Mercurial delights / Supernova in spiral galaxy M61 / Jupiter spots

Mercury shines brightly in the east-southeast more than an hour before sunrise this morning November 1. The planet remains well-placed for viewing for the coming 10 days. Credit: Bob King

Scattered thin clouds took nothing away from this morning’s otherwise clear sky. With the Moon waxing from quarter to gibbous phase, the slab of darkness between moonset and dawn gets sliced thinner every day. Starting November 4th the Moon will light the sky all night and not give back the darkness till next weekend. I took advantage of a moonless morning to set up the telescope to view two comets, a brand new supernova in the bright Virgo galaxy M61 and the planet Mercury at dawn.

Around 7 a.m. CDT (6 a.m. CDT) in bright twilight, Spica cleared the treetops about 5 degrees to the lower left of Mercury. Watch in the coming mornings as Spica slides up higher in the sky and Mercury slowly drops horizon-ward. Credit: Bob King

Normally I suggest looking for Mercury around 45 minutes before sunrise when it’s high enough for a good view, but if you have an wide open eastern horizon, go for it earlier. The planet is very bright right now at magnitude -0.6 — brighter than it’s nearest rival, Arcturus (0.0) located three outstretched fists to the upper left of Mercury. I was surprised at how bright and easy it was to see it more than an hour before sunrise.

In the next few mornings, Virgo’s brightest star Spica rises near the planet. Watch them do a do-si-do in the coming days as Spica passes Mercury.

Facing east about 50 minutes before sunrise tomorrow and Monday Nov. 2-3. Mercury will be near Spica and about three outstretched fists to the right and below Arcturus. Source: Stellarium

Gianluca Masi captured this view of the supernova 2014dt (tick marks) in the 9th magnitude barred spiral galaxy M61 in Virgo on Halloween. The galaxy is some 55 million light years from Earth. Credit: Gianluca Masi

Virgo brings more than a bright morning planet. Tucked with the broad “Y” or cup-shaped northern half of the constellation, the bright galaxy M61 glows with a brand new supernova visible in amateur telescopes.

Japanese amateur astronomer Koichi Itagaki discovered the new star on October 29 at magnitude +13.6. A little on the faint side, yes, but it has been slowly brightening. This isn’t the first time we’ve witnessed a supernova explosion in the galaxy. At least two others – 2006in and 2008ov – have been observed. Quite the hotbed!

View looking east just before the start of morning twilight. M61 is located in the big Virgo “Y” about three outstretched fists to the right and above brilliant Arcturus. Source: Stellarium

Enlarged view of Virgo to help you better track down M61. When you find it, the supernova will look like a star inside the galaxy east of the core. Click for a large version. Source: Stellarium

Right now, you’ll need an 8-inch or larger telescope and dark sky to see it. The best time is just before dawn when Virgo is highest in the eastern sky. Through the eyepiece of my 15-inch (37-cm) scope this morning the galaxy glowed big and round with a bright core. Supernova 2014dt was a dim “star” 40 arc seconds east and 7 seconds south of the nucleus. Use the maps above to help you find the galaxy.

This morning’s shadow transit of Jupiter’s largest moon Ganymede (left) and a future transit that will occur on November 8 between 3:35 – 7:12 a.m. CST. The Great Red Spot will also be nicely placed for viewing. Add 1 hour for EST, subtract 1 hour for MST and 2 hours for PST. Source: Meridian

I always save the bright planets for last not only because they provide a refreshingly bright treat after hunting comets and supernovae but also because I don’t want to destroy my night vision. But I got a great surprise when pointing the scope at Jupiter. Plain as could be, there was the shadow of the planet’s largest moon Ganymede silhouetted against the white clouds of the equatorial zone and next to it, Ganymede itself. For a minute it looked like two moons casting shadows on the planet. Compared to its shadow, Ganymede was smaller and gray-toned.

You can catch the next Ganymede shadow transit visible in the western hemisphere on the morning of November 8 from 3:35 to 7:12 a.m. CST. A 3-inch or larger telescope is all it takes to view it.

The sun rises just before 8 a.m. over the Wisconsin shoreline of Lake Superior this morning November 1. Credit: Bob King

What better way to top off a morning of sky watching than with a sunrise? Now maybe I’ll take a nap.

Moon, Mars, Saturn and Antares gather at dusk tonight

The crescent moon, Saturn and Mars will form a compact triangle in the southwestern sky in this evening August 31st. 3.5º separate the moon and Saturn; Mars and Saturn will be 5º apart. Antares is about two ‘fists’ to the east or left. Stellarium

Don’t miss tonight’s sweet gathering of crescent moon and evening planets. Just look to the southwest in late twilight to spot the trio.

