Star Reveals Beginnings of Nebula Via Bizarre Spiral

Pretty patterns of gas and dust.
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Christopher K.
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Star Reveals Beginnings of Nebula Via Bizarre Spiral

Post by Christopher K. » November 13th, 2010, 9:49 pm

In 1983 the Infrared Astronomical Satellite detected a tiny point of light in Pegasus; it was cataloged as IRAS 23166+1655. The infrared object varied in brightness so it was also designated LL Pegasi.

As it turns out, LL Pegasi is a wide binary; the pair complete an orbit every 800 years. One star is a so-called "carbon star"--a star with a greater than average store of carbon molecules. One of the stars is shedding, and as it has a companion it produces the eerie spiral picked up in the Hubble image. It also seems to be an Archimidean spiral--a spiral obtained when matter leaves the central source and a constant rate (in this case, 14.7 kilometers per second).

One important note. The spiral does not glow due to illumination from the binary. It glows due to the faint cumulative starlight of the Milky Way!

More information at:
December 2010 Sky & Telescope, p. 14

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