What is a Pulsar?

What is a Pulsar?

They are what is known as the “lighthouses” of the universe – rotating neutron stars that emit a focused beam of electromagnetic radiation that is only visible if you’re standing in it’s path. Known as pulsars, these stellar relics get their name because of the way their emissions appear to be “pulsating” out into space.

Not only are these ancient stellar objects very fascinating and awesome to behold, they are very useful to astronomers as well. This is due to the fact that they have regular rotational periods, which produces a very precise internal in its pulses – ranging from milliseconds to seconds.

Description:

Pulsars are types of neutron stars; the dead relics of massive stars. What sets pulsars apart from regular neutron stars is that they’re highly magnetized, and rotating at enormous speeds. Astronomers detect them by the radio pulses they emit at regular intervals.

An artist’s impression of an accreting X-ray millisecond pulsar. The flowing material from the companion star forms a disk around the neutron star which is truncated at the edge of the pulsar magnetosphere. Credit: NASA / Goddard Space Flight Center / Dana Berry

Formation:

The formation of a pulsar is very similar to the creation of a neutron star. When a massive star with 4 to 8 times the mass of our Sun dies, it detonates as a supernova. The outer layers are blasted off into space, and the inner core contracts down with its gravity. The gravitational pressure is so strong that it overcomes the bonds that keep atoms apart.

Electrons and protons are crushed together by gravity to form neutrons. The gravity on the surface of a neutron star is about 2 x 1011 the force of gravity on Earth. So, the most massive stars detonate as supernovae, and can explode or collapse into black holes. If they’re less massive, like our Sun, they blast away their outer layers and then slowly cool down as white dwarfs.

But for stars between 1.4 and 3.2 times the mass of the Sun, they may still become supernovae, but they just don’t have enough mass to make a black hole. These medium mass objects end their lives as neutron stars, and some of these can become pulsars or magnetars. When these stars collapse, they maintain their angular momentum.

But with a much smaller size, their rotational speed increases dramatically, spinning many times a second. This relatively tiny, super dense object, emits a powerful blast of radiation along its magnetic field lines, although this beam of radiation doesn’t necessarily line up with it’s axis of rotation. So, pulsars are simply rotating neutron stars.

And so, from here on Earth, when astronomers detect an intense beam of radio emissions several times a second, as it rotates around like a lighthouse beam – this is a pulsar.

History:

The first pulsar was discovered in 1967 by Jocelyn Bell Burnell and Antony Hewis, and it surprised the scientific community by the regular radio emissions it transmitted. They detected a mysterious radio emission coming from a fixed point in the sky that peaked every 1.33 seconds. These emissions were so regular that some astronomers thought it might be evidence of communications from an intelligent civilization.

Although Burnell and Hewis were certain it had a natural origin, they named it LGM-1, which stands for “little green men”, and subsequent discoveries have helped astronomers discover the true nature of these strange objects.

Astronomers theorized that they were rapidly rotating neutron stars, and this was further supported by the discovery of a pulsar with a very short period (33-millisecond) in the Crab nebula. There have been a total of 1600 found so far, and the fastest discovered emits 716 pulses a second.

Later on, pulsars were found in binary systems, which helped to confirm Einstein’s theory of general relativity. And in 1982, a pulsar was found with a rotation period of just 1.6 microseconds. In fact, the first extrasolar planets ever discovered were found orbiting a pulsar – of course, it wouldn’t be a very habitable place.

Interesting Facts:

When a pulsar first forms, it has the most energy and fastest rotational speed. As it releases electromagnetic power through its beams, it gradually slows down. Within 10 to 100 million years, it slows to the point that its beams shut off and the pulsar becomes quiet.

When they are active, they spin with such uncanny regularity that they’re used as timers by astronomers. In fact, it is said that certain types of pulsars rival atomic clocks in their accuracy in keeping time.

Pulsars also help us search for gravitational waves, probe the interstellar medium, and even find extrasolar planets in orbit. In fact, the first extrasolar planets were discovered around a pulsar in 1992, when astronomers Aleksander Wolszczan and Dale Frail announced the discovery of a multi-planet planetary system around PSR B1257+12 – a millisecond pulsar now known to have two extrasolar planets.

Artist's impression of the planets orbiting PSR B1257+12. Credit: NASA/JPL-Caltech/R. Hurt (SSC)
Artist’s impression of the planets orbiting PSR B1257+12. Credit: NASA/JPL-Caltech/R. Hurt (SSC)

It has even been proposed that spacecraft could use them as beacons to help navigate around the Solar System. On NASA’s Voyager spacecraft, there are maps that show the direction of the Sun to 14 pulsars in our region. If aliens wanted to find our home planet, they couldn’t ask for a more accurate map.

