Abstract
If the zero age main sequence is expressed in the (V–I) versus (B–V)–(V–I) plane the reddening lines are found to lie at a great enough angle to allow reasonably accurate spectral type classification for stars later than ∼ F5. Earlier spectral types can also be identified but with lower accuracy. Comparison with the Q method of UBV photometry and with spectra of some of the program stars shows that the BVIc technique produces reliable results. As late–type stars constitute the most numerous spectral types and are plentiful in all galactic plane directions BVIc reddening distances can be derived close to the desired direction (although to smaller distances than techniques that utilize early type stars). The applicability of the technique is further enhanced by the use of CCDs which generally have a spectral response well suited for BVIc imaging observations. Using the new technique the distance to the PN NGC2440 was found to be (3100 ± 320)pc.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: 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.