Posted on by Tammy Plotner

Neutron Stars: A Cataclysmic Conception

This "SWASI" phenomenon is an analogue of the SASI instability occurring in the supernova core, but it is one million times smaller and about one hundred times slower than its astrophysical counterpart. (Image copyrights: Thierry Foglizzo, Laboratoire AIM Paris-Saclay, CEA)

It’s one of the most intense and violent of all events in space – a supernova. Now a team of researchers at the Max Planck Institute for Astrophysics have been taking a very specialized look at the formation of neutron stars at the center of collapsing stars. Through the use of sophisticated computer simulations, they have been able to create three-dimensional models which show the physical effects – intense and violent motions which occur when stellar matter is drawn inward. It’s a bold, new look into the dynamics which happen when a star explodes.

As we know, stars which have eight to ten times the mass of the Sun are destined to end their lives in a massive explosion, the gases blown into space with incredible force. These cataclysmic events are among the brightest and most powerful events in the Universe and can outshine a galaxy when they occur. It is this very process which creates elements critical to life as we know it – and the beginnings of neutron stars.

Neutron stars are an enigma unto themselves. These highly compact stellar remnants contain as much as 1.5 times the mass of the Sun, yet are compressed to the size of a city. It is not a slow squeeze. This compression happens when the stellar core implodes from the intense gravity of its own mass… and it takes only a fraction of a second. Can anything stop it? Yes. It has a limit. Collapse ceases when the density of the atomic nuclei is exceeded. That’s comparable to around 300 million tons compressed into something the size of a sugar cube.

Studying neutron stars opens up a whole new dimension of questions which scientists are keen to answer. They want to know what causes stellar disruption and how can the implosion of the stellar core revert to an explosion. At present, they theorize that neutrinos may be a critical factor. These tiny elemental particles are created and expelled in monumental numbers during the supernova process and may very well act as heating elements which ignite the explosion. According to the research team, neutrinos could impart energy into the stellar gas, causing it to build up pressure. From there, a shock wave is created and as it speeds up, it could disrupt the star and cause a supernova.

As plausible as it might sound, astronomers aren’t sure if this theory could work or not. Because the processes of a supernova cannot be recreated under laboratory conditions and we’re not able to directly see into the interior of a supernovae, we’ll just have to rely on computer simulations. Right now, researchers are able to recreate a supernova event with complex mathematical equations which replicate the motions of stellar gas and the physical properties which happen at the critical moment of core collapse. These types of computations require the use of some of the most powerful supercomputers in the world, but it has also been possible to use more simplified models to get the same results. “If, for example, the crucial effects of neutrinos were included in some detailed treatment, the computer simulations could only be performed in two dimensions, which means that the star in the models was assumed to have an artificial rotational symmetry around an axis.” says the research team.

With the support of the Rechenzentrum Garching (RZG), scientists were able to create in a singularly efficient and fast computer program. They were also given access to most powerful supercomputers, and a computer time award of nearly 150 million processor hours, which is the greatest contingent so far granted by the “Partnership for Advanced Computing in Europe (PRACE)” initiative of the European Union, the team of researchers at the Max Planck Institute for Astrophysics (MPA) in Garching could now for the first time simulate the processes in collapsing stars in three dimensions and with a sophisticated description of all relevant physics.

“For this purpose we used nearly 16,000 processor cores in parallel mode, but still a single model run took about 4.5 months of continuous computing”, says PhD student Florian Hanke, who performed the simulations. Only two computing centers in Europe were able to provide sufficiently powerful machines for such long periods of time, namely CURIE at Très Grand Centre de calcul (TGCC) du CEA near Paris and SuperMUC at the Leibniz-Rechenzentrum (LRZ) in Munich/Garching.