Both Saturn and Mars happen to be exactly the same brightness, shining equally at magnitude 0.8, but each with a distinctly different hue. Can you see the contrast between rusty red Mars and vanilla-white Saturn?

Antares is a red supergiant that’s blowing a powerful stellar wind into space at the rate of several solar masses every million years. One day it’s likely to explode as a supernova. Credit: Wikimedia

All this happens in Libra, a dim zodiac constellation preceding the brighter and better known Scorpius. Scorpius brightest star, Antares, is similar to Mars in color and just a tad fainter.

Visually, this red supergiant star doesn’t even hint of its true proportions because it’s 620 light years away, too far to appear as anything more than a shifting point of light. Measuring in at three times the diameter of Earth’s orbit, if Antares were put in place of the sun, its bubbly surface extending beyond the orbit of Mars.

How Antares would appear if we could get close enough to see it based on simulations by A. Chiavassa and team. Huge convective cells of rising and sinking gas crinkle its surface. Click to read the group’s 2010 research paper on the star. Credit: A. Chiavassa et. all

Recent research shows the star dominated by enormous bubbles of incandescent hydrogen gas called convective cells. Although it has a mass some 18 times that of the sun, the star’s powerful winds – from convection and sheer radiant energy – blast away something like 3 solar masses of material into space every million years. Unless Antares slims down through mass loss, it’s destined to grow a core of iron, collapse and explode as a supernova in the future.

Chandra’s X-ray eyes behold catastrophe

To mark the 15th anniversary of NASA’s Chandra X-ray Observatory, four newly processed images of supernova remnants illustrate Chandra’s ability to explore high-energy processes in the cosmos. See end of article for detailed explanations of each. Click to enlarge. NASA/CXC/SAO

15 years ago to the day, NASA’s Chandra X-ray Observatory opened its eyes to the high-energy universe. It was launched aboard the space shuttle Columbia and entered a long elliptical orbit that takes it more than a third of the distance to the moon before returning to its closest approach to Earth of 9,942 miles. This specially tailored path keeps it above the Van Allen radiation belts – which would interfere with its X-ray vision – more than 85% of the time.

Chandra’s long elliptical orbit around the Earth keeps it away from the Van Allen belts and allows the telescope to study an object up to 55 hours without interference. NASA

Chandra, named for Indian-American astrophysicist Subrahmanyan Chandrasekhar who did groundbreaking work on white dwarf stars, is specially designed to detect X-rays emitted by hot and energetic objects in the universe. What we feel as heat – infrared light – is low-energy radiation. Planets, comets and asteroids warmed by the sun emit infrared as surely as our own bodies do.

Radio waves, some infrared and visible light penetrate the atmosphere and make it to the ground. Shorter wavelength light from energetic UV to gamma rays are stopped by the atmosphere. A good thing.

As we move to light of shorter wavelengths, energy content rises. Visible light is more energetic than infrared, UV light more so (it can give us a painful sunburn) and X-rays very much more so. To spew X-rays, something very powerful must be happening in space like a supernova explosion or matter heated to incandescence as it disappears down a black hole.

Earth’s atmosphere acts to filter out dangerous much of the more energetic particles and light waves careening around the cosmos, the reason Chandra had to be pitched into the vacuum of space to use its X-ray specs.

Chandra has observed objects ranging from the closest planets and comets to the most distant known quasars. It has imaged the remains of exploded stars, or supernova remnants, observed the region around the supermassive black hole at the center of the Milky Way, and discovered black holes across the universe.

To celebrate the anniversary, NASA released  four newly processed pictures of supernova remnants, the dusty, gassy leftovers of stars blown to smithereens. Let’s take a look at each in turn:

Chandra view of the Crab Nebula expansion in just 7 months

* Crab Nebula: At its center is a city-sized, extremely compact, rapidly rotating neutron star left after the original sun went supernova in 1054 A.D. Also called a pulsar, the star spews zillions of high-speed particles that plow into the expanding debris field to create a ghostly X-ray nebula.

* G292.0+1.8:  One of only three supernova remnants in the Milky Way known to contain large amounts of oxygen. These oxygen-rich supernovas are of great interest to astronomers because they are one of the primary sources of elements heavier than hydrogen and helium that are necessary to form planets and people. The image shows a rapidly expanding debris field that contains, along with oxygen (yellow and orange), other elements such as magnesium (green) and silicon and sulfur (blue) that were forged in the star before it exploded.

