In a holiday image courtesy of the Hubble Space Telescope, the Cepheid variable star RS Puppis, 10 times more massive than the sun and 200 times larger, shines in a wreath-like “gossamer cocoon” of dust, brightening and dimming over a 41.5-day cycle. RS Puppis has an average intrinsic brightness 15,000 times greater than the Sun’s and is one of the most luminous Cepheids in the Milky Way. As it pulsates, the surrounding nebula flashes in wave like “light echoes. By measuring those fluctuations and the faint light echoes moving across the nebula, astronomers have been able to establish the distance to RS Puppis with high precision. The European Southern Observatory’s New Technology Telescope found that distance to be about 6,500 light years in 2008. Follow-on studies by Hubble in 2014 came up with a slightly lower value. The European Space Agency’s Gaia spacecraft was able to directly measure the distance to RS Puppis using geometric parallax, coming up with a value of 5,580 (plus or minus 260) light years.
This striking NASA/ESA Hubble Space Telescope image depicts the low surface brightness (LSB) galaxy known as UGC 477, located just over 110 million light-years away in the constellation of Pisces. LSB galaxies appear to be dominated by dark matter, making them excellent objects to study to further our understanding of this elusive substance.
A fossilised remnant of the early Milky Way harbouring stars of hugely different ages has been revealed by an international team of astronomers. Terzan 5 resembles a globular cluster, but is unlike any other cluster known. It contains stars remarkably similar to the most ancient stars in the Milky Way and bridges the gap in understanding between our galaxy’s past and its present.
This NASA/ESA Hubble Space Telescope image reveals the simple beauty of NGC 339, a 6.5-billion-year-old massive intermediate age star cluster that lies in the SMC, a dwarf galaxy some 200,000 light-years away from us. The relationship between such clusters and true globular clusters is not yet fully understood.