Artist's conception of Kepler-88. Credit: Center for Astrophysics of the University of Porto
Planets are so very tiny next to stars outside of the solar system, making it really hard to spot exoplanets unless they transit across the face of their star (or if they are very, very big). Often, astronomers can only infer the existence of planets by their effect on the host star or other stars.
That’s especially true of the curious case of Kepler-88 c, which researchers using the Kepler space telescope said was a possible planet due to its effects on the orbit of Kepler-88 b, a planet that goes across the host of its host star. European astronomers just confirmed the Kepler data using the SOPHIE spectrograph at France’s Haute-Provence Observatory.
It’s the first time scientists have successfully used a technique to independently verify a planet’s mass based on what was found from the transit timing variation, or how a planet’s orbit varies from what is expected as it goes across the face of its sun. That means TTV can likely be used as a strong method on its own, advocates say.
Illustration of the Kepler spacecraft (NASA/Kepler mission/Wendy Stenzel)
SOPHIE’s technique relies on measuring star velocity, which also can reveal a planet’s mass by seeing its effect on the star.
“This independent confirmation is a very important contribution to the statistical analyzes of the Kepler multiple planet systems,” stated Magali Deleuil, an exoplanet researcher at Aix-Marseille University who participated in the research. “It helps to better understand the dynamical interactions and the formation of planetary systems.”
Actually, the two planets behave similarly to Earth and Mars in our own solar system in terms of orbits, according to work from a previous team (led by David Nesvorny of the Southwest Research Institute). They predicted the planets have a two-to-one resonance, which is approximately true of our own solar system since Mars takes about two Earth years to orbit the sun.
The theory of Lithopanspermia states that life can be shared between planets within a planetary system. Credit: NASA
With the recent discovery that Europa has geysers, and therefore definitive proof of a liquid ocean, there’s a lot of talk about the possibility of life in the outer solar system.
According to a new study, there is a high probably that life spread from Earth to other planets and moons during the period of the late heavy bombardment — an era about 4.1 billion to 3.8 billion years ago — when untold numbers of asteroids and comets pummeled the Earth. Rock fragments from the Earth would have been ejected after a large meteoroid impact, and may have carried the basic ingredients for life to other solar system bodies.
These findings, from Pennsylvania State University, strongly support lithopanspermia: the idea that basic life forms can be distributed throughout the solar system via rock fragments cast forth by meteoroid impacts.
Strong evidence for lithopanspermia is found within the rocks themselves. Of the over 53,000 meteorites found on Earth, 105 have been identified as Martian in origin. In other words an impact on Mars ejected rock fragments that then hit the Earth.
The researchers simulated a large number of rock fragments ejected from the Earth and Mars with random velocities. They then tracked each rock fragment in n-body simulations — models of how objects gravitationally interact with one another over time — in order to determine how the rock fragments move among the planets.
“We ran the simulations for 10 million years after the ejection, and then counted up how many rocks hit each planet,” said doctoral student Rachel Worth, lead author on the study.
Their simulations mainly showed a large number of rock fragments falling into the Sun or exiting the solar system entirely, but a small fraction hit planets. These estimations allowed them to calculate the likelihood that a rock fragment might hit a planet or a moon. They then projected this probability to 3.5 billion years, instead of 10 million years.
In general the number of impacts decreased with the distance away from the planet of origin. Over the course of 3.5 billion years, tens of thousands of rock fragments from the Earth and Mars could have been transferred to Jupiter and several thousand rock fragments could have reached Saturn.
“Fragments from the Earth can reach the moons of Jupiter and Saturn, and thus could potentially carry life there,” Worth told Universe Today.
The researchers looked at Jupiter’s Galilean satellites: Io, Europa, Ganymede and Callisto and Saturn’s largest moons: Titan and Enceladus. Over the course of 3.5 billion years, each of these moons received between one and 10 meteoroid impacts from the Earth and Mars.
