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When NASA announced its discovery of the TRAPPIST-1 system back in February it caused quite a stir, and with good reason. Three of its seven Earth-sized planets lay in the star's habitable zone, meaning they may harbour suitable conditions for life. But one of the major puzzles from the original research describing the system was that it seemed to be unstable. "If you simulate the system, the planets start crashing into one another in less than a million years," says Dan Tamayo, a postdoc at U of T Scarborough's Centre for Planetary Science. "This may seem like a long time, but it's really just an astronomical blink of an eye. It would be very lucky for us to discover TRAPPIST-1 right before it fell apart, so there must be a reason why it remains stable." Tamayo and his colleagues seem to have found a reason why. In research published in the journal Astrophysical Journal Letters, they describe the planets in the TRAPPIST-1 system as being in something called a "resonant chain" that can strongly stabilize the system. In resonant configurations, planets' orbital periods form ratios of whole numbers. It's a very technical principle, but a good example is how Neptune orbits the Sun three times in the amount of time it takes Pluto to orbit twice. This is a good thing for Pluto because otherwise it wouldn't exist. Since the two planets' orbits intersect, if things were random they would collide, but because of resonance, the locations of the planets relative to one another keeps repeating. "There's a rhythmic repeating pattern that ensures the system remains stable over a long period of time," says Matt Russo, a post-doc at the Canadian Institute for Theoretical Astrophysics (CITA) who has been working on creative ways to visualize the system. TRAPPIST-1 takes this principle to a whole other level with all seven planets being in a chain of resonances. To illustrate this remarkable configuration, Tamayo, Russo and colleague Andrew Santaguida created an animation in which the planets play a piano note every time they pass in front of their host star, and a drum beat every time a planet overtakes its nearest neighbour. Because the planets' periods are simple ratios of each other, their motion creates a steady repeating pattern that is similar to how we play music. Simple frequency ratios are also what makes two notes sound pleasing when played together. Speeding up the planets' orbital frequencies into the human hearing range produces an astrophysical symphony of sorts, but one that's playing out more than 40 light years away. "Most planetary systems are like bands of amateur musicians playing their parts at different speeds," says Russo. "TRAPPIST-1 is different; it's a super-group with all seven members synchronizing their parts in nearly perfect time." But even synchronized orbits don't necessarily survive very long, notes Tamayo. For technical reasons, chaos theory also requires precise orbital alignments to ensure systems remain stable. This can explain why the simulations done in the original discovery paper quickly resulted in the planets colliding with one another. "It's not that the system is doomed, it's that stable configurations are very exact," he says. "We can't measure all the orbital parameters well enough at the moment, so the simulated systems kept resulting in collisions because the setups weren't precise." In order to overcome this Tamayo and his team looked at the system not as it is today, but how it may have originally formed. When the system was being born out of a disk of gas, the planets should have migrated relative to one another, allowing the system to naturally settle into a stable resonant configuration. "This means that early on, each planet's orbit was tuned to make it harmonious with its neighbours, in the same way that instruments are tuned by a band before it begins to play," says Russo. "That's why the animation produces such beautiful music." The team tested the simulations using the supercomputing cluster at the Canadian Institute for Theoretical Astrophysics (CITA) and found that the majority they generated remained stable for as long as they could possibly run it. This was about 100 times longer than it took for the simulations in the original research paper describing TRAPPIST-1 to go berserk. "It seems somehow poetic that this special configuration that can generate such remarkable music can also be responsible for the system surviving to the present day," says Tamayo.


