Pluto: Secrets Of The Heart

Far away in the semi-darkness of perpetual dusk, there is a frigid domain in our Solar System's outer fringes where our Sun can shine with only a frail, faint fire. Here, in this region of icy, dancing bodies, there resides a little world with a big heart. The dwarf planet Pluto, a denizen of the Kuiper Belt--the home of a swarming sea of frozen comet nuclei--has, ever since its discovery, captured the imagination and affection of humanity. Perhaps this is because it is so remote from Earth and the golden, melting heat of our brilliant Star. On July 14, 2015, NASA's New Horizons spacecraft, at last, reached this strange world, circled by an extraordinary quintet of moons, and began to uncover some of the very well-kept secrets of this icy world. In November 2016, planetary scientists announced that their new research reveals fascinating clues about Pluto, indicating that this frozen sphere at the outer limits of our Solar System is much more active than anyone had ever imagined--and may harbor a subsurface ocean beneath its secretive big heart.

Pluto's heart holds clues about an underwater ocean on the dwarf planet. Credit: NASA/JHUAPL/SwRI.

Indeed, the presence of a liquid ocean situated deep beneath Pluto's frozen, icy surface is the best explanation for certain mysterious features unveiled by New Horizons, according to two new studies. The possibility that Pluto contains a subsurface ocean is not a new idea, but this research provides the most detailed investigation offered yet of its possible starring role in the evolution of certain important and unexplained features on Pluto--such as its low-lying, vast plain named Sputnik Planitia (Sputnik Planum).

Sputnik Planitia is a 1,000-kilometer-wide basin located within a big heart-shaped feature observed on Pluto's surface, and the new research suggests that it could be in its current location because the accumulation of ice made the ice dwarf planet that is Pluto rollover, thus forming cracks and tensions in the crust that suggest the possible presence of a liquid subsurface ocean.

Sputnik Planitia, which forms one side of Pluto's famous big heart-shaped feature observed in the first New Horizons images, is mysteriously well-aligned with Pluto's tidal axis. The probability that this is a mere chance occurrence is only about 5%. Hence, the alignment indicates that extra mass in that particular location interacted with tidal forces between Pluto and its largest moon Charon to reorient Pluto. This reorientation placed Sputnik Planitia directly opposite the side facing Charon. However, a deep basin seems unlikely to provide the additional mass necessary to result in that particular kind of reorientation.

"It's a big, elliptical hole in the ground, so the extra weight must be hiding somewhere beneath the surface. And an ocean is a natural way to get that," commented Dr. Francis Nimmo on November 16, 2016, University of California, Santa Cruz Press Release. Dr. Nimmo is a professor of Earth and Planetary Sciences at UC Santa Cruz and first author of a paper on the new findings published in the November 16, 2016 issue of the journal Nature. A second paper, appearing in the same issue of Nature, led by Mr. James Keane at the University of Arizona in Tucson, also proposes that this reorientation occurred and points to fractures on Pluto as evidence that this happened.

Dancing In The Dark

Where Pluto resides in our Solar System's deep freeze, our Sun appears in its murky sky as if it were just an especially large Star floating around in a strange sea of starlight. Mystery tickles the imagination, and Pluto has been an intriguing mystery for almost a century. Situated as it is, far from our Sun, Pluto remained unexplored until the New Horizons spacecraft successfully accomplished its historic closest approach to Pluto, at about 7,750 miles above its secretive surface--about the same distance that it is from Mumbai, India to New York City--making it the first space mission to finally explore this brave new world so far from Earth.

Pluto, Charon, and the other four relatively small moons belonging to the Pluto system reside in the frigid Kuiper Belt--a dimly lit and distant domain beyond the beautiful dark blue ice giant planet Neptune, the outermost of the eight major planets orbiting our Sun. In this previously unknown and unexplored region of our Solar System, a dazzling and icy host of tiny worldlets do a mesmerizing ballet around our distant Star. Pluto is a relatively large denizen of the Kuiper Belt, and it was originally classified as the ninth major planet from our Sun soon after its discovery in 1930. However, a better understanding of the true nature of the Kuiper Belt, and its heavy population of icy inhabitants forced astronomers to come to the realization that Pluto--a beloved, frozen, small "oddball"--is only one of the at least several large denizens of the Kuiper Belt. This realization prompted the International Astronomical Union (IAU) to formally define the term "planet" in 2006--and, as a result, poor Pluto was unceremoniously booted out of the pantheon of major planets, and re-classified as a mere dwarf planet--specifically, an ice dwarf due to its frozen nature. Nevertheless, Pluto still remains a small world of mystery and affection--and debate, since its re-classification as an ice dwarf is not universally accepted among astronomers.

