Astronomy Archives

May 5, 2014December 23, 2015 by David Dickinson

Comet Jacques Brightens: How to See it in May

Comet Jacques as imaged on March 18th, shortly after discovery. Credit: Efrain Morales Rivera.

A recently discovered comet is headed northward and is set to put on one of two fine performances for binocular observers in 2014 starting this week.

Comet C/2014 E2 Jacques was discovered on March 13^th 2014 by Cristóvão Jacques, Eduardo Pimentel and João Ribeiro de Barros while observing from the Southern Observatory for Near Earth Asteroids Research (SONEAR) facility located near Oliveira, Brazil.

The comet was just about at +15^th magnitude at the time of discovery as it glided across the southern hemisphere constellation of Centaurus.

While a majority of comet discoveries are destined to remain small and faint, Comet Jacques was immediately shown to be something special. Upon discovery of any new comet, the first task is to gain several observations hours or nights apart to accurately gauge its distance and orbit. Are astronomers looking at a small, garden variety comet close up, or a large, active one far away?

In the case of Comet Jacques, it was something in between: a comet about 1.22 Astronomical Units (A.U.s) distant at time of discovery. Comet Jacques is headed towards perihelion 0.66 A.U. from the Sun in early July and will pass 0.56 A.U. from Earth on August 28th. Follow up observations carried out using the iTelescope at Siding Spring Australia showed a slightly elongated coma about 2 arc minutes across shortly after discovery, and the comet has recently jumped up to magnitude +8 — ahead of the projected light curve — in just the past week.

The path of Comet Jacques, looking west from latitude 30 degree north 45 minutes after sunset. Credit: Starry Night.

We caught our first good look at Comet Jacques last night while setting up for the Virtual Star Party. While +10 magnitude or brighter is usually a pretty good rule of thumb for binocular visibility, we found that the comet was only apparent as a fuzzy smudge viewing it with a 8” Schmidt-Cassegrain telescope using averted vision at low power. Remember, the brightness of a comet is spread out over its apparent surface area, similar to viewing a diffuse nebula. Our first telescopic views of the ill-fated comet ISON as it breeched +10^th magnitude were similar. Certainly, a nearby waxing crescent Moon in Gemini last night didn’t help.

How bright will Comet Jacques get? Current projections call for it to perhaps break naked eye visibility around +6^th magnitude after June 1^st and reach as bright as +4^th magnitude in early July near perihelion. After its first evening act in May and June, Comet Jacques will reemerge in the dawn sky for northern hemisphere observers for Act 2 and trace a path northward paralleling the galactic plane through the star rich fields of Perseus, Cassiopeia, Cepheus and Cygnus in August and September of this year. If our luck holds out, Comet Jacques will remain above 6^th magnitude until early September.

Credit JPL — The path of Comet Jacques through the inner solar system. Credit: JPL solar system small body generator.

This comet also created a brief flurry of interest when it was revealed that it will pass just 0.085 AUs or 12,700,000 kilometers from Venus on July 13^th, 2014. Though close, this is still 31 times the distance from Earth to the Moon. The only “eyes” that humanity has currently in operation around Venus is ESA’s Venus Express orbiter. During closest approach Comet Jacques will appear just over 3 degrees away from Venus as seen from our Earthly vantage point.

Another comet is also set to photobomb a planet, as Comet A1 Siding Spring passes a nominal distance of 0.0009 A.U.s or 135,000 kilometers from Mars this Fall on October 19th.

The closest recorded passage of a comet near Earth was Comet D/1770 L1 Lexell in 1770, which passed us 0.015 A.U.s or 233 million kilometres distant.

Now on to Act 1. May finds Comet Jacques spending most of the month in the long rambling constellation of Monoceros. Currently moving just under 2 degrees a day, Comet Jacques crosses the celestial equator northward this week on May 8^th. You’ll note its high orbital inclination of 156.4 degrees as it speeds northward. Comet Jacques has a long orbital period gauged at over 30,000 years — the last time Comet Jacques visited the inner solar system, our ancestors had the Last Glacial Maximum period to look forward to.

Light curve — The projected light curve of comet Jacques with recent observations. Credit: Seiichi Yoshida/aerith.net.

