- Laser 'Ruler' Holds Promise for Hunting Exoplanets
- A Dim Star Passed Near Our Solar System 70,000 Years Ago, Astronomers Reveal
- South Korea Unveils Its Moon Rover
- Stars Akin to the Sun Also Explode When They Die
- Dawn Spacecraft Captures the Best Images of Ceres So Far
- Russian Soyuz-U Rocket Sends Cargo Spacecraft to Space Station
- Swiss Space Systems to Build a Spaceport in Croatia
- Slovakia Becomes Ninth ESA European Cooperating State
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Posted: 18 Feb 2015 01:40 AM PST
The hunt for Earth-like planets around distant stars could soon become a lot easier thanks to a technique developed by researchers in Germany. In a paper published today, 18 February, in the Institute of Physics and German Physical Society's New Journal of Physics, the team of researchers have successfully demonstrated how a solar telescope can be combined with a piece of technology that has already taken the physics world by storm--the laser frequency comb (LFC). It is expected the technique will allow a spectral analysis of distant stars with unprecedented accuracy, as well as advance research in other areas of astrophysics, such as detailed observations of the Sun and the measurement of the accelerating universe by observing distant quasars.
The LFC is a tool for measuring the colour--or frequency--of light, and has been responsible for generating some of the most precise measurements ever made. An LFC is created by a laser that emits continuous pulses of light, containing millions of different colours, often spanning almost the entire visible spectrum. When the different colours are separated based on their individual frequencies--the speed with which that particular light wave oscillates--they form a "comb-like" graph with finely spaced lines, or "teeth", representing the individual frequencies. This "comb" can then be used as a "ruler" to precisely measure the frequency of light from a wide range of sources, such as lasers, atoms or stars. In their study, the researchers, from the Max Planck Institute of Quantum Optics, the Kiepenheuer Institute for Solar Physics and the University Observatory Munich, performed an analysis on the Sun by combining sunlight from the Kiepenheuer Institute's solar telescope in Tenerife with the light of an LFC. Both sources of light were injected into a single optical fibre which then delivered the light to a spectrograph for analysis. Lead author of the study Rafael Probst, of the Max Planck Institute of Quantum Optics, said: "An important aspect of our work is that we use a single-mode fibre, which takes advantage of the wave nature of light to enable a very clean and stable beam at its output. This type of fibre is quite common in telecom and laser applications, but its applications in astronomy are still largely unexplored. The LFC at the solar telescope on Tenerife is the first installation for astronomical use based on single-mode fibres. "Our results show that if the LFC light and the sunlight are simultaneously fed through the same single-mode fibre, the obtained calibration precision improves by about a factor of 100 over a temporally separated fibre transmission. "We then obtain a calibration precision that keeps up with the best calibration precision ever obtained on an astrophysical spectrograph, and we even see considerable potential for further improvement." Indeed, the researchers envisage using the new technique to not only study the star at the centre of our solar system, but stars much further away from us, particularly to find Earth-like planets that may be orbiting around them. When a planet orbits a star, the star does not stay completely stationary, but instead moves in a very small circle or ellipse. When viewed from a distance, these slight changes in speed cause the star's light spectrum to change--a process known as a Doppler shift. If the star is moving towards the observer, then its spectrum would appear slightly shifted towards the blue end of the spectrum; if it is moving away, it will be shifted towards the red end of the spectrum. The researchers believe that an LFC would allow them to measure these Doppler shifts much more accurately and therefore increase the chances of spotting Earth-sized, habitable planets. With conventional calibration techniques, the researchers state that they could measure a change in speed of roughly 1 m/s over large time periods; an LFC could enable measurements with an accuracy of 1 cm/s. "In astronomy, LFCs are still a novelty and non-standard equipment at observatories. This however, is about to change, and LFC-assisted spectroscopy is envisioned to have a flourishing future in astronomy. Our present work shows how future astronomical LFCs could be utilized," Probst concludes. The work is a collaboration comprising the Max Planck Institute of Quantum Optics in Garching, Germany, the Kiepenheuer Institute for Solar Physics in Freiburg, Germany, and the University Observatory Munich in Munich, Germany. Among the contributors are guest scientists from the National Astronomical Observatories of China in Beijing. Menlo Systems GmbH in Martinsried, Germany, is part of the collaboration as an industrial partner.
