Hosts: Fraser Cain & Scott Lewis
Astronomers: David Dickinson, Gary Gonella, James McGee, Mike Simmons, Roy Salisbury, Shahrin Ahmad, Tom Nathe
Tonight’s views:
Jupiter with a nice view of the red spot, Venus approaching zenith, Bubble Nebula, the Pleiades, Orion Nebula, Horsehead Nebula, Flame Nebula, Running Man Nebula, the Moon, the Sun, the ISS (photo), the Rosette Nebula, Orion again, M33, Sunspots, Rosette again, California Nebula (multiple views), M81 & M82, Planet “X” (?!?), Andromeda, Flame Nebula again
We hold the Virtual Star Party every Sunday night as a live Google+ Hangout on Air. We begin the show when it gets dark on the West Coast. If you want to get a notification, make sure you circle the Virtual Star Party on Google+. You can watch on our YouTube channel or here on Universe Today.
Chang’e-3/Yutu Timelapse Color Panorama This newly expanded timelapse composite view shows China’s Yutu moon rover at two positions passing by crater and heading south and away from the Chang’e-3 lunar landing site forever about a week after the Dec. 14, 2013 touchdown at Mare Imbrium. This cropped view was taken from the 360-degree timelapse panorama. See complete 360 degree landing site timelapse panorama herein and APOD Feb. 3, 2014. Chang’e-3 landers extreme ultraviolet (EUV) camera is at right, antenna at left. Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo – kenkremer.com. See our complete Yutu timelapse pano at NASA APOD Feb. 3, 2014: http://apod.nasa.gov/apod/ap140203.htm
Chang’e-3/Yutu Timelapse Color Panorama
This newly expanded timelapse composite view shows China’s Yutu moon rover at two positions passing by crater and heading south and away from the Chang’e-3 landing site forever about a week after the Dec. 14, 2013 touchdown at Mare Imbrium. This cropped view was taken from the 360-degree timelapse panorama. See complete 360 degree landing site timelapse panorama herein and APOD Feb. 3, 2014. . Chang’e-3 landers extreme ultraviolet (EUV) camera is at right, antenna at left. Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo – kenkremer.com.
See our complete Yutu timelapse pano at NASA APOD Feb. 3, 2014: http://apod.nasa.gov/apod/ap140203.htm
Story updated[/caption]
The world famous and hugely popular ‘Yutu’ rover entered its 3rd Lunar night time hibernation period this weekend as planned, but serious technical troubles persist that are hampering science operations Chinese space managers confirmed.
“China’s lunar rover Yutu entered its third planned dormancy on Saturday, with the mechanical control issues that might cripple the vehicle still unresolved,” reports Xinhua, China’s official government news agency, in a mission status update newly released today (Feb. 23).
Yutu went to sleep on Saturday afternoon, Feb. 22, local Beijing time, according to China’s State Administration of Science, Technology and Industry for National Defence (SASTIND), responsible for the mission.
The companion Chang’e-3 lunar lander entered hibernation soon thereafter early today, Sunday, Feb 23.
360-degree time-lapse color panorama from China’s Chang’e-3 lander
This new 360-degree time-lapse color panorama from China’s Chang’e-3 lander shows the Yutu rover at five different positions, including passing by crater and heading south and away from the Chang’e-3 lunar landing site forever during its trek over the Moon’s surface at its landing site from Dec. 15-22, 2013 during the 1st Lunar Day. Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo – kenkremer.com. See our Yutu timelapse pano at NASA APOD Feb. 3, 2014: http://apod.nasa.gov/apod/ap140203.htm
The abnormality occurred due to the “complicated lunar surface,” according to SASTIND.
Chang’e-3 lander from Yutu moon rover
New mosaic of the Chang’e-3 moon lander and the lunar surface taken by the camera on China’s Yutu moon rover from a position south of the lander. Note the landing ramp and rover tracks at left. Credit: CNSA/SASTIND/Xinhua/Marco Di Lorenzo/Ken Kremer – kenkremer.com
Chinese space officials have not divulged the exact nature of the problems. And they have not released any details of the efforts to resolve the issues that “might cripple the vehicle.”
