Planetary Bullies Make Astronomers Rethink the Habitable Zone

Exoplanet orbits that seem just right for life could be bent out of shape by pushy neighbors. New simulations of extrasolar planetary systems may mean the definition of "habitable" planets needs to be completely overhauled.

When astronomers talk about the "habitable zone," they mean the shell around a star where the temperatures are right for liquid water. Any closer, and oceans will boil. Any farther, and the planet will freeze. But this definition assumes that most planets have roughly circular orbits, like the Earth and most other planets in the solar system.

"What we know from studying exoplanets is that that is definitely not the rule," said Rory Barnes of the University of Washington at the meeting of the American Astronomical Society in Miami. Many of the 454 exoplanets discovered to date have highly elliptical orbits, meaning the planets are not always the same distance from their parent star. Thanks to this uneven geometry, the planet spends more time closer to its star, which tends to make for warmer planets.

Adding another planet, especially a bullying Jupiter-sized planet, can mess with orbits and make a once-hospitable planet move in and out of the habitable zone over time. Using computer simulations of several hypothetical planetary systems, Barnes showed that a giant neighbor can pull an Earth-like planet’s orbit like a rubber band, shifting it from circular to elliptical and back to circular again in as little as a few thousand years.

"It’s a very stable, repetitive process," Barnes said.

The Earth’s orbit actually does feel similar nudges from Jupiter, known as Milankovitch Cycles. But luckily for us, these orbital shape shifts are subtle.

Barnes’ simulations predicted more-dire consequences for extrasolar planets near the edge of their habitable zones, though. If the planet is on the cooler edge of the habitable zone, it could go through cycles of freezing and thawing. If it’s on the warmer side, the temperature could fluctuate from comfy to boiling from one millennium to the next.

"The inner edge is much more dangerous," Barnes said. All the water could boil off and be lost forever, or the warming planet could experience a "runaway greenhouse" effect and end up a scorched wasteland like Venus.

But it’s not all bad news. Barnes suggests that some planets we might dismiss as snowballs could just be going through an eccentric phase.

"Our own Earth has gone through stages of glaciation — we call them snowball Earth phases — and we managed to pull out of it," he said. "On a planet like that, on the outer edge, you will have reservoirs of life, and there will be habitats that will persist."

For planets around dim, low-mass stars, which have to be especially close to be in the habitable zones, neighboring giant planets could wreak havoc with the length of the day, and the gravitational pull could cause cycles of volcanic activity and earthquakes interspersed with relative calm.

"These are fascinating worlds to think about," Barnes said. "It will do lots of interesting things as far as how climates might evolve and how evolution might happen on such a planet."

The results suggest that the current definition of "habitable zone" may be too simplistic. Astronomers may have to consider the whole family of exoplanets in a system before determining if one is habitable or not.

"One of the things that this new work is emphasizing is that one needs to be very careful about defining habitability," commented Phil Armitage of the University of Colorado, Boulder. "Those ideas about terrestrial planet formation and habitability of terrestrial planets will need to be re-evaluated from scratch."


Fuente: Wired Science

WISE Telescope Captures Heart Nebula

WISE, NASA’s newest infrared observatory, has heart. This new mosaic captures the Heart and Soul nebulas, so named because of their resemblance to hearts–both the Hallmark card and the blood-pumping variety.

"One is a Valentine’s Day heart, and the other is a surgical heart that you have in your body," said Ned Wright of the University of California, Los Angeles, who presented the image May 24 at a meeting of the American Astronomical Society.

Since its launch on December 14, 2009, the Wide-Field Infrared Survey Explorer has been circling the Earth in a polar orbit and snapping images every 11 seconds. As of yesterday, it has captured 953,880 frames and mapped about 75 percent of the sky, Wright said.

The new image is stitched together from 1,147 individual frames. The exposure took a total of 3 and a half hours spread over 11 days in February to complete. The nebulas are located in the constellation Cassiopeia, about 6,000 light years away from Earth.

The image is color-coded to make sense to human eyes, which are blind in the infrared. Blue and cyan represent the shortest wavelengths WISE is sensitive to, 3.4 and 4.6 micrometers, and highlight places where stars are being born. Green light shows small grains of dust that have been heated by starlight and glow at the 12 micrometer band. The longest wavelength, 22 micrometers, is shown in red, capturing larger dust grains.

