Mission Overview
The K2 Bright Star Survey (HALO)
Primary Investigator: Benjamin Pope
HLSP Authors: Benjamin Pope
Released: 2019-08-21
Updated: 2019-08-21
Primary Reference(s): Pope et al. (2019)
Citations: See ADS Statistics
Slideshow
Overview
The HALO project produces calibrated light curves of stars from K2 that are brighter than the saturation limit of the detector (~11th magnitude). Light curves of 161 bright stars from K2 Campaign 4 and onwards are provided, derived from the unsaturated scattered-light "halo" around the stars. Light curve creation relies on optimizing the weights of a linear combination of the pixel time series using a lagged Total Variation minimization, which is demonstrated to work on both saturated and unsaturated K2 targets. After flux extraction from the halo apertures, the light curves are further corrected using the "k2sc" Gaussian Process systematics-correction code to further correct pointing residuals.
A GitHub repository is made available, and maintained, by the HALO team. The repository includes scripts and notebooks to generate the HALO data set.
Data Products
Each target is organized into a subdirectory structure, based on the K2 Campaign it is found in. Campaign directories are not zero-padded. For Campaign 10, it follows the mission directory structure, where because the Campaign was split into two parts, the campaign directory for the second part of Campaign 10 is stored under:
<c102>/
The data file types:
_lc.fits |
extracted light curve |
_lc.pdf |
summary plot showing K2SC detrending, raw flux map, HALO weight map, and periodograms |
_lc.png |
png version of the summary plot |
The data extension (first extension) of the _lc.fits files consists of the following columns:
- TIME = time at mid-point of cadence, in K2 truncated Julian Day
- FLUX = HALO flux from the aperture (prior to running k2sc)
- FLUX_ERR = uncertainty in the FLUX column
- CENTROID_COL = ignore, use POS_CORR1 instead
- CENTROID_ROW = ignore, use POS_CORR2 instead
- QUALITY = quality flag, inherited from the mission data products
- CADENCENO = unique integer incremented by one with each cadence
- POS_CORR1 = column component of the local image motion calculated from the motion polynomials, in pixels relative to the Quarter's mid-cadence
- POS_CORR2 = row component of the local image motion calculated from the motion polynomials, in pixels relative to the Quarter's mid-cadence
- TR_POSITION = systematic trend related to (x,y) as found by the k2sc detrending
- TR_TIME = trend in time found by the k2sc detrending
- CORR_FLUX = FLUX - TR_POSITION + MEDIAN(TR_POSITION)
Note: The light curve file for 98 Tauri = EPIC 200173870, from Campaign 13 (hlsp_halo_k2_llc_200173870-c13_kepler_v1_lc.fits) was reduced poorly by the standard pipeline. Instead, the FITS file here was reduced using a custom apertured selected by hand by the HALO team.
Data Access
HALO data products are available in the MAST Portal and astroquery.mast. In addition, you can directly download the files from the table below.
-
A web-based interface for cross-mission searches of data at MAST or the Virtual Observatory. Download HALO light curves for a few targets.
-
Search for, and retrieve, HALO data products programmatically based on a list of coordinates or target names.
In addition to the services above, you can download files using the table below.