We have written many articles about stars here on Universe Today. Here’s an article about a newly discovered gamma ray pulsar, and here’s an article about how millisecond pulsars spin so fast.

If you’d like more information on stars, check out Hubblesite’s News Releases about Stars, and here’s the stars and galaxies homepage.

We have recorded several episodes of Astronomy Cast about stars. Here are two that you might find helpful: Episode 12: Where Do Baby Stars Come From, and Episode 13: Where Do Stars Go When they Die?

Pew! Pew! Laser On The Space Station Will Beam Video To Earth

Artist's conception of an astronaut installing the Optical PAyload for Lasercomm Science (OPALS) experiment, which will be installed on the Earth-facing side of the International Space Station. Credit: NASA

Videos will beam to Earth on a laser beam in a technology demonstration coming to the International Space Station soon, says NASA’s Jet Propulsion Laboratory.

The Optical PAyload for Lasercomm Science (OPALS) plans to move videos from space to an Optical Communications Telescope Laboratory in Wrightwood, Calif. Each demonstration test will last about 100 seconds, while the station and the ground receiver can “see” each other.

While the experiment sounds awesome for sending back “home videos” from space, NASA is more touting it as a boon for transferring loads of scientific data back to Earth.

“The scientific instruments in near-Earth and deep-space missions increasingly require higher communication rates to transmit their gathered data back to Earth or to support high-data-rate applications (e.g., high-definition video streams),” stated the OPALS webpage at NASA’s Jet Propulsion Laboratory.

“Optical communications (also referred to as ‘lasercomm’) is an emerging technology wherein data is modulated onto laser beams, which offers the promise of much higher data rates than what is achievable with radio-frequency (RF) transmissions.”

How the Optical PAyload for Lasercomm Science (OPALS) experiment will work on the International Space Station. Credit: NASA
How the Optical PAyload for Lasercomm Science (OPALS) experiment will work on the International Space Station. Credit: NASA

The experiment page (last updated in May) says it is intended to work for about a year, with the current Expedition 37/38 and forthcoming 39/40 crews. That said, it appears the payload is not aboard station yet.

A July update from NASA said the SpaceX Dragon spacecraft is supposed to ferry OPALS to space. There hasn’t been a Dragon flight since that time, but SpaceX is listing one more for 2013 on its launch manifest.

Diagram of the Optical PAyload for Lasercomm Science (OPALS) experiment. It includes three elements: (1) a sealed container that includes the laser, a power board and avionics (2) an optical gimbal transceiver that has an uplink camera, and laser collimater for downlink (3) a Flight Releasable Attachment Mechanism (FRAM), a mechanical and electrical link to the International Space Station and launch vehicle. Credit: NASA
Diagram of the Optical PAyload for Lasercomm Science (OPALS) experiment. It includes three elements: (1) a sealed container that includes the laser, a power board and avionics (2) an optical gimbal transceiver that has an uplink camera, and laser collimater for downlink (3) a Flight Releasable Attachment Mechanism (FRAM), a mechanical and electrical link to the International Space Station and launch vehicle. Credit: NASA

Laser communication hit headlines earlier this fall when the NASA Lunar Atmosphere and Dust Environment Explorer (LADEE) sent a packet of information by laser from the moon, breaking records in terms of download rate (622 megabits per second).

Inspiration Mars Wants To Work With NASA To Get To The Red Planet

An artist’s concept of how the spacecraft for the Inspiration Mars Foundation’s “Mission for America” might be configured. Credit: Inspiration Mars.

CORRECTION: This article has been updated after more information was received from Inspiration Mars. Tito was highlighting other countries’ interest in the Red Planet in his testimony and has no plans at this time to work with anyone but NASA.

Remember that proposal to send a couple in the direction of the Red Planet, loop around it and then come back to Earth? The founder of the Inspiration Mars project, Dennis Tito, outlined more details of his proposal before the House Science Subcommittee on Space yesterday (Nov. 20).

Inspiration Mars has released an Architecture Study Report that is the fruits of a 90-day study done not only by the foundation itself, but also working with “NASA centers and industry partners” to figure out the best way to launch humans there in late 2017 or 2018. But if it’s delayed, Tito is prepared to go to Russia or China instead, he warns.

Here’s the high-level summary:

  • Two launches using NASA’s forthcoming Space Launch System, one for cargo and one for crew;
  • The crew module would be from the crew transportation vehicle that NASA selected under its commercial crew program (see this Universe Today story yesterday for an update on funding concerns on that program);
  • The cargo and crew vehicles would dock in space and then head out to Mars.

