Photos from NASA Hubble Space Telescope Shows that the stunning Stingray Nebula is declining at an unprecedented rate.
The Stingray Nebula (formally known as Hen 3-1357) is the youngest known Planetary nebula In our sky. However, the Hubble images taken 20 years apart show a dramatic change in the shape and brightness of the nebula: According to a NASA statement, the once solid and bright blue cloud of dust and gas in the nebula has almost disappeared.
Martín A. Guerrero, a Spanish astronomer and Andalusian astronomer and a member of the research team, said: “This is very, very dramatic and very strange.”
gallery: Strange nebula shape, what do you see?
A recent study of the Stingray Nebula compared Hubble Telescope images taken in 1996 and 2016. Early photos captured a bright, blue, fluorescent hydrogen cloud towards the center. nebula. However, images taken in 2016 show that the gas has almost disappeared, causing the nebula to appear smaller and darker. The gas shell also lost its distinctive wavy edge, which gave the nebula the name of aquatic plant.
“Change in nebula The lead researcher of the project and an astronomer at the University of Washington in Seattle, Bruce Balick, said in a statement: “We have seen it before, but what we have here is that the basic structure of the nebula has changed. “
The Stingray Nebula is composed of gas and dust expelled from its central star (called SAO 244567). Normally, the star will continue to heat the material as it expands outward, causing the gas and dust to be ionized and glow.
But from Hubble Image It reveals the rapid changes in the light emitted by the luminescence of nitrogen, hydrogen and oxygen from a dying star. The statement said that, in particular, the researchers found that the star’s oxygen emissions decreased by nearly 1,000 times between 1996 and 2016.
Barrick said: “In most studies, the nebula usually grows larger. Here, it fundamentally changes its shape and becomes darker and darker, and it takes unprecedented time to do so.” Surprisingly, it hasn’t gotten bigger. Indeed, the once bright oval inner ring seems to be shrinking as it gradually disappears.”
When Hubble first photographed the Stingray Nebula in 1996, the researchers believed that the image represented the final stage of SAO 244567’s life, because the bright, gas-expanding clouds were discarded by SAO 244567. Dying star.
However, it now appears that SAO 245567 is taking a step back in its stellar evolution, because recent observations indicate that the Stingray Nebula has greatly attenuated and its brightest internal structure has shrunk rather than continued to expand. It is believed that the rapid changes in the brightness and structure of the nebula are triggered by the cooling of its central star. As the star cools, it emits less ultraviolet ionizing radiation, which would otherwise heat the discharged gas and make it glow.
A kind previous studiesResearch led by Nicole Reindl of the University of Potsdam showed that the temperature of SAO 245567 rose from less than 40,000 degrees Fahrenheit to 108,000 degrees Fahrenheit between 1971 and 2002. The peak temperature may be caused by a brief burst of helium in the star’s core. The statement said that this would help explain why the Stingray Nebula appeared brighter in 1996, but has quickly disappeared since then.
Reindel said in the new statement: “We are lucky to see it at that moment.” “During such a flash of helium shell, it develops very rapidly, which means a shorter evolutionary time scale, so we usually It is impossible to see how these stars evolve. We happened to be captured there at the right time.”
A brief period of helium fusion may cause the outer layer of the star to expand and expel large amounts of gas and dust, resulting in the bright blue fluorescent cloud that was observed in 1996.But in the 2016 photo, the reason for the fading of the Stingray Nebula is The stars are cooling now.
According to NASA’s statement, if the nebula continues to decay at its current rate, researchers estimate that the structure will be almost undetectable in 20 or 30 years.
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