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A record broken: Hubble finds the most distant star ever seen
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By NASA
2 min read
Hubble Views A Vibrant Virgo Cluster Galaxy
NASA’s Hubble Space Telescope, ESA, and J. Lee (Space Telescope Science Institute); Processing: Gladys Kober (NASA/Catholic University of America) It’s easy to get swept up in the swirling starry arms of this intermediate spiral galaxy, NGC 4654, in the constellation Virgo. The galaxy has a bright center and is labeled “intermediate” because it has characteristics of both unbarred and barred spirals. NGC 4654 is just north of the celestial equator, making it visible from the northern hemisphere and most of the southern hemisphere. The galaxy is around 55 million light-years from Earth.
NGC 4654 is one of many Virgo Cluster galaxies that have an asymmetric distribution of stars and of neutral hydrogen gas. Astronomers reason that NGC 4654 may be experiencing a process called “ram pressure stripping,” where the gravitational pull of the Virgo galaxy cluster puts pressure on NGC 4654 as it moves through a superheated plasma made largely of hydrogen called the “intracluster medium.” This pressure feels like a gust of wind – think of a biker feeling wind even on a still day – that strips NGC 4654 of its gas. This process produced a long, thin tail of hydrogen gas on the galaxy’s southeastern side. Most galaxies that experienced ram pressure stripping hold very little cold gas, halting the galaxy’s ability to form new stars, since stars generate from dense gas. However, NGC 4654 has star formation rates consistent with other galaxies of its size.
NGC 4654 also had an interaction with the companion galaxy NGC 4639 about 500 million years ago. The gravity of NGC 4639 stripped NGC 4654’s gas along its edge, limiting star formation in that region and causing the asymmetrical distribution of the galaxy’s stars.
Scientists study galaxies like NGC 4654 to examine the connection between young stars and the cold gas from which they form. NASA’s Hubble Space Telescope took this image in visible, ultraviolet, and infrared light.
Media Contact:
Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov
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Last Updated Oct 02, 2023 Editor Andrea Gianopoulos Contact Related Terms
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By NASA
4 min read
Living on the Edge: Supernova Bubble Expands in New Hubble Time-Lapse Movie
NASA’s Hubble Space Telescope, ESA, Ravi Sankrit (STScI) Though a doomed star exploded some 20,000 years ago, its tattered remnants continue racing into space at breakneck speeds – and NASA’s Hubble Space Telescope has caught the action.
The nebula, called the Cygnus Loop, forms a bubble-like shape that is about 120 light-years in diameter. The distance to its center is approximately 2,600 light-years. The entire nebula has a width of six full Moons as seen on the sky.
Astronomers used Hubble to zoom into a very small slice of the leading edge of this expanding supernova bubble, where the supernova blast wave plows into surrounding material in space. Hubble images taken from 2001 to 2020 clearly demonstrate how the remnant’s shock front has expanded over time, and they used the crisp images to clock its speed.
By analyzing the shock’s location, astronomers found that the shock hasn’t slowed down at all in the last 20 years, and is speeding into interstellar space at over half a million miles per hour – fast enough to travel from Earth to the Moon in less than half an hour. While this seems incredibly fast, it’s actually on the slow end for the speed of a supernova shock wave. Researchers were able to assemble a “movie” from Hubble images for a close-up look at how the tattered star is slamming into interstellar space.
“Hubble is the only way that we can actually watch what’s happening at the edge of the bubble with such clarity,” said Ravi Sankrit, an astronomer at the Space Telescope Science Institute in Baltimore, Maryland. “The Hubble images are spectacular when you look at them in detail. They’re telling us about the density differences encountered by the supernova shocks as they propagate through space, and the turbulence in the regions behind these shocks.”
A very close-up look at a nearly two-light-year-long section of the filaments of glowing hydrogen and ionized oxygen shows that they look like a wrinkled sheet seen from the side. “You’re seeing ripples in the sheet that is being seen edge-on, so it looks like twisted ribbons of light,” said William Blair of the Johns Hopkins University, Baltimore, Maryland. “Those wiggles arise as the shock wave encounters more or less dense material in the interstellar medium.” The time-lapse movie over nearly two decades shows the filaments moving against the background stars but keeping their shape.
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Video Credit: NASA's Hubble Space Telescope, ESA, STScI; Acknowledgment:
NSF's NOIRLab, Akira Fujii , Jeff Hester , Davide De Martin , Travis A. Rector , Ravi Sankrit (STScI), DSS “When we pointed Hubble at the Cygnus Loop we knew that this was the leading edge of a shock front, which we wanted to study. When we got the initial picture and saw this incredible, delicate ribbon of light, well, that was a bonus. We didn’t know it was going to resolve that kind of structure,” said Blair.