* Tycho’s remnant: The supernova that created the remnant was first noticed by Danish astronomer Tycho Brahe in 1572 as a brand new star in the constellation Cassiopeia. The supersonic expansion of the exploded star produced a shock wave moving outward into the surrounding interstellar gas, and another, reverse shock wave moving back into the expanding stellar debris. Heated to millions of degrees, the gas and debris produce copious X-rays.

* 3C58: 3C58 is the remnant of a supernova observed in the year 1181 AD by Chinese and Japanese astronomers. It contains a rapidly spinning neutron star surrounded by a thick ring of X-ray emission. The pulsar also has produced jets of X-rays blasting away from it to both the left and right, and extending trillions of miles. These jets are responsible for creating the elaborate web of loops and swirls.

As a kid, we used to joke about wishing we had X-ray vision. Now we really do.

Australian astronomers find oldest known star in the universe

SMSS J031300.36-670839.3 – the oldest star ever found discovered with the SkyMapper telescope at the Siding Spring observatory in Australia. The star is smaller than the sun with a mass about 0.8 (or less) that of the sun. Credit: Space Telescope Science Institute/AAP

A team of scientists at the Australian National University led by Dr. Stefan Keller has discovered the oldest known star. Named SMSS J031300.36-670839.3, a dim magnitude 14.7 speck in the southern constellation Horologium the Clock (how appropriate!)

The 1.35-meter (53.1-inch) SkyMapper telescope used to track down the oldest star. Credit: Julia Karrer / ANU

SMSS 0313 (for short) is estimated to be about 13.6 billion years old, having formed just 180 million years after the origin of the universe in the Big Bang 13.78 billion years ago. The team used the university’s SkyMapper telescope at the Siding Spring observatory near Coonabarabran in northern New South Wales, Australia to make their discovery. It was later confirmed with the giant 6.5-meter (256-inch) Magellan telescope in Chile.

How do you determine a star’s age? You look for heavy elements. Back at the start of everything, the universe consisted almost exclusively of only the lightest, simplest elements, hydrogen and helium. The first generation of stars congealed from this simple mix and cooked up heavier elements through by fusing hydrogen and helium in their cores.

When they exploded as supernovae, new stuff never seen before like carbon, oxygen and iron were released into space to seed a second generation of stars. Those stars cooked up additional elements to enrich future generations of suns with still more complex elements. Our own sun, a relative latecomer on the scene, contains small amounts of all 92 natural elements right up to uranium, though the bulk of that fiery sphere – about 98% – is still hydrogen and helium.

Astronomers learn what chemical elements and compounds make up a star by spreading its light out into a rainbow called a spectrum. Each element creates its own “fingerprint” pattern of black lines called absorption lines.

To find SMSS 0313, Keller and team sifted though the spectra of 60 million stars. Spectra reveal a star’s chemical makeup through a “fingerprinting” process based on the colors of light absorbed by elements in its outer shell. They avoided stars dirtied by heavy elements like the sun and concentrated on those with signatures showing extremely low iron content.

Iron is cooked up in the cores of supergiant stars and released during supernovae explosions. Younger generation stars show more iron in their spectra thanks to contributions from previous generations.

SMSS 0313′s light revealed 10 million times less iron than found in the sun – the lowest iron abundance ever detected in a star. Based on that miniscule amount, the astronomers pegged it as a second generation star. One

As supergiant stars age, they fuse lighter elements into heavier elements in their core. When iron (Fe) and nickel (Ni) form, the fusion process stops and the star collapses and explodes as a Type II supernova, releasing heavier elements into space. Credit: NASA

Intriguingly, SMSS 0313′s chemical balance – rich in carbon and low in iron – hints at the composition of the very first generation of stars. It’s believed a star with a mass 60 times that of the sun underwent a low-energy explosion, primarily releasing elements like carbon from its outer envelope and taking most of its core iron on a one-way trip down the black hole that formed at the heart of the explosion.

So much drama, and all to make a star that’s quietly burned its chemical firewood for nearly the age of the universe.

Supernova 2014J in M82: What’s left after the party’s over?

Supernova 2014J in M82, the Cigar Galaxy, appears to have peaked in late Jan.-early Feb. at around magnitude 10.5. It’s now slowly beginning to fade. This photo taken Jan. 31 near peak. Credit: Joseph Brimacombe

Even with the moon filling out and lighting up the sky this week, supernova 2014J remains an easy catch in 4-inch and larger telescopes. One advantage of all the bitter cold weather in the U.S. Midwest has been a succession of clear nights like we haven’t seen in months. Maybe years.