It’s statistically possible that life was carried from the Earth or Mars to one of the moons of Jupiter or Saturn. During the period of late bombardment the solar system was much warmer and the now icy moons of Saturn and Jupiter didn’t have those protective shells to prevent meteorites from reaching their liquid interiors. Even if they did have a thin layer of ice, there’s a large chance that a meteorite would fall though, depositing life in the ocean beneath.
In the case of Europa, six rock fragments from the Earth would have hit it over the last 3.5 billion years.
It has previously been thought that finding life in Europa’s oceans would be proof of an independent origin of life. “But our results suggest we can’t assume that,” Worth said. “We would need to test any life found and try to figure out whether it descended from Earth life, or is something really new.”
The paper has been accepted for publication in the journal Astrobiology and is available for download here.
The final Full Moon of 2013 occurs tonight, and along with it comes something special: the most distant and visually smallest Full Moon of 2013.
Why doesn’t the annual “mini-moon” receive the same fanfare and hype that the yearly perigee – or do you say Proxigean to be uber-obscure – “supermoon” does? The smallest Full Moon of the year does appear to have a public relations problem in this regard. But as you’ll see, the circumstances for this week’s Full Moon are no less fascinating.
The exact timing of tonight’s Full Moon occurs at 4:28 AM EST/9:28 Universal Time (UT) on Tuesday, December 17th. This occurs just two days and 14 hours prior to the Moon reaching apogee on December 19th at 6:50PM EST/23:50 UT at 406,267 kilometres distant. This is one of the three most distant apogees of 2013, and the closest to Full for the year. It’s also with 500 kilometres of the most distant apogee than can occur, as the Moon’s apogee can vary between ~404,000 and 406,700 kilometres distant.
Tonight’s Full Moon will have an apparent angular diameter of around 29.8’ arc minutes, just a shade lower than the usual value quoted of around half a degree or 30’. The visual size of the Moon as seen from the Earth varies about 12% from 34.1’ to 29.3’. Also, the Moon is also about half an Earth radius more distant when it’s on the local horizon versus at the zenith overhead!
This is also the closest Full Moon to the December solstice, which occurs four days later on Saturday, December 21st at 12:11 PM EST/17:11 UT. This marks the start of astronomical summer in the southern hemisphere and the beginning of the winter season in the north. Think of tonight’s Full Moon as a sort of “placeholder,” marking the point at which the Sun will occupy during the June solstice on the Gemini-Taurus border.
This all means that tonight’s Full Moon rides high for northern hemisphere residents towards local midnight. But the “Long Night’s Moon” of 2013 is rather lackluster in terms of declination. While it’s the northernmost Full Moon of 2013 at a declination of +18.7 degrees, it’s a far cry from the maximum declination of +28.72 degrees (the angle of the ecliptic plus the tilt of the Moon’s orbit) that it can achieve. This only occurs every 18.6 years and last occurred in 2006 and will happen again around 2025. We’re currently headed towards a shallow minimum for the Moon’s orbit in 2015. Ancient European and Native American cultures both knew of this cycle of high-flying moons.
Not weird enough? The next “most distant Full Moon of the Year” happens only one lunation later on January 16th… within just 2 hours of apogee! Perhaps January’s Full Moon is due notoriety as a “Super-Mini Moon?” Such a pairing of “mini-moons” last occurred on 2004-2005 and will next occur on 2021-2022.
The footprint for the lunar occultation of M67. (Created by the author using Occult 4.1)
The Moon also visits some other celestial sights this week. After passing five degrees north of Jupiter on December 19th, the Moon heads towards an occultation of the open cluster M67 in the constellation Cancer on December 21st for northern North America. Though the Moon will be waning gibbous, it might just be possible to note the reappearance of the cluster on the Moon’s dark limb. Other occultations for the remainder of December by the Moon include an occultation of Spica on December 27th for northern Asia, Saturn on December 29th for Antarctica, and +3.6th magnitude star Lambda Geminorum for Canada on December 18th.
The passing of the Full Moon also means it will be entering into the morning sky, which also means bad news for viewers of the Ursid meteor shower which peaks on December 22nd and hunters of Comet C/2013 R1 Lovejoy, currently shining at +5th magnitude in the constellation Hercules low in the dawn.