EPIC ID | Common Name | Campaign | Files |
---|---|---|---|
200007772 | Taygeta | 4 | FITS | PDF | PNG |
200007770 | Merope | 4 | FITS | PDF | PNG |
200007766 | del1_Tau | 4 | FITS | PDF | PNG |
200007771 | Maia | 4 | FITS | PDF | PNG |
200007768 | Atlas | 4 | FITS | PDF | PNG |
200007767 | Alcyone | 4 | FITS | PDF | PNG |
200007773 | Pleione | 4 | FITS | PDF | PNG |
200007765 | gam_Tau | 4 | FITS | PDF | PNG |
200007769 | Electra | 4 | FITS | PDF | PNG |
212573842 | Spica | 6 | FITS | PDF | PNG |
200062586 | nu2_Sgr | 7 | FITS | PDF | PNG |
200062592 | Albaldah | 7 | FITS | PDF | PNG |
200062593 | Ascella | 7 | FITS | PDF | PNG |
200062589 | omi_Sgr | 7 | FITS | PDF | PNG |
200062587 | 43_Sgr | 7 | FITS | PDF | PNG |
200062588 | Ainalrami | 7 | FITS | PDF | PNG |
200062584 | psi_Sgr | 7 | FITS | PDF | PNG |
200062591 | tau_Sgr | 7 | FITS | PDF | PNG |
200062585 | 52_Sgr | 7 | FITS | PDF | PNG |
200062590 | ksi2_Sgr | 7 | FITS | PDF | PNG |
200068397 | 73_Psc | 8 | FITS | PDF | PNG |
200068392 | eps_Psc | 8 | FITS | PDF | PNG |
200068394 | 80_Psc | 8 | FITS | PDF | PNG |
200068401 | HR_161 | 8 | FITS | PDF | PNG |
200068396 | 60_Psc | 8 | FITS | PDF | PNG |
200068398 | WW_Psc | 8 | FITS | PDF | PNG |
200068395 | 33_Cet | 8 | FITS | PDF | PNG |
200068399 | 42_Cet | 8 | FITS | PDF | PNG |
200068393 | Revati | 8 | FITS | PDF | PNG |
200068400 | HR_243 | 8 | FITS | PDF | PNG |
200084007 | FW_Vir | 102 | FITS | PDF | PNG |
200084011 | HD_107794 | 102 | FITS | PDF | PNG |
200084009 | HR_4591 | 102 | FITS | PDF | PNG |
200084005 | Zaniah | 102 | FITS | PDF | PNG |
200084004 | Porrima | 102 | FITS | PDF | PNG |
200084008 | HR_4837 | 102 | FITS | PDF | PNG |
200084010 | HR_4613 | 102 | FITS | PDF | PNG |
200084006 | 21_Vir | 102 | FITS | PDF | PNG |
200164169 | 24_Psc | 12 | FITS | PDF | PNG |
200164168 | 83_Aqr | 12 | FITS | PDF | PNG |
200164167 | kap_Psc | 12 | FITS | PDF | PNG |
200164172 | HR_8921 | 12 | FITS | PDF | PNG |
200164173 | 81_Aqr | 12 | FITS | PDF | PNG |
200164171 | 14_Psc | 12 | FITS | PDF | PNG |
200164174 | HR_8897 | 12 | FITS | PDF | PNG |
200164170 | HR_8759 | 12 | FITS | PDF | PNG |
200173857 | 97_Tau | 13 | FITS | PDF | PNG |
200173850 | tau_Tau | 13 | FITS | PDF | PNG |
200173843 | Aldebaran | 13 | FITS | PDF | PNG |
200173862 | 99_Tau | 13 | FITS | PDF | PNG |
200173849 | del3_Tau | 13 | FITS | PDF | PNG |
200173874 | HR_1554 | 13 | FITS | PDF | PNG |
200173845 | tet2_Tau | 13 | FITS | PDF | PNG |
200173854 | 15_Ori | 13 | FITS | PDF | PNG |
200173867 | HR_1403 | 13 | FITS | PDF | PNG |
200173846 | tet1_Tau | 13 | FITS | PDF | PNG |
200173856 | HR_1684 | 13 | FITS | PDF | PNG |
200173866 | 80_Tau | 13 | FITS | PDF | PNG |
200173869 | 105_Tau | 13 | FITS | PDF | PNG |
200173847 | kap1_Tau | 13 | FITS | PDF | PNG |
200173853 | 11_Ori | 13 | FITS | PDF | PNG |
200173872 | HR_1633 | 13 | FITS | PDF | PNG |
200173864 | 53_Tau | 13 | FITS | PDF | PNG |
