Amature Astronomer

LCROSS Ready to Hit Selected Moon Crater

Posted by Esse-Jay | Posted in Cabeus A, Centaur, JPL/NASA, LCROSS, Lunar Mission, Opinions | Posted on 23:36

NASA selected a final destination for its Lunar Crater Observation and Sensing Satellite (LCROSS) after a journey of nearly 5.6 million miles (9.0 million kilometers) that included several orbits around Earth and the Moon. The mission team announced September 9 that Cabeus A will be the target crater for the LCROSS dual impacts scheduled for 7:30 a.m. EDT on October 9, 2009. The crater was selected after an extensive review as the optimal location for LCROSS' evaluation of whether water ice exists at the lunar south pole.

**This illustration shows LCROSS separation from spent Centaur rocket stage during lunar approach. NASA/Northrop Grumman **

LCROSS will search for water ice by sending its spent upper-stage Centaur rocket to impact the permanently shadowed polar crater. The satellite will fly into the plume of dust left by the impact and measure the properties before colliding with the lunar surface. The LCROSS team selected Cabeus A based on a set of conditions that include proper debris plume illumination for visibility from Earth, a high concentration of hydrogen, and mature crater features such as a flat floor, gentle slopes, and the absence of large boulders.

"The selection of Cabeus A was a result of a vigorous debate within the lunar science community that included review of the latest data from Earth-based observatories and our fellow lunar missions Kaguya, Chandrayaan-1, and the Lunar Reconnaissance Orbiter," said Anthony Colaprete, LCROSS project scientist and principal investigator at NASA's Ames Research Center in Moffett Field, California. "The team is looking forward to the impacts and the wealth of information this unique mission will produce."

A cadre of professional astronomers using many of Earth's most capable observatories is helping maximize the scientific return from the LCROSS impacts. These observatories include the Infrared Telescope Facility and Keck telescope in Hawaii; the Magdalena Ridge and Apache Ridge Observatories in New Mexico; the MMT Observatory in Arizona; the newly refurbished Hubble Space Telescope; and the Lunar Reconnaissance Orbiter, among others.

"These and several other telescopes participating in the LCROSS Observation Campaign will provide observations from different vantage points using different types of measurement techniques," said Jennifer Heldmann, lead for the LCROSS Observation Campaign at Ames. "These multiple observations will complement the LCROSS spacecraft data to help determine whether or not water ice exists in Cabeus A."

During a media briefing September 11, Daniel Andrews, LCROSS project manager at Ames, provided a mission status update indicating the spacecraft is healthy and has enough fuel to successfully accomplish all mission objectives. Andrews also announced the dedication of the LCROSS mission to the memory of legendary news anchor, Walter Cronkite, who provided coverage of NASA's missions from the beginning of America's manned space program to the age of the space shuttle.

Provided by Astronomy.com

Hubble’s New Pictures

Posted by Esse-Jay | Posted in eletromagnetic spectrum, galaxies, hubble space telescope, planets, stars | Posted on 12:43

The first snapshots from the refurbished Hubble showcase the 19-year-old telescope's new vision. Topping the list of exciting new views are colorful multi-wavelength pictures of far- flung galaxies, a densely packed star cluster, an eerie "pillar of creation," and a "butterfly" nebula.

**Butterfly emerges from stellar demise in Planetary Nebula NGC 6302. (Credit: NASA, ESA, and the Hubble SM4 ERO Team)**

With the release of these images, astronomers have declared Hubble a fully rejuvenated observatory. Sen. Barbara A. Mikulski, D-Md., unveiled the images at NASA Headquarters in Washington, D.C., on Sept. 9, 2009.

With its new imaging camera, Hubble can view galaxies, star clusters, and other objects across a wide swath of the electromagnetic spectrum, from ultraviolet to near-infrared light. A new spectrograph slices across billions of light-years to map the filamentary structure of the universe and trace the distribution of elements that are fundamental to life.The telescope's new instruments also are more sensitive to light and can observe in ways that are significantly more efficient and require less observing time than previous generations of Hubble instruments.

