New Stars: Blazing and Blue

This image from the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile. Credit: ESO

A new image from ESO shows a pretty sprinkling of bright blue stars, the star cluster NGC 2547, a group of recently formed stars in the southern constellation of Vela. Even though we recently got a more precise estimate on how old the Universe is from the Planck mission (13.82 billion years), this is a look at some fairly young — new and blue — stars.

But how young are these cosmic youngsters really? ESO scientists say that although the exact ages of these stars remain uncertain, estimates range from 20 to 35 million years old. That doesn’t sound all that young, after all. However, our Sun is 4.6 billion years old and has not yet reached middle age. That means that if you imagine that the Sun as a 40 year-old person, the bright stars in the picture are three-month-old babies.

Most stars do not form in isolation, but in rich clusters with sizes ranging from several tens to several thousands of stars. Clusters are key objects for astronomers studying how stars evolve through their lives. The members of a cluster were all born from the same material at about the same time, making it easier to determine the effects of other stellar properties.

While NGC 2547 contains many hot stars that glow bright blue, also visible are one or two yellow or red stars which have already evolved to become red giants. Open star clusters like this usually only have comparatively short lives, of the order of several hundred million years, before they disintegrate as their component stars drift apart.

This picture was created from images forming part of the Digitized Sky Survey 2. It shows the rich region of sky around the young open star cluster NGC 2547 in the southern constellation of Vela (The Sail). Credit:  ESO/Digitized Sky Survey 2. Acknowledgement: Davide De Martin
This picture was created from images forming part of the Digitized Sky Survey 2. It shows the rich region of sky around the young open star cluster NGC 2547 in the southern constellation of Vela (The Sail). Credit:
ESO/Digitized Sky Survey 2. Acknowledgement: Davide De Martin

The star cluster NGC 2547 lies in the southern constellation of Vela (The Sail), about 1500 light-years from Earth, and is bright enough to be easily seen using binoculars. It was discovered in 1751 by the French astronomer Nicolas-Louis de Lacaille during an astronomical expedition to the Cape of Good Hope in South Africa, using a tiny telescope of less than two centimeters aperture.

Between the bright stars in this picture you can see plenty of other objects, especially when zooming in. Many are fainter or more distant stars in the Milky Way, but some, appearing as fuzzy extended objects, are galaxies, located millions of light-years beyond the stars in the field of view.

Source: ESO

Book Review: Vistas of Many Worlds

Vistas of Many Worlds: A Journey Through Space and Time by Erik Anderson (Ashland Astronomy Studio)

While many astronomy books are based around images that show us how the Universe appears to us right now, as seen through the sensitive electronic eyes of powerful space telescopes and observatories around the world, Erik Anderson’s Vistas of Many Worlds: a Journey Through Space and Time takes a different, but no less fascinating, approach and shows us what the night sky used to look like, will one day look like, and how it may look from other much more distant worlds.

The nearby orange dwarf star Epsilon Eridani reveals its circumstellar debris disks in this close-up perspective. (Pages 14-15)
The nearby orange dwarf star Epsilon Eridani reveals its circumstellar
debris disks in this close-up perspective. (Pages 14-15)

Written and illustrated by Erik Anderson of the Ashland Astronomy Studio in Ashland, Oregon, Vistas of Many Worlds first takes us on a tour of our local region of the galaxy, introducing us to some of our Sun’s closest neighbors in space. From Alpha Centauri to Altair, we get scientifically-based renderings of several nearby stars as they’d appear close up, along with a detailed description of each — as well as an accurate depiction of the background stars (including the Sun) as they’d appear from such slightly different vantage points. We soon find out there’s an amazing amount of variety in our own stellar neighborhood alone!

Next we get a tour through time itself with images and detailed descriptions of the night sky as it appeared at various points in Earth’s history. Based on the actual movements of the stars across the galaxy, Anderson is able to accurately show the star-filled sky as it looked when the ocean cascaded over the Strait of Gibraltar to fill in the Mediterranean 5.3 million years ago, when the ancestors of modern humans were first learning to use fire 1.5 million years ago… and also what it will look like when the Solar System eventually dips back down into the galactic plane 25 million years from now — a time when nearly all the stars in the sky will be strangers, unfamiliar to us today.

