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The Hubble Constant from Observations of the Brightest Red Giant Stars in a Virgo-Cluster Galaxy

W. E. Harris·P. R. Durrell·M. J. Pierce·J. Secker
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Abstract

The Virgo and Fornax clusters of galaxies play central roles in determining the Hubble constant H_0. A powerful and direct way of establishing distances for elliptical galaxies is to use the luminosities of the brightest red-giant stars (the TRGB luminosity, at M_I = -4.2). Here we report the direct observation of the TRGB stars in a dwarf elliptical galaxy in the Virgo cluster. We find its distance to be 15.7 +- 1.5 Megaparsecs, from which we estimate a Hubble constant of H_0 = 77 +- 8 km/s/Mpc. Under the assumption of a low-density Universe with the simplest cosmology, the age of the Universe is no more than 12-13 billion years.

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W. E. Harris, P. R. Durrell, M. J. Pierce, J. Secker. 1998-06-10. The Hubble Constant from Observations of the Brightest Red Giant Stars in a Virgo-Cluster Galaxy. https://doi.org/10.1038/25673

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