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> Cepheids in the galaxy NGC 300

Cepheids in the galaxy NGC 300

author: ESO/Novapix

reference: a-eto04-01001

Image Size 300 DPI: 10 * 8 cm

These stars constitute a key element in the measurement of distances in the Universe. It has been known since many years that the pulsation period of a Cepheid-type star depends on its intrinsic brightness (its "luminosity"). Thus, once its period has been measured, the astronomers can calculate its luminosity. By comparing this to the star's apparent brightness in the sky, and applying the well-known diminution of light with the second power of the distance, they can obtain the distance to the star. This image was obtained with the Wide-Field Imager (WFI) on the MPG/ESO 2.2-m telescope at the La Silla Observatory. 2000

Keywords for this photo:

2000 - ASTRONOMY - CEPHEID - FORNAX - HUBBLE CONSTANT - MPG/ESO 2.2m - NGC 300 - SOUTHERN HEMISPHERE - STAR - UNIVERSE EXPANSION - VARIABLE STAR -