MAC November 2011 Magazine by MAC Realta

Midlands Astronomy Club Magazine

Sky Guide - Beginner’s targets for November The Milky Way arches overhead passing through Cassiopeia and Perseus. The Summer Triangle reluctantly departs in the west, but the Square in Pegasus is still high in the south-west. Aldebaran, the red eye of Taurus the bull and the yellow Capella stand prominently in the south-east, followed by Gemini and Orion which signal the approach of winter. November Meteors Two meteor showers can be seen this month, the Taurids and Leonids. The Taurids has an extended maximum that lasts for several days either side of November 12th when about 10 meteors an hour may be seen coming from the region near the Haydes and Pliades clusters. Taurids are slow-moving and bright making a more impressive display than the low numbers might suggest. The Leonid shower which peaks around November 18th. Radiating from the constellation Leo the Leonids are swift, stabbing meteors, often flaring at the end of their paths often leaving persistent trails. Unfortunately the moon will rise around 22:45 on the evening of the 17th and spoil the view slightly. Telescope Targets High in the sky this month is the hexagonal shape of Auriga representing a man driving a chariot. The identity of Auruga is somewhat shadowy, He is usually

Issue 28- November, 2011

said to be Erichthonius, a lame king of Athens who invented the four-horse chariot. These is no mistaking the constellation’s brightest star, Alpha (α) Aurigae, better known as Capella and is the sixth-brightest star in the sky. Its name comes from the Latin meaning “little she-goat”, and the charioteer has traditionally be depicted carrying a goat on his left shoulder. Capella is actually a pair of yellow giants forming a spectrospic binary, 42 light years away. The stars Eta (η) Aurigae and Zete (ζ) Aurigae are know as the kids, the goats offspring, carried on the charioteer’s arm. Zeta (ζ) Aurigae is one of two extraordinary eclipsing binary stars in the this constellation. It consists of an orange giant some 150 times larger than the Sun, orbited by a much smaller blue-white star, about four times the diameter of our Sun. Normal Zeta (ζ) Aurigae shines at magnitude 3.7, but every 2 years and 8 months the small star is eclipsed by the red giant and the brightness falls by a third over a six week period. Even more extraordinary is Epsilon (ε) Aurigae, which has the longest known period of any eclipsing binary of 27 years. The main star is an intensely luminous white

Auriga has many open clusters and other objects because the Milky Way runs through it. The three brightest open clusters are M36, M37 and M38, all of which are visible in binoculars or a small telescope in suburban skies. The clusters are about 4100, 4400, and 4200 light years distant, respectively. supergiant shining with the light of over 100,000 Suns and large enough to contain the orbit of the Earth and lies about 2,000 light years away. Auriga is notable for an impressive trio of star clusters, M36, M37 and M38, all three being visible in the same field of view through a wide-angle binoculars. In binoculars they appear as fuzzy patches, but small telescopes resolve them into individual stars. Each cluster has its own distinct character.

years away. In binoculars it appears the most prominent of the Auriga clusters. The largest and richest of the Auriga clusters is M37, containing about 150 stars and is 4,200 light years away. At its centre is a brighter orange star. The most scattered of the clusters is M38, containing about 100 faint stars, 3,900 light years away.

M36 is the smallest and most condensed of the trio, consisting of 60 or so stars lying 3,900 light

http://members.aol.com/kdaly10475/index.html

Well, that's about it for November, clear skies and happy hunting.

By Kevin Daly

Club Notes

Latest Astronomy and Space News Kids Astronomy

Club Observing: Remember the next club meets every first Friday of the month for our observing sessions held in the MAC grounds. If you wish to be informed of these sessions please email your name and mobile number to midlandsastronomy@gmail.com who will confirm if the session is going ahead (depending on weather).

Quizzes and Games

MAC is a proud member of

Monthly Sky Guide Three open clusters in Auriga, M37 (lower left), M36 (right of centre), and M38 (upper right). by Alexander Jäger

www.midlandsastronomy.com Page - 12

Internet Highlights

Midlands Astronomy Club Magazine

Failed star is one cool companion ......................................... 7 Seven Supernovae found in single galaxy ............................. 7 Galaxy Zoo reveals curious ‘Violin Clef’ quadruple galaxy merger ..................................................................... 8

Front cover image: A jewel of the southern sky, the Great Carina Nebula, also known as NGC 3372, spans over 300 light-years, one of our galaxy's largest star forming regions. Like the smaller, more northerly Great Orion Nebula, the Carina Nebula is easily visible to the unaided eye, though at a distance of 7,500 light-years it is some 5 times farther away. The Carina Nebula is home to young, extremely massive stars, including the still enigmatic variable Eta Carinae, a star with well over 100 times the mass of the Sun. Eta Carinae is the brightest star at the left, near the dusty Keyhole Nebula (NGC 3324). While Eta Carinae itself maybe on the verge of a supernova explosion.

Credit & Copyright: Robert Gendler and Ryan Hannahoe

www.midlandsastronomy.com Page - 2

Bucket List Object #5: A Meteor Storm ................................. 9

Kids Section Kids Korner ....................................................................... 10

Quizzes and Games Exercise your brain ............................................................ 11

Monthly Sky Guide Beginners sky guide for this month .................................... 12

Internet Highlights Special content only available with the online version of the magazine ................................................................ 13

3. The first constellation in the Zodiac which represents a Ram is _______.

Aries Aquila Aquarius Andromeda 4. The brightest star in the constellation Taurus is the red giant Alpha Tauri, better known as ______.