Moon crossing Orion this week. (Credit: Stellarium).
The keen-eyed may notice the Moon also transits through the northern end of the non-zodiacal constellation of Orion on Tuesday, December 17th. Did you know that the Moon can actually stray far enough away from the ecliptic to cross through 18 constellations? The Six non-zodiacal constellations it can transit are: Orion, Ophiuchus, Corvus, Sextans, Auriga and Cetus.
Finally, a new Earthly ambassador is now roaming the lunar surface.
China’s Chang’E-3 spacecraft landed on the Moon just outside of the Bay of Rainbows (Sinus Iridum) near Montes Recti in the northern section of the Mare Imbrium on Saturday, December 14th. The landing site is visible now on the lunar nearside, and can be seen with that new Christmas telescope you’ve been itching to try out. Look for the Sinus Iridum as a wide crescent scarp, a sort of “notch” in the top of Mare Imbrium:
Finding the landing site of Chang’e-3. Photos and graphics by author.
China’s Yutu or “Jade Rabbit” rover has been beaming back some splendid images of the lunar surface!
So don’t let the cold temperatures deter you from exploring the lunar surface, and the strange but fascinating motions of our nearest natural celestial neighbor. Dress warm and be sure this Christmas season to raise a glass of ye ole Nog to the Solstice/Yule Moon.
Artist's conception of the SWIFT satellite in the act of capturing a gamma-ray burst. Credit: NASA
Supermassive black holes likely are behind most of the nearly 100,000 new X-ray sources plotted by the Swift X-ray Telescope, according to findings led by the University of Leicester in the United Kingdom. The results came from poring over eight years of data produced by the Swift space observatory.
“Stars and galaxies emit X-rays because the electrons in them move at extremely high speeds, either because they are very hot (over a million degrees) or because extreme magnetic fields accelerate them. The underlying cause is usually gravity; gas can be compressed and heated as it falls on to black holes, neutron stars and white dwarfs or when trapped in the turbulent magnetic fields of stars like our Sun,” the university stated.
“Most of the newly discovered X-ray sources are expected to signal the presence of super-massive black holes in the centers of large galaxies many millions of light-years from earth, but the catalog also contains transient objects (short-lived bursts of X-ray emission) which may come from stellar flares or supernovae.”
Plot points across the sky showing the new X-ray sources that the SWIFT satellite found. Blue represents higher-energy sources, and red lower-energy ones. The line represents the galactic plane, where many of the sources are concentrated. Source: Evans (University of Leicester)
Artist's impression of a Y-dwarf, the coldest known type of brown dwarf star. (NASA/JPL-Caltech)
When it’s a brown dwarf — but where do we draw the line?
Often called “failed stars,” brown dwarfs are curious cosmic creatures. They’re kind of like swollen, super-dense Jupiters, containing huge amounts of matter yet not quite enough to begin fusing hydrogen in their cores. Still, there has to be some sort of specific tipping point, and astronomers (being the scientists that they are) would like to know: when does a brown dwarf stop and a star begin?
Researchers from Georgia State University now have the answer.
From a press release issued Dec. 9 from the National Optical Astronomy Observatory (NOAO):
For most of their lives, stars obey a relationship referred to as the main sequence, a relation between luminosity and temperature – which is also a relationship between luminosity and radius. Stars behave like balloons in the sense that adding material to the star causes its radius to increase: in a star the material is the element hydrogen, rather than air which is added to a balloon. Brown dwarfs, on the other hand, are described by different physical laws (referred to as electron degeneracy pressure) than stars and have the opposite behavior. The inner layers of a brown dwarf work much like a spring mattress: adding additional weight on them causes them to shrink. Therefore brown dwarfs actually decrease in size with increasing mass.