Since both Chinese Moon probes are solar powered, they must power down and enter a dormant mode during every two week long lunar night period when there is no sunlight to generate energy from their solar arrays. And no communications with Earth are possible.
The rover, nicknamed ‘Jade Rabbit’ remained stationary during the just concluded two week long lunar day time period, said SASTIND. It was unable to move due to the mechanical glitches.
“Yutu only carried out fixed point observations during its third lunar day.”
But it did complete some limited scientific observations. And fortunately the ground penetrating radar, panoramic and infrared imaging equipment are functioning normally.
This time-lapse color panorama from China’s Chang’e-3 lander shows the Yutu rover at two different positions during its trek over the Moon’s surface at its landing site from Dec. 15-18, 2013. This view was taken from the 360-degree panorama. Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo. See our complete Yutu timelapse pano herein and at NASA APOD Feb. 3, 2014: http://apod.nasa.gov/apod/ap140203.htm
The six wheel robot’s future was placed in jeopardy after it suffered the “mechanical anomaly” in late January 2014 and then awoke later than the scheduled time on Feb. 10, at the start of its 3rd Lunar Day.
To the teams enormous relief, a signal was finally detected.
“Yutu has come back to life!” said Pei Zhaoyu, the spokesperson for China’s lunar probe program, according to a Feb. 12 news report by the state owned Xinhua news agency.
“Experts are still working to verify the causes of its mechanical control abnormality.”
360-degree time-lapse color panorama from China’s Chang’e-3 lander
This 360-degree time-lapse color panorama from China’s Chang’e-3 lander shows the Yutu rover at three different positions during its trek over the Moon’s surface at its landing site from Dec. 15-22, 2013 during the 1st Lunar Day. Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo – kenkremer.com. See our Yutu timelapse pano at NASA APOD Feb. 3, 2014: http://apod.nasa.gov/apod/ap140203.htm
Since then, Chinese space engineers sought to troubleshoot the technical problems and were in a race against time to find a solution before the start of Lunar Night 3 this weekend.
“Experts had feared that it might never function again, but Yutu “woke up” on Feb. 12, two days behind schedule,” reported Xinhua.
Each lunar day and night lasts for alternating periods of 14 Earth days.
During each long night, the Moon’s temperatures plunge dramatically to below minus 180 Celsius, or minus 292 degrees Fahrenheit.
Both solar powered probes must enter hibernation mode during each lunar night to conserve energy and protect their science instruments and control mechanisms, computers and electronics.
“Scientists are still trying to find a fix for the abnormalities,” said CCTV, China’s official state television network.
So Yutu is now sleeping with the problems unresolved and no one knows what the future holds.
Hopefully Jade Rabbit awakes again in about two weeks time to see the start of Lunar Day 4.
The Chang’e-3 mothership lander and piggybacked Yutu surface rover soft landed on the Moon on Dec. 14, 2013 at Mare Imbrium (Sea of Rains) – marking China’s first successful spacecraft landings on an extraterrestrial body in history.
Snow Moon 2014 showing where China’s Yutu rover lives and works on lunar surface, at upper left. Photo: Mark Usciak. Annotation: Ken Kremer
‘Jade Rabbit’ had departed the landing site forever, and was journeying southwards as the anomoly occurred – about six weeks into its planned 3 month long moon roving expedition to investigate the moon’s surface composition and natural resources.
The 140 kg Yutu robot is located some 100 m south of the lander.
The 1200 kg stationary lander is expected to return science data about the Moon and conduct telescopic observations of the Earth and celestial objects for at least one year.
Chang’e-3 and Yutu landed on a thick deposit of volcanic material.
Landing site of Chinese lunar probe Chang’e-3 on Dec. 14, 2013.