After that Anderson takes us on a hunt for exoplanets, both known and imagined. We first visit the star systems that have been recently discovered to host planets — some a little like Earth, some a little like Jupiter, and some like nothing we’ve ever seen before. Then it’s off to look for truly Earthlike worlds by looking back at how our own planet became so favorable for life in the first place. From a stable parent star like the Sun to the chance birth of a large, stabilizing moon, from the delivery of life-sustaining liquid water (that stays liquid!) to having a protective “big brother” gas giant ready to take the heavy hits, and eventually what first drew organisms up from the sea onto dry land, Anderson speculates about Earth’s distant exoplanetary twins by reflecting on our planet itself.

The Earth's ancient past is depicted as it looked 4.4 million years ago when an ancient ape, "Ardi" the Ardipithecus, roamed Africa. (Pages 36-37)
The Earth’s ancient past is depicted as it looked 4.4 million years ago
when an ancient ape, “Ardi” the Ardipithecus, roamed Africa. (Pages 36-37)

And all the while showing what stars are where in the sky.

Vistas of Many Worlds is a true gem… it inspires imagination with the turn of each page. Anderson’s photorealistic computer-generated illustrations are lush and intriguing, and he does an excellent job combining speculation with scientific knowledge. It’s science as envisioned by an artist as well as art created by a scientist — truly the best of both many worlds.

The 123-page 9″ x 12″ hardcover book can be purchased on the Ashland Astronomy Studio’s website here, as well as on Amazon.com.

An iBook edition is soon to be announced.

A primordial ocean-world orbited by two moons is depicted in Ptolemy's Cluster (star cluster M7). The scene parallels Earth's own natural history, commemorating the origins of watery oceans out of volcanic steam and infalling comets. (Pages 96-97)
A primordial ocean-world orbited by two moons is depicted in Ptolemy’s
Cluster (star cluster M7). The scene parallels Earth’s own natural history,
commemorating the origins of watery oceans out of volcanic steam and
infalling comets. (Pages 96-97)

All images ©Erik Anderson/Ashland Astronomy Studio. All rights reserved. Used with permission.

Gallery: Dragon Splashes Down Successfully

Dragon is slowed by three main parachutes prior to splashdown into the Pacific Ocean. Credit: SpaceX.

Splashdown! The SpaceX Dragon has returned home safely, splashing down in the Pacific Ocean at 16:36 UTC (12:36 p.m. EDT) on Tuesday, March 26, 2013. “Recovery ship has secured Dragon,” Tweeted SpaceX CEO Elon Musk. “Powering down all secondary systems. Cargo looks A-OK.”

A team of SpaceX engineers, technicians and divers will recover the vehicle off the coast of Baja, California, for the journey back to shore, which NASA said will take 30-48 hours.

The big job will be unloading the 3,000- plus pounds (1,360 kg) of ISS cargo and packaging inside the spacecraft. The Dragon is currently the only vehicle capable of returning cargo and important scientific experiments back to Earth.

“The scientific research delivered and being returned by Dragon enables advances in every aspect of NASA’s diverse space station science portfolio, including human research, biology and physical sciences,” said Julie Robinson, International Space Station Program
scientist. “There are more than 200 active investigations underway aboard our orbiting laboratory in space. The scientific community has
eagerly awaited the return of today’s Dragon to see what new insights the returned samples and investigations it carries will unveil.”

See more images below of Dragon’s return and mission to the ISS; we’ll be adding more as the SpaceX team supplies them!