Like many, I’ve had lots of opportunities to get out and see the progress of the star since its discovery on Jan. 21. Last night it still glowed at magnitude 10.9, a slight decline in brightness since peaking early this month at about 10.5.

M82 is also called the Starburst Galaxy. Vigorous new star formation blasts fiery-looking plumes of glowing hydrogen out of its central regions. Click to enlarge. Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA)

Color photos show the supernova tinted orange, reddened by dust clouds within the galaxy. This reddening is no surprise given how dusty the Cigar Galaxy is. M82 produces far more new stars than the Milky Way, the reason it’s also known as the Starburst Galaxy.

Powerful stellar winds from so many new stars sweeps dust and gas from the core and sends it flying across the galaxy. Later, even more dust is released when older generations of stars evolve, expand (or explode as supernova) and leave behind ice and silicate ash that filters and reddens the light of the supernova.

Curves showing how the supernova in M82 started out faint (left), and peaked at the beginning of this month. Notice how much fainter 2014J is in blue light compared to red. Visual observations are shown in green. Credit: AAVSO

You can see the dramatic effects of reddening in the light curves created by the American Association of Variable Star Observers (AAVSO) based on observations compiled by amateur astronomers. In blue light (lower curve) 2014J peaked at magnitude 11.6, but in red light (top) it was nearly two magnitudes brighter.

Had the supernova erupted in a less dusty part of the galaxy, it’s estimated that it would have peaked closer to magnitude 9, putting it within reach of 50mm binoculars!

Dust is likely behind the difficulty in finding the pre-explosion progenitor star and its companion. Professional astronomers have dug through archival pictures and data from the Chandra X-ray and Hubble Space telescopes as far back as 1999 but nothing’s turned up yet.

The progenitor and evolution of a Type Ia supernova. Credit: NASA, ESA, and A. Field (STScI)

Unlike a Type II supernova explosion of a supergiant star, 2014J involved the cataclysmic destruction of a planet-sized white dwarf star in close orbit around a red giant star. Material siphoned off the companion built up on the dwarf’s surface until it reached critical mass and self-destructed in a supernova explosion. Astronomers call this a Type Ia blast.

Clouds of dust are silhouetted against the young star cluster IC 2944 in the Milky Way galaxy. Similar clusters and dust clouds litter M82. Credit: ESO

White dwarfs and their companions are small and faint compared to a supergiant progenitor, making the search that much more difficult. Based on deep (long-time exposure) archival images taken with the Hubble Space Telescope and the galaxy’s distance of about 12 million light years, a team of astronomers recently proposed that the dwarf’s companion is a subgiant, a star larger, brighter and further evolved than the sun but not yet in the red giant stage. Procyon in the constellation Canis Minor is a good example of a subgiant.

Subgiants can be more or less massive. If more massive, they evolve into helium stars with powerful winds and rapid mass loss, making them worthy competitors in an intergalactic version of TV’s “The Biggest Loser”.

Another view of the supernova in the dusty galaxy M82 taken on Jan. 29 near Trieste, Italy with an 8-inch telescope. Credit: Giorgio Rizzarelli

If less massive, the remnant would develop into a helium white dwarf. Astronomers will be studying the explosion site for a long time looking for clues of what’s been left behind. Like detectives in a murder case, they hope to reconstruct the scene of this catalclysmic crime.

M82 supernova 2014J update … see it LIVE this afternoon

Supernova 2014J is visible in 4-inch and larger telescopes and currently shines around magnitude 11. Credit: Katzman Automatic Imaging Telescope / LOSS

The recent bright supernova SN 2014J discovered in the M82, the Cigar Galaxy, earlier this week has brightened up to magnitude 10.5 by some estimates. While I saw it last night at 11.5, I’m not complaining. Beginning and amateur astronomers the world over have been out braving the cold to get a look at this stellar beacon.

Don’t have a telescope but want to see a live image? Check out the Virtual Telescope Project 2.0 featuring Italian astrophysicist Gianluca Masi on . Starting this afternoon (Jan. 25) at 2:30 p.m. CST you can join the online observing session.