The Pluto saga began when a young farmer's son from Kansas, the astronomer Clyde Tombaugh (1906-1997) had bestowed upon him the difficult task of hunting for the elusive and possibly non-existent Planet X. According to theory, Planet X is an elusive giant planet that keeps itself well-hidden from the prying eyes of curious astronomers, where it lurks in the cold twilight zone of our Solar System's outer limits. Tombaugh, who used a telescope in Flagstaff, Arizona, did indeed discover a faint tiny pinpoint of light. However, in one of the many instances of scientific serendipity, Tombaugh did not find what he was looking for. He found something else. What Tombaugh found was not Planet X--it was the little world now known as Pluto!

Like the other Kuiper Belt Objects (KBOs), Pluto is primarily made up of ice and rock. A small world, sporting only about 1/6 the mass of Earth's Moon and about 1/3 its volume, Pluto displays a highly inclined and eccentric orbit that takes it from 30 to 49 astronomical units (AU) from our Sun. One AU is equivalent to the average distance between our Earth and the Sun, which amounts to about 93,000,000 miles. Pluto periodically wanders inward toward our Star at a closer distance than Neptune. However, luck prevails, and orbital resonance with Neptune prevents the two worlds from blasting into each other with catastrophic results.

The Kuiper Belt is very far from us, orbiting our Sun well beyond the realm of the four majestic gaseous outer planets. The Belt itself extends from Neptune's orbit to approximately 50 AU. Neptune's average distance from our Sun is about 30.1 AU--its perihelion (when it is closest to our Star) is 29.8 AU, while its aphelion (when it is furthest from our Star) is 30.4 AU

The ice dwarf Pluto was named for the Roman god of the underworld. Pluto's largest moon, Charon, was discovered in 1978 by the American astronomer James Christy. Some astronomers have suggested that Charon is really an enormous chunk of Pluto. According to this theory, Charon was once a part of Pluto that had been blasted off as a result of a violent collision between Pluto and some unidentified small world that was making a destructive rampage through the Kuiper Belt. The mess occurred when the doomed object met up with Pluto and crashed into it. Charon is the result of this ancient collision.

During most of the 20th century, astronomers thought that Pluto was a solitary small world, situated in the frigid outer limits of our Solar System. However, in 1992, the very first KBO (other than Pluto and Charon) was spotted, and astronomers came to the realization that Pluto is far from alone. The realization that Pluto is just another constituent of the madding crowd of icy KBOs, resulted in its removal from the pantheon of major planets, and its reclassification as an ice dwarf.

Launched on January 19, 2006, New Horizons successfully completed a five-month-long reconnaissance flyby of the Pluto system and is now en route to our Solar System's frozen fringes in order to study more distant small worlds inhabiting the Kuiper Belt, as part of its extended mission. New Horizons will help shed new light on the mysterious and very remote worldlets lingering in our Solar System's deep freeze. The Kuiper Belt is actually a lingering relic of our Solar System's ancient birth, and the population of frozen objects residing there has preserved in their frozen hearts some very important long-lost secrets of its past. New Horizons promises to uncover the amazing story about the origins of our Sun and its family of objects.

Pluto: Secrets Of The Heart

Like other large basins in our Solar System, Sputnik Planitia likely formed as the result of a catastrophic impact by a large crashing meteorite, which would have blasted away an enormous amount of Pluto's icy crust. If a subsurface ocean had been present, this would result in an upwelling of water pushing up against the weak, thin, and fragile shell of crustal ice. Because water is denser than ice, at equilibrium, that would still leave a rather deep basin with a slender crust of ice covering the upwelled mass of water.

"At that point, there is no extra mass at Sputnik Planitia. What happens then is the ice shell gets cold and strong, and the basin fills with nitrogen ice. That nitrogen represents the excess mass," Dr. Nimmo explained in the November 16, 2016, UC Santa Cruz Press Release.

Dr. Nimmo and his team also considered whether the extra mass could be provided by just a deep crater that is filled with nitrogen ice, in the absence of upwelling of a subsurface ocean. However, their calculations indicated that this particular scenario would demand an unrealistically deep layer of nitrogen--more than 25 miles thick! The astronomers found that a nitrogen layer approximately 4 miles thick blanketing a subsurface ocean provides sufficient mass to form a "positive gravity anomaly."