If the NASA proposal doesn’t work out, Tito warned Russia may be interested as well. said he’s quite prepared to bring his idea to another country, Russia. (Recall that Tito flew into space in 2001 on a Russian Soyuz spacecraft as a private citizen, so he does have connections over there.)

Crew of Soyuz TM-32, which flew to the International Space Station in 2001. From left, space tourist Dennis Tito, Russian cosmonaut Talgat Musabayev, and Russian cosmonaut Yuri Baturin. Credit: Wikipedia/NASA
Crew of Soyuz TM-32, which flew to the International Space Station in 2001. From left, space tourist Dennis Tito, Russian cosmonaut Talgat Musabayev, and Russian cosmonaut
Yuri Baturin. Credit: Wikipedia/NASA

“Given Russia’s clear recognition of the value and prestige of accomplishments in human space exploration, and their long-time interest in exploring Mars, my personal belief is that in all likelihood the Energia super-heavy rocket revival announcement signals Russian intent to fly this mission in 2021,” Tito stated.

“Their heavy lift rocket, along with their other designs for modules and the Soyuz, can fly this mission with modest upgrades to their systems.”

A third option would be using Chinese capabilities, he added, The Chinese may also be interested, he said, because the country — reportedly developing a large space station of its own — is likely “contemplating this opportunity to be the first on Mars.” Tito said he is informing Congress of his plans to go elsewhere as a “civic duty”, and that he wants to give NASA the first shot.

More food for thought as Congress mulls how much money to allocate to NASA in fiscal 2014. And Tito had strong words about his feelings on the funding: “If I may offer a frank word of caution to this subcommittee: The United States will carry out a Mars flyby mission, or we will watch as others do it – leaving us to applaud their skill and their daring.”

Best Evidence Yet for a High-Energy Jet Emanating from the Milky Way’s Black Hole

A composite image in X-ray and radio showing a likely candidate for a jet emanating from the supermassive black hole at the center of the Milky Way. X-ray: NASA/CXC/UCLA/Z.Li et al; Radio: NRAO/VLA

Jets of high energy particles emanating from a black hole have been detected plenty of times before, but in other galaxies, that is — not from the supermassive black hole at the center of the Milky Way, known as Sagittarius A* (Sgr A*). Previous studies and other evidence suggested that perhaps there were jets – or ghosts of past jets – but many findings and studies often contradicted each other, and none were considered definitive.

Now, astronomers using Chandra X-ray Observatory and the Very Large Array (VLA) radio telescope have found strong evidence Sgr A* is producing a jet of high-energy particles.

“For decades astronomers have looked for a jet associated with the Milky Way’s black hole. Our new observations make the strongest case yet for such a jet,” said Zhiyuan Li of Nanjing University in China, lead author of a study in The Astrophysical Journal.

The supermassive black hole at the center of the Milky Way is about four million times more massive than our Sun and lies about 26,000 light-years from Earth.

While the common notion is that black holes inhale and ingest everything that comes their way, that’s not always true. Sometimes they reject small portions of incoming mass, pushing it away in the form of a powerful jet, and many times a pair of jets. These jets also feed the surroundings, releasing both mass and energy and likely play important roles in regulating the rate of formation of new stars.

Sgr A* is presently known to be consuming very little material, and so the jet is weak, making it difficult to detect. Astronomers don’t see another jet “shooting” in the opposite direction but that may be because of gas or dust blocking the line of sight from Earth or a lack of material to fuel the jet. Or there may be just a single jet.

“We were very eager to find a jet from Sgr A* because it tells us the direction of the black hole’s spin axis. This gives us important clues about the growth history of the black hole,” said Mark Morris of the University of California at Los Angeles, a co-author of the study.

The study shows the spin axis of Sgr A* is pointing in one direction, parallel to the rotation axis of the Milky Way, which indicates to astronomers that gas and dust have migrated steadily into Sgr A* over the past 10 billion years. If the Milky Way had collided with large galaxies in the recent past and their central black holes had merged with Sgr A*, the jet could point in any direction.

The jet appears to be running into gas near Sgr A*, producing X-rays detected by Chandra and radio emission observed by the VLA. The two key pieces of evidence for the jet are a straight line of X-ray emitting gas that points toward Sgr A* and a shock front — similar to a sonic boom — seen in radio data, where the jet appears to be striking the gas. Additionally, the energy signature, or spectrum, in X-rays of Sgr A* resembles that of jets coming from supermassive black holes in other galaxies.