As Dr. Sergio Dieterich, the lead author, explained, “In order to distinguish stars from brown dwarfs we measured the light from each object thought to lie close to the stellar/brown dwarf boundary. We also carefully measured the distances to each object. We could then calculate their temperatures and radii using basic physical laws, and found the location of the smallest objects we observed (see the attached illustration, based on a figure in the publication). We see that radius decreases with decreasing temperature, as expected for stars, until we reach a temperature of about 2100K. There we see a gap with no objects, and then the radius starts to increase with decreasing temperature, as we expect for brown dwarfs. “
Dr. Todd Henry, another author, said: “We can now point to a temperature (2100K), radius (8.7% that of our Sun), and luminosity (1/8000 of the Sun) and say ‘the main sequence ends there’ and we can identify a particular star (with the designation 2MASS J0513-1403) as a representative of the smallest stars.”
The relation between size and temperature at the point where stars end and brown dwarfs begin (based on a figure from the publication) Image credit: P. Marenfeld & NOAO/AURA/NSF.
“We can now point to a temperature (2100K), radius (8.7% that of our Sun), and luminosity (1/8000 of the Sun) and say ‘the main sequence ends there’.”
Aside from answering a fundamental question in stellar astrophysics about the cool end of the main sequence, the discovery has significant implications in the search for life in the universe. Because brown dwarfs cool on a time scale of only millions of years, planets around brown dwarfs are poor candidates for habitability, whereas very low mass stars provide constant warmth and a low ultraviolet radiation environment for billions of years. Knowing the temperature where the stars end and the brown dwarfs begin should help astronomers decide which objects are candidates for hosting habitable planets.
The data came from the SOAR (SOuthern Astrophysical Research) 4.1-m telescope and the SMARTS (Small and Moderate Aperture Research Telescope System) 0.9-m telescope at the Cerro Tololo Inter-American Observatory (CTIO) in Chile.
The Helix nebula is visible in the center of this image, surrounded by tracks of asteroids that are much closer to Earth (yellow dots). Click on the image to see them. The streaks you see are from satellites or cosmic rays. Credit: NASA/JPL-Caltech/UCLA
Besides being a darn pretty picture of the Helix nebula, this snapshot is a bit of symbolism for NASA. The spacecraft that nabbed this view is called the Wide-field Infrared Survey Explorer, or WISE. If you look very carefully — you may have to click on the picture for a closer view — you can see little dots showing the paths of asteroids in the picture. (The streaks are cosmic rays and satellites.)
WISE has an interesting history. It began as a telescope seeking secrets of the universe in infrared light, but ran out of coolant in 2010 and was repurposed for asteroid searching under the NEOWISE mission. It wrapped up its mission, was put into hibernation in February 2011, then reactivated this August to look for asteroids again for at least the next three years. You can see some pictures and data WISE collected during its mission below the jump.
It’s a nice way, NASA said, to celebrate the fourth anniversary of WISE’s launch. “WISE is the spacecraft that keeps on giving,” said Ned Wright of UCLA, who was the principal investigator of WISE before it transitioned into NEOWISE.
Results from NASA’s NEOWISE survey find that more potentially hazardous asteroids, or PHAs, are closely aligned with the plane of our solar system than previous models suggested. Image credit: NASA/JPL-CaltechThis enormous section of the Milky Way galaxy is a mosaic of images from NASA’s Wide-field Infrared Survey Explorer, or WISE. The constellations Cassiopeia and Cepheus are featured in this 1,000-square degree expanse. Image credit: NASA/JPL-Caltech/UCLAThis oddly colorful nebula is the supernova remnant IC 443 as seen by WISE. Image credit: NASA/JPL-Caltech/UCLA
Artist's conception of the Kepler Space Telescope. Credit: NASA/JPL-Caltech
Exoplanets are really tiny compared to their host star, and it’s hard to imagine sometimes how astronomers can even find one of these worlds — let alone thousands of them. This nifty two-part series from PBS explains how it’s possible in an easy-to-understand and hilarious way. As an example, this is how they describe the Kepler space telescope’s capabilities:
“It can’t actually see those exoplanets because the stars that they surround are so big and bright. Instead, it looks for the tiny shadow of the planet as it passes in front of its parent star. If that sounds hard, that’s because it is. It’s like seeing a flea in a lightbulb in Los Angeles from New York City,” said host Joe Hanson in the video.