Here’s a gif image of the splashdown:

A series of images shows the Dragon splashdown. Credit: SpaceX.
A series of images shows the Dragon splashdown. Credit: SpaceX.
This picture captures the Dragon just as it hits the water in the Pacific Ocean. Credit: SpaceX.
This picture captures the Dragon just as it hits the water in the Pacific Ocean. Credit: SpaceX.
Dragon was released from the International Space Station on March 26, 2013 during the CRS-2 mission. Credit: SpaceX.
Dragon was released from the International Space Station on March 26, 2013 during the CRS-2 mission. Credit: SpaceX.

Dragon’s release from Canadarm2 occurred earlier today at 10:56 UTC. The Expedition 35 crew commanded the spacecraft to slowly depart from the International Space Station

Dragon attached to the International Space Station during the CRS-2 mission. Credit: NASA.
Dragon attached to the International Space Station during the CRS-2 mission. Credit: NASA.
Dragon in orbit during the CRS-2 mission. Credit: NASA/CSA/Chris Hadfield
Dragon in orbit during the CRS-2 mission. Credit: NASA/CSA/Chris Hadfield

Among the the scientific experiment returned on Dragon was the Coarsening in Solid-Liquid Mixtures (CSLM-3) experiment, which also launched to space aboard this Dragon. CLSM-3 studies how crystals known as dendrites form as a metal alloy becomes solid. The research could help engineers develop stronger materials for use in automobile, aircraft and spacecraft parts.

Dragon also is returning several human research samples that will help scientists continue to examine how the human body reacts to long-term spaceflight. The results will have implications for future space exploration and direct benefits here on Earth.

The mission was the second of at least 12 cargo resupply trips SpaceX plans to make to the space station through 2016 under NASA’s
Commercial Resupply Services contract.

New Kind of “Runt” Supernovae Could be Lurking Unseen

This artist's conception shows the suspected progenitor of a new kind of supernova called Type Iax. Material from a hot, blue helium star at right is funneling toward a carbon/oxygen white dwarf star at left, which is embedded in an accretion disk. In many cases the white dwarf survives the subsequent explosion. Credit: Christine Pulliam (CfA)

Imagine this “Death from the Skies” scenario; a tiny supernova lurks unseen near our Sun. Astronomers from the Harvard-Smithsonian Center for Astrophysics (CfA) announced the discovery of just such an object today and while it is not nearby, this new kind of supernova is so faint it has been hiding in the shadows.

Until now, supernovae have come in two main versions. In one scenario, a huge star, 10 to 100 times more massive as our Sun, collapses causing a colossal stellar explosion. Another scenario, known as Type Ia supernovae, occurs when material from a parent star streams onto the surface of a white dwarf. Over time, so much material falls onto the white dwarf that it raises the core temperature igniting carbon and causing a runaway fusion reaction. This event completely disrupts the white dwarf and results in a colossal stellar explosion.

Now astronomers have found a third type that is fainter and less energetic than a Type Ia. Called a Type Iax supernova, it is “essentially a mini supernova,” says lead author of the study Ryan Foley, Clay Fellow at the Harvard-Smithsonian Center for Astrophysics (CfA). “It’s the runt of the supernova litter.”

Being only about one-hundredth as bright as their supernova siblings, Foley calculates that Type Iax supernovae are about as third as common as Type Ia supernovae. The researchers also did not find them in elliptical galaxies, filled with older stars, suggesting that Type Iax supernovae come from young star systems.

So far, Foley and his team identified 25 examples of this new type of supernova. Based on observations, the team found that the new Type Iax supernovae come from binary star systems containing a white dwarf and a companion star that has burned all of its hydrogen, leaving an outer layer that is helium rich.

In a press release, Foley says they are not sure what triggers the Type Iax supernova. One explanation involves the ignition of the outer helium layer from the companion star. The resulting shockwave slams into the white dwarf and disrupts it, causing the explosion. Alternately, the white dwarf might ignite first due to the overlying helium shell it has collected from the companion star.

“Either way, it appears that in many cases the white dwarf survives the explosion unlike in a Type Ia supernova where the white dwarf is completely destroyed,” says Foley. “The star will be battered and bruised but it might live to see another day.”