Antares Aldebaran Altair Arcturus 5. A solar eclipse isn't always total. If the Moon is far enough from the Earth, its umbra fails to completely obscure the Sun. This is a called an ______.

annular eclipse azimuth aurora antiapex

6 8

radiotelescope

reflector 7. The brightness of a star as seen from Earth is measured on a logarithmic scale, and known as its _______.

absolute magnitude apparent magnitude absolute brightness astrolight 8. Right next to Pegasus is this constellation named after a mythical princess rescued by Perseus and holds the nearest galaxy to the Milky Way.

Aquila Alcyone Andromeda Ara 9. Aristarchus of Samos in 280 BCE was one of the earliest philosophers to suggest which model of the solar system?

galactocentric geocentric heliocentric lunacentric 10.A black hole is always surrounded by an ___________.

aurora accordion pleat accretion disk antimatter ring

3 7

9 2

Check your answers

Answer 1: The correct answer was aberration. This was one of the reasons Isaac Newton invented the reflecting telescope, which uses a mirror instead of lenses.

Lunar Mining Coming Soon? ................................................. 6

apogee aphelion apex antipodes

Answer 7: The correct answer was ap p ar e nt m ag nit ud e . A p p ar e nt magnitude is a star's apparent brightness, as opposed to absolute magnitude, which is what its apparent magnitude would be if all stars were at a constant distance (10 parsecs).

How comets in distant solar systems could deliver oceans to exoplanets ........................................................... 6

Answer 2: The correct answer was aphelion. The opposite, the point at which it is closest to the Sun, is called perhelion.

See Jupiter at its 2011 best.................................................. 5

Answer 8: The correct answer was Andromeda. The Andromeda galaxy, designated M31 in the Messier catalogue, is two and a half million light-years away.

You can see more about the club and its events on www.midlandsastronomy.com or contact the club via e-mail at midlandsastronomy@gmail.com Meetings are informal and are aimed at a level to suit all ages.

A most beautiful object - the constellation Cepheus .............. 5

orbiting space telescope 200 inch refractor 300 meter 300 inch Newtonian

2. The point in which a bodies orbit is furthest from the Sun is called __________.

Answer 3: The correct answer was Aries which is considered first because when the Greeks divided the apparent path of the sun into the twelve signs of the Zodiac, the vernal equinox (the beginning of spring) took place in Aries.

Gorgeous globular hides hundreds of rejuvenated stars ......... 4

Answer 9: The correct answer was heliocentric. Aristarchus demonstrated by geometry that the Sun must be larger than the Earth, so it must be the center of the solar system. Unfortunately an even more famous A, Aristotle, believed in the geocentric theory.

Uranus got knocked over by one-two punch ......................... 4

astigmatism aberration achromism annulation

SUDOKU

Answer 4: The correct answer was Aldebaran, the eye of the Bull, is a red giant, four times the diameter of the Sun.

Holmberg II – Forever blowing bubbles ................................ 3

6. The Arecibo telescope in Puerto Rico is the largest of its kind in the world. What kind of telescope is it?

Answer 5: The correct answer was annular eclipse. Annular, from the latin word for "ring".

Alien solar system disk reveals birth of a Planet .................... 3

1. A common problem with refracting telescopes is a fringe of false colour around the image. This is known as ______.

Answer 10: The correct answer was accretion disk. The accretion disk is a mass of gasses and other material which spirals into the event horizon, emitting radiation as the particles disintegrate.

Latest Astronomy and Space News

All are welcome to attend. It also holds infrequent Observing Nights at its Observing Site in Clonminch, or at a member’s house (weather permitting) on the first Friday of every month..

Exercise your brain

contents

Answer 6: The correct answer was 300 meter radiotelescope. Three hundred and five meters in diameter, the Arecibo radiotelescope is used to study pulsars, quasars and other radio objects, and has been used in the search for extraterrestrial intelligence.

MAC meets on the first Tuesday of the month in the Presbyterian Hall, High Street, Tullamore from 8pm.

Midlands Astronomy Club Magazine

www.midlandsastronomy.com Page - 11

Midlands Astronomy Club Magazine

Kid’s Korner Why is the sky dark at night? That question is not as simple as it may sound. You might think that space appears dark at night because that is when our side of Earth faces away from the Sun as our planet rotates on its axis every 24 hours. But what about all those other far away suns that appear as stars in the night sky? Our own Milky Way galaxy contains over 200 billion stars, and the entire universe probably contains over 100 billion galaxies. You might suppose that that many stars would light up the night like daytime!

is that no matter where you look in the night sky, you should see a star. Stars should overlap each other in the sky like tree trunks in the middle of a very thick forest. But, if this were the case, the sky would be blazing with light. This problem greatly troubled astronomers and became known as "Olbers' Paradox." A paradox is a statement that seems to disagree with itself.

