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 NASA/ESA Hubble Space Telescope image shows NGC 4789A, a dwarf irregular galaxy in the constellation of Coma Berenices. It certainly lives up to its name — the stars that call this galaxy home are smeared out across the sky in an apparently disorderly and irregular jumble, giving NGC 4789A a far more subtle and abstract appearance than its glitzy spiral and elliptical cousins.
In this season of post-Christmas gym memberships, black holes have shown that they too can lose a lot of the weight of the stars that surround them. One unusually star-deprived black hole at the site of two merged galaxies could provide new insight into black hole evolution and behaviour, according to observations with the Hubble Space Telescope and Chandra X-ray Observatory.
The bipolar star-forming region Sharpless 2-106 some 2,000 light-years away in the constellation Cygnus looks like a soaring, celestial snow angel in this image from the NASA/ESA Hubble Space Telescope. Twin lobes of super-hot gas, glowing blue in this image, stretch outward from the central young and massive star. This hot gas creates the “wings” of our angel.