The Chandra observations in this study were taken between September 1999 and March 2011, with a total exposure of about 17 days.

Source: Chandra

Photos: Nighttime Launch from Wallops Island Visible to Millions

The ORS-3 mission launch as it passed over Beavertail Lighthouse in Jamestown, Rhode Island, USA. Credit and copyright: Scott MacNeil.

Last night’s launch of a Minotaur I rocket from the Mid-Atlantic Regional Spaceport at NASA’s Wallops Flight Facility in eastern Virginia was visible to millions along the east coast of the US and southern Canada, and many were out with their cameras to watch the sight.

The launch sent a record payload of 29 satellites to low Earth orbit, including the first cubesat built by high school students.

Launch occurred at about 8:15 p.m. EST on November 19 (01:15 UTC, Nov. 20).

Minotaur 1 rocket from NASA's Wallops Flight Facility in Virginia on Nov. 19, 2013. Credit: NASA/Jeremy Eggers.
Minotaur 1 rocket from NASA’s Wallops Flight Facility in Virginia on Nov. 19, 2013. Credit: NASA/Jeremy Eggers.

Approximately 12 minutes after lift-off, the Air Force’s Space Test Program Satellite-3 spacecraft was deployed into its intended orbit at an altitude of approximately 500 km (310 miles). The Minotaur’s upper stage then executed a pre-planned collision avoidance maneuver before starting deployment of 28 CubeSats sponsored by the Department of Defense’s Operationally Responsive Space (ORS) office, the U.S. Air Force Space and Missile Systems Center’s Space Test Program, and NASA’s Educational Launch of Nanosatellites (ELaNa) program.

This was the 25th launch for Orbital Science’s Minotaur rocket, all of which have been successful, and the sixth Minotaur vehicle to be launched from the Wallops facility.

The launch of the Minotaur 1 from NASA's Wallops Flight Facility was photographed from Lancaster, PA on November 19, 2013. Credit and copyright: Marion Haligowski.
The launch of the Minotaur 1 from NASA’s Wallops Flight Facility was photographed from Lancaster, PA on November 19, 2013. Credit and copyright: Marion Haligowski.

Marion Haligowski took the image above, saying “I should have used a wider lens; I didn’t realize the launch would take up 1/4 of the sky from 154 miles away!” and of her image below she added, “I was surprised how high the separation was from 154 miles away from the Wallops Island launch site.”

Final separation of the Minotaur 1 is seen high in the sky of Lancaster, PA on the evening of November 19, 2013. Two exposures were stacked in StarStaX using a Canon T2i (ISO 400 / 25 seconds) and a 50 mm f/1.4 lens at f/5.6. Credit and copyright: Marion Haligowski.
Final separation of the Minotaur 1 is seen high in the sky of Lancaster, PA on the evening of November 19, 2013. Two exposures were stacked in StarStaX using a Canon T2i (ISO 400 / 25 seconds) and a 50 mm f/1.4 lens at f/5.6. Credit and copyright: Marion Haligowski.

Our own Jason Major saw the launch from near his home in Rhode Island. “I withstood the cold (and launch delay) to capture this photo of a rising Minotaur I rocket, launched 400 miles south,” Jason said. This is a 15-second exposure.

This was a portion of the second stage flight of a Minotaur I rocket launched from Wallops Island, Virginia, seen from Conimicut Point in Warwick at around 8:17 p.m. EST on Nov. 19, 2013. Credit and copyright: Jason Major.
This was a portion of the second stage flight of a Minotaur I rocket launched from Wallops Island, Virginia, seen from Conimicut Point in Warwick at around 8:17 p.m. EST on Nov. 19, 2013. Credit and copyright: Jason Major.
ORS-3 Minotaur Launch Seen from about 150 miles away in western Louisa, VA. The diffuse moonlight nearly washed out the rocket's "trail" altogether, but fortunately it was still visible. Credit and copyright: David Murr.
ORS-3 Minotaur Launch Seen from about 150 miles away in western Louisa, VA. The diffuse moonlight nearly washed out the rocket’s “trail” altogether, but fortunately it was still visible. Credit and copyright: David Murr.

Orbital Sciences Corporation’s Twitter feed had a running commentary of the launch activities and posted this image shortly after launch:

Orbital Science Corporation posted this image on their Twitter feed of the launch as seen from the public viewing are at Wallops Flight Facility. Via Orbital.
Orbital Science Corporation posted this image on their Twitter feed of the launch as seen from the public viewing are at Wallops Flight Facility. Via Orbital.

