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Kicking off the week!
#XMM-Newton takes us to the #CrabNebula in ultraviolet in our #ScienceImage of the week
#XMM-Newton takes us to the #CrabNebula in ultraviolet in our #ScienceImage of the week
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In 2014, ESA's #XMM-Newton spotted X-rays emanating from the massive star #RhoOphiuchi A and, last year, found these to ebb and flow periodically in the form of intense flares – both unexpected results. The team has now used +European Southern Observatory (ESO)'s Very Large Telescope to find that the star boasts a strong magnetic field, confirming its status as a cosmic lighthouse.
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#SpaceScience image of the week features a dying star.
A young massive star that began life around 25 times more massive than our own #Sun is shedding shells of material and fast winds to create this dynamic scene captured by ESA’s #XMM-Newton.
The image shows the detailed structure of the #CrescentNebula that shed a shell of material as it expanded into a red giant some 200 000 years ago. Fast winds emitted more recently have now collided with that material, causing the gasses in the bubble to heat up and emit X-rays, seen as blue in the image.
Read more: http://www.esa.int/spaceinimages/Images/2017/12/Crescent_nebula
Credit: ESA/XMM-Newton, J. Toalá & D. Goldman
A young massive star that began life around 25 times more massive than our own #Sun is shedding shells of material and fast winds to create this dynamic scene captured by ESA’s #XMM-Newton.
The image shows the detailed structure of the #CrescentNebula that shed a shell of material as it expanded into a red giant some 200 000 years ago. Fast winds emitted more recently have now collided with that material, causing the gasses in the bubble to heat up and emit X-rays, seen as blue in the image.
Read more: http://www.esa.int/spaceinimages/Images/2017/12/Crescent_nebula
Credit: ESA/XMM-Newton, J. Toalá & D. Goldman
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ESA’s #XMM-Newton has spotted surprising changes in the powerful streams of gas from two massive #stars, suggesting that colliding stellar winds don’t behave as expected.
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Crescent Nebula
Released 11/12/2017 9:00 am
Copyright ESA/XMM-Newton, J. Toalá & D. Goldman
Description
A young massive star that began life around 25 times more massive than our own Sun is shedding shells of material and fast winds to create this dynamic scene captured by ESA’s XMM-Newton.
The image shows the detailed structure of the Crescent Nebula that shed a shell of material as it expanded into a red giant some 200 000 years ago. Fast winds emitted more recently have now collided with that material, causing the gasses in the bubble to heat up and emit X-rays, seen as blue in the image.
Other features can also be seen, such as the green hue, generated by oxygen atoms, where the star’s wind is interacting with the surrounding interstellar medium.
Density differences in the surrounding material may give rise to the different structures, such as the extended bubble segment to the top right.
The star will likely end its life in a violent supernova explosion.
The Crescent Nebula sits in the constellation of Cygnus about 5000 light-years away, exactly at a location in the sky that has not been accessible to XMM-Newton until recently. Although it has been well studied by other X-ray telescopes, astronomers working on XMM-Newton, which was launched on 10 December 1999, had to wait patiently until the orbit of the satellite was such that this patch of sky moved into its field of view in April 2014.
More information about XMM-Newton’s observation is available in “X-ray emission from the Wolf-Rayet bubble NGC 688. II. XMM-Newton EPIC observations,” by J. Toalá et al. (2016).
Released 11/12/2017 9:00 am
Copyright ESA/XMM-Newton, J. Toalá & D. Goldman
Description
A young massive star that began life around 25 times more massive than our own Sun is shedding shells of material and fast winds to create this dynamic scene captured by ESA’s XMM-Newton.
The image shows the detailed structure of the Crescent Nebula that shed a shell of material as it expanded into a red giant some 200 000 years ago. Fast winds emitted more recently have now collided with that material, causing the gasses in the bubble to heat up and emit X-rays, seen as blue in the image.
Other features can also be seen, such as the green hue, generated by oxygen atoms, where the star’s wind is interacting with the surrounding interstellar medium.
Density differences in the surrounding material may give rise to the different structures, such as the extended bubble segment to the top right.
