In this stunning vista, based on image data from the Hubble Legacy Archive, distant galaxies form a dramatic backdrop for disrupted spiral galaxy Arp 188, the Tadpole Galaxy.
The cosmic tadpole is a mere 420 million light-years distant toward the northern constellation Draco. Its eye-catching tail is about 280 thousand light-years long and features massive, bright blue star clusters. One story goes that a more compact intruder galaxy crossed in front of Arp 188 - from right to left in this view - and was slung around behind the Tadpole by their gravitational attraction.
During the close encounter, tidal forces drew out the spiral galaxy’s stars, gas, and dust forming the spectacular tail. The intruder galaxy itself, estimated to lie about 300 thousand light-years behind the Tadpole, can be seen through foreground spiral arms at the upper left. Following its terrestrial namesake, the Tadpole Galaxy will likely lose its tail as it grows older, the tail’s star clusters forming smaller satellites of the large spiral galaxy.
The Sun emitted a significant solar flare on Oct. 22, 2012, peaking at 11:17 p.m. EDT. The flare came from an active region on the left side of the sun that has been numbered AR 1598, which has already been the source of a number of weaker flares. It was captured by SDO in the 131 Angstrom wavelength of extreme ultraviolet light. The movies covers less than an hour.
This flare was classified as an X.1-class flare. “X-class” denotes the most intense flares, while the number provides more information about its strength. An X2 is twice as intense as an X1, an X3 is three times as intense, and so on. An X-class flare of this intensity can cause degradation or blackouts of radio communications for about an hour. This event did produce an impulsive R3 Solar Flare Radio Blackout. R3 is considered “Strong”, meaning a wide area blackout of HF radio communication, loss of radio contact for about an hour on the sunlit side of Earth.
Image: An artist conception of a newly formed star surrounded by a swirling protoplanetary disk of dust and gas, where debris coalesces to create rocky ‘planetesimals’ that collide and grow to eventually form planets. A new study suggests small rocky planet may actually be widespread in our Milky Way galaxy. Credit: University of Copenhagen, Lars A. Buchhave
Planets may not be able to form without a heaping helping of heavy elements such as silicon, titanium and magnesium, a new study suggests.
Stars that host planets have higher concentrations of such “metals” — astronomer-speak for elements heavier than hydrogen and helium — compared to iron than do planetless stars, the study found.
“To form planets, one needs heavy elements,” said lead author Vardan Adibekyan, of the Centre for Astrophysics of the University of Porto in Portugal.
Connected at birth
Planets coalesce from the disk of dust and gas left over after the birth of their parent star. According to the leading theory of planet formation, the core accretion model, small particles clump together, growing larger and larger until they produce protoplanets.
Scientists have long suspected that stars with higher metallicities are more likely to have planets orbiting them. Iron has long been a primary indicator.
“Usually, in stellar physics, people use the iron content as a proxy of overall metallicity,”
Astronomers have discovered a weird compact spinning star whose rotation has sped up slightly, causing it to be hidden until now.
The star is what’s called a pulsar, made of the condensed remnants of a normal star that have been squeezed down to a much smaller volume. This compression has caused the star’s rotation to accelerate to roughly seven times a second.
Pulsars are so called because they appear to pulse on and off, as beams of light pointing from their poles sweep toward Earth and away.
WISE finds few brown dwarfs close to home
This image shows our own back yard, astronomically speaking, from a vantage point about 30 light-years away from the sun. It highlights the population of tiny brown dwarfs recently discovered by NASA’s WISE space telescope.
Astronomers are interested in brown dwarfs, objects too low in mass to shine stably as stars do, because they have cold atmospheres like those of exoplanets and are some of our nearest neighbors in space.
This rendering accurately portrays the relative positions of the sun and its surroundings as they would appear from a vantage point about 30 light-years away. The sun is the faint yellow dot at the very center. All brown dwarfs known within 26 light-years are circled. Blue circles are previously known brown dwarfs, and red circles are brown dwarfs identified for the first time by WISE.
