Astronomy Archives

June 17, 2013December 23, 2015 by Elizabeth Howell

Black Hole Bonanza! Dozens (Potentially) Found In Andromeda As Another Study Probes X-Rays

A new analysis of data from the Chandra space telescope revealed 26 black hole candidates in the Andromeda Galaxy. This is the largest collection of possible black holes found in another galaxy besides that of the Milky Way, Earth's home galaxy. Credit: X-ray (NASA/CXC/SAO/R.Barnard, Z.Lee et al.), Optical (NOAO/AURA/NSF/REU Prog./B.Schoening, V.Harvey; Descubre Fndn./CAHA/OAUV/DSA/V.Peris)

More than two DOZEN potential black holes have been found in the nearest galaxy to our own. As if that find wasn’t enough, another research group is teaching us why extremely high-energy X-rays are present in black holes.

The Andromeda Galaxy (M31) is home to 26 newly found black hole candidates that were produced from the collapse of stars that are five to 10 times as massive as the sun.

Using 13 years of observations from NASA’s Chandra X-Ray Observatory, a research team pinpointed the locations. They also corroborated the information with X-ray spectra (distribution of X-rays with energy) from the European Space Agency’s XMM-Newton X-ray observatory.

“When it comes to finding black holes in the central region of a galaxy, it is indeed the case where bigger is better,” stated co-author Stephen Murray, an astronomer at Johns Hopkins University and the Harvard-Smithsonian Center for Astrophysics.

A close-up of the candidate black holes in Andromeda, as seen by the Chandra X-Ray Observatory. Credit: X-ray (NASA/CXC/SAO/R.Barnard, Z.Lee et al.), Optical (NOAO/AURA/NSF/REU Prog./B.Schoening, V.Harvey; Descubre Fndn./CAHA/OAUV/DSA/V.Peris

“In the case of Andromeda, we have a bigger bulge and a bigger supermassive black hole than in the Milky Way, so we expect more smaller black holes are made there as well,” Murray added.

The total number of candidates in M31 now stands at 35, since the researchers previously identified nine black holes in the area. All told, it’s the largest number of black hole candidates identified outside of the Milky Way.

Meanwhile, a study led by the NASA Goddard Space Flight Center examined the high-radiation environment inside a black hole — by simulation, of course. The researchers performed a supercomputer modelling of gas moving into a black hole, and found that their work helps explain some mysterious X-ray observations of recent decades.

Researchers distinguish between “soft” and “hard” X-rays, or those X-rays that have low and high energy. Both types have been observed around black holes, but the hard ones puzzled astronomers a bit.

Here’s what happens inside a black hole, as best as we can figure:

– Gas falls towards the singularity, orbits the black hole, and gradually becomes a flattened disk;

– As gas piles up in the center of the disk, it compresses and heats up;

– At a temperature of about 20 million degrees Fahrenheit (12 million degrees Celsius), the gas emits “soft” X-rays.

So where did the hard X-rays — that with energy tens or even hundreds of times greater than soft X-rays — come from? The new study showed that magnetic fields are amplified in this environment that then “exerts additional influence” on the gas, NASA stated.

Artist's conception of the Chandra X-Ray Observatory. Credit: NASA — Artist’s conception of the Chandra X-Ray Observatory. Credit: NASA

“The result is a turbulent froth orbiting the black hole at speeds approaching the speed of light. The calculations simultaneously tracked the fluid, electrical and magnetic properties of the gas while also taking into account Einstein’s theory of relativity,” NASA stated.

One key limitation of the study was it modelled a non-rotating black hole. Future work aims to model one that is rotating, NASA added.

You can check out more information about these two studies below:

– Andromeda black holes: Chandra identification of 26 new black hole candidates in the central region of M31. (Also available in the June 20 edition of The Astrophysical Journal.)

– X-ray modelling of black holes: X-ray Spectra from MHD Simulations of Accreting Black Holes. (Also available in the June 1 edition of The Astrophysical Journal.)

Sources: Chandra X-Ray Observatory and NASA

June 17, 2013December 23, 2015 by Jason Major

Earth-Passing Asteroid is “An Entirely New Beast”

Radar images of asteroid 1998 QE2 and its satellite on June 7. Each frame in the animation is a sum of 4 images, spaced apart by about 10 minutes. (Arecibo Observatory/NASA/Ellen Howell)

On the last day of May 2013 asteroid 1998 QE2 passed relatively closely by our planet, coming within 6 million kilometers… about 15 times the distance to the Moon. While there was never any chance of an impact by the 3 km-wide asteroid and its surprise 750 meter satellite, astronomers didn’t miss out on the chance to observe the visiting duo as they soared past as it was a prime opportunity to learn more about two unfamiliar members of the Solar System.