Comet Jacques is currently the brightest comet “with a bullet,” edging out the +9^th magnitude comets C/2012 K1 PanSTARRS gilding through Canes Venatici and comet C/2012 X1 LINEAR, currently residing in the constellation of Aquila the Eagle. A great place to keep up with current observations of comets is the Comet Observation Database. We’re also pinging the IAU Minor Planet Center’s quick look page for new discoveries daily.

Here are some highlights to watch out for as Comet Jacques heads towards perihelion. Passages within one degree — twice the size of the Full Moon — near stars brighter than +5^th magnitude are noted unless mentioned otherwise:

The celestial path of Comet Jacques from May 3rd through June 1st. Credit: Starry Night.

May 8^th: Passes the +4.1 magnitude star Delta Monocerotis and crosses north of the celestial equator.

May 10^th: Passes planetary nebula NGC 2346.

May 11^th: Passes briefly into Canis Minor before reentering the constellation Monoceros.

May 14^th: Full Moon occurs, marking the start of a favorable two week period of moonless evenings soon after.

May 24^th: Passes the +4.8 magnitude star 17 Monocerotis.

May 28^th: New Moon occurs, marking the return of the Moon to early evening skies.

May 29^th: Passes the +4.7 magnitude star 15 Monocerotis.

May 30^th: Passes the Christmas tree cluster. Photo op!

May 31^st: The waxing crescent Moon passes less than 8 degrees from Comet Jacques.

June 1^st: Comet Jacques reaches naked eye visibility?

June 6^th: Crosses into the constellation Gemini.

June 11^th: Crosses into the constellation Taurus.

June 13^th: Full Moon occurs.

June 14^th:Crosses the galactic plane.

June 21^st: Passes into the field of view of SOHO’s LASCO C3 camera.

June 27^th: New Moon occurs.

July 2^nd: Reaches perihelion at 0.6638 A.U. from the Sun.

July 8^th: Crosses north of the ecliptic plane.

July 13^th: Passes 0.085 A.U. from Venus.

August 28^th: Passes 0.56 A.U. from Earth.

And thus, Comet Jacques joins the parade of fine binocular comets in the 2014 night sky, as the stage is set for Act 2 this fall. And keep in mind, the next “big one” could grace our skies at anytime… more to come!

May 4, 2014December 23, 2015 by Bob King

Revisit Halley’s Comet – Stay Up Late for This Week’s Eta Aquarid Meteor Shower

The Eta Aquarid meteor shower is active in early May and peaks before dawn on Tuesday and Wednesday May 6-7 this year. Watch for it before the start of morning twilight in the eastern sky. Created with Stellarium

UPDATE: Watch a live webcast of the meteor shower, below, from NASA’s Marshall Space Flight Center during the night of Monday, May 5 to the early morning of May 6.

Halley’s Comet won’t be back in Earth’s vicinity until the summer of 2061, but that doesn’t mean you have to wait 47 years to see it. The comet’s offspring return this week as the annual Eta Aquarid meteor shower. Most meteor showers trace their parentage to a particular comet. The Perseids of August originate from dust strewn along the orbit of comet 109P/Swift-Tuttle, which drops by the inner solar system every 133 years after “wintering” for decades just beyond the orbit of Pluto, but the Eta Aquarids (AY-tuh ah-QWAR-ids) have the best known and arguably most famous parent of all – Halley’s Comet. Twice each year, Earth’s orbital path intersects dust and rock particles strewn by Halley during its cyclic 76-year journey from just beyond Uranus to within the orbit of Venus. When we do, the grit meets its demise in spectacular fashion as wow-inducing meteors.

Video streaming by Ustream

Composite of Aquarid meteors from the 2012 shower. Credit: John Chumack

Meteoroids enter the atmosphere and begin to glow some 70 miles high. The majority of them range from sand to pebble sized but most no more than a gram or two. Speeds range from 25,000-160,000 mph (11-72 km/sec) with the Eta Aquarids right down the middle at 42 miles per second (68 km/sec). Most burn white though ‘burn’ doesn’t quite hit the nail on the head. While friction with the air heats the entering meteoroid, the actual meteor or bright streak is created by the speedy rock exciting atoms along its path. As the atoms return to their neutral state, they emit light. That’s what we see as meteors. Picture them as tubes of glowing gas.