The bright spot at the top right of the image is an active star-forming region called W3, which Wright studied with a four-pixel balloon-borne telescope for his PhD thesis in the 1970s. Wright marveled at the difference between the sketched-out contour map he made then and the glowing portrait captured by WISE.

"It’s been an amazing progress in IR astronomy, with cameras growing by a factor of a million in power in just a few decades," he said.


Fuente: Wired Science

Una hora de Gatwick en un minuto

Una hora de operaciones en el aeropuerto de Gatwick, el segundo más activo del Reino Unido, resumido en un timelapse de un minuto por Jordi Blumberg, conocido como GatwickSpotting en YouTube.

Fuente: Avion, Microsiervos

White-Light Solar Flares Finally Explained

 
The flashes of white light accompanying some solar flares are caused by the sun’s acceleration of electrons to speeds greater than half the speed of light.

The phenomenon’s new explanation derives from data recorded from a 2006 solar flare. The presence of high-energy X-rays in the same spot that scientists saw visible light tipped them off that some kind of non-thermal process was generating the light.

“These explosions are particle accelerators,” said Säm Krucker, of the Space Science Laboratories at the University of California, Berkeley. “The whole surprising thing with these flares’ light is that it could simply be heat. But that’s not the case.”

Solar flares occur when the sun’s magnetic field lines rearrange and reconnect, releasing tremendous amounts of energy. There are different types of flares, which can generate geomagnetic storms of Earth, and only some of them are accompanied by the white light flares. These were first observed in 1859 by astronomer Richard Carrington, but no one really knew how they were produced until the new observations by the Japanese satellite Hinode and the NASA SMEX mission RHESSI.

Now, it looks as if the extremely powerful electromagnetic fields somehow deliver enormous amounts of energy into particles in the sun’s photosphere. It’s not unlike what humans do at a much, much smaller scale in particle accelerators like the Large Hadron Collider.

“As opposed to the LHC where you accelerate a few particles, it would be like accelerating the whole building basically,” said Hugh Hudson, also of Berkeley’s Space Science Laboratories, who worked with Krucker.

Astronomers haven’t figured out how exactly the sun works as a particle accelerator just yet. “It’s being done by electromagnetic effects that are not really understood,” Hudson admitted.

It’s possible that as the sun eases into a more active state over the next year, scientists will have more opportunities to study the flares.

A paper on the new work, with Kyoko Watanabe of Japan Aerospace Exploration Agency as lead author, appeared May 20 in The Astrophysical Journal.

Fuente: Wired Science

Hubble Watches as Star Slowly Devours Planet

Six hundred light-years from Earth, a huge exoplanet circling close to its home star is slowly, inexorably being devoured.

WASP 12B orbits just 2 million miles from its star, which means the surface of the planet reaches temperatures over 2,800 Fahrenheit. The sun’s gravitational pull is stronger on the front surface of the planet than on the back, so the planet has been pulled into a football shape. If you were floating on the gaseous planet, and looking heavenwards, the sun would take up nearly the entire sky.

And in the next 10 million years, the star that so dominates the planet will be destroy it, according to a paper published in May in The Astrophysical Journal Letters.

It’s not exactly the kind of solar system that human beings anticipated finding in the great beyond.

"All sorts of things that we would never expected to find we’re finding,” said Carole Haswell, an astronomer at The Open University in Great Britain and the lead author on the new paper. “Our preconceptions about what planetary systems might look like were shaped by what our own solar system looked like, particularly Star Trek," she joked.

She and her team used the Hubble Space Telescope’s Cosmic Origins Spectrograph to investigate the planet by looking in the ultraviolet part of the spectrum.

"The near ultraviolet is a very sensitive probe to the presence of stuff and that allows you to deduce an effective radius for the planet," she said.

WASP 12B has a puffed up atmosphere that its star is siphoning off. That observation happily matches theoretical predictions made just a few months ago by astronomer Shu-lin Li at Peking University, Beijing. The confirmation shows yet again that exoplanetology, particularly the study of other solar systems not just individual planets, is advancing at a breakneck pace.

"It is a really nice example of theorists predicting something and we’d already observed something close to what they predicted," Haswell said.

To date, 455 exoplanets have been discovered.

Fuente: Wired Science

Stephen Hawking afirma que los viajes en el tiempo son posibles, pero sólo al futuro

Si primero fue el contacto con los extraterrestres, Stephen Hawking sigue por la vía de la ciencia ficción y le da por hablar sobre los viajes en el tiempo. En esta ocasión, el científico estadounidense británico afirma que este tipo de viajes sí serían posibles, pero únicamente hacia el futuro.

