- 3359 - WHITE DWARF - stars with perplexing behavior? A white dwarf star that completes a full rotation once every 25 seconds is the fastest spinning confirmed white dwarf. It as an extremely rare “magnetic propeller system”. The white dwarf is pulling gaseous plasma from a nearby companion star and flinging it into space at around 3,000 kilometers per second.
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--------------- 3359 - WHITE DWARF - stars with perplexing behavior?
- Astronomers have found that a white dwarf is pummeling a companion object, either a lightweight star or a planet, with incessant blasts of heat and radiation plus a relentless gravitational pull tearing it apart.
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- Most stars, including our Sun, will become "white dwarfs" after they begin to run out of fuel, expand and cool into a ‘red giant star“, and then lose their outer layers. This evolution leaves behind a stellar nub that slowly fades for billions of years.
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- Typically, white dwarfs give off low-energy X-rays. However, these particular white dwarfs had surprisingly bright X-ray emission at higher energies. The white dwarf “KPD 0005+5106 “ had high-energy X-ray emission that was regularly increasing and decreasing in brightness every 4 hours and 42 minutes.
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- This recurring ebb and flow of X-rays indicates that this star has an object in orbit around it, either a very low-mass star or a planet.
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- Material from this low-mass star or planet could be slamming into the north and south poles of the white dwarf, creating a bright spot of high-energy X-ray emission. As the white dwarf and its companion orbit around each other this hot spot would go in and out of view, causing the high-energy X-rays to regularly increase and decrease.
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- Looking for this companion with optical light telescopes haven't seen anything, which means it is a very dim star, a brown dwarf, or a planet.
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- This star located in our galaxy about 1,300 light-years from Earth, is one of the hottest known white dwarf stars, with a surface temperature of about 360,000 degrees Fahrenheit. By comparison, the surface of the Sun is about 10,000 degrees Fahrenheit.
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- The companion object is about 500,000 miles away from the white dwarf, about one thirtieth of the distance from Mercury to the Sun.
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- The researchers looked at what would happen if this object was a planet with the mass about equal to Jupiter, a possibility that agrees with the data more readily than a dim star or a brown dwarf.
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- In these models, the white dwarf would pull material from the planet onto the white dwarf, a process that the planet could only survive for a few hundred million years before eventually being destroyed. This stolen material swirls around the white dwarf, which glows in X-rays that Chandra can detect. This object that is basically being ripped apart by constant gravitational forces.
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- The two other white dwarfs were also thought to be solitary objects, but they show similar energetic X-ray emission to KPD 0005+5106. By analogy, this suggests they may also have faint companions, possibly planets.
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- A white dwarf star that completes a full rotation once every 25 seconds is the fastest spinning confirmed white dwarf. It as an extremely rare “magnetic propeller system”. The white dwarf is pulling gaseous plasma from a nearby companion star and flinging it into space at around 3,000 kilometers per second.
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- It is only the second magnetic propeller white dwarf to have been identified in over 70 years. A white dwarf is a star that has burnt up all of its fuel and shed its outer layers, now undergoing a process of shrinking and cooling over millions of years.
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- The star is the size of the Earth but is thought to be at least 200,000 times more massive. It is part of a binary star system and its immense gravity is pulling material from its larger companion star in the form of plasma.
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- This plasma was falling onto the white dwarf's equator at high speed, providing the energy that has given it this fast spin. One rotation of the planet Earth takes 24 hours, while the equivalent on J0240+1952 is a mere 25 seconds. That's almost 20 percent faster than the confirmed white dwarf with the most comparable spin rate, which completes a rotation in just over 29 seconds.
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- At some point in its evolutionary history this star developed a strong magnetic field. The magnetic field acts as a protective barrier, causing most of the falling plasma to be propelled away from the white dwarf.
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- The remainder will flow towards the star's magnetic poles. It gathers in bright spots on the surface of the star and as these rotate in and out of view they cause pulsations in the light that the astronomers observe from Earth, which they then used to measure the rotation of the entire star.
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- It is pulling material from its companion star due to its gravitational effect, but as that gets closer to the white dwarf the magnetic field starts to dominate. This type of gas is highly conducting and picks up a lot of speed from this process, which propels it away from the star and out into space.
