# Summary of K2 Program GO12111

Title: The grand K2 RR Lyrae survey

PI: Molnar, Laszlo (Konkoly Observatory)
CoIs: Kollmeier, Juna A; Plachy, Emese; Szabo, Robert; Netzel, Henryka; Magnier, Eugene A; Smolec, Radoslaw; Pal, Andras; Flewelling, Heather A; Kolenberg, Katrien

RR Lyrae stars play a crucial role in astrophysics as standard candles, tracers of galactic history, and touchstones for modeling 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.
Throughout the K2 Mission we have been building up a unique database of high precision RR Lyrae light curves from field to field, covering different parts of our Galaxy, and beyond. Our strategy assures that galactic structure studies and statistical analysis of pulsation properties (double-mode pulsation, Blazhko modulation, period doubling, low-dimensional chaos, non-radial modes) based on K2 data will be possible. Besides the ensemble studies, the boutique analysis of individual stars will be equally interesting and important. 

Targets
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Field 11 covers parts of the bulge where tens of thousands of RR Lyrae stars reside. For this proposal we selected about 1200 stars based on the OGLE-IV survey and an additional 400 stars from other sources covering the rest of the field of view. The OGLE survey discovered many stars with peculiar pulsation and modulation properties. Low-amplitude additional modes have been observed in all RR Lyrae subtypes, but their origins and occurrence rates are still largely unknown. We also included modulated RRc stars in the list. While the Blazhko effect in fundamental-mode stars has been studied extensively from space, the sample of modulated RRc stars is still scarce.  

In Field 12 we selected about 200 stars. 8 RR Lyrae stars were previously observed during the K2-E2 Engineering Test run, including a fundamental-mode star where we tentatively identified a frequency component as a g-mode signal. Re-observation of these targets present a unique opportunity to reassess our earlier findings that were based on only 9 days of data. It will also show us how did the accuracy of Kepler evolve since the early tests.  
For a number of RR Lyrae stars extensive multicolor photometry is available from the Pan-STARRS Medium Deep Field survey. The detailed color information will be a valuable addition to the K2 light curves. Beside the RR Lyrae stars, we also found an additional 30 variables belonging to various classes that we also include in this proposal.   

Field 13, towards the Galactic anticenter direction, contains 103 known RR Lyrae stars. One priority target here is BR Tau that has a short modulation period of only ~19 days. 

Methods and planned community resources
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Standard time-frequency analysis (by e.g. Period04) and study of time-dependent features are envisaged. Metallicities will be derived from empirical relations calibrated with high-resolution spectra. State-of-the-art numerical hydrocodes (Florida-Budapest, Warsaw) will be used to interpret the results. Synthetic galactic models (TRILEGAL) will be used to compare the galactic location and number of the observed sample with simulations.
Photometry of large-amplitude pulsators require special treatment, and general-purpose pipelines may provide RR Lyrae light curves with sub-optimal quality. We already released tailor-made photometry from some Kepler data sets. We intend to create custom light curves for the stars listed in this proposal too, and plan to employ special methods like differential-image photometry for the bulge field. As a value-added community resource we envisage a searchable database containing the light curves, frequency solutions and other parameters (Blazhko periods, additional modes, etc.) of the RR Lyrae stars observed by K2.