Turbulent evolution of a neutron star for six moments (0.154, 0.223, 0.240, 0.245, 0.249 and 0.278 seconds) after the beginning of the neutron star formation in a threedimensional computer simulation. The mushroom-like bubbles are characteristic of "boiling" neutrino-heated gas, whereas simultaneously the "SASI" instability causes wild sloshing and rotational motions of the whole neutrino-heated layer (red) and of the enveloping supernova shock (blue) . (Images by Elena Erastova and Markus Rampp, RZG)
Turbulent evolution of a neutron star for six moments (0.154, 0.223, 0.240, 0.245, 0.249 and 0.278 seconds) after the beginning of the neutron star formation in a threedimensional computer simulation. The mushroom-like bubbles are characteristic of “boiling” neutrino-heated gas, whereas simultaneously the “SASI” instability causes wild sloshing and rotational motions of the whole neutrino-heated layer (red) and of the enveloping supernova shock (blue) . (Images by Elena Erastova and Markus Rampp, RZG)
Given several thousand billion bytes of simulation data, it took some time before researchers could fully understand the implications of their model runs. However, what they saw both elated and surprised them. The stellar gas performed in a manner very much like ordinary convection, with the neutrinos driving the heating process. And that’s not all… They also found strong sloshing motions which transiently change to rotational motions. This behavior has been observed before and named Standing Accretion Shock Instability. According to the news release, “This term expresses the fact that the initial sphericity of the supernova shock wave is spontaneously broken, because the shock develops large-amplitude, pulsating asymmetries by the oscillatory growth of initially small, random seed perturbations. So far, however, this had been found only in simplified and incomplete model simulations.”

“My colleague Thierry Foglizzo at the Service d’ Astrophysique des CEA-Saclay near Paris has obtained a detailed understanding of the growth conditions of this instability”, explains Hans-Thomas Janka, the head of the research team. “He has constructed an experiment, in which a hydraulic jump in a circular water flow exhibits pulsational asymmetries in close analogy to the shock front in the collapsing matter of the supernova core.” Known as Shallow Water Analogue of Shock Instability, the dynamic process can be demonstrated in less technicalized manners by eliminating the important effects of neutrino heating – a reason which causes many astrophysicists to doubt that collapsing stars might go through this type of instability. However, the new computer models are able to demonstrate the Standing Accretion Shock Instability is a critical factor.

“It does not only govern the mass motions in the supernova core but it also imposes characteristic signatures on the neutrino and gravitational-wave emission, which will be measurable for a future Galactic supernova. Moreover, it may lead to strong asymmetries of the stellar explosion, in course of which the newly formed neutron star will receive a large kick and spin”, describes team member Bernhard Müller the most significant consequences of such dynamical processes in the supernova core.

Are we finished with supernova research? Do we understand everything there is to know about neutron stars? Not hardly. At the present time, the scientist are ready to further their investigations into the measurable effects connected to SASI and refine their predictions of associated signals. In the future they will further their understanding by performing more and longer simulations to reveal how instability and neutrino heating react together. Perhaps one day they’ll be able to show this relationship to be the trigger which ignites a supernova explosion and conceives a neutron star.

Original Story Source: Max Planck Institute for Astrophysics News Release.

Posted on by Elizabeth Howell

What Happens When Stars Collide? In This Case, A Newly Observed Kind of Pulsating Star

Artist's impression of the eclipsing, pulsating binary star J0247-25. (Credit: Keele University)

It sure would be interesting to watch two stars run into each other — from a safe distance, of course. One can imagine there would be quite the titanic battle going on between their competing gravitational forces, throwing off gas and matter as they collide.

They also leave behind interesting echoes, at least according to new research. A European team looked at the leftovers of one collision and found a type of pulsating star that has never been seen before.

It’s common for stars to form in groups or to be paired up, since they form from immense gas clouds. Sometimes, a red giant star in a binary system gets so big that it will bump into a companion star orbiting nearby. This crash could shave 90% of the red giant star’s mass off, but astronomers are still trying to get their heads around what happens.