By bouncing radar waves off 1998 QE2 from the giant dish at the Arecibo Observatory in Puerto Rico, researchers were able to construct visible images of the asteroid and its ocean-liner-sized moon, as well as obtain spectrum data from NASA’s infrared telescope in Hawaii. What they discovered was quite surprising: QE2 is nothing like any asteroid ever seen near Earth.

The Arecibo radar observatory in Puerto Rico (Image courtesy of the NAIC - Arecibo Observatory, a facility of the NSF) — The 305-meter dish at Arecibo Observatory in Puerto Rico (Image courtesy of the NAIC – Arecibo Observatory, a facility of the NSF)

Both Arecibo Observatory and NASA’s Goldstone Deep Space Communications Complex in California are unique among telescopes on Earth for their ability to resolve features on asteroids when optical telescopes on the ground merely see them as simple points of light. Sensitive radio receivers collect radio signals reflected from the asteroids, and computers turn the radio echoes into images that show features such as craters and, in 1998 QE2’s case, a small orbiting moon.

QE2’s moon appears brighter than the asteroid as it is rotating more slowly; thus its Doppler echoes compress along the Doppler axis of the image and appear stronger.

Of the asteroids that come close to Earth approximately one out of six have moons. Dr. Patrick Taylor, a USRA research astronomer at Arecibo, remarked that “QE2’s moon is roughly one-quarter the size of the main asteroid,” which itself is a lumpy, battered world.

Dr. Taylor also noted that our own Moon is a quarter the size of Earth.

QE2’s moon will help scientists determine the mass of the main asteroid and what minerals make up the asteroid-moon system. “Being able to determine its mass from the moon helps us understand better the asteroid’s material,” said Dr. Ellen Howell, a USRA research astronomer at Arecibo Observatory who took both radar images of the asteroid at Arecibo and optical and infrared images using the Infrared Telescope Facility in Hawaii. While the optical images do not show detail of the asteroid’s surface, like the radar images do, instead they allow for measurements of what it is made of.

“What makes this asteroid so interesting, aside from being an excellent target for radar imaging,” Howell said, “is the color and small moon.”

Radar images of asteroid 1998 QE2 (bottom) and its satellite (top) on June 6. — Radar images of asteroid 1998 QE2 and its satellite (top) on June 6. (Arecibo Observatory/NASA/Ellen Howell)

“Asteroid QE2 is dark, red, and primitive – that is, it hasn’t been heated or melted as much as other asteroids,” continued Howell. “QE2 is nothing like any asteroid we’ve visited with a spacecraft, or plan to, or that we have meteorites from. It’s an entirely new beast in the menagerie of asteroids near Earth.”

Spectrum of 1998 QE2 taken May 30 at the NASA Infrared Telescope Facility (IRTF) on Mauna Kea was “red sloped and linear,” indicating a primitive composition not matching any meteorites currently in their collection.

For more radar images of 1998 QE2, visit the Arecibo planetary radar page here.

Source: Universities Space Research Association press release.

June 13, 2013December 23, 2015 by Elizabeth Howell

Should This Alien World Even Exist? This Young Disk Could Challenge Planet-Formation Theories

An image of TW Hydrae and the protoplanetary stuff surrounding the star. Astronomers believe a planet is forming within the gas and dust and sweeping up debris, as shown by the gap in this picture. Credit: NASA, ESA, J. Debes (STScI), H. Jang-Condell (University of Wyoming), A. Weinberger (Carnegie Institution of Washington), A. Roberge (Goddard Space Flight Center), and G. Schneider (University of Arizona/Steward Observatory)

Take a close look at the blurry image above. See that gap in the cloud? That could be a planet being born some 176 light-years away from Earth. It’s a small planet, only 6 to 28 times Earth’s mass.

That’s not even the best part.

This alien world, if we can confirm it, shouldn’t be there according to conventional planet-forming theory.

The gap in the image above — taken by the Hubble Space Telescope — probably arose when a planet under construction swept through the dust and debris in its orbit, astronomers said.

That’s not much of a surprise (at first blush) given what we think we know about planet formation. You start with a cloud of debris and gas swirling around a star, then gradually the bits and pieces start colliding, sticking together and growing bigger into small rocks, bigger ones and eventually, planets or gas giant planet cores.