Supernovae explosions release so much energy as heat and light that they outshine entire galaxies for brief periods of time. The extremely hot conditions naturally create new heavier elements, such as gold, lead, nickel, zinc and copper. The explosion enriches the surrounding area leaving material for new stars to form.

“Type Iax supernovas aren’t rare, they’re just faint,” explains Foley. “For more than a thousand years, humans have been observing supernovas. This whole time, this new class has been hiding in the shadows.”

This research has been accepted for publication in The Astrophysical Journal and is available online.

Carnival of Space #294

This week’s Carnival of Space is hosted by our pal Ray Sanders at his Dear Astronomer website!

Click here to read Carnival of Space #294.

And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.

Win a Copy of “Your Ticket to the Universe”

Your Ticket to the Universe: A Guide to Exploring the Cosmos (Available April 2)

A beautiful new book, “Your Ticket to the Universe: A Guide to Exploring the Cosmos” highlights some of the most fascinating and important sites in the universe, from those closest to us in our Solar System all the way to the Milky Way galaxy and beyond. All of these celestial landmarks are illustrated with beautiful, vivid photographs that bring them to life. You can read Jason Major’s full review of this book here.

This is an awesome compilation of images and information, and the book was written by by Kimberly K. Arcand and Megan Watzke, media coordinator and press officer and for NASA’s Chandra X-ray Observatory.

Thanks to Smithsonian Books, Universe Today has five copies of this book to giveaway!

In order to be entered into the giveaway drawing, just put your email address into the box at the bottom of this post (where it says “Enter the Giveaway”) before Monday, April 1, 2013. We’ll send you a confirmation email, so you’ll need to click that to be entered into the drawing.

We’re only going to use these email addresses for Universe Today giveaways/contests and announcements. We won’t be using them for any other purpose, and we definitely won’t be selling the addresses to anyone else. Once you’re on the giveaway notification list, you’ll be able to unsubscribe any time you like.

Book Review: Your Ticket to the Universe

Your Ticket to the Universe: A Guide to Exploring the Cosmos (Available April 2)
Your Ticket to the Universe is full of images and graphics of astronomical wonders.
Your Ticket to the Universe is full of images and graphics of astronomical wonders.

Every once in a while an astronomy book comes out that combines stunning high-definition images from the world’s most advanced telescopes, comprehensive descriptions of cosmic objects that are both approachable and easy to understand (but not overly simplistic) and a gorgeous layout that makes every page spread visually exciting and enjoyable.

This is one of those books.

Your Ticket to the Universe: A Guide to Exploring the Cosmos is a wonderful astronomy book by Kimberly K. Arcand and Megan Watzke, media coordinator and press officer for NASA’s Chandra X-ray Observatory, respectively. Published by Smithsonian Books, it features 240 pages of gorgeous glossy images from space exploration missions, from the “backyard” of our own Solar System to the more exotic environments found throughout the Galaxy… and even beyond to the very edges of the visible Universe itself.

Find out how you can win a copy of this book here!

As members of the Chandra team, headquartered at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, Kim and Megan have long had firsthand experience with incredible astronomical images — they previously designed and coordinated the internationally-acclaimed From Earth to the Universe and From Earth to the Solar System photo installation projects, which helped set up presentations of space exploration images in public locations around the world.

Your Ticket to the Universe features images from some of the most recent missions - like MSL!
Your Ticket to the Universe even features images from some of the most recent missions – like MSL!

Your Ticket to the Universe takes such impressive images — from telescopes and observatories like Hubble, Spitzer, SDO, Chandra, Cassini, GOES, VLT, and many others, as well as from talented photographers on Earth and in orbit aboard the ISS — and puts them right into your hands, along with in-depth descriptions that are comprehensive yet accessible to even the most casual fans of space exploration.

This is my favorite kind of astronomy book. Although I look at images like the ones in Your Ticket to the Universe online every day, there’s something special about having them physically in front of you in print — and well-written text that can be understood by everyone is crucial, in my opinion, as it means a book may very well become an inspiration to a whole new generation of scientists and explorers.