The farther south you live, the higher the shower radiant will appear in the sky and the more meteors you’ll see. For southern hemisphere observers this is one of the better showers of the year with rates around 30-40 meteors per hour. With no moon to brighten the sky, viewing conditions are ideal. Except for maybe the early hour. The shower is best seen in the hour or two before the start of dawn.

The Eta Aquarid shower originates with material left behind by Halley's Comet when the sun boils dust and ice from its nucleus around the time of perihelion. This photo from May 1986 during its last pass by Earth. Credit: Bob King — The Eta Aquarid shower originates with material left behind by Halley’s Comet when the sun boils dust and ice off its nucleus around the time of perihelion. This photo from May 1986 during Halley’s last visit. Credit: Bob King

From mid-northern latitudes the radiant or point in the sky from which the meteors will appear to originate is low in the southeast before dawn. At latitude 50 degrees north the viewing window lasts about 1 1/2 hours; at 40 degrees north, it’s a little more than 2 hours. If you live in the southern U.S. you’ll have nearly 3 hours of viewing time with the radiant 35 degrees high.

A bright, earthgrazer Eta Aquarids streaks across Perseus May 6, 2013. Because the radiant is low for northern hemisphere observers, earthgrazers - long, bright meteors that come up from near the horizon and have long-lasting trails. Credit: Bob King — A bright, earthgrazing Eta Aquarid meteor streaks across Perseus May 6, 2013. Because the radiant is low for northern hemisphere observers, watch for earthgrazers – long, bright meteors that come up from near the horizon and have long-lasting trails. Credit: Bob King

Northerners might spy 5-10 meteors per hour over the next few mornings. Face east for the best view and relax in a reclining chair. One good thing about this event – it won’t be anywhere near as cold as watching the December Geminids or January’s Quadrantids. We must be grateful whenever we can.

Meteor shower members can appear in any part of the sky, but if you trace their paths in reverse, they’ll all point back to the radiant. Other random meteors you might see are called sporadics and not related to the Eta Aquarids. Because Aquarius is home to at least two radiants, we distinguish the Etas, which radiate from near Eta Aquarii, from the Delta Aquarids, an unrelated shower active in July and August.

Wishing you clear skies and plenty of hot coffee at the ready.

May 4, 2014December 23, 2015 by Shannon Hall

“Fossil Galaxy” Discovered From the Early Universe

According to new research, life as we know it might have emerged earlier than other intelligent life. Credit: ESO

A small galaxy circling the Milky Way may be a fossil left over from the early Universe.

The stars in the galaxy, known as Segue 1, are virtually pure with fewer heavy elements than those of any other galaxy known. Such few stars (roughly 1,000 compared to the Milky Way’s 100 billion) with such small amounts of heavy elements imply the dwarf galaxy may have stopped evolving almost 13 billion years ago.

If true, Segue 1 could offer a window into the early universe, revealing new evolutionary pathways among galaxies in the early Universe.

Only hydrogen, helium, and a small trace of lithium emerged from the Big Bang nearly 13.8 billion years ago, leaving a young universe that was virtually pure. Over time the cycle of star birth and death produced and dispersed more heavy elements (often referred to as “metals” in astronomical circles), planting the seeds necessary for rocky planets and intelligent life.

The older a star is, the less contaminated it was at birth, and the fewer metals lacing the star’s surface today. Thus the elements detectible in a star’s spectrum provide a key to understanding the generations of stars, which preceded the star’s birth.

The Sun, for example, is metal-rich, with roughly 1.4% of its mass composed of elements heavier than hydrogen and helium. It formed only 4.6 billion years ago — two thirds of the way from the Big Bang to now — and sprung from multiple generations of earlier stars.

But three stars visible in Segue 1 have an iron abundance that is roughly 3,000 times less than the Sun’s iron. Or to use the proper jargon, these three stars have metallicities below [Fe/H] = -3.5.

Researchers led by Anna Frebel of the Massachusetts Institute of Technology report that Segue 1 “may be a surviving first galaxy that experienced only one burst of star formation” in the Astrophysical Journal.

Not only do the low chemical abundances suggest this galaxy is composed of extremely old stars, but they provide tantalizing hints about the types of supernovae explosions that helped create these stars. When high-mass stars explode they disperse a mix of elements; But when low-mass stars explode they almost exclusively disperse iron.