But there’s something puzzling astronomers this time around: this planet is a heck of a long way from its star, TW Hydrae, about twice Pluto’s distance from the sun. Given that alien systems’ age, that world shouldn’t have formed so quickly.

An illustration of TW Hydrae's disk in comparison with that of Earth's solar system. Credit: NASA, ESA, and A. Feild (STScI) — An illustration of TW Hydrae’s disk in comparison with that of Earth’s solar system. Credit: NASA, ESA, and A. Feild (STScI)

Astronomers believe that Jupiter took about 10 million years to form at its distance away from the sun. This planet near TW Hydrae should take 200 times longer to form because the alien world is moving slower, and has less debris to pick up.

But something must be off, because TW Hydrae‘s system is believed to be only 8 million years old.

“There has not been enough time for a planet to grow through the slow accumulation of smaller debris. Complicating the story further is that TW Hydrae is only 55 percent as massive as our sun,” NASA stated, adding it’s the first time we’ve seen a gap so far away from a low-mass star.

The lead researcher put it even more bluntly: “Typically, you need pebbles before you can have a planet. So, if there is a planet and there is no dust larger than a grain of sand farther out, that would be a huge challenge to traditional planet formation models,” stated John Debes, an astronomer at the Space Telescope Science Institute in Baltimore.

Protoplanet Hypothesis — Like a raindrop forming in a cloud, a star forms in a diffuse gas cloud in deep space. As the star grows, its gravitational pull draws in dust and gas from the surrounding molecular cloud to form a swirling disk called a “protoplanetary disk.” This disk eventually further consolidates to form planets, moons, asteroids and comets. Credit: NASA/JPL-Caltech

At this point, you would suppose the astronomers are seriously investigating other theories. One alternative brought up in the press release: perhaps part of the disc collapsed due to gravitational instability. If that is the case, a planet could come to be in only a few thousand years, instead of several million.

“If we can actually confirm that there’s a planet there, we can connect its characteristics to measurements of the gap properties,” Debes stated. “That might add to planet formation theories as to how you can actually form a planet very far out.”

A rare double transit of Jupiter's moon Ganymede (top) and Io on Jan. 3, 2013. Here, the sun is shining from the left causing shadows cast by the moons to fall onto the planet's cloud tops. Credit: Damian Peach — A rare double transit of Jupiter’s moon Ganymede (top) and Io on Jan. 3, 2013. Here, the sun is shining from the left causing shadows cast by the moons to fall onto the planet’s cloud tops. Credit: Damian Peach

There’s a trick with the “direct collapse” theory, though: astronomers believe it takes a bunch of matter that is one to two times more massive than Jupiter before a collapse can occur to form a planet.

Recall that this world is no more than 28 times the mass of Earth, as best as we can figure. Well, Jupiter itself is 318 times more massive than Earth.

There are also intriguing results about the gap. Chile’s Atacama Large Millimeter/submillimeter Array (ALMA) — which is designed to look at dusty regions around young stars — found that the dust grains in this system, orbiting nearby the gap, are still smaller than the size of a grain of sand.

Astronomers plan to use ALMA and the James Webb Space Telescope, which should launch in 2018, to get a better look. In the meantime, the results will be published in the June 14 edition of the Astrophysical Journal.

Source: HubbleSite

June 13, 2013April 26, 2016 by Elizabeth Howell

Where Is Dark Matter Most Dense? Subaru Telescope Gets Some Hints

The Subaru Telescope. Credit: National Astronomical Observatory of Japan

Put another checkmark beside the “cold dark matter” theory. New observations by Japan’s Subaru Telescope are helping astronomers get a grip on the density of dark matter, this mysterious substance that pervades the universe.

We can’t see dark matter, which makes up an estimated 85 percent of the universe, but scientists can certainly measure its gravitational effects on galaxies, stars and other celestial residents. Particle physicists also are on the hunt for a “dark matter” particle — with some interesting results released a few weeks ago.

The latest experiment with Subaru measured 50 clusters of galaxies and found that the density of dark matter is largest in the center of these clusters, and smallest on the outskirts. These measurements are a close match to what is predicted by cold dark matter theory, scientists said.

Cold dark matter assumes that this material can’t be observed in any part of the electromagnetic spectrum, the band of light waves that ranges from high-energy X-rays to low-energy infrared heat. Also, the theory dictates that dark matter is made up of slow-moving particles that, because they collide with each other infrequently, are cold. So, the only way dark matter interacts with other particles is by gravity, scientists have said.