Eclipsing Binaries
Artists impression of a binary star system (courtesy NASA)

“Only a few stars that have recently emerged from a stellar collision are known, so it has been difficult to study the connection between stellar collisions and the various exotic stellar systems they produce,” Keele University, which led the research, stated.

Researchers who made the find were actually on the hunt for alien planets. They turned up what is called an “eclipsing” binary system, meaning that one of the stars passes in front of the other from the perspective of Earth.

The scientists then used a high-speed camera on the Very Large Telescope in Chile called ULTRACAM. The camera is capable of taking up to 500 pictures a second to track fast-moving astronomical events.

Observations revealed that “the remnant of the stripped red giant is a new type of pulsating star,” Keele stated.

The Very Large Telescope (VLT) at ESO's Cerro Paranal observing site in the Atacama Desert of Chile, consisting of four Unit Telescopes with main mirrors 8.2-m in diameter and four movable 1.8-m diameter Auxiliary Telescopes. The telescopes can work together, in groups of two or three, to form a giant interferometer, allowing astronomers to see details up to 25 times finer than with the individual telescopes. Credit: Iztok Boncina/ESO
The Very Large Telescope (VLT) at ESO’s Cerro Paranal observing site in the Atacama Desert of Chile, consisting of four Unit Telescopes with main mirrors 8.2-m in diameter and four movable 1.8-m diameter Auxiliary Telescopes. The telescopes can work together, in groups of two or three, to form a giant interferometer, allowing astronomers to see details up to 25 times finer than with the individual telescopes. Credit: Iztok Boncina/ESO

“We have been able to find out a lot about these stars, such as how much they weigh, because they are in a binary system,” stated Pierre Maxted, an astrophysicist at Keele.

“This will really help us to interpret the pulsation signal and so figure out how these stars survived the collision and what will become of them over the next few billion years.”

The next step for the researchers will be to calculate when the star will begin cooling down and become a white dwarf, which is what is left behind after a star runs out of fuel to burn.

Check out more details of the find in Nature.

Source: Keele University

Posted on by Nancy Atkinson

How to Pay for That Latte on the Moon? PayPal Has a Plan

Artist's rendition of a Moon Base. Credit: John Spencer/Space Tourism Society.

In Star Trek lore, money doesn’t exist in the 24th century. But sometime in the 21st century, when we (hopefully) can go to a Bigelow orbiting space hotel or spend a weekend at a colony on the Moon, how are we going to pay for it? Global e-commerce company PayPal has a plan. They’ve teamed up with SETI and other space folks to launch PayPal Galactic, an initiative that PayPal says will address the issues to help make universal space payments a reality.

While this doesn’t seem to be an immediate need, PayPal wants to be ready … I presume. But as of this writing, the PayPal Galactic website doesn’t seem to be up and running yet.

The launch of PayPal Galactic is in conjunction with PayPal’s 15th anniversary, as well as a new crowdfunding campaign for SETI, called Curiosity Movement.

“PayPal and the SETI Institute are well-matched to work on PayPal Galactic because together we can create a recipe for innovation,” said Jill Tarter, from the SETI Institute. “PayPal envisions exploring possibilities in space the way that we do, breaking boundaries to make real progress. When the SETI Institute succeeds in its exploration of the universe, and as we find our place among the stars, PayPal will be there to facilitate commerce, so people can get what they need, and want, to live outside of our planet.”

Apollo 11’s Buzz Aldrin even was part of a webcast to launch PayPal Galactic.

“Trips to Mars, the moon, even orbit will require we provide astronauts and astro-tourists with as many comforts from home as possible, including how to pay each other,” said astronaut and author Buzz Aldrin, who is on-board with PayPal’s plans. “Whether it’s paying a bill, or even helping a family member on Earth, we’ll need access to money. I think humans will reach Mars, and I would like to see it happen in my lifetime. When that happens I won’t be surprised if people use PayPal Galactic for the little things and the big ones.”