From Wednesday 18 February, this paper can be downloaded from http://iopscience.iop.org/
Credit: eurekalert.org  | ||
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Posted: 17 Feb 2015 02:04 PM PST
A group of astronomers from the US, Europe, Chile and South Africa have determined that 70,000 years ago a recently discovered dim star is likely to have passed through the solar system’s distant cloud of comets, the Oort Cloud. No other star is known to have ever approached our solar system this close – five times closer than the current closest star, Proxima Centauri. In a paper published in Astrophysical Journal Letters, lead author Eric Mamajek from the University of Rochester and his collaborators analyzed the velocity and trajectory of a low-mass star system nicknamed “Scholz’s star.” The star’s trajectory suggests that 70,000 years ago it passed roughly 52,000 astronomical units away (or about 0.8 light years, which equals 8 trillion kilometers, or 5 trillion miles). This is astronomically close; our closest neighbor star Proxima Centauri is 4.2 light years distant. In fact, the astronomers explain in the paper that they are 98% certain that it went through what is known as the “outer Oort Cloud” – a region at the edge of the solar system filled with trillions of comets a mile or more across that are thought to give rise to long-period comets orbiting the Sun after their orbits are perturbed.
The star originally caught Mamajek’s attention during a discussion with co-author Valentin D. Ivanov, from the European Southern Observatory. Scholz’s star had an unusual mix of characteristics: despite being fairly close (“only” 20 light years away), it showed very slow tangential motion, that is, motion across the sky. The radial velocity measurements taken by Ivanov and collaborators, however, showed the star moving almost directly away from the solar system at considerable speed.
“Most stars this nearby show much larger tangential motion,” says Mamajek, associate professor of physics and astronomy at the University of Rochester. “The small tangential motion and proximity initially indicated that the star was most likely either moving towards a future close encounter with the solar system, or it had ‘recently’ come close to the solar system and was moving away. Sure enough, the radial velocity measurements were consistent with it running away from the Sun’s vicinity – and we realized it must have had a close flyby in the past.”
To work out its trajectory the astronomers needed both pieces of data, the tangential velocity and the radial velocity. Ivanov and collaborators had characterized the recently discovered star through measuring its spectrum and radial velocity via Doppler shift. These measurements were carried out using spectrographs on large telescopes in both South Africa and Chile: the Southern African Large Telescope (SALT) and the Magellan telescope at Las Campanas Observatory, respectively.
Once the researchers pieced together all the information they figured out that Scholz’s star was moving away from our solar system and traced it back in time to its position 70,000 years ago, when their models indicated it came closest to our Sun.
Until now, the top candidate for the closest flyby of a star to the solar system was the so-called “rogue star” HIP 85605, which was predicted to come close to our solar system in 240,000 to 470,000 years from now. However, Mamajek and his collaborators have also demonstrated that the original distance to HIP 85605 was likely underestimated by a factor of ten. At its more likely distance – about 200 light years – HIP 85605’s newly calculated trajectory would not bring it within the Oort Cloud.
Mamajek worked with former University of Rochester undergraduate Scott Barenfeld (now a graduate student at Caltech) to simulate 10,000 orbits for the star, taking into account the star’s position, distance, and velocity, the Milky Way galaxy’s gravitational field, and the statistical uncertainties in all of these measurements. Of those 10,000 simulations, 98% of the simulations showed the star passing through the outer Oort cloud, but fortunately only one of the simulations brought the star within the inner Oort cloud, which could trigger so-called “comet showers.”
While the close flyby of Scholz’s star likely had little impact on the Oort Cloud, Mamajek points out that “other dynamically important Oort Cloud perturbers may be lurking among nearby stars.” The recently launched European Space Agency Gaia satellite is expected to map out the distances and measure the velocities of a billion stars. With the Gaia data, astronomers will be able to tell which other stars may have had a close encounter with us in the past or will in the distant future.
