[ad_1]
NASA’s Hubble Space Telescope recently celebrated its 31st anniversary in space by comparing two new images of an exploding star nearly 20,000 light years from Earth.
Known as AG Carinae, the star is found in the constellation Carina and is one of the brightest stars in the Milky Way.
It is considered a bright blue variable star (LBV), which exhibits sometimes unpredictable and drastic variations in both luminosity and spectrum.
The center was cleaned by dust and gas, which likely collided with the dust, leaving the thick, bright red ring that appears in the first frame. The dust (seen in blue) formed in such a way that it was probably shaped by stellar winds
The images were taken in 2020 and 2014 and combined with others taken by the Hubble 2 Wide Field Planetary Camera in 1994.
The new views show the dual nature of AG Carinae, who was the subject of Hubble’s 31st anniversary image in April.
These two images were taken in 2020 and 2014 and combined with others taken by the Hubble Wide Field Planetary Camera 2 in 1994.
“The first image shows the details of the ionized hydrogen and nitrogen emissions from the expanding nebula shell (seen here in red),” NASA wrote in a statement.
“In the second image, the color blue delineates the distribution of dust that shines in the reflected light from the stars.”
“Astronomers believe that strong stellar winds coming out of the star formed and shaped the bubbles and filaments of dust. The nebula is about five light years wide, similar to the distance from here to the nearest star beyond the Sun, Proxima Centauri. ‘
LBV stars are “quite rare” due to the fact that they are so massive, however, they are continually losing mass in the later stages of their life.
“As the star starts to run out of fuel, its radiation pressure decreases and gravity begins to set in,” NASA added.
“Stellar matter succumbs to gravity and falls inward. It heats up and is explosively ejected into the surrounding interstellar space.
“This process continues until sufficient mass is lost and the star reaches a steady state.”
The nebula that surrounds this star comes from the material it previously ejected during one of its many “explosions”.
The nebula, which is a hollow shell, is about 10,000 years old and the escaping gas leaves at 70 km / s.
The center was cleaned by dust and gas, which likely collided with the dust, leaving the thick, bright red ring that appears in the first frame.
The dust – seen in blue – formed in such a way that it was probably shaped by stellar winds.
The ring of the nebula appears to have bipolar symmetry, which may be due to a disc in the center of the ring or the star may have an unknown companion.
AG Carinae could also spin very quickly, causing bipolar symmetry, NASA added.
Since its launch in April 1990, Hubble has made more than 1.5 million observations of the universe and more than 18,000 scientific papers have been published based on its data.
It orbits the Earth at a speed of about 17,000 mph (27,300 km / h) in low Earth orbit at about 340 miles above sea level, slightly higher than the International Space Station.
The telescope is named after the famous astronomer Edwin Hubble, born in Missouri in 1889, who discovered that the universe is expanding, and the speed at which it is doing so.
The highly anticipated next-generation James Webb Space Telescope will launch on a European Space Agency Ariane 5 rocket on December 18, according to NASA
NASA will replace Hubble with the $ 10 billion James Webb Telescope, which will be the largest, most powerful and most complex space telescope.
Its launch is scheduled from French Guiana on December 18, after a series of delays.
Scientists study the atmosphere of distant exoplanets using huge space satellites like Hubble
Distant stars and their orbiting planets often have different conditions than anything we see in our atmosphere.
To understand these new worlds and what they are made of, scientists must be able to detect what their atmosphere is.
They often do this using a telescope similar to NASA’s Hubble Telescope.
These huge satellites scan the sky and fix themselves on exoplanets that NASA says could be of interest.
Here, on-board sensors perform different forms of analysis.
One of the most important and useful is absorption spectroscopy.
This form of analysis measures the light that comes out of a planet’s atmosphere.
Each gas absorbs a slightly different wavelength of light, and when this happens, a black line appears over a full spectrum.
These lines correspond to a specific molecule, which indicates its presence on the planet.
They are often referred to as the Fraunhofer lines after the German astronomer and physicist who first discovered them in 1814.
By combining all of the different wavelengths of lights, scientists can determine all of the chemicals that make up a planet’s atmosphere.
The key is that what is missing provides the clues to find out what is present.
It is vitally important that this be done by space telescopes, as the Earth’s atmosphere would then interfere.
Absorbing chemicals into our atmosphere would distort the sample, which is why it is important to study the light before it has a chance to reach Earth.
This is often used to search for helium, sodium, and even oxygen in alien atmospheres.
This diagram shows how light passing from a star and through the atmosphere of an exoplanet produces Fraunhofer lines indicating the presence of key compounds such as sodium or helium.
[ad_2]
Source link