And the launch was a topic of discussion on Twitter, too:

Here’s a short timelapse of the launch, viewed from the beach in Cape May, New Jersey. Photographer Frank Miller said that 20 minutes before the 8:15 PM launch, he photographed a meteor streaking south, which is the first “streak” you see in the video:

The next Wallops launch is an Antares rocket with a Cygnus cargo spacecraft targeted for Dec. 15-21, 2013, and as it looks now, it will again be an evening launch, so make your preparations to see it, and we’ll keep you posted on launch dates.

And if you missed the launch, here’s the replay:

Exploring Our Galaxy’s Ancient Brown Dwarfs

A brown dwarf from the thick-disk or halo is shown. Although astronomers observe these objects as they pass near to the solar system, they spend much of their time away from the busiest part of the Galaxy, and the Milky Way's disk can be seen in the background. Credit: John Pinfield

As the name implies, a brown dwarf is small… only about 7% the size of the Sun. As far as stellar senior citizens go, they’re cool. Zipping along through space at speeds of 100 to 200 kilometers per second, they may have formed back when our galaxy was young – perhaps 10 billion years ago. Now a team of astronomers headed by Dr. David Pinfield at the University of Hertfordshire has identified a pair of the oldest brown dwarfs known… a set of orbs which could be the harbinger of a huge amount of new, unseen objects.

Although we sometimes refer to them as stars, brown dwarfs are in a class of their own. Because they didn’t ignite in nuclear fusion, they don’t generate internal heat like an ordinary star. After they are formed, they continue to cool and fade as time passes. This process makes them very difficult to observe and the discovery of two very old brown dwarfs, with temperatures of 250-600 C is cause for astronomical excitement.

Just how did Pinfield’s team pick such tiny objects out of the vastness of space? The discovery was facilitated thanks to a survey made by the Wide-field Infrared Survey Explorer (WISE), a NASA observatory that scanned the mid-infrared sky from orbit in 2010 and 2011. The ancient objects are cataloged as WISE 0013+0634 and WISE 0833+0052, and they are located in the constellations of Pisces and Hydra. Because they are so elusive, they were also confirmed by large ground-based telescopes (Magellan, Gemini, VISTA and UKIRT).

However, identifying the pair wasn’t easy. Seeing through the eyes of infrared reveals a crowded space – one populated with reddened stars, distant background galaxies and pockets of nebulous gas and dust. Picking out such a small character from a stellar cast would be like finding one tiny pearl in the vastness of an ocean. But Pinfield’s researchers employed a new method which utilizes WISE’s capabilities. As it scanned the sky over and over again, it revealed the cool, brown dwarfs – picking up the faint signature that other searches had missed.

These two particular brown dwarfs are different from the other slow movers of their type. By studying their spectra, the astronomers have identified atmospheres almost entirely comprised of hydrogen. This sets them apart from younger stars which have an abundance of heavier elements. Does being lighter make them speedier? According to Pinfield, “Unlike in other walks of life, the galaxy’s oldest members move much faster than its younger population.”

Stars near to Sun are considered the “local volume” and are created with three overlapping populations – the thin disk, the thick disk and the halo. Each of these layers has a certain amount of age associated with it: the oldest being the thickest and its member stars move up and down at a higher rate of speed. The halo contains both disks, along with the initial materials which formed the very first stars. Thin disk objects abound in the local volume and account for about 97% of the local stars, while thick disk and halo objects are a meager 3%. Chances are, brown dwarfs belong to that smaller percentage which explains why these fast-moving thick-disk/halo objects are only now being revealed.

Just how many may await discovery? Scientists surmise there may be as many as 70 billion brown dwarfs in the galaxy’s thin disk, and the thick disk and halo take up significantly larger galactic volumes. Even at a tiny 3%, this means there could be an army of ancient brown dwarfs in the galaxy. “These two brown dwarfs may be the tip of an iceberg and are an intriguing piece of astronomical archaeology,” said Pinfield. “We have only been able to find these objects by searching for the faintest and coolest things possible with WISE. And by finding more of them we will gain insight into the earliest epoch of the history of the galaxy.”

Original Story Source: Royal Astronomical Society News Release. For further study: “A deep WISE search for very late type objects and the discovery of two halo/thick-disk T dwarfs: WISE 0013+0634 and WISE 0833+0052”, D. J. Pinfield et al, Monthly Notices of the Royal Astronomical Society, in press.

