Thursday, August 4, 2016
Zubeneschamali: What Is It and Where Is It?
Pronounced, zoo-ben-es-sha-mali, rhymes with Obi-Wan-Kenobi of Star Wars fame, this tongue-twister name of a star and its discovery dates back to thousands of years B.C. The name originated from the Arabic and translates to The Northern Claw. When first discovered this emerald green star (yes, green) was located in the constellation Scorpio. The name makes perfect sense in liaison with its partner star called Zubenelgenubi, which means The Southern Claw. Later, the Romans came into play when they determined that the “claws” of Scorpio should belong to the constellation Libra. They not only redrew the boundaries of these two constellations but changed the name of Zubeneschamali. It is now better known as Beta Libra.
Zubeneschamali, as the star is still tagged, is the brightest star in the constellation Libra. It is just a bit brighter than its partner star. What makes this star so unique? Well I, for one, love the fact that it is the only naked-eye star that is green. Some scientists and star-gazers disagree. If it is truly green, then it is the only green star among the vast amount of stars in the sky. Why is this? Astronomers and sky-gazers can agree on one thing: people see colors differently.
To define the debate a little more, Zubeneschamali is classified as a Class B star, which typically is a blue-white star. So you can understand the confusion. Some of the explanation can be attributed to the fact that this star is 160 light years away, four times the size of our Sun, twice as hot, and spinning rapidly. On occasion, several star-gazers will get together to observe this star in the late southern summer sky with their naked eye. If you do not see green, then try binoculars. Some will see green and others only white. I say it is GREEN.
In addition, Zubeneschamali is at the center of a centuries-old debate. Over two thousand years ago it was listed as the brightest of all stars of the constellation Scorpio, even brighter than Antares. A few centuries later, however, the great astronomer Ptolemy described Antares’ brightness equal to Zubeneschamali. Today Antares appears five times brighter. Has Zubeneschamali dimmed over the years, or has Antares gotten much brighter? A new debate is waging that this infamous star may be a “variable” star. So now we have a green star (that scientists say is not green) but may be a “binary” star (one star eclipsing another) which causes the dimming effect. You can see why this star is one of my very favorites…it has history and mystery.
My sources: EarthSky.org, UniverseToday.com, jackstargazer.com, stars.astro.Illinois.edu, constellationsofwords.com, and Wikipedia
Wednesday, May 11, 2016
Planetarium or Observatory?
Do you know the difference between the two? Maybe you have gone to a planetarium to watch a show about the stars, planets, and other objects in the universe. Perhaps you remember going to an observatory to actually look through a huge telescope or smaller ones to see objects in the night sky in real time.
A planetarium is a theater built primarily for presenting educational and entertaining shows about astronomy and the night sky or for training in celestial navigation. Astronomy is the study of those objects and celestial navigation is the position or where to find those objects to identify them in the night sky.
The dominant feature of most planetaria is the large dome-shaped projection screen at the top of the room onto which stars, planets, and other celestial objects can be made to appear and more realistically to simulate the complex motions of the heavens. These scenes can be created by using various technologies. For example there is the precision-engineered ‘star balls’ that combine optical and electro-mechanical technology, such as projectors, video, and fulldome systems and lasers. The technologies used are linked together to provide the most accurate motion of the sky. The display can depict the sky in the past or present as it would appear from any latitude on Earth.
An observatory is a location used for observing terrestrial or celestial events. Some of these disciplines would be astronomy, climatology, meteorology, geology, oceanography, and volcanology. The structure is designed to accommodate the discipline that it is studying. When I think of an observatory I think of one geared towards astronomy. This would contain an astronomical sextant and one large telescope for viewing. Some larger observatories may contain more than one telescope.
There are ground-based, radio, space, and ancient (such as Stonehenge) observatories. If you’ve never been to one and want to experience this firsthand, a planetarium is the best place to start. Some college planetariums are open to the public during certain months; usually on a Friday. Check their schedule for months, days, and times. There is usually a small fee to view and listen to the show. At some colleges, if the night sky is right for viewing, they may have a large mobile telescope they wheel outside. You may see the rings around Saturn and some of its moons for the first time or the hazy Andromeda Galaxy! Have you seen Mars? How about the great Orion Nebula? What would you like to see? Get excited, go see what’s out there!
Images and more information: http://floridaastronomy.weebly.com/planetariums-observatories.html
Sunday, March 13, 2016
Messier 31: The Andromeda Galaxy
Next to our own Milky Way galaxy, Andromeda is the most well-known galaxy in our universe. At the distance of 2.5 million light-years away, it is the most distant thing we can see with our naked eye. A spiral galaxy, approximately 260,000 light-years across, is the largest of our local group of galaxies, which includes our own Milky Way spanning 100,000 light-years across. On a clear and dark winter night, M31 can be seen as a fuzzy patch of light. It’s an inviting target for binoculars or a telescope. We are best able to see it starting in the fall when it’s high enough in the sky to be seen from nightfall until daybreak. In late September and early October Andromeda shines in the eastern sky at nightfall and stands high in the west at the onset of dawn. Winter evenings are also good for viewing.