Currently, Scholz’s star is a small, dim red dwarf in the constellation of Monoceros, about 20 light years away. However, at the closest point in its flyby of the solar system, Scholz’s star would have been a 10th magnitude star – about 50 times fainter than can normally be seen with the naked eye at night. It is magnetically active, however, which can cause stars to “flare” and briefly become thousands of times brighter. So it is possible that Scholz’s star may have been visible to the naked eye by our ancestors 70,000 years ago for minutes or hours at a time during rare flaring events.
The star is part of a binary star system: a low-mass red dwarf star (with mass about 8% that of the Sun) and a “brown dwarf” companion (with mass about 6% that of the Sun). Brown dwarfs are considered “failed stars;” their masses are too low to fuse hydrogen in their cores like a “star,” but they are still much more massive than gas giant planets like Jupiter.
The formal designation of the star is “WISE J072003.20-084651.2,” however it has been nicknamed “Scholz’s star” to honor its discoverer – astronomer Ralf-Dieter Scholz of the Leibniz-Institut für Astrophysik Potsdam (AIP) in Germany – who first reported the discovery of the dim nearby star in late 2013. The “WISE” part of the designation refers to NASA’s Wide-field Infrared Survey Explorer (WISE) mission, which mapped the entire sky in infrared light in 2010 and 2011, and the “J-number” part of the designation refers to the star’s celestial coordinates.
Credit: rochester.edu
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Posted: 17 Feb 2015 01:36 PM PST
On Feb. 16, a research team led by Dr. Gang Sung-cheol at the Korea Institute of Science and Technology (KIST) unveiled a prototype of a lunar rover, which is planned to be on the moon roving by 2020. What is notable is that a lunar rover has been developed with local technology. The machine is able to carry out its mission in extreme conditions. Since it is designed to control heat easily, it can operate in a huge daily temperature range from 170 degrees below zero to 130 degrees above zero. It can perform its tasks on rough terrain as well.
The most notable characteristic of the newly-developed KIST rover is that it is composed of two bodies. The passive double tracks of ROBHAZ, a robot designed to perform dangerous work, were used. The passive double tracks with two separate bodies connected with chains help the robot operate in a smooth manner, while maintaining its contact with the ground even in rugged terrain. The rover can move steadily up 30 degree slopes and even get over a 5-cm-tall fence. It can move up to 4 cm per second.
The size of the rover that will be included in a lunar probe measuring 50 x 70 x 25cm and weighing 20kg. Considering that cameras and equipment for communications and analysis that will be featured in the lunar probe weigh 7kg in total, the rover was designed to weigh 13kg.
To minimize the weight of the rover, 6 wheels were made of duralumin, an aluminum alloy used to make aircraft. Carbon fiber–reinforced plastic was also used to make the body. Two A4-sized solar panels in the front of the body will enable the machine to operate as much as 340 hours.
The research team has also developed a film-coating technique and a technology to design and make bearings for the rover using solid lubricants, in consideration of a moon environment with a high degree of vacuum. In a vacuum, it is impossible to use bearings containing liquid lubricant. Thus, solid lubricant is considered to be very important for the development of space systems. If Korea sends the rover to the moon in 2020, it will be the fourth country after Russia, the U.S., and China to land something on the moon.
Credit: businesskorea.co.kr
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Posted: 17 Feb 2015 01:10 PM PST
The birth of planetary nebulae, resulting from the death of low and intermediate mass stars, is usually thought of as a slow process, in contrast with the intense supernovae that massive stars produce. But a recent study led by researchers at the Institute of Astrophysics of Andalusia (IAA-CSIC), Spain in collaboration with the Center for Astrobiology (CAB, CSIC/INTA) has revealed the fact that explosive phenomena also intervene in the formation of planetary nebulae. "In a few thousand million years, the sun will exhaust its nuclear fuel, expand into a red giant and eject a major part of its mass. The final result will be a white dwarf surrounded by a glowing planetary nebula. Even though every star with a mass below ten solar masses goes through this short but important final transition, many details of the process still evade us”, says José Francisco Gómez, IAA-CSIC researcher in charge of the project.