PayPal’s President David Marcus (no, not THAT David Marcus from Star Trek) says that as space travel opens to ‘the rest of us’, this drives questions about the commercialization of space.

“We are launching PayPal Galactic, in conjunction with leaders in the scientific community, to increase public awareness of the important questions that need to be addressed,” he said in a press release. “We may not answer these questions today or even this year, but one thing is clear, we won’t be using cash in space. PayPal has already pushed payments onto the Internet, onto mobile phones and across terrestrial borders. We now look forward to pushing payments from our world to the next, and beyond.”

These are the questions PayPal hopes to answer:

• What will our standard currency look like in a truly cash-free interplanetary society?
• How will the banking systems have to adapt?
• How will risk and fraud management systems need to evolve?
• What regulations will we have to conform with?
• How will our customer support need to develop?

PayPal says this system could even help astronauts on the International Space Station be able to pay their bills back on Earth or be able to pay for e-books or online music.

But check out SETI’s Curiosity Movement, which hopes to “unite with curious thinkers across the globe in helping to expand our research and continue the search for answers on Earth and beyond.”

Posted on by Elizabeth Howell

We’ve Found 10,000 Near-Earth Objects. How To Step Up The Search?

Asteroid 2013 MZ5 as seen by the University of Hawaii's PanSTARR-1 telescope. Credit: PS-1/UH

That pale white dot up there? No. 10,000 in a list of near-Earth objects. This rock, 2013 MZ5, was discovered June 18. It is 1,000 feet (300 meters) across and will not come anywhere near to threatening Earth, NASA assures us.

But what else is out there? The agency still hasn’t found every asteroid or comet that could come by Earth. To be sure, however, it’s really trying. But is there more NASA and other agencies can do to search? Tell us in the comments.

A bit of history: the first of these objects was discovered in 1898, but in recent decades we’ve been more systematic about finding them. This means we’ve been picking up the pace on discoveries.

Congress asked NASA in 2005 to find and catalog 90 per cent of NEOs that are larger than 500 feet (140 meters) in size, about enough to level a city. The agency says it has also found most of the very largest NEOs, those that are at least six-tenths of a mile (1 kilometer) across (and none so far discovered are a threat.)

That’s not to say smaller pieces wouldn’t do damage. Remember that Russian meteor this year that blew out windows and caused injuries? It probably was only 50 feet (15 meters) across.

The two main smoke trails left by the Russian meteorite as it passed over the city of Chelyabinsk. Credit: AP Photo/Chelyabinsk.ru
The two main smoke trails left by the Russian meteorite as it passed over the city of Chelyabinsk. Credit: AP Photo/Chelyabinsk.ru

Still, NASA says once it achieves its latest goal (which it is supposed to be by 2020), “the risk of an unwarned future Earth impact will be reduced to a level of only one per cent when compared to pre-survey risk levels. This reduces the risk to human populations, because once an NEO threat is known well in advance, the object could be deflected with current space technologies.”

The major surveys for NEOs in the United States are the University of Arizona’s Catalina Sky Survey, the University of Hawaii’s Pan-STARRS survey and the Lincoln Near-Earth Asteroid Research (LINEAR) survey between the Massachusetts Institute of Technology, the Air Force and NASA. Worldwide, the current discovery rate is 1,000 per year.

In May, the European Space Agency also opened a new “NEO Coordination Centre” intended to be the one-stop shop for asteroid warnings in Europe (and worldwide, of course.) More details here.

EDIT: And NASA also recently issued an Asteroid Grand Challenge to private industry to seek solutions to find these space rocks. Check out more information here.

What more can be done to find and track threatening space rocks? Let us know below.