NASA astronauts installed the new instruments during the space shuttle servicing mission in May 2009. Besides adding the instruments, the astronauts also completed a dizzying list of other chores that included performing unprecedented repairs on two other science instruments.

**Hubble image - One among the largest ever produced with the Earth-orbiting observatory - shows gives the most detailed view so far of the entire Crab Nebula ever made. (Image credit: NASA, ESA and Jeff Hester (Arizona State University))**

Now that Hubble has reopened for business, it will tackle a whole range of observations. Looking closer to Earth, such observations will include taking a census of the population of Kuiper Belt objects residing at the fringe of our solar system, witnessing the birth of planets around other stars, and probing the composition and structure of the atmospheres of other worlds.

Peering much farther away, astronomers have ambitious plans to use Hubble to make the deepest-ever portrait of the universe in near-infrared light. The resulting picture may reveal never-before-seen infant galaxies that existed when the universe was less than 500 million years old. Hubble also is now significantly more well-equipped to probe and further characterize the behavior of dark energy, a mysterious and little-understood repulsive force that is pushing the universe apart at an ever-faster rate.

Source: JPL, ScienceDaily

NASA Approves X-ray Space Mission

Posted by Esse-Jay | Posted in black holes, galaxies, NASA, Telescope array | Posted on 12:32

NASA recently confirmed that the Nuclear Spectroscopic Telescope Array, or NuSTAR, mission will launch in August 2011. NuSTAR will carry the first high-energy X-ray focusing telescopes into orbit, providing a much deeper, clearer view of energetic phenomena such as black holes and supernova explosions than any previous instrument has provided in this region of the electromagnetic spectrum.

**Centaurus A (also known as NGC 5128) is a lenticular galaxy about 14 million light-years away in the constellation Centaurus. It is one of the closest radio galaxies to Earth**

NuSTAR is a NASA Small Explorer mission led by Caltech, managed by JPL, and implemented by an international team of scientists and engineers. Fiona Harrison, a professor of physics and astronomy at Caltech, is the team's principal investigator. The official confirmation follows two years of detailed design and reviews that have enabled NASA to determine that the NuSTAR team is ready to build the flight hardware. For more information is online at www.nustar.caltech.edu.

Source: JPL

Saturn Moon Titan and its Propane Rich Atmosphere

Posted by Esse-Jay | Posted in cassini, concept of planets, earth, european space agency, JPL/NASA, Orbits, planetary drift, saturn, Titan | Posted on 12:24

It was discovered by Dutch astronomer Christiaan Huygens in 1655, since then Saturn's most massive moon, Titan, has been known as a place of mystery and intrigue. The large, cloud-enshrouded moon is such a scientific enigma that for the past five years, it has been targeted by NASAs Cassini spacecraft with more than 60 probing flybys. One of its latest findings could be a valuable asset to future generations of space explorers hunting for materials to whip up a barbecue.

"Titan's atmosphere is extremely rich in an assortment of hydrocarbon chemicals, including propane, which we use to fill our barbecue tanks," said Cassini scientist Conor Nixon of the University of Maryland, College Park. "Titan's atmospheric inventory would fuel about 150 billion barbecue cookouts."

For those who are burger, barbecue or Titan challenged, propane is a three-carbon alkane (a chemical compound consisting of carbon and hydrogen), that is non-toxic and heavier than air. With its low boiling point of minus 43.6 degrees Fahrenheit (minus 42 degrees Centigrade), propane vaporizes as soon as it is released from its pressurized container. Here on Earth, propane is commonly used as a fuel for forklifts, flamethrowers, residential central heating, portable stoves, hot air balloons, and - of course - barbecues. On other worlds propane is an untapped resource.