To try to explain the paradox, some 19th century scientists thought that dust clouds between Until the 20th century, astronomers the stars must be absorbing a lot didn't think it was even possible to of the starlight so it wouldn't shine count all the stars in the universe. They thought the universe went on forever. In other words, they thought the universe was infinite.

through to us. But later scientists realized that the dust itself would absorb so much energy from the starlight that eventually it would glow as hot and bright as the stars themselves. Astronomers now realize that the universe is not infinite. A finite universe--that is, a universe of limited size--even one with trillions and trillions of stars, just wouldn't have enough stars to light up all of space. Although the idea of a finite universe explains why Earth's sky is dark at night, other causes work to make it even darker. Not only is the universe finite in size, it is also finite in age. That is, it had a beginning, just as you and I did. The universe was born about 15 billion years ago in a fantastic explosion called the Big Bang. It began at a single point and has been expanding ever since.

Besides being very hard to imagine, the trouble with an infinite universe

Alien solar system disk reveals birth of a Planet Astronomers have photographed first direct image of a planet in the process of forming around its star. What astronomers are calling LkCa 15 b, looks like a hot "protoplanet" surrounded by a swath of cooler dust and gas, which is falling into the still-forming planet. Above: A cloud of gas and dust, called a nebula. This one NGC 604, glows with light from newly formed stars.

Because the universe is still expanding, the distant stars and galaxies are getting farther away all the time. Although nothing travels faster than light, it still takes time for light to cross any distance. So, when astronomers look at a galaxy a million light years away, they are seeing the galaxy as it looked a million years ago. The light that leaves that galaxy today will have much farther to travel to our eyes than the light that left it a million years ago or even one year ago, because the distance between that galaxy and us constantly increases. That means the amount of light energy reaching us from distant stars dwindles all the time. And the farther away the star, the less bright it will look to us.

Images have revealed that the forming planet sits inside a wide gap between the young parent star and an outer disk of dust. Adam Kraus of the University of Hawaii Institute for Astronomy and colleague Michael Ireland of Macquarie University and the Australian Astronomical Observatory combined the power of the 10-meter Keck telescopes with a bit of optical sleight of hand.

power of Keck's Adaptive Optics with a technique called aperture mask interferometry. The former is the use of a deformable mirror to rapidly correct for atmospheric distortions of starlight. The latter involves placing a small mask with several holes in the path of the light collected and concentrated by a giant telescope. With that, the scientists can manipulate the light waves.

"LkCa 15 b is the youngest planet ever found, about 5 times younger than the previous record holder," said Kraus. "This young gas giant is being built out of the dust and gas. In the past, you couldn't measure this kind of phenomenon because it's happening so close to the star. But, for the first time, we've been able to directly measure the planet itself as well as the dusty matter around it."

"It's like we have an array of small mirrors," said Kraus. "We can manipulate the light and cancel out distortions." The technique allows the astronomers to cancel out the bright light of stars. They can then resolve disks of dust around stars and see gaps in the dusty layers where protoplanets may be hiding.

The optical sleight of hand used by the astronomers is to combine the

"Interferometry has actually been around since the 1800s, but through the use of adaptive optics has only been able to reach nearby young suns for about the last 7

Holmberg II – Forever blowing bubbles “I’m forever blowing bubbles… Pretty bubbles in the air…” Its name is Holmberg II, and it’s part of the M81 Galaxy Group and one of the few that isn’t distracted by gravity from nearby peers. Holmberg II is an active little galaxy and one that’s full of holes – the largest of which spans 5500

light years wide. But what makes this one really fascinating is that it’s expelling huge bubbles of gas…

Above: An artist's concept of LkCa 15b being surrounded by dust and gas. years." said Dr. Ireland. "Since then we've been trying to push the technique to its limits using the biggest telescopes in the world, especially Keck." The discovery of LkCa 15 b began as a survey of 150 young dusty stars in star-forming regions. That led to the more concentrated study of a dozen stars. "LkCa 15 was only our second target, and we immediately knew we were seeing something new," said Kraus. "We could see a faint point source near the star, so thinking it might be a Jupiter-like planet we went back a year later to get more data." In further investigations at varying Here the remnants of mature and dying stars have left thick waves of dust and gas, carved into shape by stellar winds. Some ended their lives as supernovae – sending rippling shockwaves through the thinner material to hang in space like fantasy ribbons. With no dense nucleus to deform it like an elliptical galaxy, nor distorting arms like a spiral, this irregular star-forming factory is the perfect place for astronomers to take a close look stellar formation in a new way. Keep thinking bubbles, because Holmberg II is the perfect example

Above: This Hubble Space Telescope “deep field” image shows about 300 galaxies in a piece of sky only a few millimetres in size!!!

http://www.marcsobservatory.com

Left: Hubble’s famous images normally show elegant spirals or softedged ellipses. But these types are only representative of large galaxies. Smaller galaxies like Holmberg II come in many shapes and types that are harder to classify.