To check this out, Subaru peered at “gravitational lensing” in the sky — areas where the light of background objects are bent around dense, massive objects in front. Galaxy clusters are a prime example of these super-dense areas.

Several dark matter maps: one based on a sample of 50 individual galaxy clusters (left), another looking at an average galaxy cluster (center), and another based on dark matter theory (right). Red is the highest concentration of dark matter, followed by yellow, green and blue. At right, in the middle, is a map based on cold dark matter theory that comes close to the average galaxy cluster observed with the Suburu Telescope. Credit: NAOJ/ASIAA/School of Physics and Astronomy, University of Birmingham/Kavli IPMU/Astronomical Institute, Tohoku University)

“The Subaru Telescope is a fantastic instrument for gravitational lensing measurements. It allows us to measure very precisely how the dark matter in galaxy clusters distorts light from distant galaxies and gauge tiny changes in the appearance of a huge number of faint galaxies,” stated Nobuhiro Okabe, an astronomer at Academia Sinica in Taiwan who led the study.

Next, the team members could compare where the matter was most dense with that predicted by cold dark matter theory. To do that, they measured 50 of the most massive, known clusters of galaxies. Then, they measured the “concentration parameter”, or the cluster’s average density.

“They found that the density of dark matter increases from the edges to the center of the cluster, and that the concentration parameter of galaxy clusters in the near universe aligns with CDM theory,” stated the National Astronomical Observatory of Japan.

The next step, researchers stated, is to measure dark matter density in the center of the galaxy clusters. This could reveal more about how this substance behaves. Check out more about this study in Astrophysical Journal Letters.

Sourcs: National Astronomical Observatory of Japan

June 12, 2013December 23, 2015 by Elizabeth Howell

What’s Going On Inside This New Kind of Variable Star?

Thirty-six of the stars in this open star cluster, NGC 3766, are a variable star never seen before. Observations were made with the European Southern Observatory's La Silla Observatory. Credit: ESO

A new kind of variable star — 36 of that type, in fact — has been found in a single star cluster. Astronomers don’t even have a name for the star type yet, but feel free to leave some suggestions in the comments!

For now, however, astronomers are wondering what the implications are for our understanding of the stellar interiors.

“The very existence of this new class of variable stars is a challenge to astrophysicists,” stated Sophie Saesen, an astronomer at Geneva Observatory who participated in the research.

“Current theoretical models predict that their light is not supposed to vary periodically at all, so our current efforts are focused on finding out more about the behaviour of this strange new type of star.”

The head-scratching began when astronomers used a European Southern Observatory telescope to gaze at the “Pearl Cluster” (NGC 3766), an open star cluster about 5,800 light years from Earth.

Over seven years of observations with the Leonhard Euler Telescope (taking periodic measurements of brightness), astronomers spotted 36 stars with variable periods of between 2 and 20 hours.

The four-foot (1.2-meter) Leonhard Euler Telescope at the European Southern Observatory. Credit: M. Tewes/ESO

Variable stars have been known for centuries, and many of them are tracked by amateur organizations such as the American Association of Variable Observers. As best as astronomers can figure, the stars become brighter and dimmer due to changes on the inside — stellar vibrations or “quakes” studied under a field called asteroseismology.

A special type of variable stars, called Cepheid variables, can provide accurate measurements of distance since they have an established ratio between luminosity and the period of their variability.

Studying various types of variable stars has provided some insights.

“Asteroseismology of ß Cep[hei] stars, for example, has opened the doors in the past decade to study their interior rotation and convective core,” the astronomers stated in a paper on the research.

The variations in brightness can be interpreted as vibrations, or oscillations within the stars, using a technique called asteroseismology. The oscillations reveal information about the internal structure of the stars, in much the same way that seismologists use earthquakes to probe the Earth's interior. Credit: Kepler Astroseismology team. — The variations in brightness can be interpreted as vibrations, or oscillations within the stars, using a technique called asteroseismology. The oscillations reveal information about the internal structure of the stars, in much the same way that seismologists use earthquakes to probe the Earth’s interior. Credit: Kepler Astroseismology team.

Despite the well-known nature of variable stars, few of them have been studied in open clusters such as NGC 3766.

The reason is it takes a lot of telescope time to take a look at the star — sometimes, years. And time with telescopes is both expensive and precious, making it difficult to allocate the time required.