This gas of many terrestrial uses was first discovered in Titan's atmosphere back in 1980 when NASA's Voyager 1 spacecraft flew past the Saturnian system. Over the years, both ground and space-based instruments have added to the research, but accurately quantifying the amount of propane on Titan has proved elusive. Then, in 2004, the Cassini spacecraft entered orbit around Saturn.

Measuring the amount of propane on Titan is important to scientists because the gas is a very complex molecule, and its signature in the infrared spectrum is close to those of several molecules scientists are hoping to discover in Titan's atmosphere.

"It was not so much that measuring propane was our endgame, but it helps enormously in our hunt for other complex molecules," said Nixon. "These include pyrimidines that are potential building blocks for biological molecules, such as the nuceleobases of our DNA." If we can detect them on Titan, that would be very significant."

Propane on Titan was measured using data from Cassini's Composite Infrared Spectrometer instrument. During multiple flybys of the moon between June 2004 and June 2008, the instrument measured infrared light from the edge of Titan's atmosphere. After a detailed analysis of the gas's characteristic 'emission bands' or signature, using computer predictions backed by the latest laboratory research into its infrared spectrum, the Composite Infrared Spectrometer team came up with an estimate of the amount of propane in Titan's atmosphere So exactly how much propane does it take to fire 150 billion cookouts?

"We estimate there are nearly 700 million barrels of propane on Titan, said Nixon. "That is enough to fill six-billion 20-pound tanks of liquefied propane gas. It sounds like a huge amount, but that would satisfy total U.S. consumption of propane for only 18 months."

Which still leaves, with regards to Saturn's biggest moon, How many hamburgers could future generations of outer-planet explorers grill using Titan's atmospheric propane?

"A dozen at a time, that's two trillion hamburgers," said Cassini's Nixon, "assuming you stop at medium-well."

Nixon is the lead author on a paper about propane on Titan to be published in an upcoming issue of Planetary and Space Science.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Cassini orbiter was designed, developed and assembled at JPL. JPL manages the mission for the Science Mission Directorate at NASA Headquarters in Washington. Cassini's Composite Infrared Spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md.

Source: http://www.nasa.gov/cassini or http://saturn.jpl.nasa.gov

Neighboring Galaxies Collided 2-3 Billion Years Ago

Posted by Esse-Jay | Posted in Andromeda, astrophysics, galaxy, milky way, Triangulum Galaxy | Posted on 23:00

An international team of astronomers, including Queen's University physicist Larry Widrow, have uncovered evidence of a nearby cosmic encounter. Their study indicates that the Andromeda and Triangulum galaxies, the two galaxies closest to our own, collided about two to three billion years ago.

**The possible orbit of the Triangulum galaxy around Andromeda. (Credit: Image courtesy of Queen's University)**

"The encounter forever changed the structure of the galaxies," says Dr. Widrow, a professor of Physics, Engineering Physics and Astronomy at Queen's. "The collision between the galaxies appears to have caused millions of stars to be ripped from the Triangulum disk to form a faint stream visible in the PAndAS data."

Dr. Widrow, along with John Dubinsky of the University of Toronto, recreated this galactic encounter using a high performance computer and theoretical modeling. Their simulations illustrate how the strong gravitational field of Andromeda could have pulled stars away from the Triangulum disk creating a stream just as the team saw.

The Pan-Andromeda Archeological Survey (PAndAS), led by Alan McConnachie of the Herzberg Institute of Astrophysics in Victoria BC, is using the Canada-France-Hawaii telescope to map the Andromeda and Triangulum galaxies. This map, the largest of its kind, will allow astronomers to test the hypothesis that galaxies grow by "cannibalizing" other galaxies. The findings from the first year of the survey are published this week in the journal Nature. Galaxies are large collections of stars, often distributed in a disk-like pattern with spiral arms. Nearly 40 years ago, astronomers learned that galaxies are embedded in extended halos of dark matter.