200173859 | kap2_Tau | 13 | FITS | PDF | PNG |
200173878 | 85_Tau | 13 | FITS | PDF | PNG |
200173860 | 81_Tau | 13 | FITS | PDF | PNG |
200173868 | 89_Tau | 13 | FITS | PDF | PNG |
200173871 | HR_1576 | 13 | FITS | PDF | PNG |
200173876 | HR_1755 | 13 | FITS | PDF | PNG |
200173877 | HR_1459 | 13 | FITS | PDF | PNG |
200173858 | HR_1585 | 13 | FITS | PDF | PNG |
200173855 | HR_1427 | 13 | FITS | PDF | PNG |
200173870 | 98 Tau | 13 | FITS | PDF | PNG |
200173848 | ups_Tau | 13 | FITS | PDF | PNG |
200173873 | HR_1741 | 13 | FITS | PDF | PNG |
200173852 | 75_Tau | 13 | FITS | PDF | PNG |
200173875 | HR_1385 | 13 | FITS | PDF | PNG |
200173861 | 56_Tau | 13 | FITS | PDF | PNG |
200173865 | 51_Tau | 13 | FITS | PDF | PNG |
200173851 | rho_Tau | 13 | FITS | PDF | PNG |
200173844 | eps_Tau | 13 | FITS | PDF | PNG |
200182928 | 53_Leo | 14 | FITS | PDF | PNG |
200182925 | 58_Leo | 14 | FITS | PDF | PNG |
200182926 | 48_Leo | 14 | FITS | PDF | PNG |
200182931 | rho_Leo | 14 | FITS | PDF | PNG |
200182930 | 43_Leo | 14 | FITS | PDF | PNG |
200182929 | 35_Sex | 14 | FITS | PDF | PNG |
200182927 | 65_Leo | 14 | FITS | PDF | PNG |
200194921 | 28_Lib | 15 | FITS | PDF | PNG |
200194911 | Zubenelhakrabi | 15 | FITS | PDF | PNG |
200194920 | HR_5620 | 15 | FITS | PDF | PNG |
200194917 | zet3_Lib | 15 | FITS | PDF | PNG |
200194914 | zet4_Lib | 15 | FITS | PDF | PNG |
200194916 | HR_5806 | 15 | FITS | PDF | PNG |
200194912 | iot1_Lib | 15 | FITS | PDF | PNG |
200194913 | 41_Lib | 15 | FITS | PDF | PNG |
200194918 | HR_5810 | 15 | FITS | PDF | PNG |
200194919 | iot2_Lib | 15 | FITS | PDF | PNG |
200194910 | Dschubba | 15 | FITS | PDF | PNG |
200194915 | HR_5762 | 15 | FITS | PDF | PNG |
200194958 | HD_138810 | 15 | FITS | PDF | PNG |
200200361 | omi2_Cnc | 16 | FITS | PDF | PNG |
200200360 | omi1_Cnc | 16 | FITS | PDF | PNG |
200200358 | ksi_Cnc | 16 | FITS | PDF | PNG |
200200728 | 45_Cnc | 16 | FITS | PDF | PNG |
200200357 | Acubens | 16 | FITS | PDF | PNG |
200200359 | eta_Cnc | 16 | FITS | PDF | PNG |
200200356 | Asellus_Australis | 16 | FITS | PDF | PNG |
200200363 | 50_Cnc | 16 | FITS | PDF | PNG |
200213055 | 68_Vir | 17 | FITS | PDF | PNG |
200213053 | 82_Vir | 17 | FITS | PDF | PNG |
200213057 | HR_5106 | 17 | FITS | PDF | PNG |
200213056 | 80_Vir | 17 | FITS | PDF | PNG |
200213054 | 76_Vir | 17 | FITS | PDF | PNG |
200213067 | Spica | 17 | FITS | PDF | PNG |
200213058 | HR_5059 | 17 | FITS | PDF | PNG |
200233190 | HR_3264 | 18 | FITS | PDF | PNG |
200233186 | gam_Cnc | 18 | FITS | PDF | PNG |
200233191 | 50_Cnc | 18 | FITS | PDF | PNG |
200233193 | HR_3222 | 18 | FITS | PDF | PNG |
200233643 | zet_Cnc | 18 | FITS | PDF | PNG |
200233195 | HR_3558 | 18 | FITS | PDF | PNG |
200233189 | 49_Cnc | 18 | FITS | PDF | PNG |
200233644 | 25_Cnc | 18 | FITS | PDF | PNG |
200233196 | 21_Cnc | 18 | FITS | PDF | PNG |
200233187 | eta_Cnc | 18 | FITS | PDF | PNG |