The Death of the Sun 

Will leave behind a hot, shining corpse called a white dwarf

This image of NGC 2440 shows the colourful
This image of NGC 2440 shows the colourful “last hurrah” of a star like our Sun. The star is ending its life by casting off its outer layers of gas, which formed a cocoon around the star’s remaining core. Ultraviolet light from the dying star makes the material glow. The burned-out star, called a white dwarf, is the white dot in the centre. Credits: NASA/Hubble

Space news (astrophysics: the death of a Sun-like star; planetary nebula NGC 2440) – 4,000 light-years from Earth toward the constellation Puppis, watching the stunning, colorful last moments of a star like our own Sun –

Death is not extinguishing the light: it is only putting out the lamp because the dawn has come (quote by Rabindranath Tagore)

NGC 2440 is another planetary nebula ejected by a dying star, but it has a much more chaotic structure than NGC 2346. The central star of NGC 2440 is one of the hottest known, with a surface temperature near 200,000 degrees Celsius. The complex structure of the surrounding nebula suggests to some astronomers that there have been periodic oppositely directed outflows from the central star, somewhat similar to that in NGC2346, but in the case of NGC 2440 these outflows have been episodic, and in different directions during each episode. The nebula is also rich in clouds of dust, some of which form long, dark streaks pointing away fromthe central star. In addition to the bright nebula, which glows becauseof fluorescence due to ultraviolet radiation from the hot star, NGC 2440 is surrounded by a much larger cloud of cooler gas which is invisible in ordinary light but can be detected with infrared telescopes. NGC 2440 lies about 4,000 light-years from Earth in thedirection of the constellation Puppis. The Hubble Heritage team made this image from observations of NGC 2440acquired by Howard Bond (STScI) and Robin Ciardullo (Penn State). Credit: NASA/ESA and The Hubble Heritage Team (AURA/STScI).
NGC 2440 is a planetary nebula ejected by a dying star, with a little bit of extra character thrown in for visual entertainment. The central star of NGC 2440 has a surface temperature of around 200,000 degrees Celsius and chaotic nature suggesting periodic oppositely flowing outbursts, similar to the process seen in NGC 2346. In the case of this planetary nebula, however,  the outflows were periodic, and in different directions during each period. The Hubble Heritage team made this image from observations of NGC 2440 acquired by Howard Bond (STScI) and Robin Ciardullo (Penn State).
Credit: NASA/ESA and The Hubble Heritage Team (AURA/STScI).

Around 5 billion years in the future, give or take a hundred million, our Sun’s expected to send last hurrahs to the cosmos as seen here in this Hubble Telescope image of planetary nebula NGC 2440. Casting off its outer layers of gas forming a cocoon around the burned-out remains called a white dwarf, it will glow as ultraviolet light it emits strikes the material surrounding it. The Milky Way galaxy’s sprinkled with similar stellar objects astronomers in the 18th and 19th centuries named planetary nebula due to their resemblance when viewed through small telescopes of the time to the disks of distant Uranus and Neptune. Shining at a surface temperature of more than 360,000 degrees Fahrenheit (200,000 degrees Celsius), NGC 2440’s one of the hottest planetary nebula discovered during the human journey to the beginning of space and time. 

It may look like a butterfly, but it's bigger than our Solar System. NGC 2346 is a planetary nebula made of gas and dust that has evolved into a familiar shape. At the heart of the bipolar planetary nebula is a pair of close stars orbiting each other once every sixteen days. The tale of how the butterfly blossomed probably began millions of years ago, when the stars were farther apart. The more massive star expanded to encompass its binary companion, causing the two to spiral closer and expel rings of gas. Later, bubbles of hot gas emerged as the core of the massive red giant star became uncovered. In billions of years, our Sun will become a red giant and emit a planetary nebula - but probably not in the shape of a butterfly, because the Sun has no binary star companion.
Planetary nebula NGC 2346 looks like a butterfly to many viewers, but you could comfortably fit our solar system within its boundaries. Two stars orbit closely together within every sixteen days. In a few billion years, our Sun will expand to become a red giant star and eject material to create a similar looking planetary nebula. Scientists think it will look different, however, because our Sun has no companion star. Credit: Massimo Stiavelli (STScI), Inge Heyer (STScI) et al., & the Hubble Heritage Team (AURA/ STScI/ NASA)

Study of this planetary nebula’s chaotic structure suggests it shed its outer layers of mass in episodic outbursts heading in different directions as seen in the two bowtie-shaped lobes observed in the image at the top. Long, dark clouds of dust forming dark streaks traveling away from NGC 2440 can also be seen, along with expelled helium indicated by blue, oxygen highlighted in blue-green, and nitrogen and hydrogen in red. Matter expelled by the white dwarf glows in different colors, depending on its composition, density, and distance from the hot star.

A full-disk multiwavelength extreme ultraviolet image of the sun taken by SDO on March 30, 2010. False colors trace different gas temperatures. Reds are relatively cool (about 60,000 Kelvin, or 107,540 F); blues and greens are hotter (greater than 1 million Kelvin, or 1,799,540 F). Credits: NASA/Goddard/SDO AIA Team
This is a full-disk multiwavelength extreme ultraviolet image of the sun taken by SDO on March 30, 2010. False colors trace different gas temperatures. Reds are relatively cool (about 60,000 Kelvin, or 107,540 F); blues and greens are hotter (greater than 1 million Kelvin, or 1,799,540 F). In a few billion years it will expand into a red giant star and eject material that will become a similar, but different, looking planetary nebula than NGC 2440. Credits: NASA/Goddard/SDO AIA Team

The final days of stars like the Sun

The present theory concerning the final days of a white dwarf star says it will end its days as a black dwarf star. Unknown billions of years in the future, astronomers believe white dwarf stars could stop emitting light and heat and become cold, stellar bodies. Cold, dark stars our telescopes and present technology would have extreme difficulty detecting accept for the effects of their gravity wells on objects traveling nearby. Unfortunately, our universe is only about 14 billions years old, which is too young for black dwarf stars to exist, if the theory is correct. 

Read about NASA’s recently issued challenge to young innovators to “Think Outside the Box”.

Learn more about NASA’s Next Generation Wide-field Infrared Survey Telescope.

Discover how astronomers measure distances to objects on the other side of the Milky Way.

Learn more about NASA’s contributions to the human journey to the beginning of space and time here.

Learn more about the Sun.

Discover more about planetary nebula here.

Learn more about white dwarf stars.

Learn more about black dwarf stars.

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