Human Spaceflight, Planetary Missions Face Potential Cuts in Latest NASA Budget Negotiations

While 2014 budget negotiations are not finalized yet, there’s already some noise of concern in different space communities that depend on NASA. Here’s a brief roundup of some of the news lately:

Could the Cassini Saturn mission get the axe? Wired’s Adam Mann warns that NASA may not be able to fund all of its planetary science missions in the coming year. Based on a statement that Jim Green, NASA’s planetary science director, made to an agency advisory council earlier this month, Mann narrows in on the Curiosity and Cassini missions as the big flagship missions that are requiring the most in terms of resources. Cassini is functioning perfectly and providing reams of data from Saturn and its moons, causing concern from planetary scientists about losing it early.

Only one commercial crew partner? NASA issued a cautious news release this week saying it is prepared to launch Americans from their own soil in 2017, “subject to the availability of adequate funding.” The agency is now moving into a new phase of its commercial crew program called Commercial Crew Transportation Capability (CCtCap), saying it is prepared to “award one or more CCtCap contracts no later than September 2014.” That means that the three companies currently funded — Boeing Co., Sierra Nevada Corp. and SpaceX — may face stiff competition for more money.

New report suggesting stopping NASA’s human spaceflight program: Before reading any further, do not jump to conclusions — making recommendations like this is a common practice by the Congressional Budget Office, which looks at all possibilities as it presents options for spending. Still, Space Politics’ Jeff Foust presents the report and generates some interesting comments after his story about the value of human spaceflight. For context, NASA and its international agency partners will need to make a decision fairly soon about continuing space station operations past 2020, so it’s possible the human spaceflight program could change.

What do you think of these proposals? Let us know in the comments.

Get Out Your Comet Scorecards: Comet Nevski Now Visible With Binoculars

Capture of Comet Nevski shortly after discovery using the ITelescope Observatory in New Mexico. (Credit: Ernesto Guido, Nick Howes & Martino Nicolini).

Is 2013 truly the “Year of the Comet?” Perhaps “Comets” might be a better term, as no less than five comets brighter than +10th magnitude grace the pre-dawn sky for northern hemisphere observers.

Comet C/2013 V3 Nevski has just brightened up 6 magnitudes — just over a 250-fold increase in brightness — and now sits at around magnitude +8.8. Comet Nevski was just recently discovered by Vitali Nevski using a 0.4 metre reflecting telescope 12 days ago on November 8th. If that name sounds familiar, it’s because Nevski discovered the comet from the Kislovodsk observatory located near Kislovodsk, Russia which is part of the International Scientific Optical Network survey which located comet ISON last year. In fact, there was some brief controversy early on in its discovery that Comet C/2012 S1 ISON should have had the moniker Comet Nevski-Novichonok.

At the time of discovery, Comet Nevski appeared to be nothing special: shining at magnitude +15.1, it was well below our +10 magnitude limit for consideration as “interesting,” and was projected to linger there for the duration of its passage through the inner solar system. About a dozen odd such comet discoveries crop up per year, most of which give astronomers a brief pause as the orbit and size of the comet become better known, only to discern that they’re most likely to be nothing extraordinary.

The orbit of comet Nevski, as seen during the closest approach to the Earth on December 21st. (Credit:  The Solar System Dynamics JPL Small-Body Database Browser).
The orbit of comet Nevski, as seen during the closest approach to the Earth on December 21st. (Credit: The Solar System Dynamics JPL Small-Body Database Browser).

Such was to be the case with Comet Nevski, until it suddenly flared up this past weekend.

Observer Gianluca Masi caught Comet Nevski in outburst, using a Celestron C14 remotely as part of the Virtual Telescope 2.0 project:

Comet Nevski captured on November 14th by
Comet Nevski captured on November 14th by Gianluca Masi. (Credit: The Virtual Telescope 2.0 Project).

You’ll note that Comet Nevski shows a small, spiky tail on the brief exposure. As of this writing, it currently sits at between magnitudes +8 and +9 and should remain there for the coming week if this current outburst holds.

Comet Nevski is well placed for northern hemisphere observers high in the morning sky, and will spend the remainder of November and early December crossing the astronomical constellation of Leo.

The celestial path of Comet Nevski from mid-November to the end of December. (Created by the author using Starry Night Education simulation software).
The celestial path of Comet Nevski from mid-November to the end of December. (Created by the author using Starry Night Education simulation software).

Here’s a blow-by-blow rundown on noteworthy events for this comet for the remainder of 2013:

November 23rd: Passes the +5.3 magnitude star Psi Leonis and crosses north of the ecliptic plane.

December 1st: Passes +3.4 magnitude star Eta Leonis.

December 6th: Passes +4.8 magnitude 40 Leonis and the bright +2nd magnitude star Algieba.

December 15th: Crosses into the constellation Leo Minor.