Blair explained that the shock is moving outward from the explosion site and then it starts to encounter the interstellar medium, the tenuous regions of gas and dust in interstellar space. This is a very transitory phase in the expansion of the supernova bubble where invisible neutral hydrogen is heated to one million degrees Fahrenheit or more by the shock wave’s passage. The gas then begins to glow as electrons are excited to higher energy states and emit photons as they cascade back to low energy states. Further behind the shock front, ionized oxygen atoms begin to cool, emitting a characteristic glow shown in blue.
The Cygnus Loop was discovered in 1784 by William Herschel, using a simple 18-inch reflecting telescope. He could have never imagined that a little over two centuries later we’d have a telescope powerful enough to zoom in on a very tiny slice of the nebula for this spectacular view.
The Hubble Space Telescope is a project of international cooperation between NASA and ESA. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C.
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Video Credits: NASA's Hubble Space Telescope, ESA, STScI; Acknowledgment:
NSF's NOIRLab, Akira Fujii , Jeff Hester , Davide De Martin , Travis A. Rector , Ravi Sankrit (STScI), DSS Share
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Last Updated Sep 29, 2023 Editor Andrea Gianopoulos Contact Related Terms
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By NASA
3 min read
Hubble Views a Glistening Red Nebula
NASA’s Hubble Space Telescope, ESA/Hubble, R. Sahai Just in time for the fall foliage season, this image from the NASA/ESA Hubble Space Telescope features a glistening scene in red. It reveals a small region of the nebula Westerhout 5, which lies about 7,000 light-years from Earth. Suffused with bright red light, this luminous image hosts a variety of interesting features, including a free-floating Evaporating Gaseous Globule (frEGG). The frEGG in this image is the small tadpole-shaped dark region in the upper center-left. This buoyant-looking bubble is lumbered with two names – [KAG2008] globule 13 and J025838.6+604259.
FrEGGs are a particular class of Evaporating Gaseous Globules (EGGs). Both frEGGs and EGGs are denser regions of gas that photoevaporate less easily than the less dense gas surrounding them. Photoevaporation occurs when gas is ionized and dispersed away by an intense source of radiation – typically young, hot stars releasing vast amounts of ultraviolet (UV) light. EGGs were identified fairly recently, most notably at the tips of the iconic Pillars of Creation captured by Hubble in 1995. FrEGGs were classified even more recently and are distinguished from EGGs because they are detached and have a distinct ‘head-tail’ shape. FrEGGs and EGGs are of particular interest because their density makes it more difficult for intense UV radiation, found in regions rich in young stars, to penetrate them. Their relative opacity means that the gas within them is protected from ionization and photoevaporation. Astronomers think this is important for the formation of protostars, and that many FrEGGs and EGGs play host to the birth of new stars.
FrEGGs are a particular class of Evaporating Gaseous Globules (EGGs). Both frEGGs and EGGs are denser regions of gas that photoevaporate less easily than the less dense gas surrounding them. Photoevaporation occurs when gas is ionized and dispersed away by an intense source of radiation – typically young, hot stars releasing vast amounts of ultraviolet (UV) light. EGGs were identified fairly recently, most notably at the tips of the iconic Pillars of Creation captured by Hubble in 1995. FrEGGs were classified even more recently and are distinguished from EGGs because they are detached and have a distinct ‘head-tail’ shape. FrEGGs and EGGs are of particular interest because their density makes it more difficult for intense UV radiation, found in regions rich in young stars, to penetrate them. Their relative opacity means that the gas within them is protected from ionization and photoevaporation. Astronomers think this is important for the formation of protostars, and that many FrEGGs and EGGs play host to the birth of new stars.
The frEGG in this image is a dark spot in the sea of red light. The red color is a type of light emission known as H-alpha emission. H-alpha occurs when a very energetic electron within a hydrogen atom loses a set amount of its energy, releasing this distinctive red light as it becomes less energetic.
Text credit: European Space Agency (ESA)
Media Contact:
Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov
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Last Updated Sep 29, 2023 Editor Andrea Gianopoulos Contact Related Terms
Astrophysics Division Goddard Space Flight Center Hubble Space Telescope Missions Nebulae Science Mission Directorate The Universe Keep Exploring Discover More Topics From NASA
Stars Stories
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By NASA
During his record-breaking mission, Rubio spent many hours on scientific activities aboard the space station, conducting a variety of tasks ranging from plant research to physical sciences studies.View the full article
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