The lack of iron suggests the stars in Segue 1 are the products of high mass stars, which explode much more quickly than low mass stars. It appears that Segue 1 underwent a rapid burst of star formation shortly after the formation of the galaxy in the early universe.

Additionally, six stars observed show some of the lowest levels of neutron-capture elements ever found, with roughly 16,000 fewer elements than those seen in the Sun. These elements are created within stars when an atomic nucleus grabs an extra neutron. So a low level indicates a lack of repeated star formation.

Segue 1 burned through its first generation of stars quickly. But after the young galaxy produced a second generation of stars it completely shut off star formation, remaining a relic of the early universe.

The findings here suggest there may be a greater diversity of evolutionary pathways among galaxies in the early universe than had previously been thought.

But before we can make any sweeping claims “we really need to find more of these systems,” said Frebel in a press release. Alternatively, “if we never find another one, it would tell us how rare it is that galaxies fail in their evolution. We just don’t know at this stage because this is the first of its kind.”

The paper will be published in the Astrophysical Journal and is available for download here.

May 4, 2014April 26, 2016 by Bob King

Spectacular Aurora Sneaks in Quietly, Rages All Night

Auroral arcs are topped by red rays light up the northeast while the moon and Jupiter shine off to the west in this photo taken last night over a small lake north of Duluth, Minn. Both moon and aurora light are reflected in puddles on the ice. Credit: Bob King

Expect the unexpected when it comes to northern lights. Last night beautifully illustrated nature’s penchant for surprise. A change in the “magnetic direction” of the wind of particles from the sun called the solar wind made all the difference. Minor chances for auroras blossomed into a spectacular, night-long storm for observers at mid-northern latitudes.

6-hours of data from NASA's Advanced Composition Explorer spacecraft, which measures energetic particles from the sun and other sources from a spot 1.5 million kilometers ahead of Earth toward the sun. By watching the Bz graph, you'll get advance notice of the potential for auroras. Click to visit the site. Credit: NOAA — 6-hours of data from NASA’s Advanced Composition Explorer spacecraft, which measures energetic particles from the sun and other sources from a spot 1.5 million kilometers ahead of Earth toward the sun. By watching the Bz graph, you’ll get advance notice of the potential for auroras. Click to visit the site. Credit: NOAA

Packaged with the sun’s wind are portions of its magnetic field. As that material – called the interplanetary magnetic field (IMF) – sweeps past Earth, it normally glides by, deflected by our protective magnetic field, and we’re no worse for the wear. But when the solar magnetic field points south – called a southward Bz – it can cancel Earth’s northward-pointing field at the point of contact, opening a portal. Once linked, the IMF dumps high-speed particles into our atmosphere to light up the sky with northern lights.

A large red patch briefly glowed above the bright green arc around 11:15 p.m. CDT last night May 3. The color was faintly visible with the naked eye. Credit: Bob King

Spiraling down magnetic field lines like firefighters on firepoles, billions of tiny solar electrons strike oxygen and nitrogen molecules in the thin air 60-125 miles up. When the excited atoms return back to their normal rest states, they shoot off niblets of green and red light that together wash the sky in multicolor arcs and rays. Early yesterday evening, the Bz plot in the ACE satellite data dipped sharply southward (above), setting the stage for a potential auroral display.

After an intial flurry of bright rays, the aurora scaled back to two bright, diffuse arcs before erupting again around 11:30 p.m. Credit: Bob King — After an initial flurry of bright rays, the aurora scaled back to two bright, diffuse arcs with subtle rayed textures before erupting again around 11:30 p.m. Credit: Bob King

Nothing in the space weather forecast would have led you to believe northern lights were in the offing for mid-latitude skywatchers last night. Maybe a small possibility of a glow very low on the northern horizon. Instead we got the full-blown show. Nearly every form of aurora put in an appearance from multi-layered arcs spanning the northern sky to glowing red patches, crisp green rays and the bizarre flaming aurora. “Flames” look like waves or ripples of light rapidly fluttering from the bottom to the top of an auroral display. Absolutely unearthly in appearance and yet only 100 miles away.

VLF Auroral Chorus by Mark Dennison

I even broke out a hand-held VLF (very low frequency) radio and listened to the faint but crazy cosmic sounds of electrons diving through Earth’s magnetosphere. When my electron-jazzed brain finally hit the wall at 4 a.m., flames of moderately bright aurora still rippled across the north.