wavelengths, the astronomers were intrigued to discover that the phenomenon was more complex than a single companion object. "We realized we had uncovered a super Jupiter-sized gas planet, but that we could also measure the dust and gas surrounding it. We'd found a planet at its very beginning" said Kraus. Drs. Kraus and Ireland plan to continue their observations of LkCa 15 and other nearby young stars in their efforts to construct a clearer picture of how planets and solar systems form. www.dailygalaxy.com

of the “champagne” model of starbirth – where new stars create even newer ones. How does it work? When a bubble is created by stellar winds, it moves outwards until it reaches the edge of the molecular cloud that spawned it. At the exterior edge, dust and gas have been compressed and form a nodule similar to a blister. Here another new star forms... and triggers again… and again… similar to the chain reaction which happens when you open a bottle of champagne. According to the Hubble team, our little dwarf also has an ultraluminous X-ray source in the middle of three gas bubbles which appears in the image’s upper right hand corner. No one is quite sure of what it just might be! Maybe black hole bubbles? www.universetoday.com

www.midlandsastronomy.com Page - 10

Page - 3

Midlands Astronomy Club Magazine Instead, the most likely scenario involves a closely spaced double impact, Morbidelli's team found.

Uranus got knocked over by one-two punch The planet Uranus got knocked on its side not by a single, massive blow but by two powerful impacts, new computer simulations hint. The model helps explain a longstanding mystery: Why do Uranus's moons also lie in unexpected positions? Unlike the other seven planets, Uranus's rotation axis has a bizarre 98-degree tilt relative to the solar system's orbital plane. In other words, the planet seems to roll around on its side as it orbits the sun. Even odder, the rings and moons of Uranus circle the planet's tilted equator.

be circling the planet's instead of its equator.

Midlands Astronomy Club Magazine

poles

Single Blow Would Have Meant "Backward" Moons To explore this conundrum, a team led by Alessandro Morbidelli, of the Observatoire de la Cote d’Azur in France, ran several simulations of possible Uranus impacts.

Bucket List Object #5: A Meteor Storm

"Our computer simulations show that two sequential impacts occurred very early in the planet's history, when it was still surrounded by a protosatellite disk, and should have occurred relatively close in time," Morbidelli said. "So far, this is the only model that explains the equatorial orbits of Uranus's satellites."

The results showed that Uranus was most likely struck when its moons and rings were still forming from a disk of debris around the ice giant's equator. When Uranus was hit, this disk was disrupted but then reformed around the planet's tilted equator, eventually giving rise to the moons in the positions we see today. In the new simulations, however, a single impact led to moons that orbit "backward"—in the opposite direction of the planet's spin.

"In general, scientists have thought that these planets formed by accreting only small planetesimals, and the Uranus tilting event was an

Gorgeous globular hides hundreds of rejuvenated stars

where stars are thickest, as you’d expect.

ancient stars around them. In a way, I suppose, they are.

Over 200 of them have been found in M 53 alone, and at first glance, if That is Hubble’s view of M53, a cluster of several hundred you didn’t know better, you’d think thousand stars crammed into ball about 60,000 light years away they were far younger than the

But don’t judge. If you were a 12 billion year old star, you might want a facelift, too.

— well outside the Milky Way itself, but bound to it, orbiting our galaxy. It’s probably 12 billion years old, but it looks like some of the stars in it have opted for a little cosmetic surgery… In our galaxy, stars are so far apart that collisions between two of them almost never happen. But in globular clusters stars are so closely packed that many of them have apparently literally collided with each other, merging into objects called blue stragglers. Globulars are old, so having blue, massive stars is weird; they have short lifespans, and should’ve all blown up as supernovae or at least turned into red giants billions of years ago. When these objects were first discovered in globulars they were really surprising, and while we still

www.midlandsastronomy.com Page - 4

don’t understand everything about them, it’s a fair bet they result from two stars having a very, very close encounter. If two older, low mass red stars pass close to each other at low speed, their gravity can cause them to become bound to each other (it helps if a third star is involved; it can steal away energy from the other two, making it easier for them to become stuck together). Over time, they can spiral together and merge, forming a single, more massive, hotter object: a blue straggler. They’re seen in many globular clusters, and tend to be more common

Sadly, the Leonids will likely remain quiet this year, and for many years to come. Perturbations of the comet by Jupiter mean the Earth may miss the usual rendezvous with this stream of concentrated comet dust for many decades, perhaps.

Over the next several months, we present our totally subjective list of ten celestial sights to see before you die, or “kick the bucket”, as they say. We call it the “Bucket List for Backyard Stargazers”. Our list is targeted at the casual stargazer, with no special expertise or training or ambition other than to see some of the most beautiful, and in some cases, transient sights in nature. For some of these objects, you’ll need access to a pair of binoculars or a small telescope. Others require travel and good timing and luck. And for others, you need to simply look So chances are, none of us may ever up. But all these sights are not that hard to see, once you know how and when and where to look see anything like the outburst of 1833, or even 1999. But there are for them. We’ll help you with that.

Big Impacts Once the Norm Among Giants? The results suggest that giant impacts may have been more common than previously thought in the early days of the solar system, when today's planets were still sweeping up smaller objects from the large debris disk surrounding our young sun. In fact, big collisions could have been important factors in the formation of planets such as Saturn and Neptune, which both display 30degree tilts in their axes.

