A Star and a Nebula

A cosmic coupleThat’s the star Hen 2-427 (aka WR 124) at the center of this picture. It’s surrounded by the nebula M1-67. They’re found in the constellation of Sagittarius about 15,000 light-years away. The star shines brightly at the very center of these hot clumps of surrounding gas that it’s ejecting into space at over 150,000 km per hour.

Hen 2-427 is a Wolf–Rayet star. Named after the astronomers Charles Wolf and Georges Rayet, Wolf–Rayet stars are super-hot and characterized by a fierce ejection of mass. In this case, that results in the nebula M1-67 which is estimated to be less than 10,000 years old, a newbie in astronomical terms,

Image Credit: ESA

NGC 2022

NGC 2022 is a planetary nebula in the constellation Orion. In early telescopes (and in today’s medium-sized amateur telescopes) such nebulae look like small grayish patches of light. Since they don’t look like stars, but a bit like the gas giant planets, early astronomers tagged them as “planetary nebula,” and the name has stuck.

When stars like the Sun grow old, they expand into red giants. They then begin to lose their outer layers into space, forming a shell of gas. As the evolving star’s core shrinks and grows hotter, it emits ultraviolet light that causes the expelled gases to glow.

Image Credit: NASA / ESA

Messier 69

This is an image of the core fo the globular star cluster Messier 69. It is made up of visible light and infrared data taken by the Hubble Space Telescope. The cluster was discovered by Charles Messier in 1780. It’s located 29,700 light-years from Earth in the constellation Sagittarius. It’s too dim to be seen with the naked eye, but it can be viewed with a pair of binoculars, especially during August.

The stars in M69 have over ten times more iron than stars in other globular clusters of the same age. Iron is the heaviest element created by fusion in a star unless it explodes as a supernova.

Image Credit: NASA / ESA

Blue Wisps

Turquoise-tinted plumes in the Large Magellanic CloudThis Hubble image shows part of the outskirts of the Tarantula Nebula in the Large Magellanic Cloud. The colors seen in this picture are different from what we normally see in the images of the Large Magellanic Cloud  because an unusual set of filters was used. The customary R filter, which passes red light, was replaced by a filter letting through the near-infrared light. Hydrogen gas normally appears pink because it shines most brightly in the red. In this case, however, other less prominent emission lines dominate in the blue and green filters.

Image Credit: NASA