China is only the 3rd country in the world to successfully soft land a spacecraft on Earth’s nearest neighbor after the United States and the Soviet Union.
Stay tuned here for Ken’s continuing Chang’e-3, Orion, Orbital Sciences, SpaceX, commercial space, LADEE, Mars and more planetary and human spaceflight news.
Chang’e-3 lander and Yutu rover – from Above And Below Composite view shows China’s Chang’e-3 lander and Yutu rover from Above And Below (orbit and surface) – lander color panorama (top) and orbital view from NASA’s LRO orbiter (bottom). Chang’e-3 lander color panorama shows Yutu rover after it drove down the ramp to the moon’s surface and began driving around the landers right side to the south. Yellow lines connect craters seen in the lander panorama and the LROC image from LRO (taken at a later date after the rover had moved), red lines indicate approximate field of view of the lander panorama. Credit: CNSA/NASA/Ken Kremer/Marco Di Lorenzo/Mark RobinsonTraverse Path of Yutu rover from Dec. 14 landing to Dec. 21. Landscape textured with Chang’e 3 imagery from space and ground. Credit: CNSA/BACC
Illustration from Parker et al, 2008, of the decomposition of the main-belt asteroid population into families and background
objects in proper a vs. sin(i) (left panels) and proper a vs. e (right panels). The top panels show all
(background and family) objects in the data subset. The two middle panels show objects from 37 identi?ed
families, and the bottom two panels show the background population. Credit: Parker et al, 2008.
Who knew asteroids could be so beautiful and mesmerizing? In 2008, a group of astronomers led by Alex Parker did a study of the size distribution of asteroid families using data from the Sloan Digital Sky Survey. Asteroid families often have distinctive optical colors, the team said, and they were able to offer an improved way to separate out the family members into their colors. This resultant animation put together just this week by Parker shows the orbital motions of over 100,000 asteroids, with colors illustrating the compositional diversity and relative sizes of the asteroids.
“The compositional gradient of the asteroid belt is clearly visible,” says Parker, “with green Vesta-family members in the inner belt fading through the blue C-class asteroids in the outer belt, and the deep red Trojan swarms beyond that.”
All main-belt asteroids and Trojan asteroids with orbits known to high precision are shown in the video and the animation is rendered with a timestep of 3 days. Via Twitter, Parker said this animation took — from start to finish — 20 hours to render on 8 CPUs.
For reference, the average orbital distances of Mercury, Venus, Earth, Mars, and Jupiter are illustrated with rings.
NASA’s next generation Global Precipitation Measurement (GPM) observatory inside the clean room at NASA Goddard Space Flight Center, MD. Technicians at work on final processing during exclusive up-close inspection tour by Universe Today. GPM is slated to launch on February 27, 2014 and will provide global measurements of rain and snow every 3 hours. Credit: Ken Kremer/kenkremer.com
NASA GODDARD SPACE FLIGHT CENTER, MARYLAND – Weather researchers and forecasters worldwide are gushing with excitement in the final days leading to blastoff of the powerful, new Global Precipitation Measurement (GPM) Core Observatory – built by NASA in a joint effort with Japan.
GPM is a next-generation satellite that will provide global, near real time observations of rain and snow from space and thereby open a new revolutionary era in global weather observing and climate science. Therefore it will have a direct impact on society and people’s daily lives worldwide.
The team is counting down to liftoff in less than 5 days, on Feb. 27 at 1:07 PM EST from the Tanegashima Space Center, on Tanegashima Island off southern Japan, atop the highly reliable Mitsubishi Heavy Industries H-IIA rocket.
The GPM launch to low Earth orbit was delayed by both natural and manmade disasters – namely the 2011 Fukushima earthquake in Japan as well as the ridiculous US government shutdown in Oct. 2013. That’s the same foolish shutdown that also delayed NASA’s new MAVEN Mars orbiter and numerous other US space & science projects.