"Our observations now show that stars also inhabit these outer halos," says Dr. Widrow. "We believe that these stars are relics of small galaxies that were destroyed by the powerful tidal fields of a larger galaxy. Our observations also suggest that the Triangulum Galaxy is being ripped apart by Andromeda."

Andromeda, and our own galaxy the Milky Way, are the two largest members of a small cluster of galaxies known as the Local Group. Triangulum, the third largest member of the Local Group, is about one-tenth the size of Andromeda.

"Within a few billion years Triangulum will be completely destroyed by Andromeda and its stars will be dispersed throughout the Andromeda halo," says Dr. Widrow. "And a few billion years after that, Andromeda and the Milky Way will collide and merge together to form a giant elliptical galaxy."

Source: AstronomyNow

The Milky Way's Look Alike

Posted by Esse-Jay | Posted in black holes, milky way, observetory | Posted on 22:46

A new image from the European Southern Observatory (ESO) reveals an edge-on galaxy much like our own Milky Way.

**Seen edge-on, NGC 4945 appears much like our own Milky Way Galaxy. Sites of active star formation – HII regions – appear pink in this image. The field of view is 30 x 30 arcminutes; north is up and east is left. Image: ESO**

Taken with the Wide Field Imager (WFI) instrument on the 2.2 metre MPG/ESO telescope at the La Silla Observatory in Chile, the image of NGC 4945 reveals a spiral galaxy with swirling arms and a bar shaped central region resembling our home galaxy the Milky Way. But NGC 4945 has a brighter centre that likely hosts a supermassive black hole which is gorging on stellar matter and burping energy out into space.

Astronomers classify NGC 4945 as a Seyfert galaxy, after American astronomer Carl Seyfert, who first identified this family of galaxies – a subclass of active galactic nuclei – to have curious light signatures emanating from their central engines. These emissions come from gas and dust falling into a disc around the black hole, which accelerates and heats it up until it emits high energy radiation such as X-rays and ultraviolet light. Most large spiral galaxies, including the Milky Way, host a black hole in their cores, though many of these monsters are at a stage of their lives where they no longer actively feed.

NGC 4945 resides 13 million light years from Earth in the constellation of Centaurs, and can be seen in modest amateur telescopes. It appears cigar-shaped from our perspective but it is actually many times wider than it is thick, with bands of stars and glowing gas marching around its centre. With the use of special optical filters to isolate the colour of light emitted by heated gases such as hydrogen, the new image from ESO displays sharp contrasts in NGC 4945 that indicate active areas of star formation.

Source: AstronomyNow

First Close up of a White Dwarf with its Companion Star

Posted by Esse-Jay | Posted in astrophysics, earth, solar masses, star, telescope, universe, white dwarf | Posted on 16:20

The European Space Agency's (ESA) XMM-Newton orbiting X-ray telescope captured the first close-up of a white dwarf star, circling a companion star, that could explode into a particular kind of supernova in a few million years. These supernovae are used as beacons to measure cosmic distances and ultimately understand the expansion of our universe.

** Illustration of the white dwarf and its companion HD49798. If it was possible to look at the system up close, it would look something like this. Francesco Mereghetti; background image: NASA/ESA/STScI (T.M. Brown)**

Astronomers have been on the trail of this mysterious object since 1997 when they discovered that something was giving off X-rays near the bright star HD 49798. Now, thanks to XMM-Newton's superior sensitivity, the mysterious object has been tracked along its orbit. The observation has shown it to be a white dwarf, the dead heart of a star, shining X-rays into space.

Sandro Mereghetti, Italian National Institute for Astrophysics - Instituto di Astrofisica Spaziale e Fisica Cosmica (INAF-IASF) Italy, and collaborators also discovered that this is no ordinary white dwarf. They measured its mass and found it to be more than twice what they were expecting. Most white dwarfs pack 0.6 solar masses into an object the size of Earth. This particular white dwarf contains at least double that mass but has a diameter just half that of Earth. It also rotates once every 13 seconds, the fastest of any known white dwarf.

