24, GO6082_LC
229228092, 202.97855, -8.56411, 18.74, GO6082_LC
229228093, 203.50414, -5.26213, 18.86, GO6082_LC
229228094, 205.39583, -6.520556, 18.94, GO6082_LC
229228095, 203.94513, -5.21726, 18.95, GO6082_LC
229228096, 207.49019, -12.35085, 19.08, GO6082_LC
229228097, 199.47917, -7.533611, 19.12, GO6082_LC
229228098, 202.47981, -8.76642, 19.15, GO6082_LC
229228099, 201.27911, -8.18636, 19.16, GO6082_LC
229228100, 205.36667, -11.509167, 19.29, GO6082_LC
229228101, 206.05179, -7.82381, 19.35, GO6082_LC
229228102, 199.60233, -8.84373, 19.38, GO6082_LC
229228103, 205.6899, -7.91425, 19.45, GO6082_LC
229228104, 208.73276, -10.89219, 19.5, GO6082_LC
229228105, 200.31116, -8.53534, 19.61, GO6082_LC
229228106, 211.04216, -13.77503, 19.69, GO6082_LC
229228107, 201.80956, -6.08786, 19.79, GO6082_LC
229228108, 210.57095, -10.07672, 19.99, GO6082_LC
229228109, 207.17905, -9.0275, 20.02, GO6082_LC
229228110, 203.30931, -9.13991, 20.28, GO6082_LC
229228111, 201.9625, -15.879167, 17.91, GO6082_LC
229228112, 198.51846, -10.43836, 17.94, GO6082_LC
229228113, 205.00833, -17.227777, 18.2, GO6082_LC
229228114, 199.62917, -10.977222, 18.34, GO6082_LC
229228115, 206.00417, -10.947778, 19.01, GO6082_LC
229228116, 200.30417, -6.783056, 19.11, GO6082_LC
229228117, 205.41026, -5.51515, 19.18, GO6082_LC
229228118, 204.6875, -4.660556, 19.3, GO6082_LC
229228119, 202.4027, -10.1178, 20.48, GO6082_LC
229228120, 210.15416, -13.935833, 17.63, GO6082_LC
229228121, 202.975, -11.276944, 17.77, GO6082_LC
229228122, 209.39166, -13.741389, 19.17, GO6082_LC