Spitzer Observations of Eclipsing Binaries with Cepheid Components: a Key to the Extragalactic Distance Scale

Details Spitzer Observations of Eclipsing Binaries with Cepheid Components: a Key to the Extragalactic Distance Scale Spitzer Observations of Eclipsing Binaries with Cepheid Components: a Key to the Extragalactic Distance Scale

May 2007

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007sptz.prop40347g&link_type=abstract

Spitzer Proposal ID #40347

Mathematics

Logic

Scientific paper

We propose SST observations of two rare and critically important LMC eclipsing binaries (EBs) containing Cepheids: a 17.3-mag EB with P(orb) = 801-d, which contains a classical 2.03-d Cepheid, and a 14.5-mag EB with P(orb) = 397.25-d containing a 4.98-d Cepheid. These systems have light and radial velocity curves, as well as HST/STIS spectra. From these data we have determined their preliminary orbital and physical properties such as stellar masses, radii, Teffs, luminosities and distances. The astrophysical and cosmological consequences of finding a Cepheid in an eclipsing binary are considerable. Such systems hold the key to simultaneously determining the zero-point of the Cepheid P-L law & the LMC distance as well as providing tests of the Baade-Wesselink parallax method. The requested SST/IRAC observations will significantly reduce (possibly eliminate) the largest source of uncertainty in the present solutions - the determination of the reddening and interstellar absorptions in the line-of-sight to the two targets. Combining the proposed SST photometry with our STIS spectrophotometry will permit the unequivocal determination of the interstellar reddening law (i.e., the value of 'R' in Av = R x E(B-V)) and A(lambda) for each system as well as providing superior determinations of the stars' temperatures & distances. Because of the importance of these systems in determining a more precise LMC distance, and for calibration of the Cepheid P-L Law, we are endeavoring to minimize all known sources of observational uncertainties with SST. Due to the relative faintness of these two EBs, and the need for IR observations to reliably determine the ISM absorptions, SST is the best-suited, and possibly the only instrument, capable of achieving our science goals. The proposed brief ~21-min of SST time (when combined with existing data) offers the unprecedented opportunity to probe the LMC distance, 'self-calibrate' the Cepheid P-L law, and determine directly the fundamental properties of the Cepheids themselves.

Affiliated with

Also associated with

No associations

Rating

Spitzer Observations of Eclipsing Binaries with Cepheid Components: a Key to the Extragalactic Distance Scale 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 Spitzer Observations of Eclipsing Binaries with Cepheid Components: a Key to the Extragalactic Distance Scale, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spitzer Observations of Eclipsing Binaries with Cepheid Components: a Key to the Extragalactic Distance Scale will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1748935