"We tried to think of other ways to get a positive gravity anomaly, and none of them looks as likely as a subsurface ocean," Dr. Nimmo continued to explain.

Dr. Douglas Hamilton, who is of the University of Maryland in College Park, and a co-author of the study, formulated the reorientation scenario, while Dr. Nimmo came up with the subsurface ocean hypothesis. The subsurface ocean hypothesis proposes a scenario that is similar to what occurred on Earth's Moon, where positive gravity anomalies have been precisely measured for several large impact basins. However, instead of a subsurface ocean, the dense mantle material buried beneath the lunar crust pushed up against the thin crust of the impact basins. Lava flows then gushed up and flooded the basins, thus providing extra mass. Icy Pluto, however, experienced this sort of scenario with a different ingredient. Instead of lava, the basin on Pluto is filled with frozen nitrogen.

"There's plenty of nitrogen in Pluto's atmosphere, and either it preferentially freezes out in this low basin, or it freezes out in the high areas surrounding the basin and flows down as glaciers," Dr. Nimmo noted in the UC Santa Cruz Press Release. Indeed, the images obtained from New Horizons reveal what appear to be nitrogen glaciers flowing out of the mountainous terrain surrounding Sputnik Planitia.

In reference to a subsurface ocean, Dr. Nimmo added that he suspects it is composed mostly of water with some unidentified antifreeze added to the mixture--which would most likely be ammonia. The slow refreezing of the ocean would cause stress on the icy shell. This stress would cause fractures that are consistent with features seen in the New Horizons images.

Pluto is not alone where it resides in the Kuiper Belt. There are other large kindred bodies dwelling in the Kuiper Belt that resemble Pluto both in size and density, and Dr. Nimmo noted that these other objects likely also contain subsurface oceans. "When we look at these other objects, they may be equally interesting, not just frozen snowballs," he added.

In a second study also appearing in the November 17, 2016 issue of the journal Nature, Dr Isamu Matsuyama and his doctoral student Mr. James Keane, of the University of Arizona's Lunar and Planetary Laboratory cite evidence of frozen nitrogen pileup that threw all of Pluto out of kilter, in a process termed true polar wander. This has been compared to a spinning top with a wad of gum stuck to it.

"There are two ways to change the spin of a planet. The first--and the one we're all most familiar with--is a change in the planet's obliquity, where the spin axis of the planet is reorienting with respect to the rest of the Solar System. The second way is through true polar wander, where the spin axis remains fixed with respect to the rest of the Solar System, but the planet reorients beneath it," Mr. Keane explained in a November 16, 2016, University of Arizona Press Release.

Planets usually spin in a way that minimizes energy. This means that planets tend to reorient in order to move extra mass closer to the equator while moving any mass deficit closer to the pole. In order to visualize this, if a large volcano were to grow in San Francisco, our planet would reorient to move San Francisco to the Earth's equator.

But, in order to visualize how polar wander works on Pluto, it first needs to be realized that unlike Earth, whose spin axis is only slightly tilted so that the regions around the equator are gifted with most of the sunlight, Pluto is more like a "spinning top that is lying on its side." This means that the dwarf planet's poles receive most of the sunlight. Depending on the season, it is either one or the other. Furthermore, Pluto's equatorial regions remain extremely frigid all the time.

Pluto is almost 40 times farther from our Star than Earth. This means that it takes the distant icy little world 248 Earth years to complete one Pluto year. At Pluto's lower latitudes close to its equator, temperatures are bitterly cold at minus 400 degrees Fahrenheit. At this almost unimaginably frigid temperature, nitrogen turns into a frozen solid.

Nitrogen and other exotic gases, over the span of a Pluto year, condense on its dark side that is kept in perpetual shadow. Eventually, as Pluto circles around our Sun, our Star's melting heat causes the nitrogen and other substances to become gaseous again and re-condense on the other side of the little world. This results in seasonal "snowfall" on Sputnik Planitia.

"Each time Pluto goes around the Sun, a bit of nitrogen accumulates in the heart. And once enough ice has piled up, maybe a hundred meters thick, it starts to overwhelm the planet's shape, which dictates the planet's orientation. And if you have an excess of mass in one spot on the planet, it wants to go to the equator. Eventually, over millions of years, it will drag the whole planet over," Mr. Keane said in the November 16, 2016, University of Arizona Press Release.

