The brightest stars in nearby galaxies. V - Cepheids and the brightest stars in the dwarf galaxy Sextans B compared with those in Sextans A

Photometry of the brightest resolved red and blue stars and of four of seven Cepheids found in the dwarf galaxy Sextans B is compared with similar data for Sextans A. The photometry is based on a magnitude sequence that extends to B = 23, V = 22. The Cepheids in Sextans B have periods between 8 and 28 days, compared with 10 to 25 days for the five Cepheids known in Sextans A. Reducing the photometric data in Sextans A to the present photometric system and combining the data for the nine Cepheids of known period shows both galaxies to be at the same distance of (m - M)<SUB>AB</SUB> = 26.2 ± ∼ 0.2 (D = 1.7 Mpc). As in Sextans A, the brightest red supergiants in Sextans B are variable, with amplitudes &lt;0.8 mag. Both the red and blue supergaints in Sextans B are fainter than those in Sextans A by ∼ 0.7 mag. The derived absolute magnitudes of the three brightest stars are [M<SUB>v</SUB>(3)] = - 7.26 and - 7.92 for the red supergiants (at random phase in their variability) for Sextans B and A, respectively, and [M<SUB>B</SUB>(3)] = - 6.75 and - 7.53 for the blue supergiants, again in B and A, respectively. Comparison of these values with the brightest stars in the ten other galaxies whose distances from Cepheids are known shows that brightest resolved stars continue to be promising candidates for high-quality distance indica- tors. The dispersion in the absolute magnitude calibration of the red supergiants in the 12 galaxies now available is σ(M<SUB>v</SUB>) &lt;0.2 mag, with only a slight dependence of [M<SUB>v</SUB>(3)] on the luminosity of the parent galaxy.