“Stellar clusters are ideal environments to study stellar variability because some basic properties and the evolutionary status of individual star members can be derived from the properties of the cluster,” the astronomers stated.

“It, however, requires extensive monitoring on an as-long-as-possible time base line. This requirement may explain why not many clusters have been studied for their variability content so far, compared to the number of known and characterized clusters.”

These particular stars in NGC 3766, however, were puzzling.

“The stars are somewhat hotter and brighter than the Sun, but otherwise apparently unremarkable,” ESO stated, yet they had variations of about 0.1% of each star’s normal brightness.

Cepheid Variable Star. Credit: Hubble Space Telescope

It’s possible, but not proven yet, that perhaps the stars’ spin has something to do with the brightness.

Some of the observed objects whip around at speeds so fast that some material might be punted away from the star and into space, the astronomers wrote in a press release.

“In those conditions, the fast spin will have an important impact on their internal properties, but we are not able yet to adequately model their light variations,” stated Nami Mowlavi, another Geneva Observatory astronomer who led the paper.

Also, astronomers haven’t named this class of stars yet. Do you have any ideas? For more information and to generate suggestions, you can read the paper here in Astronomy & Astrophysics. Then you can leave your thoughts in the comments.

Source: European Southern Observatory

June 12, 2013December 23, 2015 by Tammy Plotner

Stacking Galactic Signals Reveals A Clearer Universe

Jacinta studies distant galaxies like those shown in this image from the Hubble Space Telescope, using the new 'stacking' technique to gather information only available through radio telescope observations. Credit: NASA, STScI, and ESA.

Very similar to stacking astronomy images to achieve a better picture, researchers from the International Centre for Radio Astronomy Research (ICRAR) are employing new methods which will give us a clearer look at the history of the Universe. Through data taken with the next generation of radio telescopes like the Square Kilometer Array (SKA), scientists like Jacinta Delhaize can “stack” galactic signals en masse to study one of their most important properties… how much hydrogen gas is present.

Probing the cosmos with a telescope is virtually using a time machine. Astronomers are able to look back at the Universe as it appeared billions of years ago. By comparing the present with the past, they are able to chart its history. We can see how things have changed over the ages and speculate about the origin and future of the vastness of space and all its many wonders.

“Distant, younger, galaxies look very different to nearby galaxies, which means that they’ve changed, or evolved, over time,” said Delhaize. “The challenge is to try and figure out what physical properties within the galaxy have changed, and how and why this has happened.”

According to Delhaize a vital clue to solving the riddle lay in hydrogen gas. By understanding how much of it that galaxies contained will help us map their history.

“Hydrogen is the building block of the Universe, it’s what stars form from and what keeps a galaxy ‘alive’,” said Delhaize.

“Galaxies in the past formed stars at a much faster rate than galaxies now. We think that past galaxies had more hydrogen, and that might be why their star formation rate is higher.”

Jacinta Delhaize with CSIRO's Parkes Radio Telescope during one of her data collecting trips. Credit: Anita Redfern Photography. — Jacinta Delhaize with CSIRO’s Parkes Radio Telescope during one of her data collecting trips. Credit: Anita Redfern Photography.

When it comes to distant galaxies, they don’t give up their information easily. Even so, it was a task that Delhaize and her supervisors were determined to observe. The faint radio signals of hydrogen gas were nearly impossible to detect, but the new stacking method allowed the team to collect enough data for her research. By combining the weak signals of thousands of galaxies, Delhaize then “stacked” them to create a stronger, averaged signal,

“What we are trying to achieve with stacking is sort of like detecting a faint whisper in a room full of people shouting,” said Delhaize. “When you combine together thousands of whispers, you get a shout that you can hear above a noisy room, just like combining the radio light from thousands of galaxies to detect them above the background.”

However, it wasn’t a slow process. The researchers engaged CSIRO’s Parkes Radio Telescope for 87 hours and surveyed a large region of galactic landscape. Their work collected signals from hydrogen over a vast amount of space and stretched back over two billion years in time.

“The Parkes telescope views a big section of the sky at once, so it was quick to survey the large field we chose for our study,” said ICRAR Deputy Director and Jacinta’s supervisor, Professor Lister Staveley-Smith.

Stacking up a clearer picture of the Universe from ICRAR on Vimeo.