Hawking menciona que, una vez que se construyan naves espaciales que sean capaces de desplazarse al 98% de la velocidad de la luz, un día transcurrido abordo equivaldría a un año en la Tierra. De acuerdo a los cálculos del físico, se tardarían cerca de seis años para alcanzar esta velocidad. Aunque la afirmación suena un poco descabellada, Brian Cox, físico de partículas de la Universidad de Manchester, apoya la teoría basado en algunas observaciones hechas en el Gran Colisionador de Hadrones: “Cuando aceleramos partículas diminutas al 99.99% de la velocidad de la luz en el LHC de Ginebra, el tiempo transcurrido para ellas es un sietemilésima más lento del que medimos con nuestros relojes”.

¿Tiene esta teoría alguna aplicación práctica? Para Hawking, podría suponer la salvación de la Humanidad, ya que los viajeros en el tiempo podrían llegar una Tierra post-apocalíptica a repoblar (claro, si consiguen resolver el problema de cómo aterrizar y todo lo demás). Claro, al buen Stephen ya no le importa mucho lo que hablen de él, por lo que esperamos que este tipo de declaraciones suyas sean más recurrentes. En fin, no sé ustedes, pero yo ya puedo respirar más tranquilo ahora que la paradoja del viaje del tiempo ha quedado descartada.

Fuente:

Algunas curiosidades sobre el SR-71 Blackbird

Me crucé con esta anotación de Matt de 37Signals hablando del «avión más destacado del siglo XX» donde comenta algunas curiosidades sobre el SR-71 Blackbird que encontró por ahí.


Fuente: Microsiervos

La primera fotografía de la Materia Oscura

La misteriosa materia que compondría el 23 % (se especula) de toda la materia del universo es tan esquiva que jamás ha sido observada por nadie. Así que sólo podíamos sospechar que quizá existía. La materia oscura emite, absorbe e interactúa con radiación electromagnética de manera tan débil que no puede ser observada por medios técnicos ordinarios, no refleja la luz para ser observada.

Sin embargo, un equipo internacional de astrónomos de Japón, Gran Bretaña y Taiwan acaba de conseguir, por primera vez, imágenes que reflejan la distribución de materia oscura alrededor de 20 grandes cúmulos de galaxias. Los resultados se publicarán en la revista mensual de la Royal Astronomical Society. Las pruebas aún no son concluyentes, pero sí muy esperanzadoras.

Ni en el infrarrojo, ni en los rayos X ni en el ultravioleta la materia oscura había revelado aún su auténtica naturaleza. Pero utilizando lentes gravitacionales los científicos han sido capaces de mostrar las primeras imágenes en las que se “aprecia” la misteriosa materia oscura.

Utilizando el telescopio Subaru, los astrónomos observaron veinte cúmulos masivos de galaxias, los científicos han medido la distorsión de la luz desde estas galaxias hasta la Tierra, inferiendo la presencia, la cantidad y la distribución de materia oscura.

Analizando el efecto de lente gravitacional en estas imágenes, los investigadores comprobaron que, en general, la distribución de la materia oscura alrededor de esas veinte grandes agrupaciones galácticas no tiene un contorno esférico, sino plano y alargado.

Para que os hagáis una idea de qué se compone el universo, se conjetura que estos son los tantos por ciento de materia normal, materia oscura y, una más esquiva aún, energía oscura del universo: una forma hipotética de materia que estaría presente en todo el espacio, produciendo una presión negativa y que tiende a incrementar la aceleración de la expansión del Universo, resultando en una fuerza gravitacional repulsiva.

4% de la masa total del universo. La materia oscura, el 23%. Energía oscura, el 74%.


Fuente: Genciencia

El satélite Stereo Ahead capta la mayor erupción solar de los últimos 15 años

Desde hace tiempo tanto la NASA como el resto de agencias espaciales estudian a conciencia uno de los fenómenos más violentos de todos los que se dan en nuestro Sol: las erupciones solares. Debido a esto contamos con un gran número de imágenes de erupciones solares, a las cuales tenemos que sumarle ahora una nueva, la que veis en este post.