December 17th: Passes near the +5.5th magnitude star 40 Leonis Minoris.

December 21st: Passes closest to Earth, at 0.847 Astronomical Units (A.U.s), or 126 million kilometres distant.

December 30th: Passes into the constellation Ursae Majoris.

Note that a “close pass” denotes a passage of the comet within a degree of a bright or interesting object.

The orbit of Comet Nevski is inclined 31.5 degrees relative to the ecliptic, and it will be headed for circumpolar for observers based in high northern latitudes as it dips back down below our “interesting” threshold of magnitude +10 in early 2014.

This comet passed perihelion on October 27th, 2013 just over a week prior to discovery. Comet Nevski is Halley-type comet, with a 27.5 year orbit.

So, looking at the “Comet Scorecard,” we currently have:

Comet C/2012 X1 LINEAR: Still undergoing a moderate outburst at magnitude +8.2, very low to the north east for northern hemisphere observers at dawn in the constellation Boötes.

Comet 2P/Encke: Reaches perihelion tomorrow at 0.33 AU’s from the Sun, shining at magnitude +7.7 near Mercury in the dawn sky but is now mostly lost in the Sun’s glare.

Comet C/2013 R1 Lovejoy: is currently well placed in the constellation Ursa Major crossing into Canes Venatici in the hours before dawn. Currently shining at magnitude +5.4, Comet R1 Lovejoy is visible to the unaided eye from a dark sky site. We caught sight of the comet last week with binoculars, looking like an unresolved globular cluster as it passed through the constellations of Leo and Leo Minor.

And of course, Comet C/2012 S1 ISON: As of this writing, ISON is performing up to expectations as it approaches Mercury low in the dawn shining at just above +4th magnitude. We’ve seen some stunning pictures as of late as ISON unfurls its tail, and now the eyes of the astronomical community will turn towards the main act: perihelion on November 28th. Will it fizzle or dazzle? More to come next week!

The recent outbursts of Comets X1 LINEAR and V3 Nevski are reminiscent of the major outburst of Comet Holmes back in 2007. Of course, the inevitable attempts to link these outbursts to the current sputtering solar max will ensue, but to our knowledge, no conclusive correlations exist. Remember, the outburst from Comet Holmes occurred as we were approaching what was to become a profound solar minimum.

Also, it might be tempting to imagine that all of these comets are somehow related, but they are in fact each on unique and very different orbits, and only appear in the rough general direction in the sky as seen from our Earthly vantage point… a boon for dawn patrol sky watchers!

Got pics? Send ‘em in to Universe Today!

 

 

Asteroids Can Get Shaken And Stirred By Mars’ Gravity

Artist's conception of Mars, with asteroids nearby. Credit: NASA

Asteroids are sometimes called loose rubble piles, which leads to interesting effects if they happen to get close to a planet. A science team in 2010 found out that when asteroids get close to Earth, the gravity of our planet can stir up the dust grains and “refresh” its face, in a sense. Now, scientists have found that Mars can do the same thing.

Here’s the interesting part: the asteroid belt is in between Mars and Jupiter, which means that potentially more asteroids could be changed from the influence of Mars than what happens near Earth.

“Mars is right next to the asteroid belt, and in a way it gets more opportunity than the Earth does to refresh asteroids,” stated Richard Binzel, a professor of planetary sciences at the Massachusetts Institute of Technology who participated in both sets of research.

Artist’s impression of the asteroid (234) Barbara. Thanks to a unique method that uses ESO’s Very Large Telescope Interferometer, astronomers have been able to measure sizes of small asteroids in the main belt for the first time. Their observations also suggest that Barbara has a complex concave shape, best modelled as two bodies that may possibly be in contact. Credit: ESO/L. Calçada
Artist’s impression of the asteroid (234) Barbara. Thanks to a unique method that uses ESO’s Very Large Telescope Interferometer, astronomers have been able to measure sizes of small asteroids in the main belt for the first time. Their observations also suggest that Barbara has a complex concave shape, best modelled as two bodies that may possibly be in contact. Credit: ESO/L. Calçada

“Picture Mars and an asteroid going through an intersection, and sometimes they’ll both come through at very nearly the same time,” Binzel added. “If they just barely miss each other, that’s close enough for Mars’ gravity to tug on [the asteroid] and shake it up. It ends up being this random process as to how these things happen, and how often.”

The initial research in 2010 showed that most asteroids are redder than meteorites. On asteroids, the  surfaces get exposed to cosmic radiation and become redder as time goes on. But when as asteroid gets close to Earth, the planet’s gravity moves around the surface particles and brings fresher bits from underneath. Meteorites that break off from these asteroids would therefore not be as red.

