Astronomy Picture of the Day 4-09-03

NASA ^ | 4-09-03 | Robert Nemiroff and Jerry Bonnell

[petuniasevan]

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2003 April 9

The Egg Nebula in Polarized Light
Credit: W. Sparks (STScI) & R. Sahai (JPL), Hubble Heritage Team (STScI / AURA), NASA

Explanation: Where is the center of the unusual Egg Nebula? Like a baby chick pecking its way out of an egg, the star in the center of the Egg Nebula is casting away shells of gas and dust as it slowly transforms itself into a white dwarf star. The Egg Nebula is a rapidly evolving pre-planetary nebula spanning about one light year toward the constellation of Cygnus. Thick dust, though, blocks the center star from view, while the dust shells further out reflect light from this star. Light vibrating in the plane defined by each dust grain, the central star, and the observer is preferentially reflected, causing an effect known as polarization. Measuring the orientation of the polarized light for the Egg Nebula gives clues to location of the hidden source. The above image taken by the Advanced Camera for Surveys on the Hubble Space Telescope is false-color coded to highlight the orientation of polarization.

Have you seen this week's: HEASARC Picture of the Week?

[petuniasevan]

"The Egg Nebula, also known as CRL 2688, is shown on the left as it appears in visible light with the Hubble Space Telescope's Wide Field and Planetary Camera 2 (WFPC2) and on the right as it appears in infrared light with Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS). Since infrared light is invisible to humans, the NICMOS image has been assigned colors to distinguish different wavelengths: blue corresponds to starlight reflected by dust particles, and red corresponds to heat radiation emitted by hot molecular hydrogen."

There is more information at the Hubble Heritage site (and a gallery of photos). Here is the link for the Egg Nebula: Egg Nebula in Polarized Light

Oh, note that the last link called "Egg Nebula" in the APOD article is a PDF file. You'll need Adobe Acrobat reader to view that page.

[petuniasevan]

[Support Free Republic]

Do You Think He Wants You To Donate To Free Republic?
	Tick him off. Donate Here By Secure Server Or mail checks to FreeRepublic , LLC PO BOX 9771 FRESNO, CA 93794 or you can use PayPal at Jimrob@psnw.com
STOP BY AND BUMP THE FUNDRAISER THREAD

[GodBlessRonaldReagan]

Very cool!

[xJones]

Beautiful, thanks!

[foolish-one]

Great APOD. Appropriate for the time of year. Thanks.

[firewalk]

Thanks for the ping (-:

[RightWhale]

Polarized light. We can measure it thanks to crystal filters. We can describe it mathematically. We can use it to see fish. But what it is, is a mystery--something to be glossed over.

[mikrofon]

Although I prefer my eggs poached to polarized, that is an amazing view of the nebula...

Great work!