Credit: NASA

Posted on by Elizabeth Howell

This Supernova Had A ‘Delayed Detonation’

G1.9+0.3 in an image by the Chandra X-ray Observatory. Credit: X-ray (NASA/CXC/NCSU/K.Borkowski et al.); Optical (DSS)

In 2008, astronomers discovered a star relatively nearby Earth went kablooie some 28,000 light-years away from us. Sharp-eyed astronomers, as they will do, trained their telescopes on it to snap pictures and take observations. Now, fresh observations from the orbiting Chandra X-ray Observatory suggest that supernova was actually a double-barrelled explosion.

This composite picture of G1.9+0.3, coupled with models by astronomers, suggest that this star had a “delayed detonation,” NASA stated.

“First, nuclear reactions occur in a slowly expanding wavefront, producing iron and similar elements. The energy from these reactions causes the star to expand, changing its density and allowing a much faster-moving detonation front of nuclear reactions to occur.”

To explain a bit better what’s going on with this star, there are two main types of supernovas:

In a Type Ia supernova, a white dwarf (left) draws matter from a companion star until its mass hits a limit which leads to collapse and then explosion. Credit: NASA
In a Type Ia supernova, a white dwarf (left) draws matter from a companion star until its mass hits a limit which leads to collapse and then explosion. Credit: NASA

– Type Ia: When a white dwarf merges with another white dwarf, or picks up matter from a close star companion. When enough mass accretes on the white dwarf, it reaches a critical density where carbon and oxygen fuse, then explodes.

– Type II: When a massive star reaches the end of its life, runs out of nuclear fuel and sees its iron core collapse.

NASA said this was a Type Ia supernova that “ejected stellar debris at high velocities, creating the supernova remnant that is seen today by Chandra and other telescopes.”

New research shows that some old stars known as white dwarfs might be held up by their rapid spins, and when they slow down, they explode as Type Ia supernovae. Thousands of these "time bombs" could be scattered throughout our Galaxy. In this artist's conception, a supernova explosion is about to obliterate an orbiting Saturn-like planet. Credit: David A. Aguilar (CfA)
In this artist’s conception, a supernova explosion is about to obliterate an orbiting Saturn-like planet. Credit: David A. Aguilar (CfA)

You can actually see the different energies from the explosion in this picture, with red low-energy X-rays, green intermediate energies and blue high-energies.

“The Chandra data show that most of the X-ray emission is “synchrotron radiation,” produced by extremely energetic electrons accelerated in the rapidly expanding blast wave of the supernova. This emission gives information about the origin of cosmic rays — energetic particles that constantly strike the Earth’s atmosphere — but not much information about Type Ia supernovas,” NASA stated.

Also, unusually, this is an assymetrical explosion. There could have been variations in how it expanded, but astronomers are looking to map this out with future observations with Chandra and the National Science Foundation’s Karl G. Jansky Very Large Array.

Check out more information about this supernova in the scientific paper led by North Carolina State University.

Source: NASA

Posted on by David Dickinson

How Amateur Astronomers Can Help LADEE

An Artist's concept of LADEE in orbit around the Moon. (Credit: NASA Ames).

You can help NASA’s upcoming lunar mission.

NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) is slated to lift off from Wallops Island this September 5th in a spectacular night launch. LADEE will be the first mission departing Wallops to venture beyond low Earth orbit. A joint collaboration between NASA’s Goddard Spaceflight Center & the AMES Research Center, LADEE will study the lunar environment from orbit, including its tenuous exosphere.

Scientists hope to answer some long standing questions about the lunar environment with data provided by LADEE. How substantial is the wispy lunar atmosphere?  How common are micro-meteoroid impacts? What was the source of the sky glow recorded by the Surveyor spacecraft and observed by Apollo astronauts before lunar sunrise and after lunar sunset while in orbit?

Glows of the solar corona and crepuscular rays reported by the Apollo 17 astronauts in lunar orbit. (Credit: NASA).
Glows of the solar corona and crepuscular rays reported by the Apollo 17 astronauts in lunar orbit. (Credit: NASA).

