# Summary of K2 Program GO13047

Title: Asteroseismology of the Brightest K2 Stars

PI: Huber, Daniel (SETI Institute)
CoIs: White, Timothy R; Pope, Benjamin James Spinks; Aerts, Conny Clara; Bedding, Tim; Silva Aguirre, Victor

The most powerful tests of stellar structure and evolution come from the brightest stars in the night sky, for which complementary observational techniques (such as astrometry, asteroseismology, and interferometry) can be combined. So far, stars brighter than Kp < 6 mag were rarely observed with Kepler/K2 due to the large number of pixels required to capture the saturated pixel columns. We propose K2 long-cadence observations of the brightest K2 stars in campaigns 11-13 (including 36 Oph, the brightest K dwarf observable by K2) using a novel technique which uses a small number of unsaturated pixels. Asteroseismic studies of these targets will allow unprecedented tests of asteroseismic scaling relations for giants and insights into poorly understood internal processes of intermediate-mass stars such as convective core overshooting.

We selected 54 targets with Kp < 6.0 mag from the Hipparcos catalog. We will use small (~20x20 pixel) circular apertures around the saturated core for each target, and perform photometry using weighted sums of unsaturated pixels in the wings of the circular aperture. The method (so-called halo photometry) has been demonstrated to detect pulsations for all bright Pleiades and Hyades stars observed in Campaign 4. We will also organize spectroscopic and interferometric follow-up observations that will be combined with the K2 photometry.

Our proposal addresses fundamental stellar astrophysics, a key science goal of the K2 mission. Our project furthermore supports galactic astrophysics, another key science area identified in the NRA, through the calibration of scaling relations for galactic archeology studies. A better understanding of stellar models through the study of bright stars is relevant for science goals pursued by both present and future NASA missions such as the characterization of exoplanets (TESS, JWST) as well as stellar populations and galaxy formation/evolution (HST, JWST).

