The
Boomerang Nebula is a
protoplanetary nebula=10.5px. located 5,000
light-years away from
Earth in the constellation
Centaurus. It is also known as the
Bow Tie Nebula and catalogued as LEDA 3074547. The nebula's
temperature is measured at 1
K (−272.15
°C; −457.87
°F) making it the
coolest natural place currently known in the Universe.The Boomerang Nebula is believed to be a
star system evolving toward the
planetary nebula phase. It continues to form and develop due to the outflow of
gas from its core where a
star in its late stage life sheds mass and emits starlight illuminating dust in the nebula.
Millimeter scale dust grains mask portions of the nebula's center so most escaping visible
light is in two opposing lobes forming a distinctive hourglass shape as viewed from Earth. The outflowing gas is moving outwards at a speed of about 164 km/s and expanding rapidly as it moves out into
space; this gas expansion results in the nebula's unusually low
temperature.Keith Taylor and Mike Scarrott called it the "Boomerang Nebula" in 1980 after observing it with the
Anglo-Australian telescope at the
Siding Spring Observatory. Unable to view it with great clarity, the astronomers saw merely a slight asymmetry in the nebula's lobes suggesting a curved shape like a
boomerang. The nebula was photographed in detail by the
Hubble Space Telescope in 1998 revealing a more symmetric
hourglass shape.In 1995, using the 15-metre
Swedish-ESO Submillimetre Telescope in
Chile, astronomers revealed that it is the coldest place in the Universe found so far, besides laboratory-created temperatures. With a temperature of −272 °C, it is only 1 °C warmer than
absolute zero (the lowest limit for all temperatures). Even the −270 °C background glow from the
Big Bang is warmer than the
nebula. It is the only object found so far that has a temperature lower than the
background radiation.In 2013, observations of the
ALMA radio interferometer revealed other features of the Boomerang Nebula. The visible double lobe of the Boomerang Nebula was observed to be surrounded by a larger spherical volume of cold gas seen only in sub-millimeter radio wavelengths. The nebula's outer fringes appear to be gradually warming.As of mid-2017, it is believed that the
star at the center of the nebula is a dying
red giant.=10.5px (Wikipedia)
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