The micro-meteoroid issue is of crucial concern for any future long duration human habitation on the Moon. The Apollo missions were only days in length. No one has ever witnessed a lunar sunrise or sunset from the surface of the Moon, as all six landings occurred on the nearside of the Moon in daylight. (Sunrise to sunset on the Moon takes about two Earth weeks!)

And that’s where amateur astronomers come in. LADEE is teaming up with the Association of Lunar & Planetary Observers (ALPO) and their Lunar Meteoritic Impact Search Program in a call to watch for impacts on the Moon. These are recorded as brief flashes on the nighttime side of the Moon, which presents a favorable illumination after last quarter or leading up into first quarter phase.

We wrote recently about a +4th magnitude flash detected of the Moon on March 17th of this year. That explosion was thought to have been caused by a 35 centimetre impactor which may have been associated with the Eta Virginid meteor shower. The impact released an explosive equivalent of five tons of TNT and has set a possible new challenge for Moon Zoo volunteers to search for the resulting 6 metre crater.

An artist's illustration of a meteoroid impact on the Moon. (Credit: NASA).
An artist’s illustration of a meteoroid impact on the Moon. (Credit: NASA).

We’ve also written about amateur efforts to document transient lunar phenomena and studies attempting to pinpoint a possible source of these spurious glows and flashes on the Moon observed over the years.

NASA’s Meteoroid Environment Office is looking for dedicated amateurs to take part in their Lunar Impact Monitoring campaign. Ideally, such an observing station should utilize a telescope with a minimum aperture of 8 inches (20cm) and be able to continuously monitor and track the Moon while it’s above the local horizon. Most micro-meteoroid flashes are too fast and faint to be seen with the naked eye, and thus video recording will be necessary. A typical video configuration for the project is described here. Note the high frame rate and the ability to embed a precise time stamp is required. I’ve actually run WWV radio signals using an AM short wave radio transmitting in the background to accomplish this during occultations.

Finally, you’ll need a program called LunarScan to analyze those videos for evidence of high speed flashes. LunarScan is pretty intuitive. We used the program to analyze video shot during the 2010 Total Lunar Eclipse for any surreptitious Geminid or Ursid meteors.

Brian Cudnik, coordinator of the Lunar Meteoritic Impact Search section of the ALPO, noted in a recent forum post that we’re approaching another optimal window to accomplish these sorts of observations this weekend, with the Moon headed towards last quarter on June 30th.

An example of an impact flash recorded by the Automated & Lunar Meteor Observatory video cameras based at the Marshall Spaceflight Center in Huntsville, Alabama.
An example of an impact flash recorded by the Automated & Lunar Meteor Observatory video cameras based at the Marshall Spaceflight Center in Huntsville, Alabama.

Interestingly, the June Boötids are currently active as well, with historical sporadic rates of anywhere from 10-100 per hour.  In 1975, seismometers left by Apollo astronauts detected series of impacts on June 24th thought to have been caused by one of two Taurid meteor swarms the Earth passes through in late June, another reason to be vigilant this time of year.

Don’t have access to a large telescope or sophisticated video gear? You can still participate and make useful observations.

LADEE is also teaming up with JPL and the Lewis Center for Educational Research to allow students track the spacecraft en route to the Moon. Student groups will be able to remotely access the 34-metre radio telescopes based at Goldstone, California that form part of NASA’s Deep Space Communications Network. Students will be able to perform Doppler measurements during key mission milestones to monitor the position and status of the spacecraft during thruster firings.

And backyard observers can participate in another fashion, using nothing more than their eyes and patience. Meteor streams that are impacting the Moon affect the Earth as well. The International Meteor Organization is always looking for information from dedicated observers in the form of meteor counts. The Perseids, an “Old Faithful” of meteor showers, occurs this year around August 12th under optimal conditions, with the Moon only five days past New. This is also three weeks prior to the launch of LADEE.