The widely accepted theory for how Uranus got knocked over is that a rogue Earth-size planet slammed into the ice giant billions of years ago. That lost world was mostly likely destroyed on impact. But previous computer simulations showed that a single extreme impact wouldn't have affected Uranus's retinue of more than 25 moons, and the moons should now

peaks in 2001 and 2002 (though they did not approach the dramatic peak of 1833).

exceptional event," Morbidelli said. "But now we show that Uranus has to have been tilted at least twice, so these giant impacts were not exceptional events—they were the norm."And Pluto may be harbouring yet more diminutive moons that are waiting to be discovered, he added. With the New Horizons mission nearing its target, "we're going to go look and see." www.nationalgeographic.com

http://blogs.discovermagazine.com

Left: This picture was put together from visible and infrared exposures taken with the Wide Field Channel of Hubble's Advanced Camera for Surveys. The field of view is approximately 3.4 arcminutes across.

A meteor storm! The very term makes an honest stargazer's heart beat faster. While a good meteor shower, like the Perseids, may show 50-60 meteors every hour, a meteor storm sprays shooting stars at a rate of hundreds or thousands an hour. During a spectacular storm in 1833, the sky seemed to “fill with falling fire” for nearly half the night.

Left: An engraving showing the 1833 Leonid meteor storm

While spectacular, a meteor storm, which comes in at #5 on our “ Buc ke t Lis t f or Ba c k ya r d Stargazers”, may be the most difficult to see because they are extremely brief and rare. But take heart. NASA is already preparing to deal with a possible outburst next year from a usually lacklustre shower in Draco. And since such events are hard to predict, there may be more opportunities in the coming years. One thing for sure… if you do century observers into a glazed see a meteor storm, you'll never stupor or near-catatonic terror. forget it. Nearly everyone awakened to see the bright meteors and attending The Leonid meteor shower, which commotion on the morning of peaks this week in the early November 12. The storm lasted morning of November 18th, has nearly four hours. According to offered stargazers the most reliable astronomer Agnes Clerke, “the opportunity to see a meteor storm. frequency of meteors was The shower flares up every 33 estimated to be about half that of years to present a deluge of flakes of snow in an average meteors for a few hours on the snowstorm”. early morning on or around November 18th. Experts predict this The meteors came so quickly year's Leonids will be quite tame, during this 1833 storm, it was alas. So no meteor storm this year. clear the radiant, or apparent source, of the meteors lay towards But there have been some the Sickle of the constellation Leo. remarkable Leonids in the past. The And the radiant moved with the great Leonid meteor storm of 1833 stars during the evening, which was perhaps the most spectacular finally made it clear that meteors in recorded history. Visible from came from outside the Earth's eastern North America, the storm atmosphere. Until then, some produced as many as 200,000 believed meteors were an meteors per hour, startling 19th- atmospheric phenomenon, the

still opp or tunitie s to se e a respectable meteor storm, though it likely won't be the Leonids.

Your best near-term bet for a meteor storm lies with the Draconid meteor shower next year. The Draconids, sonamed because the meteors streak across the sky from a point in the constellation Draco. With a little luck, you'll see a rich and remarkable spray of meteors. And you can check this event off your celestial bucket list. www.oneminuteastronomer.com

belief of which coined the term “meteorology” to the study of the weather. Astronomers looked at historical records to determine the Leonids peaked at multiples of 33 years… in 1799, 1533, 1366, 1202, and 1037, for example. We now know the peaks correspond to brief periods during which Earth passes through a concentration of debris left in the path of Comet Tempel-Tuttle. The Leonids last peaked in 1999, with bonus

Above: An artists rendition of the meteor storm over Niagra Falls in 1833.

www.midlandsastronomy.com Page - 9

Midlands Astronomy Club Magazine

Galaxy Zoo reveals curious ‘Violin Clef’ quadruple galaxy merger

A most beautiful object the constellation Cepheus

About a month ago, a Galaxy Zoo contributor named Bruno discovered a very unique galaxy merger in the Sloan Digital Sky Survey data. The merger appeared to be a triple, or possibly quadruple system, which are indeed quite rare, and it includes curiously thin and long tidal tails. The Galaxy Zoo team has been informally referring to this merger as the “Violin Clef” or the “Integral” based on the unique shape as shown above.

that could form new stars?” Willett also added, “Or has the starburst already come and gone – and if so, how long-lived are these tidal tails going to be?”

The constellation Cepheus lies nearly overhead in the midevening hours for northern observers this time of year. The constellation represents the legendary husband of Cassiopeia, but it looks less like a king seated on a throne than a crooked stick-figure house drawn by a small child.

By using analysing the light given off by the merging galaxies, researchers can obtain a treasure trove of information. By measuring how much the spectra is redshifted, researchers can determine an accurate distance. In the case of the Violin Clef merger, an accurate redshift would let the team know for certain if all four galaxies genuinely belong to a single interacting group.

Cepheus contains few bright stars, but it hosts a number of remarkable stars and deep-sky objects worthy of inspection in a small telescope. One of the easiest to enjoy is mu Cephei, a gigantic swollen monster of a star in its last stages of life. This deep-red beauty is perhaps the largest star visible to the unaided eye…

What about this merger make it so interesting to scientists? What can they learn from these type of galaxy mergers? Galaxy Zoo contributor Bruno had some insights on what makes the merger so interesting, stating: “These are some really beautiful tidal tails – They are extremely long and thin and appear curiously poor

universe, the merging process is fairly quick compared to the lifetime of a galaxy. What is not common is to observe a system with long tails and multiple companions, which gives researchers an opportunity to test their models of galaxy interaction against a system “caught in the act”.