But one of the major puzzles from the original research describing the system was that it seemed to be unstable. "If you simulate the system, the planets start crashing into one another in less than a million years," says Dan Tamayo, a postdoc at U of T Scarborough's Centre for Planetary Science. "This may seem like a long time, but it's really just an astronomical blink of an eye. It would be very lucky for us to discover TRAPPIST-1 right before it fell apart, so there must be a reason why it remains stable." Tamayo and his colleagues seem to have found a reason why. In research published in the journal Astrophysical Journal Letters, they describe the planets in the TRAPPIST-1 system as being in something called a "resonant chain" that can strongly stabilize the system. In resonant configurations, planets' orbital periods form ratios of whole numbers. It's a very technical principle, but a good example is how Neptune orbits the Sun three times in the amount of time it takes Pluto to orbit twice. This is a good thing for Pluto because otherwise it wouldn't exist. Since the two planets' orbits intersect, if things were random they would collide, but because of resonance, the locations of the planets relative to one another keeps repeating. "There's a rhythmic repeating pattern that ensures the system remains stable over a long period of time," says Matt Russo, a post-doc at the Canadian Institute for Theoretical Astrophysics (CITA) who has been working on creative ways to visualize the system. TRAPPIST-1 takes this principle to a whole other level with all seven planets being in a chain of resonances. To illustrate this remarkable configuration, Tamayo, Russo and colleague Andrew Santaguida created an animation in which the planets play a piano note every time they pass in front of their host star, and a drum beat every time a planet overtakes its nearest neighbour. Because the planets' periods are simple ratios of each other, their motion creates a steady repeating pattern that is similar to how we play music. Simple frequency ratios are also what makes two notes sound pleasing when played together. Speeding up the planets' orbital frequencies into the human hearing range produces an astrophysical symphony of sorts, but one that's playing out more than 40 light years away. "Most planetary systems are like bands of amateur musicians playing their parts at different speeds," says Russo. "TRAPPIST-1 is different; it's a super-group with all seven members synchronizing their parts in nearly perfect time." But even synchronized orbits don't necessarily survive very long, notes Tamayo. For technical reasons, chaos theory also requires precise orbital alignments to ensure systems remain stable. This can explain why the simulations done in the original discovery paper quickly resulted in the planets colliding with one another. "It's not that the system is doomed, it's that stable configurations are very exact," he says. "We can't measure all the orbital parameters well enough at the moment, so the simulated systems kept resulting in collisions because the setups weren't precise." In order to overcome this Tamayo and his team looked at the system not as it is today, but how it may have originally formed. When the system was being born out of a disk of gas, the planets should have migrated relative to one another, allowing the system to naturally settle into a stable resonant configuration. "This means that early on, each planet's orbit was tuned to make it harmonious with its neighbours, in the same way that instruments are tuned by a band before it begins to play," says Russo. "That's why the animation produces such beautiful music." The team tested the simulations using the supercomputing cluster at the Canadian Institute for Theoretical Astrophysics (CITA) and found that the majority they generated remained stable for as long as they could possibly run it. This was about 100 times longer than it took for the simulations in the original research paper describing TRAPPIST-1 to go berserk. "It seems somehow poetic that this special configuration that can generate such remarkable music can also be responsible for the system surviving to the present day," says Tamayo.


News Article | May 10, 2017
Site: motherboard.vice.com

When scientists announced the discovery of a whopping seven Earth-scale worlds in orbit around the TRAPPIST-1 star system back in February, space nerds understandably went bonkers with delight. Located just 39 light years away—practically next door in cosmic terms—this ultracool red dwarf star and its wealth of tantalizing worlds suddenly became a prime destination for further exploration. Now, Toronto-based astrophysicists have sweetened the exoplanetary pot with their creative musical simulation of the system's unusual orbital dynamics. Matt Russo, a postdoctoral fellow at the Canadian Institute for Theoretical Astrophysics (CITA), partnered with Daniel Tamayo, a post-doc at both CITA and the University of Toronto Scarborough's Centre for Planetary Science, to translate the orbital periods of TRAPPIST-1's seven worlds into harmonious pitches. The result is this lively tune, composed by the cosmos itself, which would make a great first track on a playlist curated for any future interstellar missions to TRAPPIST-1. As visualized in the above simulation, a piano note is played every time one of the system's planets transits—or passes in front of—its host star from our perspective on Earth. The composition begins with the outermost planet, TRAPPIST-1h, and builds with the addition of each world. Drum beats are introduced at moments when the swifter inner worlds lap their slower outer neighbors. The song fades out with an accelerated version of the red dwarf's lightcurve, the star's oscillating brightness over time, based on data collected by the Kepler space telescope. Read More: Ultra-Cool Dwarf Stars May Host Planets With Ultra-Cool Life TRAPPIST-1 makes beautiful music because each planet happens to line up in a "resonant chain." Two orbits of the outermost planet have an equal period to three orbits of the sixth planet, four orbits of the fifth planet, six orbits of the fourth planet, nine orbits of the third planet, 15 orbits of the second planet, and 24 orbits of the innermost world, TRAPPIST-1b. Tamayo is the lead author of a new study in the Astrophysical Journal Letters about this utterly unique orbital jam band, and how it might relate to the system's formation, stability, and longevity. "TRAPPIST has the longest resonant chain of any planetary system that has ever been discovered," Tamayo told me over the phone. "It's exciting, tentative evidence that maybe around low-mass stars, the formation process is much more gentle and better able to make these configurations than around high-mass stars." Russo, who is a musician, scaled up the system's natural frequencies 212 million times, so that they could be heard by the human ear. For comparison, he tried this technique out on Kepler 90, a Sunlike star that also hosts seven planets, none of which are in resonance. This system failed its audition by churning out a chaotic jumble of notes. Tamayo, Russo, and fellow musician Andrew Santaguida have started a website, SYSTEM Sounds, where they plan to "try to convert as many things in space into music as possible," Russo told me. "But nothing will be nearly as easy as TRAPPIST," he said. "With any other system, it will be hard to get something as beautiful. That's what's so special about TRAPPIST." Subscribe to Science Solved It, Motherboard's new show about the greatest mysteries that were solved by science.