The study of IRAS 15103-5754, part of a group of sixteen objects known as ‘water fountains’, has yielded important clues concerning this final stage. ‘Water fountains’ are mature stars in a state of transition from red giants to planetary nebulae which display jets of ejected material that can be detected from intense radiation produced by water vapor molecules (water maser emission).
IRAS 15103-5754 stands out within the small group under study because it has been observed that the velocity of the material inside the jet increases in proportion to the distance from the central star. "Water molecules are generally destroyed soon after the planetary nebula is formed, and in the rare cases where a maser emission has been detected, the velocity has always been very low”, says Luis F. Miranda (IAA-CSIC, University of Vigo). “In IRAS 15103-5754 we are seeing for the first time a water maser emission at velocities of hundreds of kilometers per second. We are witnessing the transition of a star into a planetary nebula in real time".
“The high velocity can only be explained by the occurrence of an explosion”. Our results show that, contrary to the most widespread theories, when a star turns into a planetary nebula an enormous explosion is produced – short-lived but highly energetic – which will determine the evolution of the star in its last phases of life”, says José Francisco Gómez (IAA-CSIC).
This study has established the importance of ‘water fountains’ in understanding how the symmetry of stars is broken in the final stages of their lives, and thus to shed light on the outstanding variety of planetary nebulae that we encounter.
Credit: iaa.es
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Posted: 17 Feb 2015 12:25 PM PST
Craters and mysterious bright spots are beginning to pop out in the latest images of Ceres from NASA's Dawn spacecraft. These images, taken Feb. 12 at a distance of 52,000 miles (83,000 kilometers) from the dwarf planet, pose intriguing questions for the science team to explore as the spacecraft nears its destination. "As we slowly approach the stage, our eyes transfixed on Ceres and her planetary dance, we find she has beguiled us but left us none the wiser," said Chris Russell, principal investigator of the Dawn mission, based at UCLA. "We expected to be surprised; we did not expect to be this puzzled."
Dawn will be gently captured into orbit around Ceres on March 6. As the spacecraft delivers better images and other data, the science team will be investigating the nature and composition of the dwarf planet, including the nature of the craters and bright spots that are coming into focus. The latest images, which have a resolution of 4.9 miles (7.8 kilometers) per pixel, represent the sharpest views of Ceres to date.
“In its lowest altitude orbit, Dawn's images will have a resolution of better than 40 meters per pixel. So we will be able to see exquisite detail compared to what we have now,” Marc Rayman, Dawn Mission Director and Chief Engineer at NASA’s Jet Propulsion Laboratory, told astrowatch.net.
The spacecraft explored the giant asteroid Vesta for 14 months during 2011 and 2012. Scientists gained numerous insights about the geological history of this body and saw its cratered surface in fine detail. By comparing Vesta and Ceres, they will develop a better understanding of the formation of the solar system.
Dawn's mission to Vesta and Ceres is managed by the Jet Propulsion Laboratory for NASA's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK, Inc., of Dulles, Virginia, designed and built the spacecraft. JPL is managed for NASA by the California Institute of Technology in Pasadena.
The framing cameras were provided by the Max Planck Institute for Solar System Research, Gottingen, Germany, with significant contributions by the German Aerospace Center (DLR) Institute of Planetary Research, Berlin, and in coordination with the Institute of Computer and Communication Network Engineering, Braunschweig. The visible and infrared mapping spectrometer was provided by the Italian Space Agency and the Italian National Institute for Astrophysics, built by Selex ES, and is managed and operated by the Italian Institute for Space Astrophysics and Planetology, Rome. The gamma ray and neutron detector was built by Los Alamos National Laboratory, New Mexico, and is operated by the Planetary Science Institute, Tucson, Arizona.
