Wednesday, February 29, 2012

Stellar Occultation of ζ Taurus March 2, 2012

Zeta (ζ) Taurus will occult for Northeastern America and Canada March 1, 2012. It is a spectroscopic binary (a binary star of which both members cannot be detected by a telescope) in the south-left side of Taurus at magnitude 3.010, which the moon will occult. This star should be not that hard to find, as the Pleiades is to its north, and Orion to its right. The moon will pass over the star, occulting it, providing us with a stellar occultation. Below is a map of Taurus (with Orion). The red mark within the red circle reveals ζ Taurus' location in the constellation.

The location map below will alert you if, by chance, you will be able to view the occultation of ζ Taurus. The lunar magnitude at this point will be +61, meaning the moonlight might block out some of the star's light, when the moon approaches the location of the star. Read more here.

Monday, February 27, 2012

A Collection of Peculiarly-Worded Astronomy Articles

Over 2011 and early 2012, I have been keeping track of peculiarly worded astronomy articles, some of which are oxymorons, puns, and other funnily-worded phrases. [Below, for reference, is the article title, the publishing date, and the website on which it was taken | Dates are most current, first]. All of these have a corresponding article, they are not imagined - the authors did have a great imagination!

[Articles will keep on being added if they fit the bill!]

Shedding Light on the Moon's Dark Side (February 29, 2012) Earth Sky


Sheep in Wolf-Rayet's Clothing: New Image of Planetary Nebula Hen 3-1333 (February 20, 2012) Science Daily

El Gordo: A "Fat" Distant Galaxy Cluster (January 10, 2012) ESO 

Young Star Rebels Against its Parent's Cloud (December 15, 2011) Hubble European Space Agency

Sh2-239: Celestial Impasto (December 8, 2011) APOD

As sure as eggs are eggs (October 4, 2011) Supernova Condensate

Feast Your Eyes on the Fried Egg Nebula -- ESO's VLT spots a rare treat (September 28, 2011) ESO

Astronomers Crack the Fried Egg Nebula (September 27, 2011) Science Daily

Frankenstein's Moon: Astronomers Vindicate Account of Masterwork (September 26, 2011) Texas State University 

How Single Stars Lost their Companions (September 15, 2011) Royal Astronomical Society

Neutron Star Bites off More Than it Can Chew (June 28, 2011) ESA

Pandora's Cluster: A Galactic Crash Investigation (June 23, 2011) Hubble European Space Agency

Astronomers Discover that Galaxies are Either Asleep or Awake (June 22, 2011) Yale University News

Baby Stars Born to "Napping" Parents (June 15, 2011) Cardiff University

Feuding Helium Dwarfs Stars Exposed by Eclipse (May 26, 2011) Warwick University

Supernova Sonata! (May 26, 2011) APOD

Caught in the Act: Herschel Detects Gigantic Storms Sweeping Entire Galaxies Clean (May 9, 2011) Max-Planck-Institut für extraterrestrische Physik (MPE), via AlphaGalileo.

Sunday, February 26, 2012

Celebrating 100 Years of Knowledge of Cepheid Variables

March 3, 1912 - March 3, 2012

Thanks to Henrietta Leavitt (and as some might include Edwin Hubble), we know what we know today about much of the universe; and it was achieved by hard work, as is anything life-changing. As we remember these astronomers who changed history, remember not only their discoveries, but their impact on the modern world of astronomy.

Henrietta Swan Leavitt
Born on July 4, 1868 in Lancaster, Massachusetts, Henrietta Swan Leavitt soon moved to Ohio, where she would attend college and start her work as an astronomer, an occupation which was predominately dominated by men at the time. As some might suppose her interests of astronomy was kindled during her youth, it wasn't actually until her senior year of college where she took a course in astronomy, and in 1892 (when she was twenty-four) she graduated from the Society for the Collegiate Instruction for Women, known today as Radcliffe College, previously attending Oberlin college.  

The Woman Astronomer records, "Three years after graduation, she became a volunteer research assistant at Harvard College Observatory. Seven years later, in 1902, [Edward Charles] Pickering hired her on the permanent staff at $.30 per hour." This was the beginning of her career, which she had no idea could change the world.Leavitt continued her education as an assistant at Harvard College; herself capable of anything, although being given very small portions of theoretical work. Because Pickering, Leavitt's employer, did not allow Leavitt to work telescopes, he assigned her a position (at the small pay, as noted above) to measure and catalog the brightness of stars in the photographic plate collection of the observatory, as well as being a "computer", or someone who calculates sums, etc. 