The star will likely end its life in a violent supernova explosion.
The Crescent Nebula sits in the constellation of Cygnus about 5000 light-years away, exactly at a location in the sky that has not been accessible to XMM-Newton until recently. Although it has been well studied by other X-ray telescopes, astronomers working on XMM-Newton, which was launched on 10 December 1999, had to wait patiently until the orbit of the satellite was such that this patch of sky moved into its field of view in April 2014.
More information about XMM-Newton’s observation is available in “X-ray emission from the Wolf-Rayet bubble NGC 688. II. XMM-Newton EPIC observations,” by J. Toalá et al. (2016).
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"In 2014, ESA's XMM-Newton spotted X-rays emanating from the massive star Rho Ophiuchi A and, last year, found these to ebb and flow periodically in the form of intense flares – both unexpected results. The team has now used ESO's Very Large Telescope to find that the star boasts a strong magnetic field, confirming its status as a cosmic lighthouse."
Read more at: https://phys.org/news/2018-02-xmm-newton-spies-x-ray-flares-massive.html
Read more at: https://phys.org/news/2018-02-xmm-newton-spies-x-ray-flares-massive.html
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Stellar winds behaving unexpectedly!!!
Read more at:- http://sci.esa.int/xmm-newton/59956-stellar-winds-behaving-unexpectedly/
(Image credit: ESA/XMM-Newton; Y. Nazé et al. 2018)
Read more at:- http://sci.esa.int/xmm-newton/59956-stellar-winds-behaving-unexpectedly/
(Image credit: ESA/XMM-Newton; Y. Nazé et al. 2018)
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Title XMM-Newton slew tracks
Released 06/06/2017 9:30 am
Copyright ESA/XMM-Newton/A. Read/R. Saxton , CC BY-SA 3.0 IGO
Description
This blue ‘ball of string’ actually records 2114 movements made by ESA’s XMM-Newton space telescope as it shifted its gaze from one X-ray object to another between August 2001 and December 2014.
Orbiting in space since 1999, XMM-Newton is studying high-energy phenomena in the Universe, such as black holes, neutron stars, pulsars and stellar winds.
Even when moving its focus between objects, the space telescope collects scientific data, revealing X-ray sources across the entire sky. After correcting for overlaps between slews, 84% of the sky has now been covered.
The plot is in galactic coordinates such that the centre of the plot corresponds to the centre of the Milky Way. The slew paths pass predominantly through the ecliptic poles, indicated by the density of overlapping slew paths to the top left and bottom right.
The image was created as part of the XMM-Newton Slew Survey Catalogue release in March 2017, and which was featured as our Space Science Image of the Week last month.
This week, many scientists studying the X-ray universe are meeting to discuss the latest in high-energy astrophysics, including discoveries from current X-ray missions, as well as expectations of future missions.
Over 5000 papers have been published on XMM-Newton results to date. Scientists are also looking forward to the next generation of X-ray satellite, such as ESA’s Athena, the Advanced Telescope for High-ENergy Astrophysics, which is expected to be launched towards the end of the next decade.
Released 06/06/2017 9:30 am
Copyright ESA/XMM-Newton/A. Read/R. Saxton , CC BY-SA 3.0 IGO
Description
This blue ‘ball of string’ actually records 2114 movements made by ESA’s XMM-Newton space telescope as it shifted its gaze from one X-ray object to another between August 2001 and December 2014.
Orbiting in space since 1999, XMM-Newton is studying high-energy phenomena in the Universe, such as black holes, neutron stars, pulsars and stellar winds.
Even when moving its focus between objects, the space telescope collects scientific data, revealing X-ray sources across the entire sky. After correcting for overlaps between slews, 84% of the sky has now been covered.
The plot is in galactic coordinates such that the centre of the plot corresponds to the centre of the Milky Way. The slew paths pass predominantly through the ecliptic poles, indicated by the density of overlapping slew paths to the top left and bottom right.
The image was created as part of the XMM-Newton Slew Survey Catalogue release in March 2017, and which was featured as our Space Science Image of the Week last month.