The slightly larger M-dwarf stars, which are the most common type of star in the solar neighborhood, are shown with enhanced brightness to make them easier to see. They round off the rest of the local collection of objects in this region.
This updated census of our solar neighborhood now shows that brown dwarfs are much more rare than stars: there are roughly 6 stars for every known brown dwarf.
Giant black hole kicked out of home galaxy
The galaxy at the center of this image contains an X-ray source, CID-42, which astronomers think that contains a massive black hole being ejected at several million miles per hour. The galaxy is located nearly 4 billion light years from Earth.
The main panel is a wide-field optical image of CID-42 and its surroundings. The top right image from the Chandra X-ray Observatory shows the X-ray emission is concentrated in a single source, corresponding to one of the two sources seen in deep observations by Hubble, which is shown in the middle inset box. The bottom inset shows how the X-rays align with the optical data.
Astronomers think that CID-42 is the byproduct of two galaxies that have collided, producing the distinctive tail seen in the upper part of the optical image inset. When this galaxy collision occurred, the supermassive black holes in the center of each galaxy also collided.
The two black holes then merged to form a single black hole, that recoiled from gravitational waves produced by the collision, giving the newly merged black hole a sufficiently large kick for it to eventually escape from the galaxy. In this scenario, the source with the X-rays is the black hole being ejected from the galaxy.
Watch the video: http://youtu.be/-Q3jnQkvU-o: Simulation of black hole ejection.
Figure: Galactic Cannibalism of two galaxies that wandered too close to each other’s orbit.
NASA will reveal new discoveries about the violent fate of our Milky Way galaxy on Thursday (May 31), the space agency has announced.
NASA will hold a press conference at 1 p.m. EDT (1700 GMT) Thursday at the agency’s headquarters in Washington, D.C. Scientists will discuss new Hubble Space Telescope findings about the inevitable crash of the Milky Way and Andromeda galaxies, which will occur billions of years from now.
“Because of uncertainties in Andromeda’s motion, it has not been possible to determine whether the Milky Way will have a head-on collision or glancing blow with the neighboring galaxy billions of years in the future,” NASA officials said in a media alert Friday (May 25). “Hubble’s precise observations will settle this question.”
A Star Explodes and Turns Inside Out
Using very long X-ray observations of Cassiopeia A (or Cas A), a team of scientists has mapped the distribution of elements in the supernova remnant in unprecedented detail. This information shows where the different layers of the pre-supernova star are located three hundred years after the explosion, and provides insight into the nature of the supernova.
The artist’s illustration shows a simplified picture of the inner layers of the star that formed Cas A just before it exploded, with the predominant concentrations of different elements represented by different colors: iron in the core (blue), overlaid by sulfur and silicon (green), then magnesium, neon and oxygen (red).
The image from NASA’s Chandra X-ray Observatory on the right uses the same color scheme to show the distribution of iron, sulfur and magnesium in the supernova remnant. The data show that the distributions of sulfur and silicon are similar, as are the distributions of magnesium and neon.
Most of the iron that originally was in the core is now located near the outer edges of the remnant. Also, much of the silicon and sulfur, as well as the magnesium, is now found toward the outer edges of the still-expanding debris. The distribution of the elements indicates that a strong instability in the explosion process somehow turned the star inside out.
Preview of a Forthcoming Supernova
NASA’s Hubble Telescope captured this image of Eta Carinae, consisting of ultraviolet and visible light images from the High Resolution Channel of Hubble’s Advanced Camera for Surveys.
The larger of the two stars in the Eta Carinae system is a huge and unstable star that is nearing the end of its life, and the event that the 19th century astronomers observed was a stellar near-death experience. Scientists call these outbursts supernova impostor events, because they appear similar to supernovae but stop just short of destroying their star.
The huge clouds of matter thrown out a century and a half ago, known as the Homunculus Nebula, have been a regular target for Hubble since its launch in 1990. This image is the most detailed yet, and shows how the material from the star was not thrown out in a uniform manner, but forms a huge dumbbell shape.