But, Leavitt did not let her small pay and tedious work get in the way of her passion, and she fiercely took on her job, eventually discovering thousands of variable stars in the Small Magellanic Cloud, a nearby satellite-galaxy. Today, these variable stars are called Cepheid variables, as they were the stars responsible in providing a foundation for a paradigm shift, or changing, in modern astronomy. A paper was published of her findings (which can be found here), although she literally was given no recognition for her efforts during the period of her life. Below are excerpts of this influential paper, Periods of 25 Variable Stars in the Small Magellanic Cloud, describing what was to become one of the greatest findings in astronomical history.
"The measurement and discussion of these objects [1777 variable stars in the two Magellanic Clouds] present problems of unusual difficulty, on account of the large area covered by the two regions, the extremely crowded distribution of the stars contained in them, the faintness of the variables, and the shortness of their periods, as many of them never become brighter than the fifteenth magnitude. ... With the adoption of an absolute scale of magnitudes for stars in the North Polar Sequence, however, the way is open for such a determination. 
"Fifty-nine of the variables in the Small Magellanic Cloud were measured in 1904, ... and the periods of seventeen of them were published ... They resemble the variables found in globular clusters, diminishing slowly in brightness, remaining near minimum for the greater part of the time, and increasing very rapidly to a brief maximum. 
A remarkable relation between the brightness of these variables and the length of their periods will be noticed. [find chart here, Table One]
"The facts known with regard to these 25 variables suggest many other questions with regard to distribution, relations to star clusters and nebulae, differences in the forms of the light curves, and the extreme range or the length of the periods. It is hoped that a systematic study of the light changes of all the variables, nearly two thousand in number, in the two Magellanic Clouds may soon be undertaken at this observatory."

Another paper (1777 variables in the Magellanic Clouds) was published earlier, and had the same general idea. The Woman Astronomer concludes, "Her study led to the period-luminosity relationship of these variables, which in turn led to the ability to determine distances of stars from a mere one hundred light years to ten million light years. Ejnar Hertzsprung used her discovery to plot the distance of stars; Harlow Shapley used it to measure the size of the Milky Way; and Edwin Hubble used her work to ascertain the age of the Universe." It is certain Leavitt's work was utmost influential, yet it is hard to think that none of her work was heralded during her lifetime; it took Edwin Hubble to bring Leavitt's work into the light, of which he pivoted most of his studies on.

Leavitt found a relationship between luminosity in variable stars, the Observatories of the Carnegie Institution for Science, relates the steps to achieve her relationship for confirmation, "a) Measure the period of the star. b) Use Leavitt’s graph to determine how bright it really is. c) Measure how bright it appears and determine its distance." And everything works perfect today!

Today, two astronomical objects/features bear her name: asteroid 5383 Leavitt and the crater Leavitt on the Moon, are both named in her honor. After her death, Leavitt was also nominated for the Nobel Peace Prize, but it is so that such an award could not be bestowed to individuals posthumously.  

Saturday, February 25, 2012

Venus-Lunar Conjunction February 25, 2012

Yes, the night (and even day) of February 25 will bring us a special conjunction of the Mon and Venus, of which might be able to be seen in the day, it is so bright! Although it might seem that Venus is that bright, it being farthest from the Sun now, means it's luminosity is greatly increased, but viewing Venus in a sky of blue is harder than you think, and Sky and Telescope paraphrases it well, "That problem [seeing Venus in the day] is solved on Saturday, when the crescent Moon points the way. As long as the air is clear, Venus should be visible any time in the afternoon, but it will get easier as the Sun gets lower."

Venus and the Moon, February 25, 2012

Going out an hour before sunset, look for the moon (the chart above is for different locations), and then look for Venus. Try to get the Sun out of view, a building or lush tree will work, so that only the moon is in view. From there, locate the moon (it being a waxing crescent will not help any, though) and just two or three degrees the lower-right of the moon is Venus, waiting! Jupiter will be too dim to locate now, but Jupiter is easily accessible after the sun sets. Read more from Sky&Telescope. [Images below are Jupiter, Venus, and Moon after sunset on February 23, 2012].

Saturday, February 18, 2012

More on Gravitational Lenses: Hubble's Journey with these Exotic Sphinxes

As mentioned in Part the First of the article set concerning "Gravitational Lenses", Gravitational Lenses: the Mutant Truth of this Cosmic Conundrum, the term gravitational lens was defined by as "a heavy, dense body, as a galaxy, that lies along our line of sight to a more distant object, as a quasar, and whose gravitational field refracts the light of that object, splitting it into multiple images as seen from the earth." After looking at the imaging which the Hubble Space Telescope has produced (images in previous article), it is certain that such thing called a "gravitational lens" is quite a sphinx, or an inscrutable question of something, although the concept of gravitational lenses are now far from inscrutable thanks to the Hubble!