The mass determination is reliable because the XMM-Newton tracking data allowed the astronomers to use the most robust method for 'weighing' a star, one that uses the gravitational physics devised by Isaac Newton in the 17th century. Most likely, the white dwarf has grown to its unusual mass by stealing gas from its companion star, a process known as accretion. At 1.3 solar masses, the white dwarf is now close to a dangerous limit.

When it grows larger than 1.4 solar masses, a white dwarf is thought either to explode or collapse to form an even more compact object called a neutron star. The explosion of a white dwarf is the leading explanation for type Ia supernovae, bright events that are used as standard beacons by astronomers to measure the expansion of the universe. Until now, astronomers have not been able to find an accreting white dwarf in a binary system where the mass could be determined so accurately.

"This is the Rosetta stone of white dwarfs in binary systems," said Mereghetti. "Our precise determination of the masses of the two stars is crucial. We can now study it further and try to reconstruct its past so that we can calculate its future."

That future is a spectacular one. The star is likely to explode in a few million years. Although it is far enough to pose no danger to Earth, it is close enough to become an extraordinarily spectacular celestial sight. Calculations suggest that it will blaze initially with the intensity of the full Moon and be so bright that it will be seen in the daytime sky with the naked eye.
Source: ESA, Noordwijk, The Netherlands

Kepler’s Moon Hunt

Posted by Esse-Jay | Posted in concept of planets, earth mass, exomoons, galaxy, jupiter like worlds, kepler, moon, saturn, stars, sun | Posted on 16:16

Since the launch of the NASA Kepler Mission earlier this year, astronomers have been keenly awaiting the first detection of an Earth-like planet around another star. Now, in an echo of science fiction movies a team of scientists led by Dr David Kipping of University College London thinks that they may even find habitable 'exomoons,' too.

**Artist's impression of a hypothetical exomoon in orbit around a Saturn-like planet in another planetary system. (Credit: Dan Durda)**

Kepler's primary mission is to monitor thousands of stars looking for characteristic dips in their brightness as orbiting planets pass in front of them in so-called 'transit' events. The orbiting observatory should be able to time these transits to an extremely high accuracy.
Dr Kipping has already devised a method for detecting exomoons but no-one was sure whether it could really be used with current technology. He and his team have now modelled the properties of the instruments on Kepler, simulating the expected signal strength that a habitable moon would generate. An exomoon's gravity tugs on the planet it orbits, making the planet wobble during its orbit around its host star. The resulting changes in the position and velocity of the planet should be detectable by Kepler through accurate timing of the transits.

The scientists considered a wide range of possible planetary systems and found that a fluffy Saturn-like planet (the ringed world is extremely low in mass for its size) gives the best possible chance for detecting a moon, rather than a denser Jupiter-like world. This is because planets like Saturn are large – blocking out a lot of light as they pass in front of their star – but very light, meaning they will wobble much more than a heavy planet.
If the Saturn-like planet is at the right distance from its star, then the temperature will allow liquid water to be stable on any sufficiently large moons in orbit around it and these could then be habitable. The team found that habitable exomoons down to 0.2 times the mass of the Earth are readily detectable with Kepler. Potentially the observatory could look for Earth-mass habitable moons around 25,000 stars up to 500 light-years away from the Sun. In the whole sky, there should be millions of stars which could be surveyed for habitable exomoons with present technology.

Whether or not such bodies are common in the Galaxy is unknown but astronomers now have the tools and the methodology to find out. Dr Kipping says, "For the first time, we have demonstrated that potentially habitable moons up to hundreds of light years away may be detected with current instrumentation"

'As we ran the simulations, even we were surprised that moons as small as one-fifth of the Earth's mass could be spotted. 'It seems probable that many thousands, possibly millions, of habitable exomoons exist in the Galaxy and now we can start to look for them."

Source: Kipping D. M., Fossey S. J., Campanella G. On the detectability of habitable moons with Kepler-class photometry.