Credit: NASA
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Posted: 17 Feb 2015 11:35 AM PST
The Soyuz-U carrier rocket with Russia’s Progress M-26M cargo spacecraft was blasted off on Tuesday at 6:00 a.m. EST (5:00 p.m. local time) from the Baikonur cosmodrome in Kazakhstan to the International Space Station (ISS). “The Soyuz blasted off at the scheduled time…the cargo ship will deliver to the ISS fuel, oxygen, and food, including fresh apples, grapefruits, and oranges,” a Mission Control source said. Less than 10 minutes later, the capsule reached its preliminary orbit and deployed its solar arrays and navigational antennas as planned. Traveling about 257 miles above the Atlantic Ocean northeast of Puerto Rico, the unpiloted Progress cargo ship docked at 11:57 a.m. EST to the rear port of the Zvezda service module of the International Space Station.
With just 70 seconds elapsed on the mission clock, the vehicle stack was exceeding 1,100 miles (1,770 kilometers) per hour.
Two minutes and five seconds into the flight, having completed their mission, the four liquid-fueled boosters were jettisoned. They fell back to Earth, impacting the Earth far below (the region is an unpopulated section cleared of personnel).
A little less than three minutes into the flight, another component of the stack, the payload fairing, having shielded Progress M-26M through Earth’s turbulent atmosphere, is also jettisoned, left to tumble away into the black of space before burning up in Earth’s atmosphere. Three minutes elapsed time and Progress was traveling at 5,000 miles (8,047 kilometers) per hour – and accelerating. At about four minutes in the engine burn was completed marking the way to the next stage of the mission.
At just 10 seconds shy of five minutes flight time, the second stage was jettisoned. About three minutes later and Progress 58 was traveling at about 14,000 miles (22,531 kilometers) per hour. It took less than nine minutes for the Soyuz-U booster to loft the Progress M-26M vessel to orbit.
The craft is delivering three tons of food, fuel, supplies and experiment hardware to the six crew members aboard the orbital laboratory. Progress is scheduled to remain docked to the space station until August.
Earlier in the day, Russian space agency Roscosmos said that three more launches of space ships from the Progress family to the ISS will be conducted this year: on April 28, August 6 and October 22.
In October, Russia will launch the first modernized space truck Progress-MS.
The fifth and final European space truck Georges Lemaitre, developed under the Automated Transfer Vehicle (ATV) program, was undocked from the ISS on February 14.
Meanwhile, astronauts in the U.S. segment of the station are reviewing procedures for a trio of spacewalks. The first is set to begin Friday at 7:10 a.m. Spacewalkers Barry Wilmore and Terry Virts will exit the orbital lab to set the stage for a pair of new commercial crew vehicle docking ports to be installed later this year.
Outside the station on Sunday, robotics controllers on the ground maneuvered the Canadarm2 with the Dextre attached to remove and replace a faulty Remote Power Controller Module (RPCM). The RPCM provides backup commanding capability to the port Thermal Radiator Rotating Joint.
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Posted: 17 Feb 2015 10:04 AM PST
Swiss Space Systems (S3), officially inaugurated its daughter company, Swiss Space Systems Croatia, in the presence of the Ambassador of Switzerland in Croatia, as well as representatives of the national and local authorities and international guests from the aerospace sector. The company is located in Zagreb and Sladjan Zovko is its General Director. For the S3 Group, this inauguration represents a new important step in its expansion in Europe, as Croatia will play an important role in different parts of the S3 program. First activities of S3 Croatia will be the ZeroG flights, which are taking place in Croatia in the first half of 2016. In the longer term, Croatia is foreseen as an interesting location to operate. S3 Croatia also plans to build a spaceport infrastructure in Ubdina and will be involved in the development work on the upper-stage and its assembly, creating highly skilled jobs in the country. Moreover, S3 Croatia will play a role in Space Research and Education, involving the main universities and research centers from Croatia active in this field.
Swiss Space Systems (S3) is developing its activities and now counts more than 75 employees in Switzerland, Spain and the US. The engineering team, supported by their industrial and academic partners, is progressing on the Research & Development phase of a reusable, flexible, safe and affordable small satellite launching system, based on an Airbus aircraft carrying the SOAR sub-orbital shuttle on its back. The SOAR carries an expendable upper-stage, released at an altitude of 80 km to go up to 700 km and deliver the satellites in low earth orbit. After the launch it is disintegrated into the atmosphere without producing space debris. 2015 will be a crucial year for S3, with its first ZeroG flights and wind tunnel testing and a mock up flight test campaign leading to the end of its R&D phase. In Europe, S3 already counts on a strong network of industrial and institutional partners from France, Belgium, Italy and Spain. Now, this European network will be extended to Croatia with the inauguration of a daughter company in Zagreb as a first step.