Visualization of the GPM Core Observatory satellite orbiting the planet earth. Credit: NASA Goddard
The $933 Million mission is a joint venture between NASA and the Japan Aerospace Exploration Agency (JAXA), Japan’s space agency.
The mission will significantly advance our understanding of Earth’s water and energy cycles and improve forecasting of extreme weather events.
It is equipped with an advanced, higher resolution dual -frequency precipitation (DPR) radar instrument (Ku and Ka band) built by JAXA in Japan and the GPM microwave imager (GMI) built by Ball Aerospace in the US.
“The GPM satellite was built in house at NASA’s Goddard Space Flight Center in Maryland,” Art Azarbarzin, GPM project manager, told Universe Today during my exclusive up-close clean room inspection tour of the huge satellite as final processing was underway.
Global Precipitation Measurement (GPM) observatory satellite inside the clean room at NASA Goddard Space Flight Center undergoes final processing – side view. Credit: Ken Kremer/kenkremer.com
Shortly after my tour of GPM, the 3850 kilogram satellite was carefully packed up for shipment to the Japanese launch site.
“GPM will join a worldwide constellation of current and planned satellites,” Azarbarzin told me during an interview in the Goddard cleanroom with GPM.
And the imminent launch to augment the existing satellite constellation can’t come soon enough, he noted.
The GPM observatory will replace the aging NASA/JAXA Tropical Rainfall Measuring Mission (TRMM), satellite launched back in 1997.
“GPM is the direct follow-up to the currently orbiting TRMM satellite,” Azarbarzin explained.
“TRMM is reaching the end of its usable lifetime. GPM launches on February 27, 2014 and we hope it has some overlap with observations from TRMM.”
“The Global Precipitation Measurement (GPM) observatory will provide high resolution global measurements of rain and snow every 3 hours,” Dalia Kirschbaum, GPM research scientist, told me during an interview at Goddard.
NASA’s next generation Global Precipitation Measurement (GPM) observatory inside the clean room at NASA Goddard Space Flight Center, MD. Technicians at work on final processing during exclusive up-close inspection tour by Universe Today. GPM is slated to launch on February 27, 2014 and will provide global measurements of rain and snow every 3 hours. Credit: Ken Kremer/kenkremer.com
It is vital to continuing the TRMM measurements and will help provide improved forecasts and advance warning of extreme super storms like Hurricane Sandy and Super Typhoon Haiyan, Azarbarzin and Kirschbaum explained.
Researchers will use the GPM measurements to study climate change, freshwater resources, floods and droughts, and hurricane formation and tracking.
“The water-cycle, so familiar to all school-age young scientists, is one of the most interesting, dynamic, and important elements in our studies of the Earth’s weather and climate,” said John Grunsfeld, associate administrator for NASA’s Science Mission Directorate in Washington, in a statement.
“GPM will provide scientists and forecasters critical information to help us understand and cope with future extreme weather events and fresh water resources.”
GPM satellite launch site at Tanegashima Space Center, Tanegashima Island, Japan. Credit: NASA
NASA TV will carry the launch live with commentary starting at 12 Noon EST on Feb. 27.
Stay tuned here for Ken’s continuing GPM reports and onsite coverage at NASA Goddard Space Flight Center in Maryland.
And watch for Ken’s continuing planetary and human spaceflight news about Curiosity, Opportunity, Chang’e-3, SpaceX, Orbital Sciences, LADEE, MAVEN, MOM, Mars, Orion and more.