“The sky belongs to everyone. That’s the premise of this guidebook to the Universe. You don’t need a medical degree to know when you’re sick or a doctorate in literature to appreciate a novel. In the same spirit, even those of us who don’t have advanced degrees in astronomy can gain access to all the wonder and experience that the Universe has to offer.”

Kim K. Arcand holds a copy of her book during a presentation at the Skyscrapers Astronomical Society of Rhode Island
Author Kimberly K. Arcand holds a copy of her book during a presentation at the Skyscrapers Astronomical Society of Rhode Island

I’ve had the pleasure of meeting co-author Kimberly Arcand on several occasions — I attended high school with her husband — and her knowledge about astronomy imaging as well as her ability to present it in an understandable way is truly impressive, to say the least. She’s quite an enthusiastic ambassador for space exploration, and Your Ticket to the Universe only serves to further demonstrate that.

I highly recommend it for anyone who finds our Universe fascinating.

Your Ticket to the Universe will be available online starting April 2 at Smithsonian Books, or you can pre-order a copy at Barnes & Noble or on Amazon.com. Don’t explore the cosmos without it!

SpaceX Dragon Departs Station for Pacific Splashdown with Valuable Science Cargo

SpaceX Dragon was released from ISS at 6:56am ET and now begins its return trip to Earth. Credit: NASA

The SpaceX Dragon commercially developed cargo craft loaded with thousands of pounds of precious science samples has departed from the International Space Station at 6:56 a.m EDT this morning (March 26) and is heading back to Earth today for a splashdown in the Pacific Ocean at around 12:34 p.m EDT.

The ISS crew commanded the Dragon’s release by a trigger at the robotic work station inside the Cupola as they were soaring some 250 miles over the northeast coast of Australia after Mission Control gave the “GO for release”.
A video of the unberthing is below:

Cameras aboard both the ISS and Dragon transmitted breathtaking views of the departure maneuver. The entire ISS filled the video screen as Dragon slowly pulled away.

SpaceX Dragon capsule grappled by ISS robotic arm prior to today’s  departure and  return to Earth and Pacific Ocean splashdown. Credit: NASA
SpaceX Dragon capsule grappled by ISS robotic arm prior to today’s departure and return to Earth and Pacific Ocean splashdown. Credit: NASA

The private Dragon was unberthed from a docking port on the Harmony node at 4:10 a.m. EDT in anticipation of today’s return to Earth.

The capsule had been docked at the orbiting outpost for three weeks since arriving on March 3.

NASA astronaut Tom Marshburn and station commander Chris Hadfield from Canada opened the snares on the stations Canadian built robotic arm – Canadarm2 – firmly grasping the Dragon.

ISS imaged be cameras on departing Dragon. Credit: SpaceX/NASA
ISS imaged by cameras on departing Dragon. Credit: SpaceX/NASA

A series of three short departure burns executed in rapid succession took Dragon safely away from the ISS and beyond the imaginary 656-foot (200-meter) “Keep Out Sphere” around the station for the journey back to Earth.

Everything with Dragon happened as expected said NASA.

“All looks beautiful and nominal as expected,” radioed the ISS crew.

The Dragon capsule is the first private ship ever to dock at the ISS.

Dragon conducts departure burns from the ISS on March 26, 2013. Credit: NASA
Dragon conducts departure burns from the ISS on March 26, 2013. Credit: NASA

Dragon will fire its engines for the last time for the 10 minute long deorbit burn at 11:42 a.m. EDT sending it through the Earth’s atmosphere for a fiery reentry and splashdown in the Pacific Ocean around 12:34 p.m.

“Sad to see the Dragon go,” said Marshburn. “She performed her job beautifully and is heading back to her lair. Wish her all the best for the splashdown today.”

A team of SpaceX engineers, technicians and divers will recover the vehicle after splashdown about 214 miles off the coast of Baja, California.