Once researchers have a distance estimate, they can study UV and radio flux data and determine an estimate of the total star formation rate. Additionally, if researchers have very accurate data from light received (spectroscopy), it’s possible to measure the relative velocities of each interacting galaxy, and build a sort of “3-D” picture of how the four galaxies are interacting.

Above: Close-Up view of Violin Clef galaxy merger. step in the analysis will be working with simulations like the ones in Merger Zoo. Now that the team has confirmed the Violin Clef is almost certainly a quadruple merger, the number of merger models than need to be ran is greatly reduced. How can citizen scientists help the Galaxy Zoo team with this step of their research? You can start by visiting the Galaxy Zoo mergers project page at: http:// mergers.galaxyzoo.org/ Learn more about becoming a Galaxy Zoo participant at: http:// w w w . g a l a x y z o o . o r g / how_to_take_part www.universetoday.com

Shown at lower right is the Violin Clef galaxy merger. in terms of star formation, which is odd since mergers do tend to trigger star formation.” Bruno also added at the time of discovery: “There is no spectrum so we do not know the redshift of the object. It is also not clear if the objects at either end are associated or just a projection.”

Researchers are also interested in the content of galaxies and their tails – specifically the gas and stars. In most mergers, there is a compression of gas by gravity, which leads to a short burst of new star formation in the galaxies and their tails.

Based on Bruno’s curious discovery, the Galaxy Zoo team put in significant efforts to learn more about this merger. Galaxy Zoo team member Kyle Willett provided an update this week, highlighting several new insights, along with more information on this merger’s significance. One of the additional reasons the system is of scientific interest is that while merging galaxies are quite common in our

The resulting star formation results in young, hot stars which are typically blue. (Note: Younger/ hotter stars are bluer, older/cooler stars are redder). What is odd about the Violin Clef merger is that all four galaxies and the tidal tails are red. Willett stated “If that’s the case, then we want to estimate the current age of the system. Were the galaxies all red ellipticals to begin with, with very little gas

www.midlandsastronomy.com Page - 8

Since there wasn’t any existing spectral analysis data of the merger system, Danielle Berg, a graduate student at the University of Minnesota, observed the Violin Clef in September using the 6.5-meter Multiple Mirror Telescope in Arizona and provided the additional data needed to answer some of the questions the Galaxy Zoo team had about the system. After the team analysed the spectral data, they learned that all four galaxies are at the same redshift (z=0.0956 +- 0.002), and as such, are most likely members of the same group. Further analysis reinforced the lack of evidence for strong star formation, which helps to confirm the red colors see in the Sloan Digital Sky Survey data. Based on these recent discoveries, the Galaxy Zoo team is putting out a second call for assistance on analysing the Violin Clef merger. According to the team, the next

As a massive star, mu Cephei has quickly burned through the hydrogen in its core, and now burns helium or carbon. This has caused it to swell into a red supergiant. But with a diameter of 2.4 billion miles, mu Cephei is a giant even among supergiants. If mu took the place of our sun, it would extend to the orbit of Saturn!

ring system of molecules such as water, carbon monoxide, and silicon oxide. As the star has swollen, it has cooled to about 3,700K, which means it emits mostly red and infrared light. Including infrared radiation, the star shines 350,000 times brighter than our Sun. Find mu for yourself under the house-shape of Cepheus, southwest of zeta Cephei and southeast of Alderamin (alpha Cehei). The star is about 4th magnitude right now, so it’s not too hard to find in binoculars or a finder scope.

In a small telescope, mu reveals its deep red color. Herschel noted the star was “…very fine deep Mu also undergoes an irregular garnet colour… and a most variation in brightness, along with beautiful object”. It’s now often steady mass loss. The star varies called “Herschel’s Garnet Star”. from magnitude 3.4 to 5.1 over a period of 2-3 years. And it’s I see it more as a red-orange surrounded by a cooler shell and colour rather than garnet. It’s

certainly not as red as a Hind’s Crimson Star, for example, in the constellation Lepus. Herschel recommended enhancing the perceived colour by observing a white star, such as nearby Alderamin, for several minutes beforehand. It works!

The Evening Sky Map is suitable for all stargazers including newcomers to astronomy and will help you to: • identify planets, stars and major constellations. • find sparkling star clusters, wispy nebulae & distant galaxies. • locate and follow bright comets across the sky. • learn about the night sky and astronomy.

www.oneminuteastronomer.com

The largest planet in the solar system, Jupiter, reaches maximum brightness the night of October 28. On that date, the planet lies opposite the Sun from Earth in our sky — this is called • opposition. Jupiter will rise at sunset, appear highest around local midnight, and set as the Sun rises. The king of planets will glow far brighter than any other point of light in the sky. The gas giant currently lies in Aries and is about 100 times more brilliant than the brightest star in that constellation. Look for Jupiter in the east at sunset and it will climb higher in the southeastern sky as the night wears on. You can observe Jupiter’s disk through any size telescope, which makes the planet a great target for beginners. You’ll be able to spot its

dark equatorial cloud belts and even its four major moons, which align with Jupiter’s equator. The planet’s South Equatorial Belt returned in November 2010 after it mysteriously faded away for about six months. Fast facts about Jupiter • Jupiter is the largest planet in the solar system and all the other planets together make up only about 70% of Jupiter’s volume. • It takes Jupiter about 12 years

Mu Cephei lies next to the large and faint nebulous region IC 1396 which can be seen in a wide-field telescope or binoculars in very dark sky.

