images

Cepheids in the barred spiral galaxy NGC 1365

by

NASA/Novapix

Reference

a-gax13-65002

Date

2006-09-09

This color image from the Hubble Space Telescope shows a region in NGC 1365, a barred spiral galaxy located in a cluster of galaxies called Fornax. A barred spiral galaxy is characterized by a "bar" of stars, dust and gas across its center. The black and white photograph from a ground-based telescope shows the entire galaxy, which is visible from the Southern Hemisphere. Astronomers who have been measuring the distance to the Fornax cluster, have estimated it to be 60 million light-years from Earth by using Cepheids, bright, young stars that are used as milepost markers to calculate distances to nearby galaxies. The line of small blue dots in the color image shows the formation of stars in the galaxy's spiral arms, making them ideal targets for the discovery of Cepheids. 50 Cepheids have been discovered in the galaxy.