Just when you thought it was over, the whole northern sky burst into rays around 1 a.m. CDT. The whole northern sky lit up with green and red rays earlier this morning. While the green color was easy to see, the red was very pale. The human eye is much more sensitive to green light than red, one of the reasons why the aurora rarely appears red except in a camera during a time exposure. Credit: Bob King — Just when you thought it was over, the whole northern sky burst into rays around 1 a.m. CDT this morning. The human eye is much more sensitive to green light than red, one of the reasons why the aurora rarely appears red except in time exposures made with a camera. Credit: Bob King

Around 2 o'clock the northern lights displayed flaming when ripples of light pulse from top to bottom. It's very difficult to photograph, but here it is anyway! Credit: Bob King — Around 2 o’clock, flames pulsed from bottom to top in patchy aurora. It’s very difficult to photograph, but here it is anyway! Credit: Bob King

So what about tonight? Just like last night, there’s only a 5% chance of a minor storm. Take a look anyway – nature always has a surprise or two up her sleeve.

May 2, 2014December 23, 2015 by Nancy Atkinson

Falcon 9 Reusable Takes its Second Flight Test

The Falcon 9-R during a 10-second test in June 2013. Credit: Elon Musk on Twitter

No cows were harmed in the making of this video! SpaceX has released a video of a second test light of the Falcon 9 Reusable (FR9), and this time the rocket reached 1,000 meters – quadrupling its height from its previous test (see previous test flight below) — before returning to land softly.

From SpaceX: “The F9R testing program is the next step towards reusability following completion of the Grasshopper program last year. Future testing, including that in New Mexico, will be conducted using the first stage of a F9R as shown here, which is essentially a Falcon 9 v1.1 first stage with legs. F9R test flights in New Mexico will allow us to test at higher altitudes than we are permitted for at our test site in Texas, to do more with unpowered guidance and to prove out landing cases that are more-flight like.”

SpaceX has said that these first flights of F9R will have the landing legs fixed in the down position, but soon future tests will have the legs stowed against the side of the rocket and then extending them just before landing.

Here’s the first flight test:

April 30, 2014December 23, 2015 by Shannon Hall

‘Runaway’ Star Cluster Breaks Free from Distant Galaxy

This artist's illustration shows the hypervelocity star cluster HVGC-1 escaping from the supergiant elliptical galaxy M87. HVGC-1 is the first runaway star cluster discovered by astronomers. It is fated to drift through intergalactic space. David A. Aguilar (CfA)

We’ve discovered dozens of so-called “hypervelocity stars” — single stars that break the stellar speed limit. But today astronomers multiplied the number of these ‘runaway’ stars by hundreds of thousands. The Virgo Cluster galaxy, M87, has ejected an entire star cluster, throwing it toward us at more than two million miles per hour.

“Astronomers have found runaway stars before, but this is the first time we’ve found a runaway star cluster,” said lead author Nelson Caldwell of the Harvard-Smithsonian Center for Astrophysics, in a press release.

About one in a billion stars travel at a speed roughly three times greater than our Sun (which clocks in at 220 km/s with respect to the galactic center). At a speed that fast, these stars can easily escape the galaxy entirely, traveling rapidly throughout intergalactic space.

But this is the first time an entire star cluster has broken free.

What would cause an entire cluster — hundreds of thousands of stars packed together a million times more closely than in the neighborhood of our Sun — to reach such a tremendous speed?

Single hypervelocity stars have puzzled astronomers for years. But by observing their speed and direction, astronomers can trace these stars backward, finding that some began moving quickly in the Galactic Center. Here, an interaction with the supermassive black hole can kick a star away at an alarming speed. Another option is that a supernova explosion propelled a nearby star to a huge speed.

Caldwell and colleagues think M87 might have two supermassive black holes at its center. The star cluster wandered too close to the pair, which picked off many of the cluster’s outer stars while the inner core remained intact. The black holes then acted like a slingshot, flinging the cluster away at a tremendous speed.

The star cluster is moving so fast it should soon by sailing into intergalactic space. It may already be, but its distance remains unknown.