News Article | April 20, 2017
Site: globenewswire.com

Auctions of mortgage covered bonds for the refinancing of RD Euribor3® and FlexKort® Realkredit Danmark will hold auctions on SDRO’s for the refinancing of RD Euribor3® and FlexKort® as of 1 July 2017. The auctions will be held on Tuesday, 30 May 2017. Realkredit Danmark has chosen to open a 4-year mortgage covered bond (SDRO) without an interest rate floor to fund FlexKort® as of 1 July 2017. The bond will be used for new loan offers after refinancing. The bond will be sold on auction on 30 May 2017, where investors make their bid on the spread to CITA 6M. RD Euribor3® is refinanced into DK0004603461, an existing bond currently open for loan offers. The bond matures on 1 July 2019 and has an embedded interest rate floor. After refinancing, the same ISIN will be used for new loan offers. The auction will take place on 30 May 2017, where investors make their bid on the bond price. The terms and conditions as well as the preliminary amount of bonds to be refinanced are set out in the appendix to this announcement. The final amounts to be auctioned will be announced early May. Any additional questions should be addressed to Christian Rosenstand, Head of RD Funding, phone


News Article | April 20, 2017
Site: globenewswire.com

Auctions of mortgage covered bonds for the refinancing of RD Euribor3® and FlexKort® Realkredit Danmark will hold auctions on SDRO’s for the refinancing of RD Euribor3® and FlexKort® as of 1 July 2017. The auctions will be held on Tuesday, 30 May 2017. Realkredit Danmark has chosen to open a 4-year mortgage covered bond (SDRO) without an interest rate floor to fund FlexKort® as of 1 July 2017. The bond will be used for new loan offers after refinancing. The bond will be sold on auction on 30 May 2017, where investors make their bid on the spread to CITA 6M. RD Euribor3® is refinanced into DK0004603461, an existing bond currently open for loan offers. The bond matures on 1 July 2019 and has an embedded interest rate floor. After refinancing, the same ISIN will be used for new loan offers. The auction will take place on 30 May 2017, where investors make their bid on the bond price. The terms and conditions as well as the preliminary amount of bonds to be refinanced are set out in the appendix to this announcement. The final amounts to be auctioned will be announced early May. Any additional questions should be addressed to Christian Rosenstand, Head of RD Funding, phone


News Article | April 20, 2017
Site: globenewswire.com

Auctions of mortgage covered bonds for the refinancing of RD Euribor3® and FlexKort® Realkredit Danmark will hold auctions on SDRO’s for the refinancing of RD Euribor3® and FlexKort® as of 1 July 2017. The auctions will be held on Tuesday, 30 May 2017. Realkredit Danmark has chosen to open a 4-year mortgage covered bond (SDRO) without an interest rate floor to fund FlexKort® as of 1 July 2017. The bond will be used for new loan offers after refinancing. The bond will be sold on auction on 30 May 2017, where investors make their bid on the spread to CITA 6M. RD Euribor3® is refinanced into DK0004603461, an existing bond currently open for loan offers. The bond matures on 1 July 2019 and has an embedded interest rate floor. After refinancing, the same ISIN will be used for new loan offers. The auction will take place on 30 May 2017, where investors make their bid on the bond price. The terms and conditions as well as the preliminary amount of bonds to be refinanced are set out in the appendix to this announcement. The final amounts to be auctioned will be announced early May. Any additional questions should be addressed to Christian Rosenstand, Head of RD Funding, phone


Smeti S.,Laboratoire Of Productions Animales Et Fourrageres | Smeti S.,University of Carthage | Atti N.,Laboratoire Of Productions Animales Et Fourrageres | Mahouachi M.,ESA Kef | Munoz F.,CITA
Small Ruminant Research | Year: 2013