In time, over the next several hundred thousand years, mu

See Jupiter at its 2011 best

To help find your way around the night sky, Skymaps.com makes available for free each month.

Cephei will run out of fuel in its core and explode as a supernova.

•

to orbit the Sun once, but only about 10 hours to rotate completely, making it the fastestspinning of all the solar system’s planets. Jupiter reflects 52% of the sunlight falling on it, more than any other planet except Venus (65%). Jupiter’s four large moons — Io, Europa, Ganymede, and Callisto — are easily visible through small telescopes. Our line of sight lies in the plane of the jovian moons’ orbits, so we see occultation's (when a moon moves behind Jupiter), eclipses (when Jupiter’s shadow falls on a moon), and transits (when a moon passes in

front of Jupiter) at various times.

• Jupiter’s moon Ganymede is the solar system’s largest satellite, with a diameter of nearly 3,300 miles which is greater than that of Mercury. www.dailygalaxy.com

www.midlandsastronomy.com Page - 5

Midlands Astronomy Club Magazine

How comets in distant solar systems could deliver oceans to exoplanets A pair of new comet studies from two space telescopes show how other planets might grow oceans. For the first time, astronomers have detected a ring of cold water vapor encircling a young star’s dusty planetary disk. And a separate study in a different star system shows a hailstorm of icy bodies could be bombarding a young planet. Together, the studies bolster a theory about how comets may have delivered Earth’s oceans — and they show this is not a unique occurrence in the universe. A recent issue of the journal Science contains a paper describing cold water surrounding a young star called TW Hydrae, located in the Hydra constellation. Astronomers have previously found warm water around planet-forming regions, but not huge amounts of cold water. This cold reservoir demonstrates how comets form in a solar system’s outer reaches. "Our observations of this cold vapour indicate enough water exists in the disk to fill thousands of Earth oceans," said lead author Michiel Hogerheijde of Leiden Observatory in The Netherlands. TW Hydrae is just 10 million years old, and it is believed the dusty disk surrounding it will eventually coalesce to form planets. The frosty water vapour will probably coalesce to form comets, some of which might rain down on those new planets.

the planet, delivering water and other things. (Earth was too hot after its formation to hold on to any native H2O.) Earlier this month, researchers using the European Space Agency’s Herschel Space

Midlands Astronomy Club Magazine same type of bombardment happening at Eta Corvi.

So it sounds like comet clouds and water reservoirs are not uncommon at all. Perhaps around each star’s a pool of water — which could mean very interesting things for the search for extraterrestrial life. www.popsci.com

This does indeed happen in other solar systems, as a separate study shows. Astronomers using the cold -observing Spitzer space telescope described finding a dusty band around a star called Eta Corvi, a billion-year-old star system in the constellation Corvus, the crow. The band’s contents strongly match that of an obliterated comet, suggesting a massive collision, perhaps with a planet. This sounded like what happened during Earth’s own Late Heavy Bombardment. The system has a second, bigger ring much farther out, just like our own Kuiper Belt. And the bombardment is even happening around the same time that ours did, about a billion years after the Earth formed.

Observatory said they found the chemical isotope signature of Earth water out in the distant reaches of our solar system, suggesting that Oort Cloud comets may have been one source of this bombardment, not necessarily just asteroids. This new Spitzer study suggests the

During the Late Heavy Bombardment here, a cascade of frosty space rocks rained down on

Lunar Mining Coming Soon?

Above: Cool, Clear Water The nearby star TW Hydrae has a burgeoning solar system with a sprawling cloud of cold water vapour. The vapour is cold enough to eventually form comets, which could deliver oceans to dry planets that are forming in the system.

A team from the School of Earth and Space Exploration at Arizona State University has created a map of the Moon that shows areas rich in titanium ores. The highest titanium abundances in similar kinds of rocks on Earth are around 1% or less. The new map shows that titanium abundances range up to 10%. In the highlands, the abundance of titanium is less than 1%. As specific minerals reflect/absorb certain parts of the electromagnetic s p e c tr um , the w a ve le ng t hs detected can help scientists better understand the chemical composition of the lunar surface.