# Targets requested by this program that have been observed (56)
EPIC ID, RA (J2000) [deg], Dec (J2000) [deg], magnitude, Investigation IDs
200173843, , , , GO13047_LC
200173844, , , , GO13023_LC|GO13039_LC|GO13047_LC|GO13077_LC|GO13083_LC|GO13085_LC
200173845, , , , GO13023_LC|GO13025_LC|GO13039_LC|GO13047_LC|GO13077_LC|GO13122_LC
200173846, , , , GO13023_LC|GO13039_LC|GO13047_LC|GO13077_LC|GO13083_LC
200173847, , , , GO13023_LC|GO13039_LC|GO13047_LC|GO13077_LC
200173848, , , , GO13023_LC|GO13039_LC|GO13047_LC|GO13077_LC|GO13122_LC
200173849, , , , GO13023_LC|GO13036_LC|GO13039_LC|GO13047_LC|GO13077_LC
200173850, , , , GO13047_LC|GO13122_LC|GO13127_LC
200173851, , , , GO13023_LC|GO13039_LC|GO13047_LC|GO13077_LC|GO13122_LC
200173852, , , , GO13039_LC|GO13047_LC
200173853, , , , GO13047_LC|GO13122_LC
200173854, , , , GO13047_LC|GO13122_LC
200173855, , , , GO13006_LC|GO13023_LC|GO13025_LC|GO13039_LC|GO13047_LC|GO13077_LC|GO13122_LC
200173856, , , , GO13047_LC
200173857, , , , GO13019_LC|GO13023_LC|GO13039_LC|GO13047_LC|GO13077_LC
200173858, , , , GO13047_LC
200173859, , , , GO13019_LC|GO13023_LC|GO13039_LC|GO13047_LC|GO13077_LC|GO13122_LC
200173860, , , , GO13006_LC|GO13019_LC|GO13023_LC|GO13039_LC|GO13047_LC|GO13077_LC
200173861, , , , GO13019_LC|GO13047_LC|GO13122_LC
200173862, , , , GO13019_LC|GO13047_LC
200173864, , , , GO13019_LC|GO13039_LC|GO13047_LC|GO13122_LC|GO13127_LC
200173865, , , , GO13019_LC|GO13023_LC|GO13039_LC|GO13047_LC|GO13077_LC|GO13122_LC
200173866, , , , GO13019_LC|GO13023_LC|GO13036_LC|GO13039_LC|GO13047_LC|GO13077_LC
200173867, , , , GO13019_LC|GO13023_LC|GO13039_LC|GO13047_LC|GO13077_LC|GO13122_LC
200173868, , , , GO13019_LC|GO13023_LC|GO13039_LC|GO13047_LC|GO13077_LC
200173869, , , , GO13019_LC|GO13047_LC|GO13122_LC|GO13127_LC
200173870, , , , GO13019_LC|GO13039_LC|GO13047_LC|GO13122_LC
200173871, , , , GO13019_LC|GO13047_LC|GO13122_LC|GO13127_LC
200173872, , , , GO13047_LC|GO13123_LC
200173873, , , , GO13019_LC|GO13036_LC|GO13047_LC
200173874, , , , GO13019_LC|GO13024_LC|GO13047_LC|GO13083_LC|GO13122_LC
200173875, , , , GO13019_LC|GO13023_LC|GO13024_LC|GO13039_LC|GO13047_LC|GO13077_LC|GO13122_LC|GO13902_LC|GO13903_LC|GO13904_LC
200173876, , , , GO13047_LC
200173877, , , , GO13019_SC|GO13023_SC|GO13024_SC|GO13039_SC|GO13047_SC|GO13077_SC|GO13122_SC
200173878, , , , GO13002_SC|GO13019_SC|GO13023_SC|GO13039_SC|GO13047_SC|GO13077_SC|GO13122_SC
200173879, , , , GO13023_SC|GO13025_SC|GO13039_SC|GO13047_SC|GO13077_SC|GO13122_SC
200173880, , , , GO13023_SC|GO13039_SC|GO13047_SC|GO13077_SC
200173881, , , , GO13023_SC|GO13039_SC|GO13047_SC|GO13077_SC|GO13122_SC
200173882, , , , GO13023_SC|GO13039_SC|GO13047_SC|GO13077_SC|GO13122_SC
200173883, , , , GO13006_SC|GO13023_SC|GO13025_SC|GO13039_SC|GO13047_SC|GO13077_SC|GO13122_SC
200173884, , , , GO13019_SC|GO13023_SC|GO13039_SC|GO13047_SC|GO13077_SC
200173885, , , , GO13019_SC|GO13023_SC|GO13039_SC|GO13047_SC|GO13077_SC|GO13122_SC
210513593, 67.535824, 15.637839, 5.673, GO13047_LC|GO13023_LC|GO13077_LC|GO13036_LC|GO13039_LC|GO13019_LC
210548567, 67.640136, 16.194012, 4.814, GO13047_LC|GO13122_LC|GO13023_LC|GO13006_LC|GO13025_LC|GO13077_LC|GO13039_LC
210745602, 66.238031, 19.042009, 5.946, GO13047_LC|GO13122_LC|GO13023_LC|GO13024_LC|GO13077_LC|GO13039_LC|GO13019_LC|GO13902_LC|GO13903_LC|GO13904_LC
210924194, 64.902937, 21.773492, 5.509, GO13047_LC|GO13122_LC|GO13019_LC
210950988, 66.35423, 22.199997, 5.29, GO13047_LC|GO13122_LC|GO13023_LC|GO13077_LC|GO13039_LC|GO13019_LC
246786764, 77.424824, 15.597234, 4.812, GO13047_LC|GO13122_LC
246795385, 67.66204, 15.691878, 5.472, GO13047_LC|GO13023_LC|GO13006_LC|GO13077_LC|GO13039_LC|GO13019_LC
246810368, 67.965656, 15.85156, 5.985, GO13047_LC|GO13122_LC|GO13002_LC|GO13023_LC|GO13077_LC|GO13039_LC|GO13019_LC
247220058, 80.235892, 19.814346, 5.974, GO13047_LC
247254216, 79.811208, 20.134592, 5.927, GO13047_LC|GO13036_LC|GO13019_LC
247649941, 69.12141, 23.340858, 5.979, GO13047_LC|GO13122_LC|GO13023_LC|GO13024_LC|GO13077_LC|GO13039_LC|GO13019_LC
247733919, 74.452694, 23.948561, 5.608, GO13047_LC|GO13019_LC
247893813, 74.539142, 25.050406, 5.897, GO13047_LC|GO13122_LC|GO13039_LC|GO13019_LC
248242432, 73.196322, 27.897486, 5.941, GO13047_LC|GO13122_LC|GO13024_LC|GO13083_LC|GO13019_LC