Lots more data on the supernova has been pouring in. Here’s what we know so far:

Wide field photo showing M82 “The Cigar Galaxy” and its true physical neighbor M81. The supernova is marked. Hundreds of supernovae are found each year by wide-ranging professional and amateur surveys of thousands of galaxies. The last recorded supernova visible with the naked eye in the Milky Way galaxy was in 1604. Click to learn more. Credit: Joseph Brimacombe

* SN 2014J is a Type Ia-HV supernova. HV stands for high-velocity and indicates that explosive gases have been rushing outward from the obliterated star at exceptional speeds. Early measurements on Jan. 22 clocked clouds of gas at over 12,400 miles per second (20,000 km/sec). To put this in context, the debris would make the trip from California to Maine in 1/4 second.

* Astronomers estimate it was discovered about a week before maximum brightness. That would indicate a peak on or around Jan. 29.

* SN 2014J is “highly reddened”, meaning that there is a great deal of dust in the host galaxy it has to shine through for its light to reach us. Without reddening, the explosion would be even brighter.

* White dwarf stars – one of which was the progenitor of this M82 supernova – are typically made of carbon and oxygen, the waste products left by the fusion of hydrogen and helium during the star’s lifetime. Once a star becomes a white dwarf it’s done fusing elements, so it twiddles its thumbs cooling off over the next trillion years.

Spectrum of supernova 2014J taken on Jan. 25, 2014 by William Wiethoff of Port Wing, Wisconsin U.S. shows the light of silicon at 6099.91 angstroms in the orange part of the visible spectrum. At the time, the star’s debris was traveling toward us at about 7,500 miles (12,000 km) per second. Inset photo and diagram: William Wiethoff

BUT … when it explodes as a supernova, waste carbon and oxygen fuse in the fury of heat and pressure to create a new element, silicon. That’s exactly what astronomers are seeing now in SN 2014J’s spectrum, a map of the star’s light made with a spectrograph. Spectrographs spread out a star’s light to “fingerprint” the elements of which it’s composed. Silicon is also produced “naturally” by fusion in the cores of supergiant stars, some of which can explode as Type II supernovae.

Silicon combined with oxygen is the most common compound in Earth’s crust. Next time you admire an agate or feel the sand between your toes, look up and thank a supernova.

Updated sketch of M82, the supernova and nearby stars with magnitudes shown. To make your own chart, click image to go to the AAVSO star plotter, then type in SN 2014J in the “Name” box. Illustration: Bob King

Closest, brightest supernova in 21 years goes boom in M82, the Cigar Galaxy

Before and after photo animation of the new bright supernova discovered overnight in the galaxy M82 in Ursa Major. Credit: Ernesto Guido, Nick Howes & Martino Nicolini

Like one of those famous exploding cigars in a Groucho Marx movie, nature imitates life by producing an exploding cigar of its own – a brand new, bright supernova in the “Cigar Galaxy” M82 in the Great Bear. It was discovered only last night by astronomer S. J. Fossey at magnitude 11.7. Very bright!

Even a 3-inch telescope under a dark sky can snare this one. While there have been brighter supernovae – and who knows, this one may very well get brighter yet – this is the brightest, closest supernova since SN 1993J popped off in neighboring galaxy M81.

The supernova in M82 is located 54″ west and 21″ south of the galaxy’s center along its long axis. Credit: Leonid Elenin

M82 goes by the nickname the Cigar Galaxy from its highly elongated shape. Through a small telescope it looks like a ghostly streak of light. At just 12 million light years from Earth it’s one of the closer galaxies to our home, making it bright enough to see in binoculars. Through a telecope, M82 is closely accompanied by the equally bright galaxy M81. Together they’re a favorite target on winter and spring nights for beginning and amateur astronomers.

M82 as pictured by the Hubble Space Telescope. A huge burst of new star formation is happening in the galaxy’s core. Click to enlarge. Credit: NASA/ESA

The big surprise is that no one found the object sooner. Most supernovae are spotted either by professional survey programs or amateur versions of the same when they’re around 15th magnitude or fainter. Not this one. It was brighter than 12th magnitude at discovery, but had someone been looking, it was easily visible in amateur instruments as early as January 16 at magnitude 13.9, brightening to 13.3 on the 17th and 12.2 on the 19th. Yikes! Why wasn’t I out looking at this galaxy?

The new supernova, with the temporary name of PSN J09554214+6940260, is a Type Ia explosion. In plain English, what we’re witnessing back here from our cozy homes on Earth is the complete annihilation of a super compact planet-size star called a white dwarf. Before anyone knew the star would explode, it spent millenia gravitationally siphoning off gas from a very close companion star. That material accumulated on its sizzling surface, adding to the weight of the little star. When the star reached the ultimate limit of 1.4 times the mass of the sun, it imploded under its own weight, heated up to billions of degrees and burned explosively. Boom! A supernova was born.