Near the end, he provides an interesting segway into the question of life beyond Earth: “The question we’re really interested in is not how common are planets, but how common are we.” That gets tackled in part 2 of the video, which you can see below the jump.
Remember that 2014 will be an interesting year for Kepler as NASA figures out what to do next with the observatory. It isn’t able to perform its primary mission (seeking exoplanets in Cygnus) because two of its four reaction wheels or pointing devices are malfunctioning. NASA, however, has an innovative fix on the books that could allow it to swing different fields of view during the year — check out this infographic for more details.
Fast radio bursts — eruptions of extreme energy that occur only once and last a thousandth of a second — are continuing to defy astronomers. At first observations suggested they came from billions of light years away. A new study, however, points to sources much closer to home: nearby flaring stars.
“We have argued that fast radio burst sources need not be exotic events at cosmological distances, but rather could be due to extreme magnetic activity in nearby Galactic stars,” said Harvard professor Abraham Loeb in the study.
All radio bursts show a dispersion measure — a frequency dependent time delay — as the long-wavelength component arrives a fraction of a second after the short-wavelength component. When the burst travels through a medium, the long-wavelength component moves slightly slower than short-wavelength component.
This dispersion may easily be created when light travels through intergalactic space. The farther the light travels, the more electrons it will have to travel through, and the greater time delay between the arriving wavelength components.
With this assumption, fast radio bursts are likely to have originated anywhere from five to 10 billion light years away. Universe Today covered an extra-galactic origin a few months ago (read it here).
However, Loeb and his colleagues turned their eyes instead to electrons in stellar corona. These electrons are tightly packed, more so than diffuse intergalactic electrons, and would create the same observable effect.
Flaring stars — variable stars that can undergo unpredictable increases in brightness — are a likely source of fast radio bursts. Two circumstances may create flaring stars: young, low mass stars and solar-mass contact binaries, which orbit so close to one another that they share a common envelope.
In order to test this theory, Loeb and his colleagues searched the vicinities of three of the six known fast radio bursts for flaring stars.
“We were surprised that, apparently, no one had done this before,” said graduate student Yossi Shvartzvald in a press release. Shvartzvald led the observations at Tel-Aviv University’s Wise Observatory in Mitspe Ramon, Israel.
The team discovered a contact binary system in one location. Two sun-like stars orbit one another every 7.8 hours. They calculate a five percent chance that the contact binary is there by coincidence.
No flaring stars, however, were detected in the two other fields.
“Whenever we find a new class of sources, we debate whether they are close or far away,” Loeb said in a press release. Initially we thought gamma-ray bursts were faint stars within the Milky Way. Today we know they are bright explosions in distant galaxies.
It seems the distance debate for fast radio bursts has only begun.
The paper has been accepted for publication in the Monthly Notices of the Royal Astronomical Society and is available for download here. The original press release may be found here.
Messier 1 Hubble Image: Credit - NASA, ESA, J. Hester and A. Loll (Arizona State University)
There are only six of them: radon, helium, neon, krypton, xenon and the first molecules to be discovered in space – argon. They are all odorless, colorless, monatomic gases with very low chemical reactivity. So where did a team of astronomers using ESA’s Herschel Space Observatory make their rather unusual discovery? Try Messier 1… The “Crab” Nebula!
In a study led by Professor Mike Barlow (UCL Department of Physics & Astronomy), a UCL research team was taking measurements of cold gas and dust regions of this famous supernova remnant in infrared light when they stumbled upon the chemical signature of argon hydrogen ions. By observing in longer wavelengths of light than can be detected by the human eye, the scientists gave credence to current theories of how argon occurs naturally.
“We were doing a survey of the dust in several bright supernova remnants using Herschel, one of which was the Crab Nebula. Discovering argon hydride ions here was unexpected because you don’t expect an atom like argon, a noble gas, to form molecules, and you wouldn’t expect to find them in the harsh environment of a supernova remnant,” said Barlow.