# Targets requested by this program that have been observed (161)
EPIC ID, RA (J2000) [deg], Dec (J2000) [deg], magnitude, Investigation IDs
206432153, 343.889742, -6.098094, 15.057, GO12111_LC
245915449, 352.579017, -12.535008, 15.088, GO12111_LC
245930016, 353.61076, -11.716294, 18.036, GO12111_LC
245941200, 352.96392, -11.168787, 18.357, GO12111_LC
245945883, 353.948316, -10.990382, 13.852, GO12111_LC
245950399, 349.088416, -10.842915, 17.206, GO12111_LC
245954410, 354.403294, -10.71607, 15.874, GO12111_LC
245960344, 349.352269, -10.547592, 15.174, GO12111_LC
245962939, 355.377388, -10.474741, 16.657, GO12111_LC
245963638, 349.523027, -10.454732, 20.04, GO12111_LC
245964413, 348.276178, -10.433694, 16.908, GO12111_LC
245965362, 355.653607, -10.408348, 17.371, GO12111_LC
245970988, 352.352886, -10.253063, 18.088, GO12111_LC
245974758, 349.306822, -10.148914, 17.681, GO12111_LC|GO12111_SC
245979174, 355.264236, -10.031159, 17.361, GO12111_LC
245983480, 354.095647, -9.914525, 17.031, GO12111_LC
245984157, 354.575088, -9.896091, 16.959, GO12111_LC
245984456, 351.879873, -9.887698, 17.624, GO12111_LC
245986522, 346.623662, -9.831737, 16.561, GO12111_LC
245992976, 353.846807, -9.664082, 18.343, GO12111_LC
245993700, 353.80128, -9.645191, 14.616, GO12111_LC
245993724, 351.227498, -9.64455, 15.798, GO12019_LC|GO12111_LC
246003196, 353.790833, -9.403178, 19.128, GO12111_LC
246004530, 346.658772, -9.370095, 16.441, GO12111_LC
246004916, 354.033766, -9.35923, 16.705, GO12111_LC
246006501, 354.637038, -9.31874, 10.863, GO12052_LC|GO12111_LC
246011239, 354.342618, -9.197251, 17.984, GO12111_LC
246014035, 347.646827, -9.125988, 17.197, GO12111_LC
246024126, 345.979515, -8.872959, 18.064, GO12111_LC
246024360, 354.253218, -8.867177, 17.354, GO12111_LC
246031813, 350.031492, -8.675023, 18.125, GO12111_LC
246041776, 350.800235, -8.442142, 19.328, GO12111_LC
246045130, 353.049314, -8.364836, 14.99, GO12111_LC
246046601, 355.303527, -8.332024, 16.669, GO12111_LC
246050597, 350.74918, -8.242527, 16.228, GO12111_LC
246054790, 345.480076, -8.147005, 15.996, GO12111_LC
246058914, 351.421022, -8.050081, 16.891, GO12111_LC|GO12111_SC
246060557, 350.891766, -8.012499, 14.146, GO12111_LC
246061984, 352.928867, -7.980541, 16.881, GO12111_LC
246064096, 346.32426, -7.931661, 15.198, GO12111_LC
246068203, 353.515401, -7.839976, 15.068, GO12111_LC|GO12040_LC
246069268, 346.002718, -7.816139, 17.228, GO12111_LC
246075393, 358.50556, -7.677495, 12.022, GO12019_LC|GO12111_LC|GO12122_LC
246078531, 348.985826, -7.607162, 17.871, GO12111_LC
246081582, 350.296427, -7.540005, 16.912, GO12111_LC
246084693, 356.48302, -7.47259, 15.818, GO12111_LC|GO12902_LC|GO12903_LC
246101889, 350.216283, -7.100666, 17.388, GO12111_LC
246103409, 345.703182, -7.067511, 13.723, GO12111_LC|GO12122_LC
246111572, 345.546418, -6.885955, 15.459, GO12111_LC
246115789, 349.902713, -6.795892, 14.714, GO12111_LC
246122912, 347.936611, -6.641968, 18.304, GO12111_LC
246128960, 348.400286, -6.511743, 14.997, GO12111_LC
246136316, 344.687369, -6.354664, 14.537, GO12111_LC
246138672, 349.959528, -6.303252, 19.773, GO12111_LC
246138791, 349.530292, -6.300711, 14.986, GO12111_LC
246182115, 353.115223, -5.393144, 15.089, GO12111_LC|GO12902_LC|GO12903_LC
246184278, 351.790434, -5.348135, 19.205, GO12111_LC
246184470, 347.979897, -5.343851, 15.789, GO12111_LC
246194263, 350.254972, -5.14018, 16.75, GO12111_LC
246204836, 352.993268, -4.924227, 17.323, GO12111_LC|GO12902_LC|GO12903_LC
246209002, 347.372057, -4.840597, 17.28, GO12111_LC
246212379, 348.227247, -4.771691, 17.698, GO12111_LC
246213473, 351.017124, -4.749263, 14.2, GO12111_LC
246214672, 348.207467, -4.724429, 17.034, GO12111_LC
246217239, 347.587202, -4.672107, 16.798, GO12111_LC
246217656, 358.145557, -4.66419, 17.465, GO12111_LC
246222564, 358.022886, -4.570943, 16.147, GO12111_LC
246233565, 353.955135, -4.360739, 16.978, GO12111_LC
246234034, 354.339916, -4.351035, 16.214, GO12111_LC
246249667, 348.205401, -4.054202, 17.221, GO12111_LC
246249944, 348.476472, -4.048925, 17.113, GO12111_LC
246255932, 350.325172, -3.934629, 13.665, GO12111_LC|GO12122_LC
246256076, 347.861973, -3.931681, 15.297, GO12019_LC|GO12111_LC
