Astronomy and Astrophysics – Astronomy
Scientific paper
Jan 2009
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009aas...21340715d&link_type=abstract
American Astronomical Society, AAS Meeting #213, #407.15; Bulletin of the American Astronomical Society, Vol. 41, p.205
Astronomy and Astrophysics
Astronomy
Scientific paper
In the first paper in this series the stars listed as Field Horizontal-Branch Stars in the SIMBAD data base were discussed. In that paper the set of 64 Crawford and Barnes (1970) four color standards was reviewed.The conclusion is that the present four color photometry is on the standard system of Crawford and Barnes. Scondary FHB standards were measured an average of 57 times each. The mean square errors in (b-y), c1 and m1 were ±0.010, 0.022 and 0.021 respectively and probable errors were ±0.0073, ±0.0147, ±0.0141.
In four color photometry, for stars of spectral type A and F the FHB stars have several distinct properties differentiating them from normal Pop I stars of the same spectral type. The c1 index is about 0.2 mags larger for Pop II (giant) stars than for Pop I (dwarfs). For giant stars the Balmer jump is larger than for Pop I stars and thus the (u-b) color index becomes larger, making the c1 index larger. A word of warning however. There are giant stars of Pop I and they will have the larger c1 indices.
So if you are working with brighter stars you always have this problem But if you are working with faint stars, there will not be any Pop I stars that far from the Galactic plane. The m1 index is about 0.05 mag smaller for FHB stars than for Pop I stars. This happens because the Pop II stars have a lower metalicity than Pop I stars. In this program, to help solve the problem of the brighter stars spectra for many stars were taken with IUE and the spectra clearly determined which type of star had been observed. In summary, the four color Strömgren system is an ideal system to use for classification of A- and F-type stars.
No associations
LandOfFree
Studies of FHB Stars III - Summary of FHB Stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Studies of FHB Stars III - Summary of FHB Stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Studies of FHB Stars III - Summary of FHB Stars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1701529