Concretamente la instantánea ha sido capturada este pasado día 12 por uno de los dos satélites que forman la misión Stereo de la NASA, el Ahead, y en ella vemos la erupción solar más potente de los últimos 15 años (esa lengua de fuego que aparece en la parte de arriba). Aunque así a primera vista podría parecer “que no es para tanto”, la lengua de materia eyectada hacia el espacio en esta erupción alcanzó más de 80.000 kilómetros de longitud, que se dice pronto.

Otra espectacular imagen que me deja pensando en lo que siempre reflexiono tras ver este tipo de foto: pero que insignificantes somos.


Fuente: ALT1040

¿Por qué es tan peligrosa la ceniza volcánica para los aviones?

Hoy el caos ha tomado el cielo del norte de Europa al entrar en erupción el volcán situado bajo el glaciar Eyjafjälla situado al sur de Islandia. Debido a la gran nube de cenizas que ha expulsado el mentado volcán (que podéis ver en la imagen de la derecha) Irlanda, Dinamarca, Finlandia, Suecia y Noruega han cerrado algunos sectores de su espacio aéreo, lo que se ha traducido en la cancelación del 15% de los vuelos europeos.

Seguramente muchos estén pensado que la medida es algo exagerada, sobre todo los que hayan visto cancelado su vuelo, y no se terminen de creer que simple ceniza pueda causar problemas serios a por ejemplo un mastodonte de última generación como el Airbus A380. Pues amigos, en esta ocasión, las autoridades no han exagerado ni un pelo, la ceniza volcánica es para los aviones algo así como lo que para nosotros los humanos una enfermedad terminal.

Por un lado tenemos que este tipo de ceniza, muy fina, es una estupenda “arma anti motores”, tanto para los de hélice como para reactores. Una vez en el interior de los mismos “invade” todas las partes móviles del motor y las colapsa por completo al fusionarse con ellas (la ceniza volcánica está compuesta por minerales que contienen silicio, el cual se funde más o menos a la temperatura que encontramos dentro de un motor de avión).

Por el otro los impactos de la ceniza contra el parabrisas de la cabina pueden provocar pequeñas perforaciones en el mismo y también en el propio fuselaje o en otros elementos importantes como las luces. Incluso se pueden llegar a formar capas de ceniza sobre partes sensibles del avión, como la cola, lo que se traduce en un aumento de peso que desequilibraría el aparato.

Como vemos el cerrar parte de los espacios aéreos y cancelar cientos de vuelos ha sido en este caso una medida acertada, y nada exagerada, para evitar desgracias humanas y también importantes pérdidas económicas (reparar un avión que ha conseguido salir de una pieza de un vuelo entre cenizas volcánicas es extremadamente costoso. Más de 60 aviones han sido desechados por el daño producido por ceniza).


Fuente: ALT1040

Cassini capta el primer vídeo de una tormenta eléctrica en Saturno

Le tengo cierto cariño a Cassini, pocas como esta sonda nos han permitido conocer tanto y tan sorprendente acerca de un planeta, cambiando incluso profundamente en varias ocasiones las teorías que se tenían del mismo. Si ya vimos los sorprendentes datos que reveló sobre los anillos de Saturno y su composición atmosférica ahora nos ha permitido observar por primera vez una tormenta eléctrica en la superficie del planeta.

El vídeo que pude verse arriba corresponde a 10 minutos comprimidos en 10 segundos. Supone ajustar los sonidos que capta la radio de la sonda, mucho más sensible que el oído humano y se han juntado posteriormente con el vídeo. El sonido que se oye no es el que en realidad capta la sonda, es sintético y procura aproximarse al que capta la sonda, que no suena realmente como un trueno propiamente dicho.

Puede que el vídeo no tenga la mejor calidad del mundo precisamente, ni el sonido sea el más agradable que hayamos escuchado, pero es increíble ver una serie de puntitos brillantes en una pantalla siendo consciente al mismo tiempo de que han sido grabados muy, muy lejos de aquí, mostrando la tormenta eléctrica acaecida más lejos de casa que el ser humano haya tenido el placer de observar.


Fuente: ALT1040

Rampaging Hot Jupiters May Keep Earthlike Planets Out of Their Systems

A bevy of backward-orbiting exoplanets could challenge theories of planet formation, new research suggests. The planets’ wonky orbits might also rule out the presence of Earthlike bodies in some planetary systems.

The wrong-way planets got where they are by cartwheeling over their stars’ heads, Andrew Collier Cameron of the University of St Andrews in Scotland proposed in an April 13 presentation at the Royal Astronomical Society’s National Astronomy Meeting in Glasgow, Scotland.