NASA/JAXA Global Precipitation Measurement (GPM) satellite inside the clean room at NASA Goddard Space Flight Center, MD, undergoes final processing during exclusive up-close inspection tour by Universe Today: Dr. Art Azarbarzin/NASA GPM project manager, Dr. Ken Kremer/Universe Today and Dr. Dalia Kirschbaum/NASA GPM research scientist. Credit: Ken Kremer/kenkremer.com
NASA astronaut Dale Gardner captures the malfunctioning WESTAR-VI satellite in 1984. Gardner was using the Manned Maneuvering Unit, a sort of space backpack that was discontinued for astronaut use after the Challenger explosion of 1986. Credit: NASA
I’ll admit it: I’m too young to remember 1984. I wish I did, however, because it was a banner year for the Manned Maneuvering Unit. NASA astronaut Dale Gardner, for example, used this jet backpack to retrieve malfunctioning satellites, as you can see above. (FYI, Gardner died Wednesday (Feb. 19) of a brain aneurysm at the age of 65.)
After three shuttle flights, however, NASA discontinued use of the backpack in space for several reasons — most famously, safety considerations following the shuttle Challenger explosion of 1986. But thirty years on, the problem of dead satellites is growing. There are now thousands of pieces whipping around our planet, occasionally causing collisions and generally causing headaches for people wanting to launch stuff into orbit safely.
Space agencies such as NASA and the European Space Agency have been working hard on reducing debris during launches, but there’s still stuff from decades before. And when a satellite goes dead, if it’s in the wrong orbit it could be circling up there for decades before burning up. How do you fix that?
Robotics has come a long way in 30 years, so space agencies are looking to use those instead to pick up derelict satellites since that would pose far less danger to astronauts. One example is the e.DeOrbit mission recently talked about by ESA, which would pick up debris in polar orbits of altitudes between 800 and 1,000 kilometers (about 500 to 620 miles).
One design idea for the e.DeOrbit mission, which would retrieve dead satellites from orbit. Credit: European Space Agency
The mission would use autonomous control and image sensors to get up close to the drifting satellite, and then capture it in some way. Several ideas are being considered, ESA added. A big enough net could easily nab the satellite, or perhaps one could clamp on using tentacles or grab it with a harpoon or robotic arm. Here’s a 2013 proposal with more information on e.DeOrbit. ESA noted there is a symposium coming up May 6 to discuss this in more detail.
e.DeOrbit is one of just several proposals to pick satellites up. A Swiss idea called CleanSpace One appears to use a sort of pincer claw to grab satellites for retrieval. The Phoenix program (proposed by Defense Advanced Research Projects Agency) would take useable parts off of broken satellites for use in new satellites, and in past years DARPA had some ideas to remove satellites from orbit as well. Another option is satellite refueling to make these machines useable again, a possibility that NASA, Canada and many others are taking seriously.
What do you think is the best solution? Leave your thoughts in the comments.
Dale Gardner (left) prior to the launch of STS-8 in 1983, along with the rest of his crew. Moving left, Guy Bluford, Bill Thornton, Daniel Brandenstein and Dick Truly. Credit: NASA
When Dale Gardner smiled for this preflight picture somewhere around 1983, there was another mission on his horizon: picking up a broken satellite … using a jet backpack. And while we believe that all astronauts have an element of derring-do to them, strapping on a device to bring you away from the shuttle’s safety must have taken a special kind of confidence in your equipment.
Gardner, who died Wednesday (Feb. 18) of a brain aneurysm at the age of 65, was one of a handful of astronauts who used the Manned Maneuvering Unit. In his case, it was to retrieve the malfunctioning Westar 6 satellite. Listen to his account of the story (around 9:25 here), however, and you’ll hear a man more focused on favorable sun angles and learning from the experience of another crewmate on STS-51A.
“I essentially just had a lot of fun on Flight Day 7,” he said in the video. And as the sequence of pictures below shows you, technical as the procedure was, the view must have been breathtaking.
Sequence of images showing NASA astronaut Dale Gardner approaching and capturing the malfunctioning Westar 6 satellite in 1984 during STS-51A. Click for a larger version. Credit: NASA (images) / Elizabeth Howell (photo combination)
Gardner, who was born in Minnesota, joined the U.S. Navy after graduating from the University of Illinois in 1970. He earned his wings the following year, then made his way through assignments to the prestigious Naval Air Test Center in Patuxent River, Maryland (the training ground for many future astronauts).