This time around, Binzel’s team looked at other possibilities to “refresh” asteroids, such as collisions or energy from the sun, but concluded that the planets are probably the big reason we see the changed surfaces. You can read more details on the research in the journal Icarus or the preprint version on Arxiv. The lead author on the article was MIT planetary scientist Francesca DeMeo.

Source: MIT

What Day 1 On The International Space Station Was Like For The Astronauts

Astronaut Jerry Ross during one of three December 1998 spacewalks to get the space station ready for human habitation. Reflected in his helmet is NASA astronaut James Newman. Behind is one of the solar arrays for the Russian Zarya module. Credit: NASA

There wasn’t a lot of elbow room when six people from the Endeavour shuttle floated into the baby International Space Station on Dec. 10, 1998, but the cramped quarters resonated with possibility in STS-88 commander Bob Cabana’s mind.

“It’s hard to believe 15 years ago we put those first modules together, and we have this facility today that’s the size of a football field,” said Cabana in an interview today (Nov. 20) with Universe Today.

Cabana, who is now the director of the Kennedy Space Center, oversaw a complex mission that included joining the Russian Zarya and U.S. Unity modules, three spacewalks to get the modules powered and ready for humans to enter, and the pressure of public relations activities surrounding the opening of the station itself.

“That was a very special day, when we went into Unity and Zarya for the first time. There was a lot of excitement and anticipation,” Cabana said. He and Russian Sergei Krikalev — who would go on to become the person who spent the most time in space, at 803 days — entered the tiny hatches side by side to emphasize the international participation.

As is typical of spaceflight, the astronauts spent most of their day at work, busily waking up the station and testing its systems. NASA astronauts Jerry Ross and James Newman put together a communications system. Other crew members tested the videoconference equipment — important for press conferences as well as talking to scientists on the ground. Equipment and supplies in Zarya had to be unstowed and organized.

There also was the first repair on station, when Krikalev and NASA astronaut Nancy Currie replaced a faulty unit in Zarya  “which controlled the discharging of stored energy from one of the module’s six batteries,” NASA wrote in an update at the time.

Cabana wanted his crew to get eight hours of sleep, but the excitement of that first day kept everybody up until 2:30 in the morning despite the wakeup call coming at 7 a.m.

A space station is born. The Russian Zarya module (top) is connected to the U.S. Unity module using the Canadarm on Dec. 6, 1998. Shot is a still from an IMAX camera carried on board shuttle Endeavour. Credit: NASA
A space station is born. The Russian Zarya module (top) is connected to the U.S. Unity module using the Canadarm on Dec. 6, 1998. Shot is a still from an IMAX camera carried on board shuttle Endeavour. Credit: NASA

“We were talking  about what the ISS means, what will be accomplished with this cornerstone,” Cabana recalled, and said he is pleased with what has come to pass in the next 15 years. “It had come true. Everything we thought that could be has come together. That was a very special night, thinking about the future and how important the International Space Station was.”

The heaviest construction finished in 2011, and larger crews of six were allowed on board rather than the beginning crews of just three. NASA is now trying to position the station as a venue for microgravity science to justify the expense of running it. The astronauts, however, must balance their time doing science with the normal chores and maintenance the station requires. (The recent Expedition 35/36 missions were extremely productive in terms of science return, NASA astronaut Chris Cassidy told Universe Today in a past interview.)

All buildings on Earth require upgrades from time to time to stay safe and up to date, and the ISS is no different. Cabana said analysis will be done to “extend the life on some of the modules, but we don’t see that as a large issue.” The reason? The crews do “an outstanding job” keeping the station humming along with routine maintenance, he said.

Today (Nov. 20) marks the 15th anniversary of Zarya’s launch into orbit. The station partners are currently committed until 2020, meaning negotiations are forthcoming to see what to do with the station in the years afterwards. It’s unclear what will happen next — the recession is still reverberating in the United States and overseas — but today, the agencies focused on the successes.

Each partner agency tweeted facts and science concerning the ISS under the hashtag #ISS15, and invited people using all forms of social media to share their thoughts on the station. What are some notable things about the station, and what is a good use of it in the future, in your opinion? Let us know in the comments.

NASA astronaut Bob Cabana (left) and Russian cosmonaut Sergei Krikalev just outside the hatch to the Zarya Russian module  on Dec. 10, 1998. Credit: NASA
NASA astronaut Bob Cabana (left) and Russian cosmonaut Sergei Krikalev just outside the hatch to the Zarya Russian module on Dec. 10, 1998. Credit: NASA