Velocity distribution of objects toward Virgo, includ- ing all confirmed GCs, all Hectospec velocities, and galaxies (from Rines & Geller 2008). The distinct stellar and GC distributions are clear, as is the broader galaxy distribution (dotted and shaded magenta). HVGC-1 is the marked extreme left outlier. Image Credit: Caldwell et al. — Velocities of stars, globular clusters and galaxies toward Virgo. HVGC-1 is the marked extreme left outlier.
Image Credit: Caldwell et al.

The team found the globular cluster — dubbed HVGC-1 — with a stroke of luck. They had been analyzing 2,500 globular cluster candidates for years. While a computer algorithm automatically calculated the speed of every cluster, any oddity was analyzed by hand.

Over 1,000 candidates have measured velocities between 500 and 3000 km/s. These speeds are typical for Virgo Cluster members. But HVGC-1 has a radial velocity of -1026 km/s. “This is the most negative, bulk velocity ever measured for an astronomical object not orbiting another object,” writes Caldwell.

“We didn’t expect to find anything moving that fast,” said coauthor Jay Strader of Michigan State University.

Future measurements pinpointing the exact distance to the globular cluster will help shed light on its exact origins.

The paper will be published in The Astrophysics Journal Letters and is available for download here.

April 30, 2014December 23, 2015 by Elizabeth Howell

Spin! Exoplanet’s Day Finishes Blazing Fast Compared To Earth

Artist's impression of Beta Pictoris b. Credit: ESO L. Calçada/N. Risinger (skysurvey.org)

Between the time you got to work this morning and the time you leave today — assuming an eight-hour work cycle — an entire day will have passed on Beta Pictoris b, according to new measurements of the exoplanet.

This daily cycle, mapped for the first time on a planet outside of the solar system, may reveal a link between how big a planet is and how fast it rotates, astronomers stated. That said, caution is needed because there are only a handful of planets where the rotation is known: the eight planets of our Solar System and Beta Pictoris b.

The planet’s day is shorter than any other planet in our Solar System, which at first blush makes sense because the planet is also larger than any other planet in our Solar System. Beta Pictoris b is estimated at 16 times larger and 3,000 times more massive than Earth. (For comparison, Jupiter is about 11 times larger and 318 times more massive than Earth.)

“It is not known why some planets spin fast and others more slowly,” stated says co-author Remco de Kok, “but this first measurement of an exoplanet’s rotation shows that the trend seen in the Solar System, where the more massive planets spin faster, also holds true for exoplanets. This must be some universal consequence of the way planets form.”

Planets in our Solar system size comparison. Largest to smallest are pictured left to right, top to bottom: Jupiter, Saturn, Uranus, Neptune, Earth, Venus, Mars, Mercury. Via Wikimedia Commons. — Planets in our Solar system size comparison.
Largest to smallest are pictured left to right, top to bottom: Jupiter, Saturn, Uranus, Neptune, Earth, Venus, Mars, Mercury. Via Wikimedia Commons.

Astronomers mapped the planet’s equatorial rotation using the CRIRES instrument on the Very Large Telescope. What helped was not only the planet’s large size, but also its proximity to Earth: it’s about 63 light-years away, which is relatively close to us.

As the planet ages (it’s only 20 million years old right now) it is expected to shrink and spin more quickly, assuming no other external forces. The Earth’s rotation is slowed by the moon, for example.

The study (“Fast spin of a young extrasolar planet” will soon be up on Nature’s website and was led by Leiden University’s Ignas Snellen.

Source: European Southern Observatory

April 29, 2014December 23, 2015 by Shannon Hall

It’s Freezing on the Surface of this Nearby Star-like Object

This artist's conception shows the object named WISE J085510.83-071442.5, the coldest known brown dwarf. Image credit: Penn State University/NASA/JPL-Caltech

Our stellar neighborhood just got a little busier … and a little colder.

A brown dwarf that’s as frosty as the Earth’s North Pole has been discovered lurking incredibly close to our Solar System. Astronomer Keven Luhman from Pennsylvania State University used NASA’s Wide-field Infrared Survey Explorer (WISE) and the Spitzer Space Telescope to pinpoint the object’s temperature and distance. This is the coldest brown dwarf found so far, and it’s a mere 7.2 light-years away, making it the seventh closest star-like object to the Sun.

“It is very exciting to discover a new neighbor of our Solar System that is so close,” said Luhman in a press release.