Use this map to point yourself in the right direction. It shows the sky facing north around 8 p.m. local time. M82 is paired with M81 about a “fist” above the bowl of the Big Dipper in the constellation Ursa Major. Stellarium

I know that the cold won’t keep you from wanting to see the new star so I’ve prepared a couple charts to help you find it. The first is a wide view to get situated; the second hones in to bring your directly to the galaxy. Be careful not to mix up M82 with its neighbor M81. M81 has a much rounder shape with a bright, distinct central core or nucleus. M82, an edge-on spiral galaxy, looks like a thin streak of light with a mottled texture. You’ll find the supernova west and south of M82′s center along the galaxy’s long axis. Look for a small star shining against the galaxy unresolved haze of stars.

To navigate to M82 find the Dipper Bowl and look above it for the easy naked eye star (mag. 3.5) 23 UMa. From there you can star hop to the triangular figure and down to the two stars forming a line. The galaxy is just below it. Stellarium

UPDATE: Sketch made Jan. 22 at 9 p.m. CST of M82 of the supernova, now called SN 2014J, through a 15-inch (37 cm) telescope. A wonderful arc of three bright stars (on left) guides you straight to it. You can’t miss it in telescopes 3 inches and up as the object is the only bright star shining in the galaxy. Numbers shown next to the stars are magnitudes to help you track the supernova’s brightness changes. Illustration: Bob King

Good luck in your quest to see one of the coolest sights in the night sky.

“Hand of God” fancied in X-ray glow of pulsar wind nebula

The pattern of an open hand is easy to imagine in this recent X-ray photo of a supernova’s cloudy remains. The structure radiating high-energy X-rays is shown in blue. Lower-energy X-ray light previously detected by NASA’s Chandra X-ray Observatory is shown in green and red. Click to enlarge. Credit: NASA/JPL-Caltech/McGill

A new X-ray photo taken by NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) showing a cloud of ejected material from a former supernova shows an eerie shape reminiscent of a hand reaching into space. A thumb of glowing gas extends from the palm; higher up, ghostly fingers touch a speckled red haze. Nicknamed the “Hand of God” it’s the remnant debris cloud from a long-ago exploding star.

Model of a pulsar, a tiny, rapidly rotating star that’s had its electrons and protons crunched together into pure neutrons during the core collapse in a supernova explosion. Beams of electromagnetic radiation and particles shoot out from the star’s poles as it rotates. Credit: NASA

Buried within lies the pulsar PSR B1509-58, itself a remnant of the supernova.This superdense, city-sized star spins around seven times a second and fires a wind of particles and radiation into the cloud. As they interact with the magnetic fields threading the supernova’s dregs, X-rays are released causing the cloud to glow.

A pulsar is the rapidly rotating neutron star that beams a pulse of radiation like a lighthouse during every spin. It’s what remains of a supergiant star’s core after it collapses and compacts in the wake of a supernova explosion. Almost all the empty space between and within atoms is squeezed out as electrons and protons are crushed into neutrons.

Not only are neutron stars fantastically dense – all the people of the Earth would fit in one teaspoon of pulsar star matter – but incredibly small. Pulsars pack at least one to three sun’s worth of material into a sphere some 6-15 miles (10-25 km) across.

When the pulsar’s beam sweeps in Earth’s direction we see a quick blip of light. The fastest spinning pulsar, named PSR J1748-2446ad, revolves at 716 times per second! Credit: W. Kramer

The pulsar is located inside the bright white spot and can’t be seen in the photo, but it’s energetic interaction with the remaining supernova gases creates the hand-shaped nebula. The red cloud at the end of the finger region is a different structure, called RCW 89. Astronomers think the pulsar’s wind is heating the cloud, causing it to glow with lower-energy X-ray light. One of the unanswered questions is whether the pulsar’s emissions light up the cloud in the shape of a hand or whether the cloud really has a natural hand shape.

Terms like “God particle” and “Hand of God” are great ways of making a human connection to cosmic wonders, but I’ll admit I cringe a little whenever I hear them because they might imply a supernatural explanation when there’s a perfectly natural one at hand.

Left image is normal while the right side of the right image has been darkened using the “hand of God” burning technique in Photoshop. Credit: Bob King

Funny. Back in the darkroom days when we used enlargers to project a negative image on a sheet of photo-sensitive paper and then dipped the sheets into developer to watch the images magically appear, “Hand of God” had an entirely different meaning.