Above: A Barrage of Comets: This artist's concept illustrates a storm of comets around a star near our own, called Eta Corvi. Evidence for this barrage comes from NASA's Spitzer Space Telescope, whose infrared detectors picked up indications that one or more comets was recently torn to shreds after colliding with a rocky body.

www.midlandsastronomy.com Page - 6

Arizona State University’s professor Mark Robinson had previously developed a technique using HST images to map the abundance of titanium around a small area centred on the Apollo 17 landing site. By comparing the Apollo data from the ground with the Hubble images, the team found that the

Failed star is one cool companion Astronomers have located a planet-like star that’s barely warmer than a balmy summer day on Earth… it’s literally the coldest object ever directly imaged outside of our solar system! WD 0806-661 B is a brown “Y dwarf” star that’s a member of a binary pair. Its companion is a much hotter white dwarf, the remains of a Sun-like star that has shed its outer layers. The pair is located about 63 light-years away, which is pretty close to us as stars go. The stars were identified by a team led by Penn State Associate Professor of Astronomy and Astrophysics Kevin Luhman using images from NASA’s Spitzer Space Telescope. Two infrared images

Above: These two infrared images were taken by the Spitzer Space Telescope in 2004 and 2009. They show a faint object moving through space together with a white dwarf.

taken in 2004 and 2009 were overlaid on top of each other and show the stars moving in tandem, indicating a shared orbit. Of course, locating the stars wasn’t quite as easy as that. To find this stellar duo Luhman and his team searched through over six hundred images of stars located near our solar system taken years apart, looking for any shifting position as a pair.

Above: Artist's impression of a brown-dwarf object (left foreground) orbiting a distant white dwarf --the collapsed-core remnant of a dying star.

estimate the temperature of WD 0806-661 B to be in the range of about 80 to 130 degrees Fahrenheit (26 to 54 degrees C, or 300 – 345 The use of infrared K)… literally body temperature! imaging allowed the team to locate Six to nine times the mass of a dim brown dwarf Jupiter, WD 0806-661 B is more like star like WD 0806- a planet than a star. It never 661 B, which emits accumulated enough mass to ignite little visible light thermonuclear reactions and thus but shines brightly more resembles a gas giant like in infrared. (Even Jupiter or Saturn. But its origins are th ou g h b r ow n most likely star-like, as its distance dwarfs are extremely cool for stars from its white dwarf companion – they are still much warmer than about 2,500 astronomical units – the surrounding space. And, for indicates that it developed on its the record, brown dwarfs are not own rather than forming from the actually brown.) Measurements other star’s disc.

There is a small chance, though, that it did form as a planet and gradually migrated out to its current distance. More research will help determine whether this may have been the case.

diameter of the Earth itself. But since we can't build such gigantic telescopes, we use interferometry to simulate them."

40 radio sources near the centre of Arp 220. By watching how these sources changed over time in two d if fe r e nt r a d i o w a ve le ng t hs , astronomers could tell that seven of the objects were stars that had exploded around the same time.

Seven Supernovae found in single galaxy

In astronomy, interferometry uses

Brown dwarfs, first discovered in 1995, are valuable research targets because they are the next best thing to studying cool atmospheres on planets outside our solar system. Scientists keep trying to locate new record-holders for the coldest brown dwarfs, and with the discovery of WD 0806-661 B Luhman’s team has done just that! http://www.universetoday.com

titanium levels corresponded to the ratio of ultraviolet to visible light reflected by the lunar soils.

In a galaxy 250 million light-years from Earth, astronomers have the combined power of an array of spotted a record-breaking seven supernovae all found at the telescopes—rather than a single, huge telescope—to create high- Astronomers estimate that our galaxy same time.

To discover whether the technique would work across broader areas, or whether there was something special about the Apollo 17 area, Robinson’s team constructed a mosaic from approximately 4000 LROC WAC images. Using the technique they had developed with the Hubble imagery, they used the ratio of the brightness in the ultraviolet to visible light in the WAC im ag es to d ed uce titanium abundance, backed up by surface samples gathered by Apollo and Luna space missions.

"As far as we know, only three supernovae in a single galaxy were found at once so far, but we can confirm seven supernovae [in a single galaxy], thanks to a 17-year monitoring of the radio sources in Arp 220." The unprecedented find may offer a unique cosmic laboratory for studying galaxy evolution. The prodigious galaxy, known as Arp 220, is thought to have formed from the merger of two smaller galaxies and is well known to host a very intense burst of star formation, easily seen in visible wavelengths.

www.dailygalaxy.com

Telescope Como Revealed Supernovae Each of the supernovae found in Arp 220 spans less than a lightyear, and at such a great distance, each radio signal covers an angle in the sky less than 0.5 milliarcseconds across. "To give you an idea of how small this is, this size corresponds to what you would see if you would look into a straw of about 1,500 kilometres long. In order to see such small objects, we would need a telescope of 10,000 kilometres across, which is a bit less than the

resolution images that can probe deep into the universe. Batejat's team used 57 of the largest radio telescopes on Earth, which are spread across two continents and five countries.

The heart of Arp 220 is highly obscured by dust that can't be penetrated by visible wavelengths. But radio waves can travel through such a dense environment to reach telescopes on Earth. Supernova Discovery Is "Something Amazing" Ultimately the data revealed around

sees only a single supernova every hundred years, on average but the highly active Arp 220 behaves more like how young galaxies probably did more than ten billion years ago. "We hope this might lead to interesting discoveries on how stars formed [and died] in the early universe," Batejat said. What's more, such relatively fresh supernovae "are rare, and they have short lives of a few decades maximum" before they settle into supernova remnants, he said. "So discovering seven such supernovae at once is something amazing." http://www.universetoday.com

www.midlandsastronomy.com Page - 7