"I think this idea of a whole planet being dragged around by the cycling of volatiles is not something many people had really thought about," Mr. Keane added.

The two University of Arizona researchers used observations made during New Horizons' flyby and combined them with supercomputer models that enabled them to take a surface feature such as Sputnik Planitia, shift it around on Pluto's surface, and observe how it alters the ice dwarf's spin axis.

As a result, in the computer models, the geographic location of Sputnik Planitia wound up intriguingly close to where one would expect it to be.

If Sputnik Planitia were a large positive mass anomaly--possibly as a result of the loading of nitrogen ice--it would migrate to Pluto's tidal axis with respect to Charon, as it approaches a minimum energy state. Therefore, the massive building up of ice would wind up where it would cause the least wobble in Pluto's spin axis.

In addition, the supercomputer simulations and calculations predicted that the accumulation of frozen volatiles in Pluto's big heart would result in cracks and faults in the planet's surface in precisely the same locations where New Horizons spotted them.

The presence of tectonic faults on Pluto suggests the existence of a subsurface ocean at some point in Pluto's history, Mr. Keane noted. He added that "Before New Horizons, people usually only thought of volatiles in terms of a thin frost veneer, a surface effect that might change the color, or affect local or regional geology. That the movement of volatiles and shifting ice around a planet could have a dramatic, planet-moving effect is not something anyone would have predicted."

Judith E Braffman-Miller

Article Source: Pluto: Secrets Of The Heart

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Seven Sisters Stars Spin In Space

The Pleiades, or Seven Sisters, is an open star cluster that contains a glittering population of searing-hot B-Type stars. The Pleiades, less colorfully termed Messier 45 or M45, is one of the closest star clusters to our own planet, and it is also the cluster that is most easily observed with the naked eye--especially during the winter months--as it sparkles in the clear, dark, and star-blasted night sky in the constellation Taurus (The Bull). The cluster is dominated by very hot, blue, and dazzling stars that were born within the last 100 million years--a mere wink of the eye on stellar time scales. In August 2016, a team of astronomers announced their intriguing and important new observations showing that, like cosmic figure skaters caught in a fantastic pirouette, the stars of the Seven Sisters cluster are spinning--however, these celestial ice-skaters are twirling around at different speeds!

M45 - The Pleiades, or Seven Sisters, imaged by Kevin D. and Jenna F. - Students of the
Plymouth Community Intermediate School.

Astronomers for a very long time have wondered about what it is that determines the rotation rates of these sparkling stellar sisters. Now, NASA's Kepler Space Telescope, during its second life as the K2 mission, has helped astronomers obtain the most complete catalog of rotation rates for the stars in a cluster. This important information can enable astronomers to gain a new understanding of where and how planets are born around these distant stars--and how stars evolve as they age.

Like the phoenix bird of Greek mythology, NASA's Kepler Space Telescope got a second chance at "life"--despite a crippling malfunction that brought its primary mission to an end in May 2013. Rather than giving up on the spacecraft, whose original mission was to discover how often Earth-like exoplanets occur within our own Milky Way Galaxy, a team of astronomers and engineers succeeded in developing a new strategy. The resulting second mission of this plucky spacecraft, re-named K2, not only continued Kepler's original search for distant Earth-like worlds in our Galaxy but also introduced some new opportunities for astronomers.

"We hope that by comparing our results to other star clusters, we will learn more about the relationship between a star's mass, its age, and even the history of its solar system," explained Dr. Luisa Rebull in an August 12, 2016, NASA Press Release. Dr. Rebull is a research scientist at the Infrared Processing and Analysis Center at the California Institute of Technology (Caltech) in Pasadena, California. She is the lead author of two new papers and a co-author of a third paper about these findings, all published in the Astronomical Journal.

Twirling Sister Stars

The name of the Pleiades is derived from the ancient Greek, likely from Plein ("to sail") because of the cluster's importance during the sailing season in the Mediterranean Sea. However, the name eventually became mythologized as the name of seven divine sisters who were the daughters of Pleione--hence, the designation Pleiades--or, alternatively, the "seven sisters." Historically, the Pleiades were viewed as a group of "seven" sister stars: Alcyone, Atlas, Electra, Maia, Merope, Taygeta, and Pleione. It is generally thought that the name of the star cluster came first, and Pleione was created later in order to explain it.

