Open AccessHipparcos absolute magnitudes for metal‐rich K giants and the calibration of DDO photometry
Author(s) -
Høg Erik,
Flynn Chris
Publication year - 1998
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1998.01165.x
Subject(s) - physics , absolute magnitude , photometry (optics) , astrophysics , observatory , calibration , astronomy , magnitude (astronomy) , photometric system , stars , quantum mechanics
Parallaxes for 581 bright K giants have been determined using the Hipparcos satellite. We combine the trigonometric parallaxes with ground‐based photometric data to determine the K giant absolute magnitudes. For all these giants, absolute magnitude estimates can also be made using the intermediate‐band photometric David Dunlop Observatory (DDO) system. We compare the DDO absolute magnitudes with the very accurate Hipparcos absolute magnitudes, finding various systematic offsets in the DDO system. These systematic effects can be corrected, and we provide a new calibration of the DDO system allowing absolute magnitude to be determined with an accuracy of 0.35 mag in the range 2 > M v > −1. The new calibration performs well when tested on K giants with DDO photometry in a selection of low‐reddening open clusters with well‐measured distance moduli.