This week, many scientists studying the X-ray universe are meeting to discuss the latest in high-energy astrophysics, including discoveries from current X-ray missions, as well as expectations of future missions.
Over 5000 papers have been published on XMM-Newton results to date. Scientists are also looking forward to the next generation of X-ray satellite, such as ESA’s Athena, the Advanced Telescope for High-ENergy Astrophysics, which is expected to be launched towards the end of the next decade.
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Stellar winds behaving unexpectedly
ESA’s XMM-Newton has spotted surprising changes in the powerful streams of gas from two massive stars, suggesting that colliding stellar winds don’t behave as expected.
Massive stars – several times larger than our Sun – lead turbulent lives, burning their nuclear fuel rapidly and pouring large amounts of material into their surroundings throughout their short but sparkling lives.
These fierce stellar winds can carry the equivalent of Earth’s mass in a month and travel at millions of kilometres per hour, so when two such winds collide they unleash enormous amounts of energy.
The cosmic clash heats the gas to millions of degrees, making it shine brightly in X-rays.
Normally, colliding winds change little because neither do the stars nor their orbits. However, some massive stars behave dramatically.
This is the case with HD 5980, a pairing of two huge stars each 60 times the mass of our Sun and only about 100 million kilometres apart – closer than we are to our star.
One had a major outburst in 1994, reminiscent of the eruption that turned Eta Carinae into the second brightest star in the sky for about 18 years in the 19th century.
While it is now too late to study Eta Carinae’s historic eruption, astronomers have been observing HD 5980 with X-ray telescopes to study the hot gas.
In 2007, Yaël Nazé of the University of Liège, Belgium, and her colleagues discovered the collision of winds from these stars using observations made by ESA’s XMM-Newton and NASA’s Chandra X-ray telescopes between 2000 and 2005.
Then they looked at it again with XMM-Newton in 2016.
“We expected HD 5980 to fade gently over the years as the erupting star settled back to normal – but to our surprise it did just the opposite,” says Yaël.
They found the pair was two and a half times brighter than a decade earlier, and its X-ray emission was even more energetic.
“We had never seen anything like that in a wind–wind collision.”
With less material ejected but more light emitted, it was difficult to explain what was happening.
Finally, they found a theoretical study that offers a fitting scenario.
“When stellar winds collide, the shocked material releases plenty of X-rays. However, if the hot matter radiates too much light, it rapidly cools, the shock becomes unstable and the X-ray emission dims.
“This somewhat counterintuitive process is what we thought happened at the time of our first observations, more than 10 years ago. But by 2016, the shock had relaxed and the instabilities had diminished, allowing the X-ray emission to rise eventually.”
These are the first observations that substantiate this previously hypothetical scenario. Yaël’s colleagues are now testing the new result in greater detail through computer simulations.
“Unique discoveries like this demonstrate how XMM-Newton keeps providing astronomers with fresh material to improve our understanding of the most energetic processes in the Universe,” says Norbert Schartel, XMM-Newton project scientist at ESA.
ESA’s XMM-Newton has spotted surprising changes in the powerful streams of gas from two massive stars, suggesting that colliding stellar winds don’t behave as expected.
Massive stars – several times larger than our Sun – lead turbulent lives, burning their nuclear fuel rapidly and pouring large amounts of material into their surroundings throughout their short but sparkling lives.
These fierce stellar winds can carry the equivalent of Earth’s mass in a month and travel at millions of kilometres per hour, so when two such winds collide they unleash enormous amounts of energy.
The cosmic clash heats the gas to millions of degrees, making it shine brightly in X-rays.
Normally, colliding winds change little because neither do the stars nor their orbits. However, some massive stars behave dramatically.
This is the case with HD 5980, a pairing of two huge stars each 60 times the mass of our Sun and only about 100 million kilometres apart – closer than we are to our star.
One had a major outburst in 1994, reminiscent of the eruption that turned Eta Carinae into the second brightest star in the sky for about 18 years in the 19th century.
While it is now too late to study Eta Carinae’s historic eruption, astronomers have been observing HD 5980 with X-ray telescopes to study the hot gas.
