Other
Scientific paper
Jul 2004
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004hst..prop10116g&link_type=abstract
HST Proposal ID #10116
Other
Hst Proposal Id #10116 Hot Stars
Scientific paper
The young open cluster NGC 7790 is unique and astrophysically important because it contains three classical Cepheid variables {CF Cas, CE Cas A, and CE Cas B}. If the distance of NGC 7790 were known with certainty, these Cepheids would define the zero point for the galactic Cepheid Period-Luminosity {P-L} relationship. By a stroke of good luck, NGC 7790 also contains a 10th-mag eclipsing binary located near the turnoff of the main-sequence of the color-magnitude diagram of the cluster. This important eclipsing binary has been little studied until now and contains two B1IV-V+B3V stars with an orbital period of P=6.005 days. With HST we propose to secure the accurate distance and reddening of QX Cas {and thus of the Cepheids} by using eclipsing binaries as precise standard candles, as we have demonstrated in our work on the Large Magellanic Cloud. With absolute radii, temperatures, and luminosities of the stars known from ground-based and HST observations, the method is essentially geometric and free from many of the uncertainties that plague other less direct methods. Light and radial velocity curve data will be combined with the proposed HST/STIS spectrophotometry {1150-8000 A} to determine the physical properties of the eclipsing binary and thus to secure an accurate distance and reddening for NGC 7790. The determination of the stars' temperatures, reddenings and chemical abundances, and therefore the cluster's distance, with the necessary accuracy can only be accomplished with HST. According to our previous experience, we expect a resulting distance determination with an accuracy of about 2-3%. HST/STIS spectrophotometry will be carried out also for the three Cepheids to determine their properties and individual reddenings. Thus, the proposed HST observations could help eliminate the current nagging uncertainty of the galactic Cepheid zero point and provide the key for a firm calibration of the P-L relationship.
No associations
LandOfFree
Towards an Accurate Calibration of the Galactic Cepheid P-L Zero Point 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 Towards an Accurate Calibration of the Galactic Cepheid P-L Zero Point, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Towards an Accurate Calibration of the Galactic Cepheid P-L Zero Point will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1010960