New Images from Mars

Posted by Esse-Jay | Posted in HiRISE, JPL/NASA, mars, mission, observations | Posted on 16:05

Thousands of newly released images from more than 1,500 telescopic observations by NASA's Mars Reconnaissance Orbiter show a wide range of gullies, dunes, craters, geological layering and other features on the Red Planet.

The High Resolution Imaging Science Experiment (HiRISE) camera on the orbiter recorded these images from the month of April through early August of this year. The camera team at the University of Arizona, Tucson, releases several featured images each week and periodically releases much larger sets of new images, such as the batch just posted.

**This image from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter shows gullies near the edge of Hale crater on southern Mars. (Credit: NASA/JPL-Caltech/University of Arizona)**

Each full image from HiRISE covers a strip of Martian ground 6 kilometers (3.7 miles) wide, about two to four times that long, showing details as small as 1 meter, or yard, across.
The Mars Reconnaissance Orbiter has been studying Mars with an advanced set of instruments since 2006. It has returned more data about the planet than all other past and current missions to Mars combined. For more information about the mission, visit: http://www.nasa.gov/mro.

The Mars Reconnaissance Orbiter is managed by the Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Science Mission Directorate, Washington. JPL is a division of the California Institute of Technology, also in Pasadena. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace & Technologies Corp., Boulder, Colo.

Source: NASA/Jet Propulsion Laboratory.

New Galaxy with Most Distant Supermassive Black Hole

Posted by Esse-Jay | Posted in black holes, distant universe, earth, galaxy, milky way | Posted on 15:58

University of Hawaii astronomer Tomotsugu Goto and colleagues have discovered a giant galaxy surrounding the most distant black hole ever found. The galaxy, which is 12.8 billion light-years from Earth, is as large as the Milky Way galaxy and harbors a supermassive black hole that contains at least a billion times as much matter as does our Sun.

** False-color image of the QSO (CFHQSJ2329-301), the most distant black hole currently known. In addition to the bright central black hole (white), the image shows the surrounding host galaxy (red). Tomotsugu Goto, University of Hawaii**

"It is surprising that such a giant galaxy existed when the universe was only one-sixteenth of its present age, and that it hosted a black hole one billion times more massive than the Sun," Goto said. "The galaxy and black hole must have formed very rapidly in the early universe."

Knowledge of the host galaxies of supermassive black holes is important to understand the long-standing mystery of how galaxies and black holes have evolved together. Until now, studying host galaxies in the distant universe has been extremely difficult because the blinding bright light from the vicinity of the black hole makes it more difficult to see the already faint light from the host galaxy.

Unlike smaller black holes, which form when a large star dies, the origin of supermassive black holes remains an unsolved problem. A currently favored model requires several intermediate black holes to merge. The host galaxy discovered in this work provides a reservoir of such intermediate black holes. After forming, supermassive black holes often continue to grow because their gravity draws in matter from surrounding objects. The energy released in this process accounts for the bright light that these black holes produce.
To see the supermassive black hole, the team of scientists used new red-sensitive CCDs installed in the Suprime-Cam camera on the Subaru telescope on Mauna Kea. Satoshi Miyazaki of the National Astronomy Observatory of Japan (NAOJ) is lead investigator for the creation of the new CCDs and a collaborator on this project. "The improved sensitivity of the new CCDs has brought an exciting discovery as its very first result," Miyazaki said

A careful analysis of the colors revealed that 40 percent of light around 9100 angstroms is from the host galaxy itself and 60 percent is from the surrounding ionized nebulae illuminated by the black hole.

"We have witnessed a supermassive black hole and its host galaxy forming together," said Yousuke Utsumi from the Graduate University for Advanced Studies/NAOJ and a member of the project team. "This discovery has opened a new window for investigating galaxy-black hole co-evolution at the dawn of the universe."

Source: Univ. of Hawaii at Manoa's Institute