There, he participated in the development and evaluation of the Grumman F-14 Tomcat, an aircraft eventually used in Operation Desert Storm in the 1990s, among many other missions. Gardner was in fact part of the first F-14 squadron from none other than the USS Enterprise (the aircraft carrier, not the Star Trek ship.)
Gardner came to NASA as part of an immense astronaut class in 1978 that was later known as the “Thirty-Five New Guys” (which, it should be noted, also included six women, a first for the agency). With shuttle flights about to begin — a program that was then expected to launch dozens of flights a year — there appeared to be plenty of room for new recruits. Gardner’s first space-based assignment came upon STS-8, which flew in 1983 to deploy an Indian satellite called Insat-1B.
But it was for STS-51A’s eight-day mission in November 1984 where Gardner will be best remembered, because he did this:
NASA astronaut Dale Gardner captures the malfunctioning Westar 6 satellite during STS-51A in 1984. Gardner was using the Manned Maneuvering Unit, a sort of space backpack that was discontinued for astronaut use after the Challenger explosion of 1986. Credit: NASA
The shuttle mission was packed with satellite activity, with crew members deploying the Canadian communications satellite Anik D2, and U.S. defense communications satellite Leasat-1. Then it was time to pick up a couple of broken satellites to haul back to Earth.
Using a sort of grapple tool and his MMU, Joe Allen successfully retrieved Palapa-B2 on Flight Day 5. After Allen told his crewmates that he had some trouble with the sun in his eyes, Gardner used that information on his own MMU trip to pick up Westar 6 two days later. Specifically, Gardner and the crew had him approach in such a way that the shadow of the satellite fell across the astronaut, stopping the sun glare from becoming a problem.
NASA astronaut Dale Gardner holds a “For Sale” sign during STS-51A in 1984, referring to two satellites captured and retrieved on that mission. Credit: NASA
Both satellites had been in improper orbits due to problems with motors, but Gardner and his crew nabbed them safely for a return back to Earth, allowing insurers to resell the satellites for separate launches in 1990. But Gardner had a parting gotcha before handing them back: he held up a “For Sale” sign that you’ve likely seen reprinted somewhere, as it’s among the most famous shots of the shuttle program.
Gardner returned to the Navy in October 1986 (almost a year after the shuttle Challenger explosion), where he joined U.S. Space Command and held several senior positions. He retired from the Navy in 1990 to work in the private sector.
His death this week from a brain aneurysm was said to be sudden, and prompted a Twitter comment from the Association of Space Explorers saying that it was “devastating news.”
Spectacular photo of Comet ISON taken Nov. 15 from Charleston, Rhode Island, USA showing the recent outburst. Click to enlarge. Credit: Scott MacNeill
Comet ISON — that bright comet last year that broke up around Thanksgiving weekend — included two forms of nitrogen in its icy body, according to newly released observations from the Subaru Telescope.
Of the two types found, the discovery of isotope 15NH2 was the first time it’s ever been seen in a comet. Further, the observations from the Japanese team of astronomers show “there were two distinct reservoirs of nitrogen [in] the massive, dense cloud … from which our Solar System may have formed and evolved,” stated the National Astronomical Observatory of Japan.
Besides being pretty objects to look at, comets are considered valuable astronomical objects because they’re a sort of time capsule of conditions early in the universe. The “fresh” comets are believed to come from a vast area of icy bodies called the Oort Cloud, a spot that has been relatively untouched since the solar system formed about 4.6 billion years ago. Spying elements inside of comets can give clues as to what was present in our neighborhood when the sun and planets were just coming to be.
“Ammonia (NH3) is a particularly important molecule, because it is the most abundant nitrogen-bearing volatile (a substance that vaporizes) in cometary ice and one of the simplest molecules in an amino group (–NH2) closely related to life. This means that these different forms of nitrogen could link the components of interstellar space to life on Earth as we know it,” NAOJ stated.