Planets are thought to form from the disk of gas and dust that surrounds a young star. Because the star and the disk both coalesce from the same cloud of material, theory holds that both should spin in the same direction — and so should any planets that arise. The "disk migration theory" posits that some planets should end up close to their stars by gently migrating inward over time, maintaining an orbital plane in line with the star’s rotation.

Last summer, astronomers first discovered a handful of planets that threw that idea for a loop. These planets orbit backward, opposite to the direction of their stars’ spin (SN: 9/12/09, p. 12). And other newly discovered planets that did have "forward" orbits were tilted 20 degrees or more with respect to the plane of the stellar disk where they were born.

These planets belong to a class of extrasolar planets called hot Jupiters — giants that sit scorchingly close to their stars.

"If I had to stick my neck out and make a prediction, it’s probably not a good idea to go looking for terrestrial planets in systems that have hot Jupiters in them," Cameron says.

Cameron and his colleagues think a single mechanism pushed the tilted and backwards planets into their offbeat orbits and also drew them close to their stars. If these slanted orbits are common, it could be a death knell for the migration theory, says study coauthor Didier Queloz of the Geneva Observatory.

"Migration cannot produce misaligned systems," Queloz says. The new study brings the total number of planets for which astronomers have angle data up to 27. Of those many are misaligned, with half tilted at steep angles and six orbiting backwards.

"Since most hot Jupiters are indeed misaligned, most cannot be formed by migrations," Queloz says. "We’re kind of killing this first idea of migration."

The more likely explanation, the researchers say, is the Kozai mechanism. In this scenario, a second, distant large body like a planet or a companion star gravitationally perturbs a planet’s orbit. The orbital plane can flip over the top of the star like a jump rope. When the orbit is flipped more than 90 degrees, the planet is orbiting backwards. At the same time, the shape of the orbit squishes and stretches like a rubber band. As the planet gets closer to the star, its orbit gets more circular, and the cartwheels become less dramatic. When the orbit finally settles into a circle near the star the tilt freezes.

Earlier research predicted that most orbits of giant planets perturbed by the Kozai mechanism should end up tilted around either 40 degrees — a forward but slanted orbit — or 140 degrees — a backwards orbit.

"That looks very much like what we’re now observing," Cameron says. "It looks almost too good to be true."

Some critics think he’s right — it is too good to be true. "I think they’re eliminating the standard mechanism of disk migration prematurely," says Adam Burrows of Princeton University. Some combination of migration, scatter and the Kozai mechanism is still possible, he says. "Their data isn’t that definitive to eliminate any other possibilities."

Astronomers had hoped that smaller, more Earthlike planets could be hiding in the neighborhoods of hot Jupiters, but the recent slug of orbital data suggests that may be unlikely. The giant planets’ orbits can take hundreds of thousands of years to settle, "during which you have a rampaging Jupiter on a cometlike crazy tumbling orbit, which would simply fling any remaining debris out of the system," Cameron says.


Fuente: Wired Science

Gigantic Baby Stars Discovered in Cloud of Space Dust

Huge new baby stars shine bright in this image of the Rosette Molecular Cloud.

The previously undiscovered protostars are the small points of orangey light in the center of the image. They are up to 10 times more massive than the sun.

The Herschel Space Observatory, operated by the European Space Agency, obtained the new image, which is a composite of three different wavelengths of light all in the infrared part of the spectrum. Infrared light waves are longer and scatter less than visible light, allowing scientists to probe dust-shrouded areas of space. In this image, the shortest wavelength is blue, the medium green, and the longest red.

The intense star-forming region of the Milky Way is about 5,000 light-years away in the direction of the constellation Monoceros, the Unicorn. This image shows only part of the massive cloud of dust. If the whole thing, seen below, were visible to the naked eye, it would be large in the sky, appearing around five times the size of a full moon.

Fuente: Wired Science

Cómo se congela el Polo Norte en invierno, en 20 segundos

El centro espacial Goddard de la NASA ha hecho esta animación de la formación del hielo en el polo norte. La reconstrucción va desde el 1 de Septiembre de 2009, momento en el que el hielo se encuentra en su mínimo, hasta el 30 de Marzo de 2010, momento máximo.



Según la NASA, “la cobertura helada del mar oscila durante el año, creciendo cada vez más durante el invierno y llegando a su punto máximo en Febrero o Marzo. Este año el crecimiento del hielo ha sido mayor que el de años anteriores, pero inferior a la media si tenemos en cuenta lo registros de hace treinta años”.