The choice of expanding in Croatia is part of a strategic plan for S3, as Croatia will play an integral part in the different aspects of its project. Croatia has a lot of assets to be a future important aerospace player at the European level and Swiss Space Systems chose this country to expand their activities in Europe.
First activities of S3 Croatia will be the ZeroG flights to take place in the first half of 2016. Croatia has some interesting locations for future operations as well as satellite launches and, in the longer term, suborbital passenger flights. A project of Spaceport in Croatia based on the concept of the S3 Spaceport to be built in Switzerland is in its early stage, with possible location in Ubdina.
Croatia will play a role in the engineering of the upper-stage of S3 system. The upper-stage is currently being developed and designed by S3 in its Swiss headquarters with the help of its Russian partner RKK Energia, providing its propulsion systems. S3 Croatia will be implicated in work packages related to the development of the upper-stage, involving Croatian partners as well. The upper-stage is the only part
of S3’s launching system that is not reusable, meaning that one unit has to be built for each satellite launch. This assembly-line production of upper-stages could later be done in the spaceport facilities, which would create a significant number of high-skilled jobs. S3 will then rely on facilities in Spain for the integration and testing of the upper-stage, and for processing of its payload in a clean-room prior to the launch campaign, thanks to its Spanish partners.
In addition to these industrial activities, S3 Croatia will play a role in Space Research and Education activities, involving the main universities and research centers of the country for applied research, education as well as aerospace technology testing in the field of small satellites.
Sladjan Zovko, General Director of Swiss Space Systems Croatia outlines: “All these industrial as well as Education & Research activities are important for Croatia in order to develop its aerospace activities. The goal is to make of the new member of the European Space Agency that is Croatia a country with a strong aerospace sector and Swiss Space Systems Croatia wants to act as a catalyst in order to reach this goal. A Spaceport in Croatia will definitely bring an added value in this regard.”
“This is a win-win collaboration for Swiss Space Systems and Croatia and I look forward to the next steps. S3 always wants to develop long term partnerships and Croatia is definitely another good example as Swiss Space Systems Croatia will play an important role in main aspects of the S3 program: ZeroG, future operations, engineering work and assembly of the upper-stage as well as research & education. This is another milestone in S3 short history, with many more to come in 2015 and beyond.” stated Pascal Jaussi, founder and CEO of Swiss Space Systems Holding.
Credit: s-3.ch
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Posted: 17 Feb 2015 09:46 AM PST
Slovakia becomes the ninth country to sign the European Cooperating State Agreement with ESA. This agreement strengthens Slovakia’s relations with ESA, after the signature of the first Cooperation Agreement in April 2010. ESA’s Head of the Director General’s Cabinet, Mr Karlheinz Kreuzberg, and the Slovak Minister of Education, Science, Research and Sport, Mr Juraj Draxler, signed the agreement in Bratislava on 16 February.
The Slovak Republic has been actively involved in space physics research and in astronautics, having two cosmonauts, the Czechoslovak Vladimír Remek (who flew in space in 1978) and the Slovak citizen Ivan Bella, who spent nine days on board the Mir space station in 1999. In addition, the first Slovak satellite, called ‘skCube’, a CubeSat-type satellite dedicated to space research and technology, is currently under development.
Following a technical visit of ESA experts to Slovak organisations in May 2014, several potential projects were identified in various domains: space weather, adoption of the use of satellite data in GIS, validation of Earth observation satellite data, multipath propagation of GNSS signals, improved estimation of reliability and lifetime of electronic circuits, use of new pulp-based materials for space applications, adaptation of mechanism devices to space use and exploration of the use of Google Earth man/machine interface in space and generic IT activities.
The selection of the potential Plan for European Cooperating State (PECS) projects will start soon after the signature.
Credit: ESA
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