The aim of the present study was to determine the increase in shelf life of fresh Barbarine lamb's meat due to the effect of rosemary essential oils (RE) dietary. Thirty-two Barbarine lambs (19.9. kg body weight (BW)) were divided into 2 homogeneous groups receiving 50% dried alfalfa and 50% concentrate. Two types of concentrate were used, the Control (C) and the experimental, which corresponds to C with 0.06% of RE. At the end of the experiment (60 days), all animals were slaughtered. Lipid oxidation (TBARS) and color coordinates of longissimus dorsi (LD) of fresh lamb meat were analyzed on days 1, 3, 7 and 9.The RE incorporation has not affected the ultimate pH and cooking losses. TBARS values significantly increased for both treatments with storage time without any significant effect of regimen. At the ninth day of storage, meat of RE group tended to have higher redness (a*) and lower yellowness (b*) values (11.49 and 5.35 for RE vs. 10.30 and 5.58 for C). Lightness (L*) of meat from both treatments was in the range of acceptability (42-38) throughout the storage period. Panelists reported no significant effect of RE addition on the eating quality of lamb meat which was generally acceptable. The results showed that the dose rate of RE used in the present study did not affect lipid oxidation and had no significant effect against lamb meat discoloration across the storage period. © 2013 Elsevier B.V.


Levine R.,CITA | Gnedin N.Y.,Fermi National Accelerator Laboratory | Gnedin N.Y.,University of Chicago | Hamilton A.J.S.,University of Colorado at Boulder
Astrophysical Journal | Year: 2010

Using cosmological simulations with a dynamic range in excess of 10 7, we study the transport of gas mass and angular momentum through the circumnuclear region of a disk galaxy containing a supermassive black hole (SMBH). The simulations follow fueling over relatively quiescent phases of the galaxy's evolution (no mergers) and without feedback from active galactic nuclei (AGNs), as part of the first stage of using state-of-the-art, high-resolution cosmological simulations to model galaxy and black hole co-evolution. We present results from simulations at different redshifts (z = 6, 4, and 3) and three different black hole masses (3 × 107, 9 × 107, and 3 × 108 M ⊙; at z = 4), as well as a simulation including a prescription that approximates optically thick cooling in the densest regions. The interior gas mass throughout the circumnuclear disk shows transient and chaotic behavior as a function of time. The Fourier transform of the interior gas mass follows a power law with slope -1 throughout the region, indicating that, in the absence of the effects of galaxy mergers and AGN feedback, mass fluctuations are stochastic with no preferred timescale for accretion over the duration of each simulation (∼1-2 Myr). The angular momentum of the gas disk changes direction relative to the disk on kiloparsec scales over timescales less than 1 Myr, reflecting the chaotic and transient gas dynamics of the circumnuclear region. Infalling clumps of gas, which are driven inward as a result of the dynamical state of the circumnuclear disk, may play an important role in determining the spin evolution of an SMBH, as has been suggested in stochastic accretion scenarios. © 2010. The American Astronomical Society.


Zimmerman A.,CITA | Mark Z.,California Institute of Technology
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2016

Despite recent progress, the complete understanding of the perturbations of charged, rotating black holes as described by the Kerr-Newman metric remains an open and fundamental problem in relativity. In this study, we explore the existence of families of quasinormal modes of Kerr-Newman black holes whose decay rates limit to zero at extremality, called zero-damped modes in past studies. We review the nearly extremal and WKB approximation methods for spin-weighted scalar fields (governed by the Dudley-Finley equation) and give an accounting of the regimes where scalar zero-damped and damped modes exist. Using Leaver's continued fraction method, we verify that these approximations give accurate predictions for the frequencies in their regimes of validity. In the nonrotating limit, we argue that gravito-electromagnetic perturbations of nearly extremal Reissner-Nordström black holes have zero-damped modes in addition to the well-known spectrum of damped modes. We provide an analytic formula for the frequencies of these modes, verify their existence using a numerical search, and demonstrate the accuracy of our formula. These results, along with recent numerical studies, point to the existence of a simple universal equation for the frequencies of zero-damped gravito-electromagnetic modes of Kerr-Newman black holes, whose precise form remains an open question. © 2016 American Physical Society.


Consumers’ preferences towards peaches with Protected Designation of Origin (PDO) “Melocotón de Calanda”, in the city of Zaragoza, have been analysed in order to provide insights to design future policy to increase fruit demand and improve their marketing. The regular consumers’ preferences (those who consume PDO Calanda peaches at least once a week during its marketing season) and PDO Calanda sporadic consumers’ preferences have been compared. In total, 316 consumers were surveyed in 2008 and 212 consumers in 2009. Chi-square and U of Mann-Whitney tests were performed. Results show that regular consumers represent the major part of the market of this fruit with 2/3 of the respondents. Sporadic consumers are younger than regulars, which is worrying because future demand depends greatly on young people current behaviour. Sporadic consumers have less knowledge about peaches production techniques. New packaging is an alternative to improve the commercialization of peaches. However, this strategy could be risky because regular consumers believe that peaches taste is affected by packaging. Extending the peaches marketing season will have a good acceptability among consumers, especially among regular consumers. © 2016, Asociacion Interprofesional para el Desarrollo Agrario. All rights reserved.

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