Starship Asterisk*

heehaw wrote: ↑Wed May 01, 2019 9:24 am
It does amaze me that to our human eyes these celestial objects (almost all of them) appear .... beautiful!

NCTom wrote: ↑Wed May 01, 2019 11:36 am
Toward what stage is the central star heading? White dwarf?

https://en.wikipedia.org/wiki/Cat%27s_Eye_Nebula wrote:
<<It is suspected that the central WR:+O7 spectral class PNN star [HD 1064963] of the nebula may be generated by a binary star. The existence of an accretion disk caused by mass transfer between the two components of the system may give rise to polar jets, which would interact with previously ejected material. Over time, the direction of the polar jets would vary due to precession.

Outside the bright inner portion of the nebula, there are a series of concentric rings, thought to have been ejected before the formation of the planetary nebula, while the star was on the asymptotic giant branch of the Hertzsprung–Russell diagram. These rings are very evenly spaced, suggesting that the mechanism responsible for their formation ejected them at very regular intervals and at very similar speeds. The total mass of the rings is about 0.1 solar masses. The pulsations that formed the rings probably started 15,000 years ago and ceased about 1000 years ago, when the formation of the bright central part began.

Further, a large faint halo extends to large distances from the star. The halo again predates the formation of the main nebula. The mass of the halo is estimated as 0.26–0.92 solar masses.>>

https://en.wikipedia.org/wiki/Planetary_nebula wrote:

Star moves onto the AGB from the Horizontal Branch after core helium exhaustion

---

<<After a star passes through the asymptotic giant branch (AGB) phase, the short planetary nebula phase of stellar evolution begins as gases blow away from the central star at speeds of a few kilometers per second. The central star is the remnant of its AGB progenitor, an electron-degenerate carbon-oxygen core that has lost most of its hydrogen envelope due to mass loss on the AGB. As the gases expand, the central star undergoes a two-stage evolution, first growing hotter as it continues to contract and hydrogen fusion reactions occur in the shell around the core and then slowly cooling when the hydrogen shell is exhausted through fusion and mass loss. In the second phase, it radiates away its energy and fusion reactions cease, as the central star is not heavy enough to generate the core temperatures required for carbon and oxygen to fuse. During the first phase, the central star maintains constant luminosity, while at the same time it grows ever hotter, eventually reaching temperatures around 100,000 K. In the second phase, it cools so much that it does not give off enough ultraviolet radiation to ionize the increasingly distant gas cloud. The star becomes a white dwarf, and the expanding gas cloud becomes invisible to us, ending the planetary nebula phase of evolution. For a typical planetary nebula, about 10,000 years passes between its formation and recombination of the resulting plasma.>>

orin stepanek wrote: ↑Wed May 01, 2019 1:12 pm
I love the colors that the combination of optical and X-Ray create! Such a beautiful purple!

The color reminds me of when mom would smash mulberries in cream! Yummy!

http://en.wikipedia.org/wiki/Pyramus_and_Thisbe wrote:

Click to play embedded YouTube video.

<<In Ovid's 's Metamorphoses, Pyramus and Thisbe is the story of two lovers in the city of Babylon who occupy connected houses/walls, forbidden by their parents to be wed, because of their parents' rivalry. Through a crack in one of the walls, they whisper their love for each other. They arrange to meet near Ninus' tomb under a mulberry tree and state their feelings for each other. Thisbe arrives first, but upon seeing a lioness with a mouth bloody from a recent kill, she flees, leaving behind her veils. When Pyramus arrives he is horrified at the sight of Thisbe's veil, assuming that a fierce beast had killed her. Pyramus kills himself, falling on his sword in proper Roman fashion, and in turn splashing blood on the white mulberry leaves. Pyramus' blood stains the white mulberry fruits, turning them dark. Thisbe returns, eager to tell Pyramus what had happened to her, but she finds Pyramus' dead body under the shade of the mulberry tree. Thisbe, after a brief period of mourning, stabs herself with the same sword. In the end, the gods listen to Thisbe's lament, and forever change the colour of the mulberry fruits into the stained colour to honour the forbidden love.>>

De58te wrote: ↑Wed May 01, 2019 1:40 pm
Nice choice of picture for May Day. Kind of looks like a blossoming flower petal, which the month of May brings flowers. Even though astronomically the star is dying. Happy May Day.

https://apod.nasa.gov/apod/ap100509.html wrote:
The Cat's Eye Nebula's (NGC 6543) haunting symmetries are seen in the very central region of this stunning false-color picture, processed to reveal the enormous but extremely faint halo of gaseous material, over three light-years across, which surrounds the brighter, familiar planetary nebula. Made with data from the Nordic Optical Telescope in the Canary Islands, the composite picture shows extended emission from the nebula. Planetary nebulae have long been appreciated as a final phase in the life of a sun-like star. Only much more recently however, have some planetaries been found to have halos like this one, likely formed of material shrugged off during earlier active episodes in the star's evolution. While the planetary nebula phase is thought to last for around 10,000 years, astronomers estimate the age of the outer filamentary portions of this halo to be 50,000 to 90,000 years.

neufer wrote: ↑Wed May 01, 2019 1:33 pm

orin stepanek wrote: ↑Wed May 01, 2019 1:12 pm
I love the colors that the combination of optical and X-Ray create! Such a beautiful purple!

The color reminds me of when mom would smash mulberries in cream! Yummy!

http://en.wikipedia.org/wiki/Pyramus_and_Thisbe wrote:

Click to play embedded YouTube video.

<<In Ovid's 's Metamorphoses, Pyramus and Thisbe is the story of two lovers in the city of Babylon who occupy connected houses/walls, forbidden by their parents to be wed, because of their parents' rivalry. Through a crack in one of the walls, they whisper their love for each other. They arrange to meet near Ninus' tomb under a mulberry tree and state their feelings for each other. Thisbe arrives first, but upon seeing a lioness with a mouth bloody from a recent kill, she flees, leaving behind her veils. When Pyramus arrives he is horrified at the sight of Thisbe's veil, assuming that a fierce beast had killed her. Pyramus kills himself, falling on his sword in proper Roman fashion, and in turn splashing blood on the white mulberry leaves. Pyramus' blood stains the white mulberry fruits, turning them dark. Thisbe returns, eager to tell Pyramus what had happened to her, but she finds Pyramus' dead body under the shade of the mulberry tree. Thisbe, after a brief period of mourning, stabs herself with the same sword. In the end, the gods listen to Thisbe's lament, and forever change the colour of the mulberry fruits into the stained colour to honour the forbidden love.>>

[When we were growing up; my dad had a mulberry tree! During the summer months; my siblings and I spent a lot of time savoring the fruit of this tree! Very Yummy! Today we pretty much avoid cultivation oh this delicious fruit because bird droppings of said tree leave stains on cars! They are however; easy to grow and the fruit is very healthy and delicious!/quote]