In 2007, Yaël Nazé of the University of Liège, Belgium, and her colleagues discovered the collision of winds from these stars using observations made by ESA’s XMM-Newton and NASA’s Chandra X-ray telescopes between 2000 and 2005.
Then they looked at it again with XMM-Newton in 2016.
“We expected HD 5980 to fade gently over the years as the erupting star settled back to normal – but to our surprise it did just the opposite,” says Yaël.
They found the pair was two and a half times brighter than a decade earlier, and its X-ray emission was even more energetic.
“We had never seen anything like that in a wind–wind collision.”
With less material ejected but more light emitted, it was difficult to explain what was happening.
Finally, they found a theoretical study that offers a fitting scenario.
“When stellar winds collide, the shocked material releases plenty of X-rays. However, if the hot matter radiates too much light, it rapidly cools, the shock becomes unstable and the X-ray emission dims.
“This somewhat counterintuitive process is what we thought happened at the time of our first observations, more than 10 years ago. But by 2016, the shock had relaxed and the instabilities had diminished, allowing the X-ray emission to rise eventually.”
These are the first observations that substantiate this previously hypothetical scenario. Yaël’s colleagues are now testing the new result in greater detail through computer simulations.
“Unique discoveries like this demonstrate how XMM-Newton keeps providing astronomers with fresh material to improve our understanding of the most energetic processes in the Universe,” says Norbert Schartel, XMM-Newton project scientist at ESA.
3/2/18
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RCW 86: Historical Supernova Remnant
Credit: X-ray: XMM-Newton, Chandra / IR: WISE, Spitzer
In 185 AD, Chinese astronomers recorded the appearance of a new star in the Nanmen asterism - a part of the sky identified with Alpha and Beta Centauri on modern star charts. The new star was visible for months and is thought to be the earliest recorded supernova. This multiwavelength composite image from orbiting telescopes of the 21st century, XMM-Newton and Chandra in X-rays, and Spitzer and WISE in infrared, shows RCW 86, understood to be the remnant of that stellar explosion. The false-color view traces interstellar gas heated by the expanding supernova shock wave at X-ray energies (blue and green) and interstellar dust radiating at cooler temperatures in infrared light (yellow and red). An abundance of the element iron and lack of a neutron star or pulsar in the remnant suggest that the original supernova was Type Ia. Type Ia supernovae are thermonuclear explosions that destroy a white dwarf star as it accretes material from a companion in a binary star system. Shock velocities measured in the X-ray emitting shell and infrared dust temperatures indicate that the remnant is expanding extremely rapidly into a remarkable low density bubble created before the explosion by the white dwarf system. Near the plane of our Milky Way Galaxy, RCW 86 is about 8,200 light-years away and has an estimated radius of 50 light-years.
Credit: X-ray: XMM-Newton, Chandra / IR: WISE, Spitzer
In 185 AD, Chinese astronomers recorded the appearance of a new star in the Nanmen asterism - a part of the sky identified with Alpha and Beta Centauri on modern star charts. The new star was visible for months and is thought to be the earliest recorded supernova. This multiwavelength composite image from orbiting telescopes of the 21st century, XMM-Newton and Chandra in X-rays, and Spitzer and WISE in infrared, shows RCW 86, understood to be the remnant of that stellar explosion. The false-color view traces interstellar gas heated by the expanding supernova shock wave at X-ray energies (blue and green) and interstellar dust radiating at cooler temperatures in infrared light (yellow and red). An abundance of the element iron and lack of a neutron star or pulsar in the remnant suggest that the original supernova was Type Ia. Type Ia supernovae are thermonuclear explosions that destroy a white dwarf star as it accretes material from a companion in a binary star system. Shock velocities measured in the X-ray emitting shell and infrared dust temperatures indicate that the remnant is expanding extremely rapidly into a remarkable low density bubble created before the explosion by the white dwarf system. Near the plane of our Milky Way Galaxy, RCW 86 is about 8,200 light-years away and has an estimated radius of 50 light-years.
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