When it comes to a star, they are hot and ignite the visible spectrum. Cold objects like nebular dust are better seen in infrared, but there’s only one problem – Earth’s atmosphere interferes with the detection of that end of the electromagnetic spectrum. Even though we can see nebulae in visible light, what shows is the product of hot, excited gases, not the cold and dusty regions. These invisible regions are the specialty of Herschel’s SPIRE instruments. They map the dust in far-infrared with their spectroscopic observations. In this instance, the researchers were somewhat astounded when they found some very unusual data which required time to fully understand.
“Looking at infrared spectra is useful as it gives us the signatures of molecules, in particular their rotational signatures,” Barlow said. “Where you have, for instance, two atoms joined together, they rotate around their shared center of mass. The speed at which they can spin comes out at very specific, quantized, frequencies, which we can detect in the form of infrared light with our telescope.”
According to the news release, elements can exist in varying forms known as isotopes. These have different numbers of neutrons in the atomic nuclei. When it comes to properties, isotopes can be somewhat alike to each other, but they have different masses. Because of this, the rotational speed is dependent on which isotopes are present in a molecule. “The light coming from certain regions of the Crab Nebula showed extremely strong and unexplained peaks in intensity around 618 gigahertz and 1235 GHz.” By comparing data of known properties of different molecules, the science team came to the conclusion the mystery emission was the product of spinning molecular ions of argon hydride. What’s more, it could be isolated. The only argon isotope which could spin like that was argon-36! It would appear the energy released from the central neutron star in the Crab Nebula ionized the argon, which then combined with hydrogen molecules to form the molecular ion ArH+.
Professor Bruce Swinyard (UCL Department of Physics & Astronomy and Rutherford Appleton Laboratory), a member of the team, added: “Our discovery was unexpected in another way — because normally when you find a new molecule in space, its signature is weak and you have to work hard to find it. In this case it just jumped out of our spectra.”
Is this instance of argon-36 in a supernova remnant natural? You bet. Even though the discovery was the first of its kind, it is doubtless not the last time it will be detected. Now astronomers can solidify their theories of how argon forms. Current predictions allow for argon-36 and no argon-40 to also be part of supernova structure. However, here on Earth, argon-40 is a dominant isotope, one which is created through the radioactive decay of potassium in rocks.
Noble gas research will continue to be a focus of scientists at UCL. As an amazing coincidence, argon, along with other noble gases, was discovered at UCL by William Ramsay at the end of the 19th century! I wonder what he would have thought had he known just how very far those discoveries would take us?
Original Story Source: University College London (UCL) Press Release
An innovative solar observatory is adding a key piece to the puzzle of the enigma that is our Sun.
Its two of key questions in heliophysics: why does our Sun have a corona? And why is the temperature of the corona actually higher than the surface of the Sun?
This week, researchers released results from the preliminary first six months of data from NASA’s Interface Region Imaging Spectrograph, known as IRIS. The findings were presented at the Fall American Geophysical Union Meeting this past Monday.
IRIS was launched on June 27th of this year on a Pegasus-XL rocket deployed from the belly of a Lockheed L-1011 aircraft flying out of Vandenberg Air Force Base. IRIS can focus in on a very specific interface region of the Sun sandwiched between the dazzling solar photosphere and the transition to the corona. To accomplish this, IRIS employs an ultraviolet slit spectrograph looking at ionized gas spectra.
IRIS in the clean room. The spacecraft is only about 2 metres in length, about the height of a person. (Credit: Lockheed Martin).
“The quality of images and spectra we are receiving is amazing,” IRIS Principal Investigator Alan Title said in a recent press release from the NASA Goddard Space Flight Center. While other missions may take over a decade to go from the drawing board to the launch pad, IRIS was developed and deployed into Low Earth Orbit in just 44 months.
