A Brilliant Star in Milky Way's Core

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The Pistol Nebula, one of the intrinsically brightest stars in our galaxy, appears as the bright white dot in the center of this image taken with NASA's Hubble Space Telescope. Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) was needed to take the picture, because the star is hidden at the galactic center, behind obscuring dust. NICMOS' infrared vision penetrated the dust to reveal the star, which is glowing with the radiance of 10 million suns.

The image also shows one of the most massive stellar eruptions ever seen in space. The radiant star has enough raw power to blow off two expanding shells (magenta) of gas equal to the mass of several of our suns. The largest shell is so big (4 light-years) it would stretch nearly all the way from our sun to the next nearest star. The outbursts seen by Hubble are estimated to be only 4,000 and 6,000 years old, respectively. Despite such a tremendous mass loss, astronomers estimate the extraordinary star presently may be 100 times more massive than our Sun, and may have started with as much as 200 solar masses of material, but it is violently shedding much of its mass.

The star is 25,000 light-years away in the direction of the constellation Sagittarius. Despite its great distance, the star would be visible to the naked eye as a modest 4th magnitude object if it were not for the dust between it and the Earth. This false-color image is a composite of two separately filtered images taken with the NICMOS on Sept. 13, 1997. The field of view is 4.8 light-years across.

Image credit: NASA and Don F. Figer (UCLA)

Star's Mysterious Light

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In January 2002, a dull star in an obscure constellation suddenly became 600,000 times more luminous than our sun, temporarily making it the brightest star in our Milky Way galaxy. The mysterious star has long since faded back to obscurity, but observations by NASA's Hubble Space Telescope of a phenomenon called a "light echo" have uncovered remarkable new features. These details promise to provide astronomers with a CAT-scan-like probe of the three-dimensional structure of shells of dust surrounding an aging star.

Image Credit: NASA, ESA and H.E. Bond (STScI)

 

Stellar Fireworks

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Resembling an aerial fireworks explosion, this dramatic image of the energetic star WR124, taken by the Hubble Space Telescope, reveals that it is surrounded by hot clumps of gas being ejected into space at speeds of over 100,000 miles per hour.

Also remarkable are vast arcs of glowing gas around the star, which are resolved into filamentary, chaotic substructures, yet with no overall global shell structure. Though the existence of clumps in the winds of hot stars has been deduced through spectroscopic observations of their inner winds, Hubble resolves them directly in the nebula M1-67 around WR124 as 100 billion-mile wide glowing gas blobs. Each blob is about 30 times the mass of the Earth.

The massive, hot central star is known as a Wolf-Rayet star. This extremely rare and short-lived class of super-hot star is going through a violent, transitional phase characterized by the fierce ejection of mass. The blobs may result from the furious stellar wind that is unstable as it flows into space. As the blobs cool, they eventually will dissipate into space and so don't pose any threat to neighboring stars.

The star is 15,000 light-years away, located in the constellation Sagittarius. The picture was taken with Hubble's Wide Field Planetary Camera 2 in March 1997. The image is false-colored to reveal details in the nebula's structure.

Image credit: NASA/Yves Grosdidier (University of Montreal and Observatoire de Strasbourg), Anthony Moffat (Universitie de Montreal), Gilles Joncas (Universite Laval), Agnes Acker (Observatoire de Strasbourg)

From the Sun

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Hinode, a collaborative mission of the space agencies of Japan, the United States, United Kingdom and Europe, captured these very dynamic pictures of our sun's chromosphere on Jan. 12, 2007. Taken by Hinode's Solar Optical Telescope, this image of the sun reveals the filamentary nature of the plasma connecting regions of different magnetic polarity. The chromosphere is a thin layer of solar atmosphere sandwiched between the visible surface, photosphere and corona.

Image credit: JAXA/NASA