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APOD: MyCn 18: The Engraved Hourglass... (2023 Oct 03)
Posted: Tue Oct 03, 2023 4:07 am
by APOD Robot
MyCn 18: The Engraved Hourglass Planetary Nebula
Explanation: Do you see the hourglass shape -- or does it see you? If you can picture it, the rings of
MyCn 18 trace the outline of an hourglass -- although one with an unusual eye in its center. Either way, the sands of time are running out for the central star of this hourglass-shaped
planetary nebula. With its
nuclear fuel exhausted, this brief, spectacular, closing phase of a
Sun-like
star's life occurs as its outer layers are ejected - its core becoming a cooling, fading
white dwarf. In 1995, astronomers used the
Hubble Space Telescope (HST) to make a series of images of
planetary nebulae, including the one featured here. Pictured, delicate rings of colorful glowing gas (
nitrogen-red,
hydrogen-green, and
oxygen-blue) outline the tenuous walls of the
hourglass. The unprecedented sharpness of the Hubble images has revealed
surprising details of the
nebula ejection process that are helping to resolve the outstanding mysteries of the
complex shapes and symmetries of planetary nebulas like MyCn 18.
Re: APOD: MyCn 18: The Engraved Hourglass... (2023 Oct 03)
Posted: Tue Oct 03, 2023 6:36 pm
by AVAO
APOD Robot wrote: ↑Tue Oct 03, 2023 4:07 am
MyCn 18: The Engraved Hourglass Planetary Nebula
Explanation: Do you see the hourglass shape -- or does it see you? If you can picture it, the rings of
MyCn 18 trace the outline of an hourglass -- although one with an unusual eye in its center. Either way, the sands of time are running out for the central star of this hourglass-shaped
planetary nebula. With its
nuclear fuel exhausted, this brief, spectacular, closing phase of a
Sun-like
star's life occurs as its outer layers are ejected - its core becoming a cooling, fading
white dwarf. In 1995, astronomers used the
Hubble Space Telescope (HST) to make a series of images of
planetary nebulae, including the one featured here. Pictured, delicate rings of colorful glowing gas (
nitrogen-red,
hydrogen-green, and
oxygen-blue) outline the tenuous walls of the
hourglass. The unprecedented sharpness of the Hubble images has revealed
surprising details of the
nebula ejection process that are helping to resolve the outstanding mysteries of the
complex shapes and symmetries of planetary nebulas like MyCn 18.
Exciting picture. I find it interesting that the central star is almost not visible at today's APOD.
jac berne (flickr)
bigger: https://live.staticflickr.com/65535/532 ... 54d0_o.jpg
Re: APOD: MyCn 18: The Engraved Hourglass... (2023 Oct 03)
Posted: Tue Oct 03, 2023 7:27 pm
by Chris Peterson
AVAO wrote: ↑Tue Oct 03, 2023 6:36 pm
Exciting picture. I find it interesting that the central star is almost not visible at today's APOD.
Not unusual, of course, with narrowband images. The hot central star isn't putting out much energy in these tiny slices of the visible spectrum.
Re: APOD: MyCn 18: The Engraved Hourglass... (2023 Oct 03)
Posted: Tue Oct 03, 2023 8:54 pm
by orin stepanek
Beautiful: This Nebula is almost perfect in symmetry!
![Cool 8-)](./images/smilies/icon_cool.gif)
Re: APOD: MyCn 18: The Engraved Hourglass... (2023 Oct 03)
Posted: Tue Oct 03, 2023 9:56 pm
by Fred the Cat
Seems to be an eye, staring back at us. Or some
advanced civilization’s version of Webb.
If so, I’ll take
two small ones please. Equipped with their version of
glasses.
![Shocked :shock:](./images/smilies/icon_eek.gif)