As Delhaize explains, observing such a massive volume of space means more accurate calculations of the average amount of hydrogen gas present in particular galaxies at a certain distance from Earth. These readings correspond to a given period in the history of the Universe. With this data, simulations can be created to depict the Universe’s evolution and give us a better understanding of how galaxies formed and evolved with time. What’s even more spectacular is that next generation telescopes like the international Square Kilometre Array (SKA) and CSIRO’s Australian SKA Pathfinder (ASKAP) will be able to observe even larger volumes of the Universe with higher resolution.

“That makes them fast, accurate and perfect for studying the distant Universe. We can use the stacking technique to get every last piece of valuable information out of their observations,” said Delhaize. “Bring on ASKAP and the SKA!”.

Original Story Source: International Centre for Radio Astronomy Research.

June 11, 2013April 26, 2016 by Elizabeth Howell

‘Space Selfie’ Telescope Could Hunt Alien Planets … If It Raises A Cool $2M

Example of an orbital 'selfie' that Planetary Resources' ARKYD telescope could provide to anyone who donates to their new Kickstarter campaign. Credit: Planetary Resources.

A crowdfunded telescope — best known for offering “space selfies” for backers as an incentive to send money — is now considering a search for alien planets.

Planetary Resources Inc. (the proposed asteroid miners) announced a new “stretch goal” for its asteroid-hunting Arkyd-100 telescope.

If the company can raise $2 million — double its original goal — it promises to equip the Arkyd telescope to look at star systems for exoplanets. The project is still short the $1 million required to receive any money, but the target appears to be close enough now to give Planetary Resources confidence that more funds will come for new initiatives.

The motivation for planet hunting was mechanical trouble besetting the famous Kepler space telescope. Kepler recently lost the second of its four reaction wheels, devices that are used to stabilize the telescope in space as it seeks alien worlds.

Artist's conception of the Kepler Space Telescope. Credit: NASA/JPL-Caltech — Artist’s conception of the Kepler Space Telescope. Credit: NASA/JPL-Caltech

Because Kepler needs at least three reaction wheels to point towards targets, its future is uncertain. Some planet searching is still possible with ground-based observatories, however.

“With NASA’s recent equipment failure on the Kepler telescope (RIP, Kepler!), our search for extrasolar planets nearly came to a grinding halt. If we can meet our stretch goal, we can resume some of this progress by enhancing the Arkyd,” Arkyd organizers stated on their Kickstarter campaign website.

“We’re partnering with exoplanet researchers at MIT [the Massachusetts Institute of Technology] to equip citizen scientists like YOU with the tools to join a search that’s captivated us for generations.”

Arkyd would use two methods to hunt down planets:

– Transiting, or seeing the dip in a star’s brightness when a planet passes in front of it;

– Gravitational microlensing, or finding planets by measuring how the gravity of the star (and its planets) distorts light from stars and galaxies behind.

With 19 days to go, Arkyd is at about $857,000 of its preliminary $1 million goal that it must reach to receive any money.

If it can raise $1.3 million, Planetary Resources proposes to build a ground station at an undisclosed “educational partner” that would double the download speed of data from the orbiting observatory.

The project has more than 9,500 backers. Two more stretch goals will be revealed if Arkyd receives 11,000 backers and 15,000 backers, Planetary Resources stated.

More information on the Arkyd Kickstarter campaign is here.

June 10, 2013December 23, 2015 by David Dickinson

Catch the Moon pairing with Mercury & Venus Tonight

Looking west at sunset from latitude 30 degrees north. The ecliptic and Mercury's orbit along with a 10 degree field of view outlined for reference. All graphics created by the author using Starry Night).

If you’ve never seen Mercury, this week is a great time to try.

Over the past few weeks, observers worldwide have been following the outstanding tight triple conjunction of Mercury, Venus and Jupiter low to the west at dusk.

Jupiter has exited the evening sky, headed for conjunction with the Sun on June 19th. I caught what was probably our last glimpse of Jupiter for the season clinging to the murky horizon through binoculars just last week. If you’re “Jonesin’ for Jove,” you can follow its progress this week through superior conjunction as it transits the Solar Heliospheric Observatory’s LASCO C3 camera.

This leaves the two innermost worlds of our fair solar system visible low to the west at dusk. And tonight, they’re joined by a very slender waxing crescent Moon, just over two days after New phase.

The Moon, Venus and Mercury as seen from 30 degrees north tonight at 9PM EDT.

The evening of June 10^th finds a 4% illuminated Moon passing just over 5 degrees (about 10 Full Moon diameters) south of Venus and Mercury. Venus will be the first to appear as the sky darkens, shining at magnitude -3.9 and Mercury will shine about 40 times fainter above it at magnitude +0.3.