SpaceX recovery crews will pluck the capsule from the Pacific Ocean for the journey back to shore which will take about 30 hours.

Dragon had been scheduled to return yesterday on Monday, March 25, but was postponed due to inclement weather developing near its targeted splashdown site in the Pacific Ocean.

There was no affect on the return of the science samples and gear weighing a hefty 2668 pounds. Dragon is the only vehicle that can safely return significant amounts of science cargo and gear from the ISS following the retirement of NASA’s space shuttle orbiters.

The SpaceX Dragon CRS-2 capsule blasted off on March 1 atop a SpaceX Falcon 9 rocket from Cape Canaveral Air Force Station in Florida.

A thruster failure shortly after liftoff nearly doomed the mission. But fast acting SpaceX engineers saved the day and restarted the engines a few hours later – read my earlier story here.

Falcon 9 SpaceX CRS-2 launch on March 1, 2013 to the ISS – shot from the roof of the Vehicle Assembly Building. Credit: Ken Kremer/www.kenkremer.com
Falcon 9 SpaceX CRS-2 launch on March 1, 2013 to the ISS – shot from the roof of the Vehicle Assembly Building. Credit: Ken Kremer/www.kenkremer.com

The resupply mission carried aloft some 1200 pounds of food, water and science experiments for the station crew.

After a two day flight, Marshburn captured the Dragon just 32 feet away from the station with the Canadarm2 on March 3. Ground controllers then took over Canadarm2 operations and berthed Dragon to the Harmony node.

SpaceX is under contract to NASA to deliver about 44,000 pounds of cargo to the ISS during a dozen flights over the next few years at a cost of about $1.6 Billion.

SpaceX and Orbital Sciences Corp are partnered with NASA’s Commercial Resupply Services program to replace the cargo up mass capability the US lost following the retirement of NASA’s space shuttle orbiters in 2011.

The maiden launch of Orbital’s Antares/Cygnus ISS cargo resupply program is now slated to occur on April 16-18 from NASA Wallops Flight Facility in Virginia – read my onsite photo report here.

The inaugural Antares launch will be a test flight with a simulated Cygnus.

The next SpaceX Dragon flight – dubbed CRS-3 – is slated to blast off in late November 2013.

Ken Kremer

Dragon and Earth from the ISS. Credit: NASA
Dragon and Earth from the ISS. Credit: NASA

NASA’s Operation IceBridge Surveys Greenland and Earth’s Polar Ice Sheets

NASA P-3B waits outside the hangar at Thule Air Base with the Greenland Ice sheet in the background. The aircraft is set to begin the 2013 season of NASA’s Operation IceBridge mission to survey Earth's polar ice sheets in unprecedented three-dimensional detail. The plane just arrived from NASA Wallops Flight Facility in Virginia - see my P-3B photos below. Credit: NASA/Goddard/Michael Studinger

NASA’s Operation IceBridge has begun the 2013 research season of Ice Science flights in Greenland and the Arctic to survey the regions ice sheets and land and sea ice using a specially equipped P-3B research aircraft from NASA’s Wallops Flight Facility in Wallops Island, Va.

Operation IceBridge began in 2009 as part of NASA’s six-year long effort to conduct the largest airborne survey of Earth’s polar ice ever flown.

The goal is to obtain an unprecedented three-dimensional, multi-instrument view of the behavior of Greenland, Arctic and Antarctic ice sheets, ice shelves and sea ice which have been undergoing rapid and dramatic changes and reductions.

“We’re starting to see how the whole ice sheet is changing,” said Michael Studinger, IceBridge project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “Thinning at the margins is now propagating to the interior.”

The P-3 exiting the hanger pre-flight in Thule. Credit: NASA
The P-3 exiting the hanger pre-flight in Thule. Credit: NASA

The airborne campaign was started in order to maintain a continuous record of measurements in changes in polar ice after NASA’s Earth orbiting ICESat (Ice, Cloud and Land Elevation Satellite) probe stopped collecting data in 2009.