-
- Astronomers have found that a white dwarf is pummeling a companion object, either a lightweight star or a planet, with incessant blasts of heat and radiation plus a relentless gravitational pull tearing it apart.
-
- Most stars, including the Sun, will become "white dwarfs" after they begin to run out of fuel, expand and cool into a red giant, and then lose their outer layers. This evolution leaves behind a stellar core that slowly fades for billions of years.
-
- The white dwarf “KPD 0005+5106” had high-energy X-ray emission that was regularly increasing and decreasing in brightness every 4.7 hours. This recurring ebb and flow of X-rays indicates that the star has an object in orbit around it, either a very low-mass star or a planet.
-
- Material from the low-mass star or planet could be slamming into the north and south poles of the white dwarf, creating a bright spot of high-energy X-ray emission. As the white dwarf and its companion orbit around each other this hot spot would go in and out of view, causing the high-energy X-rays to regularly increase and decrease.
-
- This star is located in our galaxy about 1,300 light-years from Earth. It is one of the hottest known white dwarf stars, with a surface temperature of about 360,000 degrees Fahrenheit. By comparison, the surface of the Sun is about 10,000 degrees Fahrenheit.
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- This companion object is about 500,000 miles away from the white dwarf, only about one thirtieth of the distance from Mercury to the Sun.
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- The researchers looked at what would happen if this object was a planet with the mass about that of Jupiter, a possibility that agrees with the data more readily than a dim star or a brown dwarf. In their models, the white dwarf would pull material from the planet onto the white dwarf, a process that the planet could only survive for a few hundred million years before eventually being destroyed. This stolen material swirls around the white dwarf, which glows in X-rays that Chandra can detect.
-
- The two other white dwarfs were also thought to be solitary objects, but they show similar energetic X-ray emission. This suggests they may also have faint companions, possibly planets.
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- Microlensing involves looking for the magnification and bending of light from distant sources around intervening objects. Microlensing has shown that a planet can survive the evolution of a white dwarf through its red giant phase.
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- Scientists will need to do more theoretical modeling of the evolution of double stars to understand how the planet or low-mass star might end up so close to the white dwarf.
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- Another white dwarf star completes a full rotation once every 25 seconds is the fastest spinning confirmed white dwarf. The spin period of the star confirms it as an extremely rare example of a magnetic propeller system: the white dwarf is pulling gaseous plasma from a nearby companion star and flinging it into space at around 3,000 kilometers per second ( 2,237 miles per our). It is only the second magnetic propeller white dwarf to have been identified in over 70 years.
-
- A white dwarf is a star that has burnt up all of its fuel and shed its outer layers, now undergoing a process of shrinking and cooling over millions of years. Another one is the size of the Earth but is thought to be at least 200,000 times more massive. It is part of a binary star system and its immense gravity is pulling material from its larger companion star in the form of plasma.
-
- This plasma was falling onto the white dwarf's equator at high speed, providing the energy that has given it this fast spin. One rotation of the planet Earth takes 24 hours, while the equivalent on “J0240+1952” is a 25 seconds.
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- That's almost 20 percent faster than the confirmed white dwarf with the most comparable spin rate, which completes a rotation in just over 29 seconds.
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- At some point in its evolutionary history J0240+1952 developed a strong magnetic field. The magnetic field acts as a protective barrier, causing most of the falling plasma to be propelled away from the white dwarf.
-
- The remainder will flow towards the star's magnetic poles. It gathers in bright spots on the surface of the star and as these rotate in and out of view they cause pulsations in the light that the astronomers observe from Earth, which they then used to measure the rotation of the entire star.
-
- The rotation is so fast that the white dwarf must have an above average mass just to stay together and not be torn apart. It is pulling material from its companion star due to its gravitational effect, but as that gets closer to the white dwarf the magnetic field starts to dominate.
-
- This type of gas is highly conducting and picks up a lot of speed from this process, which propels it away from the star and out into space. This is one of only two stars with this magnetic propeller system discovered in the past 70 years.
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- Although material being flung out of the star was first observed in 2020, astronomers had not been able to confirm the rapid spin that is a main ingredient of a magnetic propeller, as the pulses are too fast and dim for other telescopes to observe.
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November 28, 2021 WHITE DWARF - stars with perplexing behavior? 3356
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