April 24, 2024

Hubble Reveals the Final Stages of a Dying Star

In April 2021 Hubble released its 31st-anniversary image. Its a picture of AG Carinae, among the most luminescent stars in the whole Milky Way. AG Carinae is in a reckless battle with itself, periodically ejecting matter up until it reaches stability at some point in the future.
Thanks to the Hubble, we get to view the fantastic struggle.

Now the individuals behind the Hubble have actually launched another image, or rather images, of AG Carinae. Its comprised of Hubble observations of the star from 2020, 2014, and also as far back as 1994. AG Carinae is a luminescent blue variable (LBV) and its look changes gradually. The images bring those modifications to life.
AG Carinaes battle is between the inward pressure of gravity and the outside pressure from blend. When those two forces are out of balance, stars battle. Stars always look for equilibrium.
The star is continually losing mass at this late phase of its life. As the star runs out of fuel for combination, its external radiation pressure reduces. Gravity draws some of the stars mass inward toward the center of the star.
Two Hubble views of the luminescent blue variable AG Carinae. The images reveal dust bubbles and a gas shell made up of material regularly ejected from the star. Image Credit: ESA/Hubble and NASA, A. Nota, C. Britt
In this case, the image on the left shows ionized hydrogen and nitrogen emissions. Theyre part of the expanding emission nebula surrounding the star. The star is extremely hot, and high-energy ultraviolet photons from the star energize the hydrogen and nitrogen, triggering them to discharge light.
The image on the right reveals dust in blue, lit up by shown starlight. Its a reflection nebula, a cloud of dust thats showing the light from the star. AG Carinae is like 2 nebulae in one: an emission nebula and a reflection nebula. Astronomers think that effective excellent winds are forming the filaments and bubbles of dust and gas surrounding the star, providing their diaphanous appearance. AG Carinaes nebula is around 5 light-years broad.
AG Carinae is about 20,000 light-years away in the constellation Carinae. Its difficult to see, both since of its range and due to the fact that its obscured by dust in noticeable light. As a variable star, its apparent brightness swings wildly, between 5.7 and 9, contributing to the trouble. Its no problem for the Hubble though.
The nebula itself includes about 15 solar masses of product. A few of that was ejected from the star about 10,000 years back. At that time, humanity was near the end of its paleolithic duration and starting its neolithic period. Humans were living in caverns or basic structures and using fundamental tools made from stone and bone. In case you were questioning what your forefathers were up to at the time.
The nebula has to do with 0.4 to 1.2 parsecs from the star, and beyond that, theres a huge cavity in the interstellar medium, about 8.8 parsecs large. It was taken long back, by AG Carinaes powerful stellar winds.
The gas in the nebula is travelling quickly, about 69 km (43 miles) per second. The outstanding winds coming from the star are even faster. Theyre moving at about 200 km (124 miles) per second.
AG Carinae has suffered multiple outbursts, most likely. AG Carinaes outstanding winds are extremely effective. Massive stars like it have winds that can be one billion times more powerful than our Suns excellent winds.
AG Carinae is well-studied, but theres still lots astronomers do not know about it. The nebula appears to be non-spherical and instead has bipolar balance. That might indicate that the massive star has a hidden binary buddy. Or it might suggest that it turns extremely rapidly, like other massive stars.
The massive stars future doubts. Some proof recommends that itll ultimately take off as a supernova. Its excellent spectrum matches that of some stars that are approaching core collapse. However the designs that predict that are understood to be suitable to stars with 20 to 25 stellar masses. AG Carinae contains between 55 and 70 solar masses, after starting life with about 100 solar masses. So its possible supernova ending is unpredictable.
Whatever AG Carinaes eventual fate is, a minimum of we have the Hubble to let us question and gaze.
More:

Its a picture of AG Carinae, one of the most luminous stars in the whole Milky Way. Gravity draws some of the stars mass inward toward the center of the star. The images reveal dust bubbles and a gas shell made up of product regularly ejected from the star. The star is extremely hot, and high-energy ultraviolet photons from the star stimulate the hydrogen and nitrogen, causing them to discharge light.
Its a reflection nebula, a cloud of dust thats showing the light from the star.

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