# Summary of K2 Program GO16003

Title: Asteroseismology of the Brightest K2 Stars

PI: Huber, Daniel (University of Hawaii)
CoIs: Aerts, Conny Clara; Silva Aguirre, Victor; Boyajian, Tabetha Suzanne; Pope, Benjamin James Spinks; White, Timothy R; Creevey, Orlagh; Bedding, Tim

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 < 8 mag were rarely observed with Kepler/K2 due to the large number of pixels required to capture the saturated pixel columns. We propose K2 observations of the brightest stars in campaigns 14-16, including a novel technique which uses a small number of unsaturated pixels. Asteroseismic studies of these targets will allow unprecedented tests of asteroseismic scaling relations which will pave the way for the success of the K2 Galactic Archeology Program, and insights into poorly understood internal processes of intermediate-mass stars such as convective core overshooting.

We will select all targets with Kp < 8 mag from the Hipparcos catalog. We will use conventional apertures and small (~24 pixel diameter) circular apertures around the saturated core for very bright (Kp < 6) targets. For the latter, we will 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 (26)
EPIC ID, RA (J2000) [deg], Dec (J2000) [deg], magnitude, Investigation IDs
200200356, , , , GO16003|GO16063|DELTA_CANCRI-LC-BRIGHT_STAR_DISC
200200357, , , , GO16001|GO16003|GO16021|GO16063|ALPHA_CANCRI-LC-BRIGHT_STAR_DISC
200200358, , , , GO16003|XI_CANCRI-LC-BRIGHT_STAR_DISC
200200359, , , , GO16003|GO16063|ETA_CANCRI-LC-BRIGHT_STAR_DISC
200200360, , , , GO16003|GO16021|GO16063|OMICRON1_CANCRI-LC-BRIGHT_STAR_DISC
200200361, , , , GO16003|GO16021|GO16063|OMICRON2_CANCRI-LC-BRIGHT_STAR_DISC
200200363, , , , GO16003|GO16021|GO16063|50_CANCRI-LC-BRIGHT_STAR_DISC
200200728, , , , GO16003|GO16081|45_CANCRI-SC-BRIGHT_STAR_DISC
211514553, 136.242085, 13.343948, 7.198, GO16003_LC
211612703, 137.034965, 14.711396, 8.07, GO16003_LC
211621378, 132.482696, 14.833385, 7.558, GO16001_LC|GO16003_LC|GO16021_LC|GO16028_LC
211706383, 132.795024, 15.999429, 8.092, GO16003_LC|GO16004_LC
211716813, 129.915043, 16.141552, 8.2, GO16003_LC
211723555, 134.395454, 16.233643, 7.712, GO16003_LC
211732180, 133.244751, 16.356873, 8.365, GO16003_LC
211756677, 137.14246, 16.701681, 7.392, GO16003_LC
211810753, 137.259632, 17.469652, 6.949, GO16003_LC
211865588, 133.483664, 18.233593, 7.792, GO16003_LC
211954451, 129.961314, 19.540814, 6.409, GO16001_LC|GO16003_LC|GO16031_LC
211962912, 130.092028, 19.669939, 6.236, GO16001_LC|GO16003_LC|GO16031_LC
212052751, 127.029797, 21.148487, 6.699, GO16003_LC
212091650, 134.271444, 21.860447, 6.81, GO16003_LC|GO16004_LC
212112028, 135.711288, 22.258552, 8.427, GO16003_LC
251315548, 140.700985, 18.13201, 8.22, GO16003_LC
251326747, 140.157887, 19.090631, 7.003, GO16003_LC
251360981, 137.586908, 21.996418, 5.795, GO16003_LC|GO16004_LC