246260319, 350.032829, -3.853071, 17.049, GO12111_LC
246266488, 348.397886, -3.735633, 17.111, GO12111_LC
246266581, 349.260498, -3.733602, 16.203, GO12111_LC
246271889, 354.87639, -3.630888, 12.728, GO12111_LC|GO12122_LC|GO12902_LC|GO12903_LC
246272964, 347.662737, -3.607772, 14.021, GO12111_LC|GO12111_SC
246280947, 353.746435, -3.443639, 19.186, GO12111_LC
246283185, 350.970209, -3.400761, 17.523, GO12111_LC
246300909, 345.180131, -3.047583, 14.764, GO12111_LC|GO12111_SC
246302440, 347.911485, -3.018344, 13.943, GO12111_LC
246311689, 348.873056, -2.828779, 18.332, GO12111_LC
246318453, 350.811599, -2.693269, 15.064, GO12111_LC
246323447, 349.196562, -2.594604, 15.519, GO12019_LC|GO12111_LC
246326642, 346.975792, -2.532331, 18.956, GO12111_LC
246328599, 350.223366, -2.493834, 16.479, GO12111_LC
246330087, 351.045731, -2.465437, 19.454, GO12111_LC
246337452, 351.774934, -2.31796, 18.194, GO12111_LC|GO12902_LC|GO12903_LC
246340736, 344.930306, -2.253368, 18.768, GO12111_LC
246342589, 349.748566, -2.216919, 16.241, GO12111_LC
246342837, 354.155923, -2.212427, 12.873, GO12050_LC|GO12111_LC|GO12122_LC|GO12071_LC|GO12902_LC|GO12903_LC
246356898, 352.166251, -1.937302, 18.989, GO12111_LC
246360595, 353.195199, -1.864128, 17.839, GO12111_LC
246361328, 344.523655, -1.849862, 17.572, GO12111_LC
246362540, 349.343205, -1.825979, 16.46, GO12111_LC
246362864, 349.615416, -1.819754, 15.199, GO12019_LC|GO12111_LC
246363180, 350.414507, -1.813892, 18.074, GO12111_LC
246368257, 352.488838, -1.716816, 18.267, GO12111_LC
246369173, 351.862421, -1.698859, 19.255, GO12111_LC
246378494, 345.685962, -1.515127, 17.317, GO12111_LC
246379528, 353.426625, -1.494322, 15.441, GO12019_LC|GO12111_LC|GO12902_LC
246379593, 352.867167, -1.493294, 19.813, GO12111_LC
246383793, 352.241019, -1.408066, 14.322, GO12111_LC
246388977, 351.385854, -1.304263, 19.475, GO12111_LC
246391384, 352.925925, -1.24972, 17.71, GO12111_LC
246393886, 353.123909, -1.177149, 16.022, GO12111_LC|GO12042_LC|GO12022_LC
246396334, 347.854165, -1.108033, 16.072, GO12111_LC
246396790, 348.643133, -1.094449, 17.968, GO12111_LC
246398262, 352.251401, -1.050725, 15.743, GO12111_LC
246401629, 348.098327, -0.947137, 19.093, GO12111_LC
246406635, 352.604326, -0.790209, 18.459, GO12111_LC
246407820, 351.758305, -0.754435, 15.469, GO12111_LC
246408673, 351.913666, -0.729625, 12.164, GO12111_LC|GO12122_LC|GO12071_LC
246411315, 351.926625, -0.645729, 15.417, GO12111_LC|GO12123_LC
246421164, 352.64177, -0.337903, 16.051, GO12111_LC
246425340, 352.976819, -0.205945, 18.468, GO12111_LC
246427702, 352.776841, -0.126747, 16.866, GO12111_LC
246433273, 350.861028, 0.052891, 18.378, GO12111_LC
246434480, 352.604929, 0.089755, 17.349, GO12111_LC
246434558, 350.11716, 0.091926, 17.15, GO12111_LC
246437545, 352.701057, 0.183797, 17.048, GO12111_LC
246453655, 348.553039, 0.696813, 16.184, GO12111_LC
246455590, 351.832019, 0.762808, 15.452, GO12111_LC|GO12123_LC
246456572, 351.671586, 0.795609, 15.659, GO12111_LC|GO12123_LC|GO12902_LC|GO12903_LC
246456810, 348.462041, 0.804751, 18.509, GO12111_LC
246459054, 350.405935, 0.879516, 18.362, GO12111_LC
246463406, 352.163747, 1.028546, 15.533, GO12111_LC|GO12902_LC|GO12903_LC|GO12111_SC
246476873, 349.818122, 1.440812, 15.311, GO12111_LC
251455748, , , , GO12111_LC|GO12013_LC
251456074, , , , GO12111_LC|GO12013_LC
251456127, , , , GO12111_LC|GO12013_LC
251456807, , , , GO12111_LC
251456808, , , , GO12111_LC
251456810, , , , GO12111_LC
251456811, , , , GO12111_LC
251456812, , , , GO12111_LC
251456813, , , , GO12111_LC
251456814, , , , GO12111_LC
251456815, , , , GO12111_LC
251456816, , , , GO12111_LC
251456818, , , , GO12111_LC
251456819, , , , GO12111_LC
251456820, , , , GO12111_LC
251456821, , , , GO12111_LC
251456822, , , , GO12111_LC
251456823, , , , GO12111_LC
251456825, , , , GO12111_LC
251456829, , , , GO12111_LC
251456830, , , , GO12111_LC
251456831, , , , GO12111_LC
251456833, , , , GO12111_LC
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251456835, , , , GO12111_LC
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251456837, , , , GO12111_LC
251456839, , , , GO12111_LC
251456840, , , , GO12111_LC
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251456844, , , , GO12111_LC