Ashen light, also known as Earthshine will also be apparent on the darkened limb of the Moon. Another old-time term for this phenomenon is “the Old Moon in the New Moon’s Arms.” Ashen light is caused by sunlight being reflected off of the Earth and illuminating the nighttime Earthward facing portion of the Moon. Just how prominent this effect appears can vary depending on the total amount of cloud cover on the Earth’s Moonward facing side.

....and the orientation of the Moon, Mercury and Venus on the night of June 12th and ~9PM EDT. — ….and the orientation of the Moon, Mercury and Venus on the night of June 12th and ~9PM EDT.

This week sets the stage for the best dusk apparition of Mercury for northern hemisphere viewers in 2013. Orbiting the Sun every 88 Earth days, we see Mercury either favorably placed east of the Sun in the dusk sky or west of the Sun in the dawn sky roughly six times a year. Mercury’s orbit is markedly elliptical, and thus not all apparitions are created the same. An elongation near perihelion, when Mercury is 46 million kilometers from the Sun, can mean its only 17.9 degrees away from the Sun as viewed from the Earth. An elongation near aphelion, 69.8 million kilometers distant, has a maximum angular separation of 27.8 degrees.

This week’s greatest elongation of 24.3 degrees occurs on June 12^th. It’s not the most extreme value for 2013, but does have another factor going for it; the angle of the ecliptic. As we approach the solstice of June 21^st, the plane of the solar system as traced out by the orbit of the Earth is at a favorable angle relative to the horizon. Thus, an observer from 35 degrees north latitude sees Mercury 18.4 degrees above the horizon at sunset, while an observer at a similar latitude in the southern hemisphere only sees it slightly lower at 16.9 degrees.

Venus and the Moon make great guides to locate Mercury over the next few nights. It’s said that Copernicus himself never saw Mercury with his own eyes, though this oft repeated tale is probably apocryphal.

We also get a shot at a skewed “emoticon conjunction” tonight, not quite a “smiley face” (: as occurred between Jupiter, Venus and the Moon in 2008, but more of a “? :” Stick around until February 13^th, 2056 and you’ll see a much tighter version of the same thing! A time exposure of a pass of the International Space Station placed near Mercury and Venus could result in a planetary “meh” conjunction akin to a “/:” Hey, just throwing that obscure challenge out there. Sure, there’s no scientific value to such alignments, except as testimony that the universe may just have a skewed sense of humor…

Through the telescope, Venus currently shows a 10” diameter gibbous phase, while Mercury is only slightly smaller at 8” and is just under half illuminated. No detail can be discerned on either world, as a backyard telescope will give you the same blank view of both worlds that vexed astronomers for centuries. These worlds had to await the dawn of the space age to give up their secrets. NASA’s MESSENGER spacecraft entered a permanent orbit around Mercury in 2011, and continues to return some outstanding science.

Both planets are catching up to us from the far side of their orbits. Mercury will pass within 2 degrees of Venus on June 20^th, making for a fine wide field view in binoculars.

And now for the wow factor of what you’re seeing tonight. The Moon just passed apogee on June 9^th and is currently about 416,500 kilometers or just over one light second distant. Mercury meanwhile, is 0.86 astronomical units (A.U.), or almost 133 million kilometers, or about 7 light minutes away. Finally, Venus is currently farther away from the Earth than the Sun at 1.59 A.U.s, or about 13.7 light minutes distant.

All this makes for a great show in the dusk skies this week. And yes, lunar apogee just after New sets us up for the closest Full Moon of 2013 (aka the internet sensation known as the “Super Moon”) on June 23^rd. More to come on that soon!

June 10, 2013December 23, 2015 by Bob King

Observing Alert: Rare Meteor Shower May ‘Outburst’ on June 11

The rare and rarely heard of meteor shower called the Gamma Delphinids will appear to radiate from the constellation Delphinus (del-FINE-us) the Dolphin high in the southern sky shortly before dawn tomorrow morning June 11. This map shows the sky facing south at 3:30 a.m. local time. Delphinus is near the bottom of the bright 3-star figure the Summer Triangle. Stellarium

Back on June 11, 1930 three members of the American Meteor Society (AMS) in Maryland saw a half-hour-long bright outburst of meteors from the little constellation Delphinus the Dolphin. No one had predicted the shower, but it came out of nowhere and hasn’t been seen since. Attempts to catch a repeat performance in subsequent years met with no success.