ICESat-2 won’t be launched until 2016, so NASA’s IceBridge project and yearly P-3 airborne campaigns will fill in the science data gap in the interval.

The P-3B Orion just arrived from NASA’s Wallops Flight Facility in Virginia where I visited it before departure – see my P-3B photos herein.

NASA IceBridge P-3B research aircraft prepares for departure from runway at NASA Wallops Flight Facility in Virginia to Thule Air Base in Greenland.  Credit: Ken Kremer (kenkremer.com)
NASA IceBridge P-3B research aircraft prepares for departure from runway at NASA Wallops Flight Facility in Virginia to Thule Air Base in Greenland. Credit: Ken Kremer (kenkremer.com)

IceBridge is operating out of airfields in Thule and Kangerlussuaq, Greenland, and Fairbanks, Alaska.

The P-3B survey flights over Greenland and the Arctic will continue until May. They are conducted over Antarctica during October and November.

A sunny view of the ramp at Thule Air Base, Greenland, shortly after the NASA P-3B research aircraft arrived on Mar. 18, 2013. Credit: NASA / Jim Yungel
A sunny view of the ramp at Thule Air Base, Greenland, shortly after the NASA P-3B research aircraft arrived on Mar. 18, 2013. Credit: NASA / Jim Yungel

The measurements collected by IceBridge instruments will characterize the annual changes in thickness of sea ice, glaciers, and ice sheets. The data are used to help predict how climate change affects Earth’s polar ice and the resulting rise in sea-levels.

Researchers with the U.S. Army Corps of Engineers are collaborating with the IceBridge project to collect snow depth measurements near Barrow , Alaska. High school science teachers from the US, Denmark and Greenland will fly along on the P-3B survey flights to learn about polar science.

NASA Wallops has a wide ranging research and development mission and is home to the Virginia launch pad for the new Antares/Cygnus commercial ISS resupply rocket set for its maiden launch in mid April 2013; detailed in see my new story – here.

Ken Kremer

Sea ice in the southern Beaufort Sea. Credit: NASA
Sea ice in the southern Beaufort Sea. Credit: NASA
IceBridge departing to Fairbanks to start their sea ice flights that will cover the Beauford and Chukchi seas - via the Laxon sea ice route for the transit. Credit: NASA
IceBridge departing to Fairbanks to start their sea ice flights that will cover the Beauford and Chukchi seas – via the Laxon sea ice route for the transit. Credit: NASA

See Mercury at its Greatest Elongation for 2013

Mercury gives a clue to Super-Mercuries
Astronomers have found a star system with two planets like Mercury, but bigger. Our own Mercury could supply clues to their composition and formation. (Credit: NASA/Johns Hopkins University/Applied Physics Laboratory.Carnegie Institution of Washington).

A fine apparition of the planet Mercury graces the dawn skies this week, leading up to its greatest elongation from the Sun for 2013.

It seems that nearly every appearance of the planet Mercury is touted as the “best” these days. Such was the case with the inner-most world’s dusk showing early last month. Truth is, all elongations of Mercury (and Venus, for that matter) are not created equal, and visibility of each apparition isn’t the same for observers worldwide. We’ll show you why.

Mercury orbits the Sun once every 88 days. With an orbit interior to our own, it never strays far from the Sun in the sky and thus can only appear low in the dawn or dusk. Its orbit is also elliptical, with an eccentricity of 0.206, the greatest of any planet in our solar system. This means that greatest elongations can vary considerably, from 17.9° away from the Sun in the sky near perihelion of the planet to 28.7° near aphelion. And although reaching greatest elongation near aphelion means the tiny world is above the muck of the horizon, it also means it’s also intrinsically a bit fainter; Mercury can vary in brightness from magnitude -0.2 at a perihelic-elongation to half a magnitude fainter at +0.3 for an aphelic-elongation.

A comparison of elongations of Mercury as seen from the Earth at perihelion  versus aphelion. (Created by the author).
A comparison of elongations of Mercury as seen from the Earth at perihelion versus aphelion. (Created by the author).