How do we find the Andromeda galaxy? The easier way I have found is to use the constellation Cassiopeia, the Queen. It’s easy to recognize because it is in the shape of a “W.” I generally look northward on the sky’s dome to find this constellation. By finding Polaris (the North Star) and by finding the Big Dipper nearby, I can easily see that the Big Dipper and Cassiopeia move around Polaris like hands on a clock. In Cassiopeia, the star “Schedar” points right to Andromeda. Schedar is the second bottom star in the “W.”
When Andromeda was first photographed in 1900 it was thought to be a cloud of gas within our Milky Way and called the Andromeda Nebula. It wasn’t until the 1920’s that Edwin Hubble determined that Andromeda was outside the Milky Way, that it was an individual galaxy, and that these points of light were indeed stars. It wasn’t until 2006 that the Spitzer Space Telescope revealed that Andromeda contained one trillion stars. That’s over twice the amount of stars in the Milky Way, which is estimated to be 200-400 billion.
So what have we learned since 964 when a Persian astronomer found Andromeda and described it as a “small cloud?” Well, new stars, as well as old stars, could be found there with a dense concentration toward the center. It has a double nucleus, which I interpret as a double “massive black hole,” at the center. As a matter of fact, 26 black holes have been found in the galaxy to date, but not all are massive. There are 450 globular clusters orbiting in and around Andromeda. More recently the KELT North Telescope has detected two large planets in this galaxy: KELT-1b and KELT-1ab. An ancient companion galaxy was ripped up and consumed by Andromeda; the clouds are the remains of the stars of this prior galaxy. There are 14 dwarf galaxies nearby that it regularly bullies. Andromeda is blue-shifted, which means that it and the Milky Way galaxies are on a collision course. But we needn’t worry; this won’t happen for another 4 billion years.
Images and more information: http://wise.ssl.berkeley.edu/gallery_andromeda.html
References: EarthSky.org, NASA.org, Space.com, HubbleSite, AstronomyNow.com, CalTech, WISE.ssi.berkley.edu, and Wikipedia.org.
Friday, January 22, 2016
Jean E. Lane's Imagine This: ALMA: InSearch of Cosmic Knowledge
ALMA, short fo...: ALMA: In Search of Cosmic Knowledge ALMA, short for “Atacama Large Millimeter Array,” is the largest observatory ever built. The ob...
ALMA, short fo...: ALMA: In Search of Cosmic Knowledge ALMA, short for “Atacama Large Millimeter Array,” is the largest observatory ever built. The ob...
ALMA: In Search of Cosmic Knowledge
ALMA, short for “Atacama Large Millimeter Array,” is the largest observatory ever built. The observatory is located at an altitude of 3.1 miles high on the Chajnantor plateau in the Chilean desert near San Pedro De Atacama, in a place so dry and red it appears that it could be Mars. Dozens of antennas stare at the sky in unison. There is an array of 66 radio telescopes with a diameter of 39 feet and 23 feet observing the sky at millimeter and sub-millimeter wavelengths. They can see deeper and farther in this light than any telescope before. ALMA’s purpose is to provide insight on the birth of stars as well as detailed imaging of local star and planet formation.
As you might expect, a project like this was an international partnership between Europe, the United States, Canada, several countries from East Asia and the Republic of Chile. With 30 years of planning and 10 years of construction the entire project took thousands of scientists and engineers from around the world to complete. The total price tag was approximately $1.3 billion dollars and was split by the three sponsoring regions. Of the total cost the United States taxpayers contributed about $500 million.
The Llano de Chajnantor Observatory in Chile has been fully operational since March of 2013. ALMA combines dozens of these individual radio telescope dishes into a single observing instrument. What is amazing to me is that the resolution will be five times greater than that of the Hubble Space Telescope.
Some facts about ALMA that intrigued me:
· The observatory is accurate enough to detect a golf ball nine miles away.
· This high altitude is one of the driest places on Earth. This means no clouds.
· The dish design is almost perfect which prevent any loss of incoming radio waves.
· Each ALMA antenna must be kept at a chilling -452 degrees Fahrenheit to prevent noise.
· This will allow astronomers to see into distant gas clouds to study star and planet formation.
ALMA means “soul” in Spanish and “learned” or “knowledgeable” in Arabic. It will be interesting to see what information we can learn from our collective efforts in our search for knowledge about our universe. I find it a bit ironic that ALMA, in her otherworldly setting, sitting high atop a snow-capped plateau, surrounded by volcanoes, is also stepping up the search for alien life…somewhere…out there.