IRIS offers scientists a new tool to probe the Sun and a complimentary instrument to platforms such as Hinode, the Solar Heliospheric Observatory (SOHO) and NASA’s Solar Dynamics Observatory. In fact, IRIS has a better resolution than SDO’s AIA imagers or Hinode when it comes to this key solar interface region. IRIS has a 20x greater resolution in time, and 25x the spatial resolution of any former space-based UV spectrometer deployed.
“We are seeing rich and unprecedented images of violent events in which gases are accelerated to very high velocities while being rapidly heated to hundreds of thousands of degrees,” said Lockheed Martin science lead on the IRIS mission Bart De Pontieu. These observations are key to backing up theoretical models of solar dynamics as well as testing and formulating new ones of how our Sun works.
IRIS bridges this crucial gap between the photosphere and the lower chromosphere of the Sun. While the solar surface roils at relatively placid 6,000 degrees Celsius, temperatures rise into the range of 2-3 million degrees Celsius as you move up through the transition region and into the corona.
Two key solar phenomena that are of concern to solar researchers can be examined by IRIS in detail. One is the formation of prominences, which show up as long looping swirls of solar material rising up from the surface of the Sun. Prominences can be seen from backyard telescopes at hydrogen alpha wavelengths. IRIS can catch and track their early modeling with unprecedented resolution. Images released from IRIS show the fine structure of targeted prominences as they evolve and rise off the surface of the Sun. When a prominence and accompanying coronal mass ejection is launched in our direction, disruption of our local space environment caused by massive solar storm can result.
Slit jaw spectra images (the two strips to the left) and imaging of spicules (to the right) as seen by IRIS. (Credit: NASA/IRIS).
The second phenomenon targeted by IRIS is the formation of spicules, which are giant columns of gas rising from the photosphere. Although the spicules look like hair-fine structures through Earth-based solar telescopes, they can be several hundred kilometres wide and as long as the Earth. Short-lived, spicules race up from the surface of the Sun at up to 240,000 kilometres per hour and seem to play a key role in energy and heat transfer from the solar surface up through the atmosphere. IRIS is giving us a view of the evolution of spicules for the first time, and they’re proving to be even more complex than theory previously suggested.
“We see discrepancies between these observations and the models, and that is great news for advancing knowledge. By seeing something we don’t understand, we have a chance of learning something new,” Said University of Oslo astrophysicist Mats Carlsson.
Like SDO and SOHO, data and images from IRIS are free for the public to access online. Though the field of view for IRIS is a narrow 2’ to 4’ arc minutes on a side – the solar disk spans about 30’ as seen from the Earth – IRIS gives us a refined view of “where the action is.”
Where is IRIS looking? This snapshot gives some context of the IRIS field of view (green and red boxes) and black and white insets versus SDO’s AIA full disk view of the Sun. (Credit: NASA/SDO/IRIS).
And this all comes at an interesting time, as our nearest star crosses the sputtering solar maximum for Cycle #24.
The equivalent of 50 million CPU hours were utilized in constructing and modeling what IRIS sees. The reconstruction was an international effort, spanning the Partnership for Advanced Computing in Europe, the Norwegian supercomputing collaboration, and NASA’s Ames Research Center.
IRIS also faced the additional challenge of weathering a 2.5 week period of inactivity due to the U.S. government shutdown this fall. Potential impacts due to sequestration remain an issue, though small explorer missions such as IRIS demonstrate how we can do more with less.
“We’ve made a giant step forward in characterizing the heat transfer properties of this region between the visible surface and the corona, which is key to understanding how the outer atmosphere of the Sun exists, and is key to understanding the outer atmosphere that the Earth lies in,” said Alan Title, referring to the tenuous heliosphere of the Sun extending out through the solar system.
Understanding the inner working of our Sun is vital: no other astronomical body has as big an impact on life here on Earth.
IRIS is slated for a two-year mission, though as is the case with most space-based platforms, researchers will work to get every bit of usefulness out of the spacecraft that they can. And it’s already returning some first-rate science at a relatively low production cost. This is all knowledge that will help us as a civilization live with and understand our often tempestuous star.