But there’s more. Compounding this situation is the angle of the ecliptic, or the imaginary plane of the orbit of the Earth. Near the March equinox the ecliptic rides high in the dusk to the west and low in the dawn to the east for northern hemisphere observers. In the southern hemisphere, the reverse is true. It’s a strange sight for a northerner to head “Down Under” and watch the Sun rise in the east, transit to the north and set to the west!

The path of Mercury looking east ~45 minutes prior to sunrise from latitude 30 degrees north from March 26th through April 30th, (Created by the author using Starry Night).
The path of Mercury looking east ~45 minutes prior to sunrise from latitude 30 degrees north from March 26th through April 30th, (Created by the author using Starry Night).

Thus what may be a terrible apparition of Mercury for one hemisphere may be a grand one for another, as is the case this week. Yes, northern observers can catch the fleeting world, if they know exactly where to look for it. For observers based at longitude 40° north, Mercury will never peak above an altitude of 10° in the dawn sky. Observers based near 35° south will however see the planet reach its maximum possible elevation of over 25° degrees above the horizon.

We would qualify this as “The best dawn appearance of Mercury for 2013… as seen from the southern hemisphere.” Greatest elongations of Mercury occur in pairs, with dusk-to-dawn apparitions about 45 days apart as the planet passes between us and the Sun, followed by a longer period of about 70 days as the world loops back around behind the Sun. The orbit of Mercury is tilted about 7° with respect to our own. Otherwise, we would see a transit of the planet every inferior conjunction, as last occurred on November 8th, 2006 and will happen next on May 9th, 2016.

The path of Mercury from March 26th through April 26th looking east from latitude 35 degrees south ~45 minutes prior to sunrise. (Created by the author using Starry Night).
The path of Mercury from March 26th through April 26th looking east from latitude 35 degrees south ~45 minutes prior to sunrise. (Created by the author using Starry Night).

Mercury will show a maximum illumination area of 38.5” square arc seconds as seen from the Earth March 30th on just before reaching its greatest elongation west of the Sun on March 31st on Easter Day at 22:00 UT/18:00EDT. Through a telescope, Mercury will display a 7.7” diameter disk with a 50% illuminated “half-Moon” phase. Mercury reaches greatest elongation just 28 hours prior to aphelion which occurs on April 2nd, the closest this has occurred date-wise since April 8th, 2006. This won’t be matched again until March 24th, 2020. Shining at magnitude +0.3, Mercury will then race ahead of the Earth on its inside track and will begin to gradually sink lower on successive mornings in early April. The morning of April 8th may well offer the last good chance to spy the tiny world when the old crescent Moon passes just 8° degrees north of the planet within two days of reaching New phase on April 10th. Mercury reaches superior conjunction opposite to the Earth and on the far side of the Sun on May 11th, 2013, and will again head into the dusk skies for its next greatest eastern elongation on June 12th.

From our Earthly vantage point, Mercury completes 3.15 orbits of the Sun a year. This means that we see 6 greatest elongations on average most years, 3 westerns (dawn) and 3 easterns (dusk). The most elongations of Mercury that you can have in a calendar year are 7, which occurred in 2011 and will happen again in 2015. It’s fascinating to think that until the advent of the Space Age, the orbit and the rough size of Mercury was all we knew about the planet. It would take the first flyby of the Mariner 10 spacecraft to give us a close up view of Mercury in 1974. The precession of the orbit of Mercury was a mystery until explained by Einsteinian physics, and still stands as one of the great proofs of general relativity. Today, we have a permanent ambassador around Mercury, NASA’s MESSENGER spacecraft. MESSENGER has mapped to world in detail, sampled its tenuous exosphere, and observed hints of ancient volcanic activity. MESSENGER will be followed by the joint European Space Agency/Japan Aerospace Exploration Agency mission BepiColombo set to launch in 2015 which will arrive at Mercury in 2022. All fascinating things to ponder as you search for the diminutive world low in the dawn skies this coming Easter weekend!