Brown dwarfs emerge when clouds of gas and dust collapse. But unlike stars, they never grow dense enough or burn hot enough to ignite nuclear fusion in their cores. They live their lives less massive than stars, but more massive than gas giants. So they burn hot at first, then cool over time. And this newly discovered brown dwarf is as cold as ice. Literally.

WISE surveyed the entire sky twice in its short 14-month lifetime, looking at cooler objects, which radiate in infrared light (but often remain invisible in visible light). It saw cold asteroids, dust clouds, proto-planetary disks, distant galaxies and hundreds of brown dwarfs.

But one of these objects — dubbed WISE J085510.83-071442.5 — was moving rapidly, suggesting it was extremely close to the Solar System. All stars orbit around the Milky Way, with apparent motions seen on the timescale of hundreds of years. Stars close to the Sun, however, can be seen to make the slightest of movements on the timescale of just a few years. This object appeared to move in just a few months.

This animation shows the coldest brown dwarf yet seen, and the fourth closest system to our sun. Called WISE J085510.83-071442.5, this dim object was discovered through its rapid motion across the sky. It was first seen in two infrared images taken six months apart in 2010 by NASA's Wide-field Infrared Survey Explorer, or WISE (see orange triangles). Two additional images of the object were taken with NASA's Spitzer Space Telescope in 2013 and 2014 (green triangles). All four images were used to measure the distance to the object -- 7.2 light-years -- using the parallax effect. › See animation The Spitzer data were used to show that the body is as cold as the North Pole (or between minus 54 and 9 degrees Fahrenheit, which is minus 48 to minus 13 degrees Celsius). Image credit: NASA/JPL-Caltech/Penn State — Click on the image above to see an animation of WISE J085510.83-071442.5. It was first seen in two infrared images taken six months apart in 2010 by WISE (see orange triangles). Two additional images of the object were taken with NASA’s Spitzer Space Telescope in 2013 and 2014 (green triangles). Image credit: NASA/JPL-Caltech/Penn State

After first spotting this wacky object in the WISE data, Luhman analyzed additional images taken with the Spitzer Space Telescope and the Gemini South Pole Telescope in Chile. The combined detections taken from different positions around the Sun enabled the measurement of the objects parallax — the apparent position of the object against a background set of stars as seen along multiple lines of sight — allowing Luhman to determine the objects distance.

Spitzer’s additional observations helped pin down the objects chilly temperature, which can be determined based on how much light it gives off in different colors. Like a flame, the hottest part is blue, while the coldest part is red. Luhman found the brown dwarfs temperature to be between –54° and 9° Fahrenheit (–48° to –13° Celsius). Previous record-holders for the coldest brown dwarfs were about room temperature.

“It is remarkable that even after many decades of studying the sky, we still do not have a complete inventory of the Sun’s nearest neighbors,” said Michael Werner from NASA’s Jet Propulsion Laboratory. “This exciting new result demonstrates the power of exploring the universe using new tools, such as the infrared eyes of WISE and Spitzer.”

With a stretch of the imagination and advanced technology, it’s possible that other cooler objects, be them brown dwarfs of even rogue exoplanets, are yet closer to the Sun.

The paper will be published in the Astrophysics Journal and is available for download here.

April 29, 2014December 23, 2015 by David Dickinson

Amazing Images of Today’s Solar Eclipse from Earth and Space

The images are pouring in. While most of North America slept this AM, Australians were treated to the very first solar eclipse of 2014 earlier today. And while this particular eclipse was a partial one only from the Australian continent, it still offered observers a fine view of an often elusive natural spectacle.

The partial eclipse as seen from Adelaide. Credit: Michael Drew (@MichaelDrew1234)

Although rain and clouds frustrated attempts to view the eclipse from much of southern Australia, clouds parted long enough in Queensland to the east and areas around Perth to the west to offer observers a fine view. Many eclipse watchers on the Australian east coast had the additional bonus of catching the setting Sun during the eclipse.

A quick screen shot from ESA’s Proba-2 spacecraft during one of the three passes of the solar eclipse. Credit: ESA/Proba-2.