The great Italian astronomer Galileo Galilei was the first astronomer to observe the Pleiades through a primitive telescope, called a "spyglass,"--the first of its kind to be used for astronomical purposes. Galileo discovered that the cluster contains many stars that are far too faint to be observed with the naked eye. He published his observations, including a sketch of the Pleiades showing 36 stars, in his Sidereus Nuncius in March 1610.

The cluster radius has a core of approximately eight light-years, and the tidal radius is about 43 light-years. The cluster itself hosts more than 1,000 statistically confirmed members. However, this figure excludes unresolved binary stars. It is also dominated by bright, young, hot blue stars, up to 14 of which can be observed with the naked eye, depending on local observing conditions. The total mass contained in the cluster is estimated to be approximately 800 solar masses.

The Pleiades hosts many brown dwarfs, which are sub-stellar objects, frequently referred to as "failed stars", that sport less than approximately 8% of our Sun's mass. This basically means that brown dwarfs are not heavy enough for nuclear fusion reactions to occur in their cores, thus lighting their stellar fires. Therefore, puny little brown dwarfs are unable to attain true stardom status. Brown Dwarfs may account for up to 25% of the total population of the Pleiades--although they constitute less than 2% of the total stellar mass. Astronomers have made recent important discoveries in their efforts to detect and analyze brown dwarfs in the Pleiades, as well as in other youthful star clusters. This is because the youth of these sub-stellar objects render them bright and observable--while more elderly brown dwarfs, dwelling within older star clusters, have faded and grown very dim, making them considerably more difficult to observe and study.

The true age of a star can be calculated by comparing the Hertzsprung-Russell Diagram Of Stellar Evolution for the cluster with theoretical models of stellar evolution. Using this technique, ages for the Pleiades of between 75 and 150 million years have been estimated. The widespread in estimated ages is the result of existing uncertainties in stellar evolution models.

Another way to calculate the true age of a star cluster is by studying its lowest-mass members. In common main-sequence (hydrogen-burning) stars--as still "living" stars are categorized in the Hertzsprung-Russell Diagram-- lithium is very quickly destroyed in nuclear fusion reactions. Little brown dwarfs--stellar "failures" that they unfortunately are--can nonetheless succeed in holding on to their lithium. Because of lithium's very low ignition temperature of 2.5 million Kelvin, the highest-mass brown dwarfs will go on to burn it eventually, and so determining the highest mass of brown dwarfs still containing lithium in the cluster can provide a clue to its age. Applying this particular technique to the Pleiades yields an age of approximately 115 million years.

The cluster is in the process of slowly making a journey in the direction of the feet of the Orion (The Hunter) constellation. Like most open clusters, the Seven Sisters will not stay gravitationally together forever. Some of the component stars will be unceremoniously evicted from the cluster as a result of unfortunate close encounters with other stars--and some will be stripped by tidal gravitational fields. Calculations indicate that the cluster will take approximately 250 million years to disintegrate, and gravitational interactions with giant, dark, and cold molecular clouds--the cradles of newborn stars--as well as with the spiral arms of our Milky Way, will also hasten the dispersion of the once-close sister stars.

Our own Sun is thought to have experienced a similar disruption of the sibling stars composing its own natal stellar family. Today, our Sun is solitary, a lonely, searing-hot, brilliant, and roiling stellar inhabitant of our Milky Way Galaxy. However, it probably was not always so bereft of the company of others of its kind. Our Sun was likely born a member of a dense open cluster, along with thousands of other sparkling sister stars. Many astronomers think that the baby Sun was either rudely tossed out of its birth cluster or it simply wandered away from its sisters about 4.5 billion years ago. The long-lost, missing sisters of our Star have long since wandered away themselves to more distant regions of our Galaxy--and there very well may be as many as 3,500 of these nomadic stellar sisters of our Star.

Seven Sister Stars Spin In Space!

Because the Pleiades is one of the closest star clusters to Earth, it is the easiest to observe. It is located a mere 445 light-years away from our planet, on average, and the stars inhabiting the cluster--known individually as Pleiads--have reached stellar adolescence. At this youthful and active stage of their "lives", the stars are likely spinning as fast as they can--or ever will again.

As a typical young star evolves into stellar adulthood, it loses some of its vigor as a result of its copious emission of charged particles. Astronomers term these charged particles the stellar wind. However, when our Sun's emission of charged particles occurs in our own Solar System, it is called the solar wind. The charged particles are taken for a ride on the star's magnetic fields, which generally exert a braking effect on the rotation rate of the young star.