We’d often darken the bright borders of our photographs so they’d look better in the newspaper by creating a small aperture with our fist under the enlarger lens.  Light pouring through the hole would be directed to this or that area of paper like a flashlight to darken or “burn it in”. We called it “hand of God” burning because it was artificial – not in the original photo – and sometimes used or misused to overpowering effect.

However you see the wonder of the universe from darkroom to pulsar winds, may it always buoy your spirits.

Team of Swift and Hubble nabs “kilonova” blast

Hubble pictures taken in infrared light of the fading afterglow left after the merger of two neutron stars in a distant galaxy in Leo. Credit: NASA, ESA, N. Tanvir (University of Leicester), A. Fruchter (STScI), and A. Levan (University of Warwick)

Astronomers using the Hubble Space Telescope have spotted the afterglow of an enormous gamma-ray fireball from a merging pair of stars in a galaxy almost 4 billion light years away.

Dubbed a “kilonova”, the blast occurs when two neutron stars the size of a city like Duluth, Minn. merge into one. “Kilo” in kilonova refers to the explosion being 1,000 times brighter than a nova, an eruption on the surface of a white dwarf star. A nearby nova in our home galaxy might become as bright as a 1st magnitude star; a similar kilonova would shine 6 times brighter than Venus.

This all-sky map shows the locations of Swift’s 500 gamma-ray bursts through 2010, color coded by the year in which they occurred. In the background, an infrared image shows the location of our galaxy. The bursts come from all around, mostly outside out galaxy. Credit: NASA/Swift/Francis Reddy

For years, gamma ray bursts coming from random directions in space have confounded scientists. What causes them? Where do they originate?

The blasts come in two varieties – short (lasting less than 2 seconds) and long (more than 2 seconds). Abundant evidence points to the collapse of extremely massive stars in supernova explosions as the origin of the long bursts. Big blasts pour out radiation of every kind, while biggest blasts create gamma-rays, which pack 10,000 times more energy than sunlight.

Illustration showing how two compact stars merge to make a kilonova. Radioactive material released in the merger heats up and expands, emitting a burst of light called a kilonova as well as a slew of gamma-rays. While kilonovas are 1,000 times brighter than a nova, they’re 1/10th to 1/100th the brightness of a typical supernova. Credit: NASA, ESA, and A. Field (STScI)

Prior to Hubble’s recent discovery, astronomers suspected the short blasts might originate from the merger of two extremely tiny, dense neutron stars. Neutron stars are born in the fires of a supernova when a massive star runs out of fuel, collapses and then explodes. Sometimes the massive star’s core, now compressed to incredible density by the implosion, remains after the blast to live on as a neutron star.

Put two neutron stars in a tight binary system and they’ll eventually spiral together into one or take the next step and snap into a black hole. As the whirl in an every tighter orbit, the stars emit gravitation radiation – literally ripples in the fabric of space-time – causing them to approach one another ever more closely until they finally meld into one. At that moment the fireworks begin.

Gamma rays are the most energetic form of radiation in the universe, produced in extreme heat and violent stellar explosions. Luckily, our atmosphere protects us from getting hit. Credit: NASA

NASA’s Swift space telescope detected the initial gamma ray blast on June 3. The explosion lasted only 1/10 of a second but was 100 billion times brighter than the subsequent kilonova flash. On June 12-13 Hubble swung its 94-inch eye at the remote galaxy SDS J112848.22+170418.5 in Leo and discovered a rosy red afterglow at the source of the gamma-ray burst.

Hubble spotted the explosion site in near-infrared light (a deeper, heat-radiating “red” light just beyond the color red) which faded away in early July. While this sounds unremarkable, it’s exactly what you’d expect if two neutron stars merged, shot out a blast of gamma rays and then settled back into relative peace as a newly minted black hole. The fading fireball and debris cloud temporarily blocks our view of the system but glows in telltale infrared until the smoke clears.

Like a thief caught red-handed, the team of Swift and Hubble nabbed the system in an act of merger and camouflage, providing astronomers with the hard data they needed to lock up an explanation for a most puzzling phenomenon.