¿Significará esto que el calentamiento global se está frenando? ¿O no tiene nada que ver? ¿Estará el pingüino de Linux más feliz? Para resolver alguna de estas preguntas, en la página de la NASA podéis ver vídeos de la científica Lora Koenig, que investiga la criosfera terrestre (sí, hay gente que se dedica a estudiar hielo).


Fuente: Gizmodo

Impressive New Hubble Image of Odd Galaxy Triplet

It’s been a little while since the Hubble Space telescope bestowed a mind-blowing space photo on us, but this one was worth the wait.

This swirly, spooky, sparkly shot is of Messier 66, the largest of three spiral galaxies that make up the Leo triplet, 35 million light-years away. The galaxy measures around 100,000 light-years across and has odd, asymmetrical arms that were most likely pulled out of place by the gravity of the other two galaxies in the triplet.

The brown stripes are made up of dust, and the blue and pink bright areas in the galaxies are star clusters. Messier 66 is popular with astronomers because it has had an impressive three supernova explosions since 1989.


Fuente: Wired Science

Venus Orbiter Finds Potential Active Volcanoes

The Venus Express spacecraft has found convincing evidence that Earth is not the only geologically active planet in the solar system.

Infrared emissions from lava flows on the surface of Venus indicate that they are relatively young, which means the planet may still be capable of volcanic eruptions.

“The solidified lava flows, which radiate heat from the surface, seem hardly weathered. So we can conclude that they are younger than 2.5 million years old — and the majority are probably younger than 250,000 years,” Jörn Helbert of the DLR Institute of Planetary Research in Germany, co-author of a study published April 8 in Science, said in a press release. “In geological terms, this means that they are practically from the present day.”

The results could explain why there are fewer asteroid impacts than expected on the planet’s surface. Volcanism has been the prime suspect, because lava flows can fill in and obscure craters. But scientists were unsure whether a major episode of volcanic activity resurfaced much of the planet all at once in the past, or if intermittent activity has slowly filled in craters over time. The existence of a recent flow suggests the latter is more likely, and that volcanism may be ongoing.

Venus is shrouded in a thick cloud cover which obscures the visible light emissions form the surface. So a team led by Suzanne Smrekar of NASA’s Jet Propulsion Laboratory studied the thermal emissions of the surface using the Visible and Infrared Thermal Imaging Spectrometer on the Venus Express orbiter. Older surfaces tend to be smoothed by weathering over time, while younger surfaces are more rough and have higher thermal emissions.

Several areas on the surface had been identified as potential volcanic centers by radar imagery data from the Magellan mission, which ended in 1994 when the spacecraft was intentionally crashed into the surface. Smrekar’s team targeted three of these areas and found they had higher thermal emissions than the surrounding areas.

“Now we have strong evidence right at the surface for recent eruptions,” Smrekar said in a press release.

Because Venus is similar in size and internal structure to Earth, comparisons between the two planets can help scientists understand our own planet’s evolution. If volcanism on Venus is also similar to Earth, as the new study indicates, that narrows the factors that could have sent the planets on such different paths that ended with Earth being habitable and Venus being bone dry and hellishly hot.

In order to determine what the young rock is made of, Helbert plans to build a lab that can heat various rock types to around 900 degrees Fahrenheit, the planet’s surface temperature, and study their thermal emission signatures to compare to the Venus Express readings.

Fuente: Wired Science

El eclipse que dura 18 meses por fin observado

Por primera vez hemos podido observar directamente un misterioso eclipse que que esconde una estrella en el sistema binario de Epsilon Aurigae, a 2.000 años luz de la Tierra, del que teníamos constancia desde el siglo XIX.

El cuerpo que provoca el eclipse es una nube de escombros, un disco de polvo espacial se coloca frente a la estrella principal del sistema cada 27 años… durante 18 meses. La observación ha podido ser realizada gracias a un instrumento desarrollado por investigadores de la norteamericana Universidad de Michigan.

“No hay otro sistema conocido como éste. Además, al parecer se trata de una fase excepcional de la vida de la estrella. Y está ocurriendo tan cerca de nosotros. Es realmente una suerte”, afirmó el astrónomo John Monnier, autor de la investigación, para la revista Nature.