We wrote about the prospects for catching this bizarre eclipse previously. The eclipse was a rare, non-central annular with one limit only, meaning the antumbra or inner core of the Moon’s shadow just grazed the edge of the planet over Antarctica. We haven’t yet heard if anyone witnessed it from the southern polar continent, though two year round research stations were located near the path of annularity. The European Space Agency operates Concordia Station nearby as part of its Human Spaceflight Activities program and they were aware of the upcoming event. We’ll keep you updated if reports or images surface!

The eclipse seen through clouds. Photographer David Herne also noted that while he used his D3100 DSLR for the shot, his homemade pinhole camera offered fine views as well! Credit: David Herne(@AunaEridu)/Perth Western Australia.

As predicted, another solar observing sentinel in low Earth orbit did indeed witness the eclipse. ESA’s Proba-2 spacecraft caught the eclipse on three passes in this amazing raw animation from its SWAP-2 camera. The final third pass goes by extremely quick –these are measured in minutes from Proba-2’s swift vantage point – but the Sun looks well nigh to greater than 95% eclipsed by the Moon as it flies by.

The partial solar eclipse as seen from Adelaide, Australia. Credit: Silveryway.

There’s no word as of yet if the joint NASA/JAXA mission Hinode caught the eclipse as well, but we’ll keep you posted!

UPDATE: Courtesy of the European Space Agency and the Royal Observatory of Belgium, we now give you the full YouTube timelapse of the eclipse courtesy of Proba-2:

You’ll note that Proba-2 caught the partial phases on four separate passes… we also checked the sequence frame by frame, and although it looks like Proba-2 “may” have seen an annular – or even total – eclipse from space, it looks like it did so between captures!

This eclipse is one of two solar eclipses and four eclipses total for 2014. An interesting discussion occurred leading up to this eclipse as to the minimum number of eclipses that can occur in a year, which is four. If, however, you exclude faint lunar penumbrals, that number does indeed drop to two, both of which must be solar, which occurs in 2016. This also sparked a lively debate as to the naming of such a year on Twitter, with everything from a “Dwarf Eclipse Year” to “Nano Eclipse Cycle” and “Spurious Eclipse Year” being proposed. We liked the suitably esoteric and ready tweet-able term “declipsy” ourselves… thanks for the proposals and the lively discussion!

The partially-eclipsed Sun sinks into the west as seen from Brisbane, Australia on April 29, 2014. Credit and copyright: Teale Britstra.

Partial solar eclipse in Adelaide, South Australia on April 29, 2014. Credit and copyright: Silveryway on Flickr.

Thanks also to all who sent in pics. We’ll be updating this post as more come in… and although eclipse season 1 of 2 may be over for now, 2014 still has another total lunar eclipse and a good partial solar in October, both visible from North America.

…And we’re only three years out and have just two more total solar eclipses to go until the historic total solar eclipse of August 21^st, 2017…

Let the countdown begin!

UPDATE: Missed out on the solar eclipse today? Hey so did we, it happens to the best of us… luckily, YOU can now relive the all of the excitement of the eclipse courtesy of the folks from the Virtual Telescope Project in YouTube Splendor:

And finally: got pics of the partial solar eclipse that you took today and you want to share with the world? Put ’em up on Universe Today’s Flickr community and let us know!

April 28, 2014December 23, 2015 by Jason Major

Hello From Mars! Curiosity Smiles in Her Latest “Selfie”

A mosaic of MSL MAHLI images acquired on Sol 613 (NASA/JPL-Caltech/MSSS. Edit by Jason Major.)

This is very cute — Curiosity’s latest “selfie,” a mosaic I assembled from about a dozen images acquired with the rover’s Mars Hand Lens Imager (MAHLI) instrument on April 27-28, 2014 (Sol 613), with the 5.5-km-high Mount Sharp (Aeolis Mons) rising in the background. Click the image for a high-res version.

While it’s far from a perfect image — there are plenty of discrepancies in the mosaic tiling, I admit — I really like the character it imparts to Curiosity, who almost seems to be giving a toothy (if slightly dusty) grin there on the left with her cylindrical RUHF antenna and a bit of her RTG visible in the lower center. And with almost 21 Earth-months on Mars and lots of discoveries already under her robot belt, Curiosity (and her team) certainly have plenty to smile about!

See these and all the raw images from the MSL mission here, and read more about Curiosity’s latest work in Gale Crater in Ken Kremer’s article here.