New supernova in Phantom Galaxy M74 makes Milky Way look like a slacker

The recently discovered bright supernova 2013ej in the spiral galaxy M74 in the constellation Pisces the Fish seen here on July 28. The object is located 93″ east and 135″ south of the galaxy’s center. Credit: Ernesto Guido and Nick Howes (also for animation below)

I think I’m ready to move to another galaxy. M74 has it all. Beautiful spiral arms, puffy pink star clouds and a brand new bright supernova, the third to appear in fewer than a dozen years. Its latest exploding star, dubbed SN 2013ej was discovered by the Lick Observatory Supernova Search at Lick Observatory near San Jose, Calif.

The galaxy M74 is the 74th entry in a catalog of star clusters, nebula and galaxies compiled by French astronomer Charles Messier in the 18th century. M74 is 32 million light years away and about 30,000 light years across or about 1/3 the size of the Milky Way. Credit: Hubble Space Telescope / NASA / ESA

The Lick search uses a fully robotic or automated 30-inch (76 cm) telescope dedicated to scanning the skies for new supernovae. It scooped up M74′s latest exploding star on July 25 shining at a respectable 12.4 magnitude. Two previous supernovae flared in the galaxy - SN 2002ap and SN 2003gd - and rose to 12th and 13th magnitude respectively.

A combination optical and X-ray image of the expanding remains of the supernova that Kepler saw in 1604. The explosion was a Type Ia event that involved the destruction of a white dwarf star 13,000 light years from Earth. Credit: X-ray: NASA/CXC/NCSU/M. Burkey et al. Optical: DSS

So what’s going on with the Milky Way? The last supernova to flare in our neighborhood was seen by Johannes Kepler in 1604 before the telescope had even been invented. Since then, we’ve “suited up” with instruments of every kind ready to splice and dice the light of a nearby supernova in every imaginable way. Part of the reason for our perception of the Milky Way as a slacker may have to do with dust. Astronomers have discovered two recent supernovae that might have visible with the naked eye were it not for their locations deep within the galaxy, hidden by dense, dark clouds of interstellar dust.

Animation showing the supernova before and after discovery.

Over the weekend I made a pilgrimage to the countryside to see this newcomer to the intergalactic scene. It still shines brightly – for a star 32 million light years from Earth – at 12.5 magnitude, making it an easy catch in 8-inch and larger telescopes. The last quarter moon was less than a fist away from M74 at the time, rendering the galaxy itself invisible. Since then, the moon has since slimmed to a thick crescent and its glare is no longer an issue.

That’s why I encourage you to use the maps provided here to seek out the star’s final farewell for yourself.

While M74 is relatively bright and appears spectacular in long-exposure photos, it looks like a large, dim featureless glow in smaller telescopes. That’s how it got its nickname the “Phantom Galaxy”. Be patient and take your time to “star hop” to the supernova.

The galaxy M74 is about 1.5 degrees east-northeast of the star Eta Piscium just to the right of the small constellation Aries the Ram. The map shows the sky facing east around 1 a.m. in early August. Stellarium

In photos SN 2013ej looks much like the other faint stars nearby, which twinkle in the foreground and belong to the Milky Way, but it’s important to remember you’re seeing the annihilation of supergiant star at least 8 times the size of the sun.

Only days ago astronomers found an image of the likely progenitor (original star) before it blew up. They estimate is was at least 17,000 times more luminous than the sun before it ran out of fuel in its core and imploded. Now it shines with the light of nearly 10 million suns!

Supernovas come in a variety of gradations but they’re broadly divided into Type Ia and Type II. Type Ia involve the rapid and uncontrolled burning of a planet-sized white dwarf star when its penchant for funneling gas from a companion star causes it to gain too much weight. Once it passes the dreaded Chandrasekhar Limit, the dwarf becomes a thermonuclear bomb the size of the Earth with the mass of the sun.

Type II supernova explosions involve the destruction of a massive supergiant star. Credit: ESO

A Type II supernova happens when a massive star burns through its fuel supply until the needle hits empty. Without nuclear burning to produce the heat to fight back the force of gravity, which has been trying to crush the star into a point ever since it was born, the star collapses and then rebounds in a titanic explosion.

Besides a legacy of radiant light, star debris, the creation of heavy elements like gold and lead, a Type II event will sometimes leave behind a tiny, city-sized, rapidly-spinning neutron star – the much compressed core of the original star.

This map measures only about 1/2-degree wide and shows the galaxy and supernova in close. Selected star magnitudes from the AAVSO will  help you navigate to the object as well as estimate its brightness. North is up, west to the right. Map created with Chris Marriott’s SkyMap software

While I remain hopeful about seeing a Milky Way supernova in my remaining years on Earth, I’m happy to have the opportunity a dozen times or more a year to watch one from afar.