Dr. Rebull and her colleagues delved deeper into the dynamics of stellar spin using Kepler. Because of the field of view on the sky, Kepler observed approximately 1,000 stellar inhabitants of the Pleiades over a 72-day time span. The telescope measured the rotation rates of over 750 stars in the Pleiades, including approximately 500 of the lowest mass, faintest, and smallest stellar runts, whose rotations could not be detected previously from ground-based instruments.

Kepler's measurements of starlight suggest the spin rate of a star by picking up small alterations in its brightness. These alterations are the result of "starspots," which, like the more familiar sunspots that blemish our Sun's glaring face, form when magnetic field concentrations do not allow the normal release of energy at a star's surface. The affected regions grow to become cooler than their surroundings and appear to be dark in comparison.

As a star rotates, its starspots come in and out of Kepler's view, providing a new method for determining a spin rate. Unlike the small, sunspot blemishes that mark our middle-aged Sun, starspots can be enormous in stars as youthful as those twirling around in the Pleiades. This is because stellar youth is associated with greater turbulence and magnetic activity. These starspots trigger larger decreases in brightness, and also make spin rate measurements easier to obtain.

During the astronomers' observations of the Pleiades, a clear pattern began to show itself. The more massive stars tended to rotate slowly, while the less massive stars rotated rapidly. The massive and lazy stars' periods ranged from one to 11 Earth days. However, a large number of low-mass stars took less than a day to complete a single twirl. As a comparison, our own middle-aged, calm, and sedated Sun spins around completely only once every 26 days. The population of slow-rotating stars includes some ranging from a little bit larger, more massive, and hotter than our own Star, down to other stars that are somewhat smaller, less massive, and cooler. On the far end, the fast-rotating, swift, lowest-mass stars possess as little as a tenth of our Sun's mass.

"In the 'ballet' of the Pleiades, we see those slow rotators tend to be more massive, whereas the fastest rotators tend to be very light stars," Dr. Rebull continued to note in the August 12, 2016, NASA Press Release.

Dr. Rebull and her team propose that the primary cause of these differing spin rates is the internal structure of the individual stars. The larger and more massive stars contain an enormous core that is blanketed by a slender layer of stellar material that is experiencing convection. Convection is a familiar process to most people who have watched the circular swirls of boiling water in a pot. On the other hand, smaller, less massive stars, are made up almost entirely of convective, roiling regions. As the age of the star, this braking mechanism--derived from magnetic fields--more readily slows the spin rate of the outermost, slender layer of large, massive stars, in contrast to the comparatively turbulent and thick bulk of small, swift stars.

Because the Pleiades is close to Earth, astronomers suggest that it should be possible to unravel the complex interactions between stellar spin rates and other stellar properties. Those additional properties, in turn, can exert an important influence on stellar climates, as well as the habitability of any orbiting exoplanets that a given star may host. For example, as a dancing star's pirouette slows down, the generation of starspots also slows down, and the resulting stellar storms that go hand-in-hand with starspots become far less frequent. Fewer stellar storms result in less powerful and destructive blasts of radiation into space, so dangerous to orbiting planets and their potentially emerging delicate tidbits of budding life.

"The Pleiades star cluster provides an anchor for theoretical models of stellar rotation going both directions, younger and older. We still have a lot we want to learn about how, when, and why stars slow their spin rates and hang up their 'dance shoes,' so to speak," Dr. Rebull added.

Currently, Dr. Rebull and her team are analyzing the K2 mission data of an older star cluster, named Praesepe, which is more popularly known as the Beehive Cluster. The team of astronomers seeks to further study the phenomenon of stellar evolution and structure.

"We're really excited that K2 data of star clusters, such as the Pleiades, have provided astronomers with a bounty of new information and helped advance our knowledge of how stars rotate throughout their lives," explained Dr. Steve Howell in the August 12, 2016, NASA Press Release. Dr. Howell is the project scientist for the K2 mission at NASA's Ames Research Center in Moffett Field, California.

Judith E. Braffman-Miller is a writer and astronomer whose articles have been published since 1981 in various newspapers, magazines, and journals. Although she has written on a variety of topics, she particularly loves writing about astronomy, because it allows her to communicate to others the many wonders of her field. Her first book, "Wisps, Ashes, and Smoke," will be published soon.

Judith E Braffman-Miller

Article Source: Seven Sister Stars Spin In Space

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