That may change tomorrow morning, June 11, 2013. Peter Jenniskins, research scientist with the SETI Institute and NASA Ames Research Center, has examined dust outbursts from long-period comets and suggests the Gamma Delphinids may return for a brief moment of splendor, as Earth passes through this stream of cometary debris not seen since 1930.

Bright meteors photographed in Ohio during the Eta Aquarid meteor shower in 2012. The Gamma Delphinids may send similar bright meteors our way tomorrow morning. Credit: John Chumack

The expected time of maximum activity is 4:30 a.m. Eastern Daylight Time, 3:30 a.m. Central, 2:30 a.m. Mountain and 1:30 a.m. Pacific. These times are ideal for the Americas where Delphinus is high in southern sky at the peak time. Robert Lunsford of the AMS recommends starting your Gamma Delphinid vigil 2 hours ahead of time in case the shower’s early. If these meteors really do happen, you’ll see them anywhere in the sky, but they’ll all trace back to a point near the star Gamma Delphini in the dolphin’s nose.

The map above shows the worldwide possible visibility for the gamma Delphinid shower. Visibility will be best in the bright green areas, which have the highest radiant elevation. Unshaded areas on the map will not have a view of the shower. Credit: Geert Barentsen, International Meteor Organization

No one knows how strong the shower might be or even the duration though it’s likely to be brief. Time estimate range from one hour to 15 minutes. Lunsford expects bright meteors to appear a minute or two apart. If you’re game, split the difference and set up in a comfy lawn chair facing south an hour before the expected maximum. Should you see any of these rare dolphin tears, consider e-mailing a report to: [email protected]

Tonight June 10-11 from 10 p.m. – 2 a.m. CDT, Dr. Bill Cooke of NASA’s Meteoroid Environment Office will take your questions via live web chat. He’ll offer viewing tips about the shower and include a live Ustream telescope view of the skies over Huntsville, Ala.

If you shoot video or images and want to help improve our understanding of this elusive meteor shower, you can upload them to the Office’s Flickr group and also to Universe Today’s Flickr group. We’ll post images if this meteor shower proves to show up!

June 10, 2013December 23, 2015 by Elizabeth Howell

Kapow! Keck Confirms Puzzling Element of Big Bang Theory

Illustration of the Big Bang Theory — The Big Bang Theory: A history of the Universe starting from a singularity and expanding ever since. Credit: grandunificationtheory.com

Observations of the kaboom that built our universe — known as the Big Bang — is better matching up with theory thanks to new work released from one of the twin 33-foot (10-meter) W.M. Keck Observatory telescopes in Hawaii.

For two decades, scientists were puzzled at a lithium isotope discrepancy observed in the oldest stars in our universe, which formed close to the Big Bang’s occurrence about 13.8 billion years ago. Li-6 was about 200 times more than predicted, and there was 3-5 times less Li-7 — if you go by astronomical theory of the Big Bang.

The fresh work, however, showed that these past observations came up with the strange numbers due to lower-quality data that, in its simplifications, created more lithium isotopes detections than are actually present. Keck’s observations found no discrepancy.

Artist's conception of a metal-poor star. Astronomers modelled a portion of its surface to figure out its abundance of lithium-6, an element that was previously in discrepancy between Big Bang theory and observations of old stars. Credit: Karin Lind, Davide De Martin. — Artist’s conception of a metal-poor star. Astronomers modelled a portion of its surface to figure out its abundance of lithium-6, an element that was previously in discrepancy between Big Bang theory and observations of old stars. Credit: Karin Lind, Davide De Martin.

“Understanding the birth of our universe is pivotal for the understanding of the later formation of all its constituents, ourselves included,” stated lead researcher Karin Lind, who was with the Max Planck Institute for Astrophysics in Munich when the work was performed.

“The Big Bang model sets the initial conditions for structure formation and explains our presence in an expanding universe dominated by dark matter and energy,” added Lind, who is now with the University of Cambridge.

To be sure, it is difficult to measure lithium-6 and lithium-7 because their spectroscopic “signatures” are pretty hard to see. It takes a large telescope to be able to do it. Also, modelling the data can lead to accidental detections of lithium because some of the processes within these old stars appear similar to a lithium signature.

Keck used a high-resolution spectrometer to get the images and gazed at each star for several hours to ensure astronomers got all the photons it needed to do analysis. Modelling the data took several more weeks of work on a supercomputer.

The research appeared in the June 2013 edition of Astronomy & Astrophysics. You can check out the entire paper here.

Source: Keck Observatory