For images and information visit: http://www.almaobservatory.org/
Tuesday, November 24, 2015
Quintenary Star System: Anything But Ordinary
We’ve all heard about binary stars (one star revolving around another). The most popular binary stars are Mizar and its fainter companion star Alcor. To find them, look for the Big Dipper and find the handle; you’ll spot Mizar first as the middle star of the Big Dipper’s handle. Look closely and you’ll see Alcor right next to Mizar.
Harder to find are the trinary star systems, or triple star systems. It’s interesting to me because usually two of the stars form a close binary system while the third star orbits this pair at a distance in a much larger orbit. One such system is the Alpha Centauri star system with Proxima Centauri at a distance of 4.22 light years. It is the closest star to Earth beyond our own Sun.
The Kepler Space Telescope observed KIC 2856960 for four straight years before astronomers seemed to have enough data to make a determination. But when three astronomers, Marsh, Armstrong, and Carter in the UK started digging into the numbers, they discovered the system was anything but ordinary. First they observed two stars in close orbit of one another: a binary system. The smaller star seemed to orbit the larger one every 6 hours. However, there appeared to be a third star that entered into the equation every 204 days. This was throwing off their results. As they diligently worked out their dilemma on paper, other astronomers became involved. It’s the fact that they could not find a precise set of masses and radii for the component stars. We can’t explain why this star system is producing an ‘impossible’ light curve.
As the team studied the data from KIC 2856960 they saw a small dip in brightness about 4 times a day and a larger dip every 204 days. Okay, not a big deal; it’s a triple star system, so let’s move on to other data. But they were drawn back to their results to look at it with even more detail. After all, this was tricky, and there were all sorts of things that threw off results, such as starspots and other stellar activity. The more they looked at the data, the more confusing things got. At first glance, it looked like a triple star system, but the stars’ orbits didn’t seem to fit. They kind of fit, but there were fluctuations in the data. So the team tried another scenario and found that a four-star system worked—a quintenary system—two sets of binary stars!
This is anything but ordinary, and further data needs to be collected, but it’s clear that this is not a simple, boring triple-star system. We just don’t understand it yet. Perhaps the Transiting Exoplanet Survey Satellite, or TESS, will be able to shed some light on this. TESS is scheduled to launch in 2017. Until then KIC 2856960 is likely to remain a mystery. Is this a quintenary star system? Is there a planet hidden in this system? Don’t you love a good mystery?
Recommended link: http://www.atlasoftheuniverse.com/orbits.html
My sources: AtlasoftheUniverse.com, space.com, phys.org, pbs.org, atrobites.org, astronomy.com, and American Association of Variable Star Observers (AAVSO)
Sunday, September 6, 2015
Mordor Macula, Vader Crater, Nostromo Chasma…
By Jean E. Lane
New Horizons’ flyby of Pluto and Charon, its largest moon provided us with many incredible images. But the highly detailed images gave the New Horizons team an unanticipated problem: What do they call all those mountain ranges, plains, and craters?
What happens next is that the team intends to submit them to the International Astronomical Union (IAU), who is the official governing body for names of celestial objects. Here’s what’s currently being proposed to the committee; how about choosing names from Star Trek, Star Wars, Doctor Who, Firefly, Alien, and Lord of the Rings? The New Horizons team actually asked for submissions from the public, and they were only too happy to oblige.
Since Pluto was named after a god of the underworld, the names must be drawn from underworld mythology. NASA offered the Cthulu regio (a large region with color variances). Also chosen was the name Balrog macula (meaning dark spot) which honored Lovercraft’s dark god and the underground demons from stories by J.R.R. Tolkein.
All that’s wonderful news, but it’s Charon, Pluto’s moon, and the IAU rules permit names that reference “destinations and milestones of fictional space” as well as fictional spaceships and travelers. This notion grabbed the imaginations of many space fans, and their thoughts went directly to the iconic science fiction shows and movies that they revere.
Thus, the suggestions were presented, and the unofficial names, of craters are Vader, Skywalker and Leia Organa. For the plains they propose names of Spock, Kirk, Sulu, and Uhura, which would dot the Vulcan Planum. How about the Tardis chasma that crosses the Gallifrey macula? This name, of course is in reference to The Doctor’s (Doctor Who) vessel and planet. It also has been proposed that names from Alien, such as Ripley crater and Nostromo chasma, would be excellent choices. The name Serenity chasma in respect for Firefly also has a chance to become a real place on Charon. There’s room for one from Lord of the Rings, the giant Mordor macula at Charon’s North Pole.
Although they are nevertheless provisional, “We still have a decent chance of getting these names approved,” stated New Horizons planetary scientist Mark Showalter. After all, the IAU has previously approved features on Saturn’s moon, Titan, named Frodo and Bilbo, and the first landing site on Mars is now called Bradbury’s Landing!
Ah, this is news that stirs the creative abyss of a science fiction or science “faction” heart!
References: NASA, The Planetary Society, Mashable.com, International Astronomical Union, EarthSky, Washington Post, and National Geographic