Eta Carinae is one of the closest stars to Earth that is likely to explode in a supernova in the relatively near future. When it does, expect an impressive view from Earth, far brighter still than its last outburst: SN 2006gy, the brightest supernova ever observed, came from a star of the same type, though from a galaxy over 200 million light-years away.
NASA’S Chandra Finds Fastest Wind From Stellar-Mass Black Hole
This artist’s impression shows a binary system containing a stellar-mass black hole called IGR J17091-3624, or IGR J17091 for short. The strong gravity of the black hole, on the left, is pulling gas away from a companion star on the right. This gas forms a disk of hot gas around the black hole, and the wind is driven off this disk.
New observations with NASA’s Chandra X-ray Observatory have clocked the fastest wind ever seen blowing off a disk around this stellar-mass black hole. Stellar-mass black holes are born when extremely massive stars collapse and typically weigh between five and 10 times the mass of the Sun.
The record-breaking wind is moving about twenty million miles per hour. This is nearly ten times faster than had ever been seen from a stellar-mass black hole, and matches some of the fastest winds generated by supermassive black holes, objects millions or billions of times more massive. The wind, which comes from a disk of gas surrounding the black hole, may be carrying away much more material than the black hole is capturing.
NASA’s Fermi Space Telescope explores new energy extremes
Fermi’s Large Area Telescope (LAT) scans the entire sky every three hours, continually deepening its portrait of the sky in gamma rays, the most energetic form of light. While the energy of visible light falls between about 2 and 3 electron volts, the LAT detects gamma rays with energies ranging from 20 million to more than 300 billion electron volts (GeV).
Any object producing gamma rays at these energies is undergoing extraordinary astrophysical processes. More than half of the 496 sources in the new census are active galaxies, where matter falling into a supermassive black hole powers jets that spray out particles at nearly the speed of light.
Fermi’s view of the gamma-ray sky continually improves. The top image of the entire sky includes three years of observations and shows how the sky appears at energies greater than 1 billion electron volts (1 GeV). Brighter colors indicate brighter gamma-ray sources. A diffuse glow fills the sky and is brightest along the plane of our galaxy (middle). These sources include pulsars and supernova remnants within our galaxy as well as distant galaxies powered by supermassive black holes.
The second image is an all-sky Fermi view that includes only sources with energies greater than 10 GeV. From some of these sources, Fermi’s LAT detects only one gamma-ray photon every four months. Brighter colors indicate brighter gamma-ray sources.
Astronomers reach new frontiers of dark matter
For the first time, astronomers have mapped dark matter on the largest scale ever observed. The results reveal a Universe comprised of an intricate cosmic web of dark matter and galaxies that spans more than one billion light years.
Their project, known as the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS), analysed images of about 10 million galaxies in four different regions of the sky collected over five years. They studied the distortion of the light emitted from these galaxies, which is bent as it passes massive clumps of dark matter during its journey to Earth.
Galaxies included in the survey are typically six billion light years away. The light captured by the telescope images used in the study was emitted when the Universe was six billion years old - approximately half the age it is today.
The team’s result has been suspected for a long time from studies based on computer simulations, but was difficult to verify owing to the invisible nature of dark matter. This is the first direct glimpse at dark matter on large scales showing the cosmic web in all directions.
Above: The observations show that dark matter in the Universe is distributed as a network of gigantic dense (light) and empty (dark) regions, where the largest dense regions are about the size of several Earth moons on the sky. The densest regions of the dark matter cosmic web host massive clusters of galaxies.
Pictured Above: This image from the Hubble Space Telescope shows Sh 2-106, or S106 for short. This is a compact star forming region in the constellation Cygnus (The Swan). Credit: NASA/ESA
Just in time for the holidays, the Hubble Space Telescope has snapped a spectacular view of a star-forming region in our Milky Way galaxy that looks like a snow angel in deep space.
A newly-formed star called S106 IR is shrouded in dust at the centre of the image, and is responsible for the surrounding gas cloud’s hourglass-like shape and the turbulence visible within. Light from glowing hydrogen is coloured blue in this image.