You can read more details about the finding at the NAOJ website, or in Astrophysical Journal Letters.
An oblique view from the Lunar Reconnaissance Orbiter of Icarus Crater on the Moon. The shadow created by the unusual central peak in the crater is reminiscent of a certain Star Wars character. Icarus is approximately 94 km in diameter. Credit: NASA/GSFC/Arizona State University.
Scientists from the Lunar Reconnaissance Orbiter say that Icarus Crater is one of a kind on the Moon because its central peak rises higher than about half its rim. Most central peaks rise only about halfway to the crater rim. But at just the ring angle and lighting conditions, the shadow this central peak creates on the rolling and jagged crater rim looks like the Star Wars Character Yoda. Interestingly, this crater is located on what some people erroneously call the “Dark Side” of the Moon – what is actually the lunar farside.
Yoda meditates about moons. Via Blastr.com
Below you can see a closeup of the central peak of Icarus crater rising out of the shadows to greet a new lunar day.
The central peak of Icarus Crater on the Moon’s farside, as seen by LROC. Image width is approximately 10 km, north is to the right. Credit: NASA/GSFC/Arizona State University.
Icarus is located just west of Korolev crater on the lunar farside. The light-colored plains surrounding the craters were deposited during the formation of the Orientale basin, which is located over 1500 km away.
Image from LRO’s Wide Angle Camera of Icarus crater and vicinity. Image width is approximately 365 km. Credit: NASA/GSFC/Arizona State University.
Find out more about these images from LRO and see larger versions at the LROC website.
The speeding rogue star Kappa Cassiopeiae sets up a glowing bow shock in this Spitzer image (NASA/JPL-Caltech)
That might seem like a sensational headline worthy of a supermarket tabloid but, taken in context, it’s exactly what’s happening here!
The bright blue star at the center of this image is a B-type supergiant named Kappa Cassiopeiae, 4,000 light-years away. As stars in our galaxy go it’s pretty big — over 57 million kilometers wide, about 41 times the radius of the Sun. But its size isn’t what makes K Cas stand out — it’s the infrared-bright bow shock it’s creating as it speeds past its stellar neighbors at a breakneck 1,100 kilometers per second.
K Cas is what’s called a runway star. It’s traveling very fast in relation to the stars around it, possibly due to the supernova explosion of a previous nearby stellar neighbor or companion, or perhaps kicked into high gear during a close encounter with a massive object like a black hole.
As it speeds through the galaxy it creates a curved bow shock in front of it, like water rising up in front of the bow of a ship. This is the ionized glow of interstellar material compressed and heated by K Cas’ stellar wind. Although it looks like it surrounds the star pretty closely in the image above, the glowing shockwave is actually about 4 light-years out from K Cas… slightly less than the distance from the Sun to Proxima Centauri.
The bow shock of Zeta Ophiuchi, another runaway star observed by Spitzer (NASA/JPL-Caltech)
Although K Cas is visible to the naked eye, its bow shock isn’t. It’s only made apparent in infrared wavelengths, which NASA’s Spitzer Space Telescope is specifically designed to detect. Some other runaway stars have brighter bow shocks — like Zeta Ophiuchi at right — which can be seen in optical wavelengths (as long as they’re not obscured by dust, which Zeta Oph is.)
The bright wisps seen crossing K Cas’ bow shock may be magnetic filaments that run throughout the galaxy, made visible through interaction with the ionized gas. In fact bow shocks are of particular interest to astronomers precisely because they help reveal otherwise invisible features and allow deeper investigation into the chemical composition of stars and the regions of the galaxy they are traveling through. Like a speeding car on a dark country road, runaway stars’ bow shocks are — to scientists — like high-beam headlamps lighting up the space ahead.
Runaway stars are not to be confused with rogue stars, which, although also feel the need for speed, have been flung completely out of their home galaxies.