Epsilon Aurigae es el quinto sistema estelar más brillante en la constelación de Auriga, y desde hace tiempo los científicos se preguntaban por qué la luz de la estrella que se encuentra en la constelación disminuía a intervalos. Por fin, las imágenes de su apagón fueron captadas gracias a una colección de seis telescopios con lentes de un metro de diámetro que, al combinarse, funcionan como un interferómetro, instrumento que emplea la interferencia de las ondas de luz para medir la longitud de onda de las mismas con gran precisión.

Tal es la resolución de las imágenes captadas por estos telescopios que supera 100 veces mayor la del telescopio Hubble.


Fuente: Genciencia

PIXELS by PATRICK JEAN

New York invasion by 8-bits creatures !
PIXELS is Patrick Jean' latest short film, shot on location in New York.

Written, directed by : Patrick Jean
Director of Photograhy : Matias Boucard


Fuente: Dailymotion

¿La Luna tiene colores? sí, pero como explica Rogelio Bernal, autor de la fotografía, hay un pequeño truco. Primero neutralizó los colores, de tal forma que los valores RGB son los mismos, y después saturó la imagen. Es decir, esos colores están ahí, pero están exagerados en el post-proceso.

Por cierto, Rogelio es conocido en el internet hispano por su blog, Buenos Días Silicon Valley y publica este tipo de fotos en Deep Sky Colors.

Fuente: ALT1040

Mystery Object Defies Astronomical Classification

A mysterious object discovered near a brown dwarf doesn’t fit into any known astronomical category.

The newly discovered mystery companion forms a binary system with the brown dwarf, located 460 light-years away in the Taurus star-forming system. The object is too light to be another brown dwarf, but it’s too young to have formed by accretion, the way a typical planet does.

“Although this small companion appears to have a mass that is comparable to the mass of planets around stars, we don’t think it formed like a planet,” said astronomer Kevin Luhman of Penn State University, co-author of the study April 5 in The Astrophysical Journal. “This seems to indicate that there are two different ways for nature to make small companions.”

Luhman’s team made the discovery with the Hubble Space Telescope and the Gemini Observatory. The discovery was made using the Wide Field Planetary Camera 2 on the Hubble Space Telescope and the Gemini Observatory.

The new object and its companion brown dwarf are orbiting as a binary pair, 15 astronomical units from each other. If they were superimposed on our solar system, the companion would be orbiting midway between Saturn and Uranus. The oddball object’s mass is somewhere between five and 10 Jupiter masses, making it too small to fuse deuterium. The International Astronomical Union currently uses this fusion line, which occurs at about 13 Jupiter masses, as the defining characteristic of a brown dwarf.

But the object appears to be around the same age as its binary partner, which doesn’t fit conventional ideas about planet formation. Traditional theories describe planets forming from the gaseous disk that swirls around the equator of a newly formed star. Particles in the gas and dust cloud collide, and gradually accrete into larger objects, eventually becoming planets. These rocky planets can grow into sizes up to 10 Earth masses before they become gas giants.

And 1 million years is much shorter than the expected time for a planet to be born this way. Planets can form this quickly when there is a gravitational instability in the gaseous disk, but the brown dwarf’s disk probably didn’t have enough material to form a planet larger than a single Jupiter mass.

“It looks like this new system formed by the collapse and fragmentation process that forms binary star systems,” Alan Boss, president of the IAU Commission on Extrasolar Planets said in an e-mail to Wired.com. Boss theorized that these sorts of planet-sized objects exist in a paper published in 2001.

“While people like to use the ‘p-word’ to describe objects with masses below 13 Jupiter masses, given the attention given to exoplanets these days, they should more properly be called ’sub-brown dwarfs,’” Boss said.

Because this strange object seems more likely to have formed the same way as its binary partner, the brown dwarf, Luhman believes it is probably best classified as a very small brown dwarf.

“This object, because it formed like a star, its composition is probably the same throughout,” Luhman said. This homogenous composition is in stark contrast to the innards of gas giants, like Jupiter, which probably have a heavy-element rocky core surrounded by a gaseous shell composed mainly of hydrogen and helium.

The presence of another nearby binary system, of a red star and a brown dwarf, supports Luhman’s theory. It seems to have been formed around the same time as the mystery pair, indicating that all four may have formed the same way, as stars.

“This configuration — two tight pairs that are widely separated from each other — is called a hierarchical configuration and is commonly seen in quadruple star systems,” Luhman said.


Fuente: Wired Science