Abstract
We confirm the existence of an excess in the mean dereddened ( U B)0 colour of active single-lined spectroscopic giants over quiescent stars of the same spectral type and find evidence for this excess in ( B V)0, although at a lower scale, when plotted against (R I)0. This result suggests that the use of ( B V)0 calibrations to determine fundamental parameters or spectral types for late-type active stars should be taken with caution. Since magnetic activity is definitely involved, these and similar calibrations using (U B)0 and/or (B V)0 should not be used for the study of late-type young clusters' members or late-type pre-main sequence stars without some consideration. Instead, near-infrared colours like ( R I)0 should be better temperature indicators for these stars.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