This region, called Sharples 2-106 (or S106 for short) is located nearly 2,000 light-years away in the direction of the constellation of Cygnus (The Swan). The nebula is found in a relatively isolated part of the Milky Way, researchers said.
The S106 nebula measures several light-years across, and contains vast clouds of gas that resemble outstretched wings amidst an hourglass shape. The light from the glowing gas is colored blue in this image. A video and photo of the “snow angel” based on Hubble’s observations reveals a spectacular view of the cosmic sight.
What Is Hydrogen Alpha?
Imaged Above: Combination of 3 surveys (image compilations of data) in Ha - Hydrogen Alpha. Credit: Harvard.Edu
So some of you might have noticed I started posting more Ha images than I normally would, aside from showing more activity in space than you normally would with your unaided eyes, this way of seeing images is essentially good to highlight just how much hydrogen a star or a cosmic environment contains since it is the most abundant thus shows activity very clearly when possible. Here’s a nice explanation courtesy of AstronomyKnow-How on what Ha actually is and what it’s used for:
The sun contains many elements but the most abundant by far is hydrogen. The visible layers (the photosphere and the chromosphere) is the only part of the sun that is cool enough for hydrogen to exist in it’s atomic form and it is here that we can see the absorption and emission spectra (colors) for hydrogen.
It is helpful to think of a hydrogen atom as a small ‘solar system’ with the heavy nucleus as the ‘sun’ in the middle. This particular solar system has only one planet orbiting - ie a single electron. Due to the laws of quantum physics, this electron can only orbit the nucleus in specific orbits which are given a number n.
When electrons jump from the lower to the higher number orbits, they absorb a particular amount of energy and we can observe the absorption spectrum. When they fall back again they release the same amount of energy and we can observe the emission spectrum. The amount of energy absorbed or released in this way can be mathematically directly related to the wavelength at which we see the absorption and emission lines on the spectrum. [Side note: Essentially, you’re viewing the action of these movements of energy as emissions on the full spectrum of colors. Red typically highlighting hydrogen emissions.]
Hydrogen can absorb and emit in the ultraviolet region of the spectrum (the Lyman series) but the emissions and absorptions we see in the visible part of the spectrum are the Balmer series and occur when electrons jump from and fall to the n=2 orbit.
The Balmer series lines that we see are imaginatively called alpha, beta, gamma…. and so looking at the diagram below you can see the whole picture:
The line that appears in the red part of the spectrum is created when an electron moves between the second and third orbit (N=2 and N=3) and the wavelength at which this occurs is 656nm. It is this line that is called the Hydrogen alpha line and hydrogen alpha filters are designed to block out as much of the spectrum as possible leaving only a very small bandwidth through which light can pass at the H-alpha frequency.
Hydrogen Alpha filters typically have a bandpass in the region of 0.5Å to 1Å (Å = Angstrom) where 1Å is 0.1nm.
Weighing in on the Dumbbell Nebula
The Dumbbell nebula (Messier 27) pumps out infrared light in this image from the Spitzer Space Telescope.
Planetary nebulae are known to be the remains of stars that once looked a lot like our sun. When sun-like stars die, they puff out their outer gaseous layers. These layers are heated by the hot core of a white dwarf, and shine with infrared and visible-light colors. Our own sun will blossom into a planetary nebula when it dies in about five billion years.
The Dumbbell nebula is 1,360 light-years away in the Vulpecula constellation, and stretches across 4.5 light-years of space. That would more that fill the space between our sun and the nearest star, and it demonstrates how effective planetary nebulae are at returning much of a stars material back to interstellar space at the end of their lives.
The diffuse green glow, which is brightest near the center, is probably showing us hot gas atoms being heated by the ultraviolet light from the central white dwarf. A collection of clumps fill the central part of the nebula, and red-colored radial spokes extend well beyond, which are molecules of hydrogen gas mixed with heavier elements. Much of this material may survive intact and mix back into interstellar gas clouds, helping to fuel the next generation of stars.