Since it was launched in 1990, the Hubble Space Telescope has revolutionized space exploration through its exceptional cameras and imaging: such images which Hubble has seen are gravitational lenses, or "zoom lenses" as also referred to. Earlier this month, on February 2, 2012, the Astrophysics Journal published an article on the brightest magnitude gravitational lens yet photographed by Hubble, a galaxy named RCS2 032727-132623.

"Hubble's view of the distant background galaxy is significantly more detailed than could ever be achieved without the help of the gravitational lens," tells us. This object in the night sky has beautifully metamorphosed into a horseshoe-fashioned semi-circlet, and Hubble was there to record such findings. HubbleSite is definitely correct when it proclaims this objects one of the "most striking" gravitational lenses discovered!

It's reflection on modern astronomy has helped in understanding of gravitational lenses and the distant & young universe, as when we look back far into the universe, we are looking back into time.

Wednesday, February 15, 2012

Gravitational Lenses: the Mutant Truth of this Cosmic Conundrum

As defined by's resources, gravitational lenses are most appropriately "a heavy, dense body, as a galaxy, that lies along our line of sight to a more distant object, as a quasar, and whose gravitational field refracts the light of that object, splitting it into multiple images as seen from the earth." Although this might seem confusing and rather arcane, this cosmic conundrum is mysterious and yet beautiful, all beginning with an Albert Einstein theorem: the theorem of relativity. Just barely scratching the surface on such a complex theory (which has been proven to be truth, see following paragraph), relativity scope deals that space and time are bent, causing things (i.e., distant objects) to be bent, or distorted. 

How was such a theorem actually confirmed to be true? Developed in 1915, it took three separate tests to confirm its reality; I will only contemplate one: the total solar eclipse. In the article published by Arthur Eddington (and other astronomers) entitled, A determination of the deflection of light by the Sun's gravitational field, from observations made at the total eclipse of 29 May 1919, Einstein's theory was claimed to be true, as Eddington writes describing the purpose, then the outcome of the endevour:
PURPOSE: "The purpose of the expeditions was to determine what effect, if any, is produced by a gravitational field on the path of a ray of light traversing it. Apart from possible surprises, there appeared to be three alternatives, which it was especially desired to discriminate between—  (1) The path is uninfluenced by gravitation. (2) The energy or mass of light is subject to gravitation in the same way as ordinary matter. If the law of gravitation is strictly the Newtonian law, this leads to an apparent displacement of a star close to the sun's limb amounting to 0” 87 outwards. (3) The course of a ray of light is in accordance with EINSTEIN’S generalized relativity theory. This leads to an apparent displacement of a star at the limb amounting to 1” 75 outwards."
RESULT: "Thus the results of the expeditions ... can leave little doubt that a deflection of light takes place in the neighborhood of the sun and that it is of the amount demanded by Einstein's generalized theory of relativity, as attributable to the sun’s gravitational field."

Now that we have determined that this is true and that time and space are actually bent, we can now look further into the mysteries of gravitational lenses. As stated before, a gravitational lens is the distortion of an object behind a closer object, which its light is seen differently than it would be seen. These are also referred to as Einstein rings. Before you try to comprehend this, look at the image below. The yellow object is a galaxy, the ring around it is as well, but not as you would expect it to have been.

Gravitational lenses are at work in the above image! The object above is known as LRG 3-757, and APOD (Astronomy Picture of the Day, December 21, 2011) calls this a "mirage," which is indeed what it is. Watch this animation of a black hole lens, which distorts the galaxy behind it. Below is an image of the event, more like a series, which proves my point: 

You know that the galaxy behind the black hole in the images is straight, but when that black hole moves over it, we see a halo around it: that is the rings we see around galaxies, like LRG 3-757 above. These are not only beautiful in form, but intrinsic in its true scientific properties. These gravitational lenses are quite spectacular! You might think that only a few of these exist. This is not true, but rather astronomers have seen this effect in many different instances, of which each separate event being just as different as another. [Image index: 1)  Abel 1689 in Virgo. You can see the small, different mutation circlets in the background if you look hard enough. 2) Abel 370 in Cetus. These are more pronounced. 3) Abel 2280. These are thin and wispy, quite spectacular.   

Considered quite different than the above gravitational lenses, the Einstein's Cross in Pegasus (pictured below) is the most exotic of them all. Known by its appropriate name, Q2237+030 or QSO 2237+0305, is a gravitationally-lensed quasar behind ZW 2237+030, another object. Wikipedia states that "four images of the same distant quasar appear around a foreground galaxy due to strong gravitational lensing."