Whichever way you choose to participate, be sure to follow the progress of LADEE and our next mission to study Earth’s Moon!

-Listen to Universe Today’s Nancy Atkinson and her interview with Brian Day of the NASA Lunar Science Institute.

-Also listen to the 365 Days of Astronomy interview with Brian Day and Andy Shaner from the Lunar Planetary institute on the upcoming LADEE mission.

Posted on by Nancy Atkinson

Astrophoto: Houston Super Moonrise

37 separate images showing the movement of the Moon as it rises behind the buildings in downtown Houston, Texas on June 22, 2013. Credit and copyright: Sergio Garcia Rill/SGR Photo.

While we recently posted a huge batch of images from the recent “Super Moon,” this new image from Sergio Garcia Rill in Houston is something special. It’s a composite photo of the Moonrise on June 22nd, and is a mosaic made from 37 separate images that show the Moon rising over the course of three hours, with the buildings of downtown Houston in the foreground.

“I stayed in place for over three hours,” Sergio explained on Flickr. “The hardest part was selecting which shots showed a sequential movement of the Moon, since I was altering shutter speeds between shots to compensate for changing light conditions.”

The full Moon of June 2013 was at perigee — or at its closest point in its orbit to Earth, and appeared up to 14% bigger and 30% brighter than other full Moons of 2013.

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Posted on by Nancy Atkinson

New Android App Makes it Easier to Use Your Phone While Stargazing

The red filter on the Sunset app doesn't ruin your night vision.

Ever have to take a call while stargazing, or do you use astronomical apps on your phone, only to have the white screen ruin your night vision? A new app called Sunset is a screen filter that essentially adds a dimmed red-color filter onto an Android device’s screen so you can use your smartphone during those extra dark moments and not lose your dark-adapted night-vision.

The app’s description says it best:

Sunset is a screen filter adds an additional layer of dimming color to help soothe your eyes during those extra dark hours. Perfect for astronomers/stargazers looking to preserve their night vision, late night smartphone users, and movie theater texters. Sunset goes darker than Android’s brightness settings to provide your eyes with that extra layer of comfort.

Sunset is easy to use, too. Just select a color theme, choose the maximum intensity, and hit start. The color themes are specifically designed to help your eyes in different environments, as there are several other color options.

The Sunset app is just 99 cents, USD, but the app’s creator Rohan Puri will send a refund to the first 20 Universe Today readers who buy this app. Just send your e-mail via Direct Message on Twitter to @RohanSPuri after your purchase, and you will receive a full refund.


You can find Sunset at the Google Play Store

Thanks to Rohan for sharing this app with Universe Today and our readers!

Posted on by Nancy Atkinson

Another Exoplanet Hunting Mission Ends: CoRoT Spacecraft Can’t be Recovered

The COROT spacecraft. Credits: CNES/D. Ducros

More bad news on the exoplanet-hunting front: While the final fate of the Kepler spacecraft remains unknown, the CoRoT (Convection, Rotation and Planetary Transits) satellite has now been officially shut down. CoRoT suffered a computer failure on November, 2, 2012 and although the spacecraft is capable of receiving navigational commands, the French Space Agency CNES reports it can no longer retrieve data from its 30-centimeter telescope. After a valiant effort to try and restore the computer, CNES announced this week that the spacecraft has been retired. CoRoT’s journey will come to a fiery end as it will be deorbited and it will burn up on re-entry in Earth’s atmosphere.

While it’s always hard to see the end of successful mission, we can’t be too sad about CoRoT, however. The mission lasted twice as long as expected and it gathered a remarkable haul of exoplanets. CoRoT looked for planetary transits — a dimming in brightness of the host star as a planet crossed in front. CoRoT was the first mission to find a planet using the transit method.

In all, CoRoT has spotted 32 confirmed planets and at least 100 more are awaiting confirmation. The mission also allowed astronomers to study the stellar physics and the interior of stars.

This is not the first computer failure for the mission. CoRoT launched in December of 2006, and in 2009 the main computer failed and has since been running on the backup computer. When the second computer failed in November, engineering teams have tried to reboot both computers, with no success.

But space radiation is tough on spacecraft, and after enduring 6 years of intense bombardment by high-energy particles in space, both computers have been deemed unrecoverable.

CNES said a series of operations will be performed to lower CoRoT’s orbit and conduct some technology experiments before passivating and deorbiting the satellite. Its journey will end as it burns up on re-entry in Earth’s atmosphere.

Family portrait of the first 15 CoRoT planets. Credit: Patrice Amoyel (CNES)
Family portrait of the first 15 CoRoT planets. Credit: Patrice Amoyel (CNES)

CoRoT discovered a diverse array of planets, mostly gas giants. Some of the planets discovered, like CoRoT-7b, orbit their star in less than 24 hours and have a blistering hot surface, while others like CoRoT-9b have an orbital period of 95 days and is one of very few known “warm” transiting exoplanets.

CoRoT was also the first to obtain measurements of the radius of brown dwarves, intermediate objects between a planet and a star, and literally opened up a whole new field of study of temporal analysis of the micro-variability of stars by measuring the frequencies and amplitudes of stellar vibrations with unprecedented precision.

CNES did not provide a timetable for CoRoT’s demise, but we’ll keep you posted.

Source: CNES

Posted on by Elizabeth Howell

Discovery! More Planets Found Orbiting In A Star Cluster

An artist's conception of an exoplanet transiting its home star. Credit: NASA's Goddard Space Flight Center

As Earthlings, we’re so used to thinking about planets being in simple orbits around a single star. But the Sun likely didn’t begin its life alone. It formed as part of a cluster of stars, all feeding from the same well of gas.

Could star clusters also host planets? Or do they have to wait for the little guys until the stars evolve and move further apart? Well, astronomers have actually just found planets — yes, two planets — orbiting Sun-like stars in a cluster 3,000 light-years from Earth.

 

These are the third and fourth star cluster planets yet discovered, but the first found “transiting” or passing across the face of their stars as seen from Earth. (The others were found through detecting gravitational wobbles in the star.)

This is no small feat for a planet to survive. In a telescope, a star cluster might look pretty benign, but up close it’s pretty darn harsh. A press release about the discovery used a lot of words like “strong radiation”, “harsh stellar winds” and “stripping planet-forming materials” in a description of what NGC 6811 would feel like.

An artist's conception of a planet in a star cluster. Credit: Michael Bachofner
An artist’s conception of a planet in a star cluster. Credit: Michael Bachofner

“Old clusters represent a stellar environment much different than the birthplace of the Sun and other planet-hosting field stars,” stated lead author Soren Meibom of the Harvard-Smithsonian Center for Astrophysics.

“We thought maybe planets couldn’t easily form and survive in the stressful environments of dense clusters, in part because for a long time we couldn’t find them.”

The find, as you would expect, comes from the prolific planet-hunting NASA Kepler spacecraft that is now battling problems with pointing in the right direction. Although the telescope is in the penalty box, there still are reams of data waiting to be analyzed and released.

The planets are known as Kepler-66b and Kepler-67b, and are both approaching the size of Neptune (which is four times the size of Earth). Their parent cluster, NGC 6811, is one billion years old. Astronomers are still puzzled as to how these little worlds survived for so long.

“Highly energetic phenomena including explosions, outflows and winds often associated with massive stars would have been common in the young cluster,” stated the journal paper in Nature.

“The degree to which the formation and evolution of planets is influenced by a such a dense and dynamically and radiatively hostile environment is not well understood, either observationally or theoretically.”

Check out the entire study in the latest edition of Nature.

Source: Harvard-Smithsonian Center for Astrophysics