Tag: astronomy

Hubble Discovery of Runaway Star Yields Clues to Breakup of Multiple-Star System

As British royal families fought the War of the Roses in the 1400s for control of England’s throne, a grouping of stars was waging its own contentious skirmish — a star war far away in the Orion Nebula.

The stars were battling each other in a gravitational tussle, which ended with the system breaking apart and at least three stars being ejected in different directions. The speedy, wayward stars went unnoticed for hundreds of years until, over the past few decades, two of them were spotted in infrared and radio observations, which could penetrate the thick dust in the Orion Nebula.

Three-panel hubble image shows star motion

This three-frame illustration shows how a grouping of stars can break apart, flinging the members into space. Panel 1: members of a multiple-star system orbiting each other. Panel 2: two of the stars move closer together in their orbits. Panel 3: the closely orbiting stars eventually either merge or form a tight binary. This event releases enough gravitational energy to propel all of the stars in the system outward, as shown in the third panel.

Credits: NASA, ESA, and Z. Levy (STScI)

Now NASA’s Hubble Space Telescope has helped astronomers find the final piece of the puzzle by nabbing a third runaway star. The astronomers followed the path of the newly found star back to the same location where the two previously known stars were located 540 years ago. The trio reside in a small region of young stars called the Kleinmann-Low Nebula, near the center of the vast Orion Nebula complex, located 1,300 light-years away.

“The new Hubble observations provide very strong evidence that the three stars were ejected from a multiple-star system,” said lead researcher Kevin Luhman of Penn State University in University Park, Pennsylvania. “Astronomers had previously found a few other examples of fast-moving stars that trace back to multiple-star systems, and therefore were likely ejected. But these three stars are the youngest examples of such ejected stars. They’re probably only a few hundred thousand years old. In fact, based on infrared images, the stars are still young enough to have disks of material leftover from their formation.”

All three stars are moving extremely fast on their way out of the Kleinmann-Low Nebula, up to almost 30 times the speed of most of the nebula’s stellar inhabitants. Based on computer simulations, astronomers predicted that these gravitational tugs-of-war should occur in young clusters, where newborn stars are crowded together. “But we haven’t observed many examples, especially in very young clusters,” Luhman said. “The Orion Nebula could be surrounded by additional fledging stars that were ejected from it in the past and are now streaming away into space.”

The team’s results will appear in the March 20, 2017 issue of The Astrophysical Journal Letters.

Luhman stumbled across the third speedy star, called “source x,” while he was hunting for free-floating planets in the Orion Nebula as a member of an international team led by Massimo Robberto of the Space Telescope Science Institute in Baltimore, Maryland. The team used the near-infrared vision of Hubble’s Wide Field Camera 3 to conduct the survey. During the analysis, Luhman was comparing the new infrared images taken in 2015 with infrared observations taken in 1998 by the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). He noticed that source x had changed its position considerably, relative to nearby stars over the 17 years between Hubble images, indicating the star was moving fast, about 130,000 miles per hour.

hubble nebula image with annotations and insets

The image by NASA’s Hubble Space Telescope shows a grouping of young stars, called the Trapezium Cluster (center). The box just above the Trapezium Cluster outlines the location of the three stars. A close-up of the stars is top right. The birthplace of the multi-star system is marked “initial position.” Two of the stars — labeled BN, and “I,” for source I — were discovered decades ago. Source I is embedded in thick dust and cannot be seen. The third star, “x,” for source x, was recently discovered to have moved noticeably between 1998 and 2015, as shown in the inset image at bottom right.

Credits: NASA, ESA, K. Luhman (Penn State University), and M. Robberto (STScI)

BN was discovered in infrared images in 1967, but its rapid motion wasn’t detected until 1995, when radio observations measured the star’s speed at 60,000 miles per hour. Source I is traveling roughly 22,000 miles per hour. The star had only been detected in radio observations; because it is so heavily enshrouded in dust, its visible and infrared light is largely blocked.

The three stars were most likely kicked out of their home when they engaged in a game of gravitational billiards, Luhman said. What often happens when a multiple system falls apart is that two of the member stars move close enough to each other that they merge or form a very tight binary. In either case, the event releases enough gravitational energy to propel all of the stars in the system outward. The energetic episode also produces a massive outflow of material, which is seen in the NICMOS images as fingers of matter streaming away from the location of the embedded source I star.

Future telescopes, such as the James Webb Space Telescope, will be able to observe a large swath of the Orion Nebula. By comparing images of the nebula taken by the Webb telescope with those made by Hubble years earlier, astronomers hope to identify more runaway stars from other multiple-star systems that broke apart.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

By The Space Telescope Science Institute (STScI) in Baltimore, Md.

Editor: Karl Hille

Photo Credit: NASA


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Hubble Dates Black Hole’s Last Big Meal

For the super-massive black hole at the center of our Milky Way galaxy, it’s been a long time between dinners. NASA’s Hubble Space Telescope has found that the black hole ate its last big meal about 6 million years ago, when it consumed a large clump of in-falling gas. After the meal, the engorged black hole burped out a colossal bubble of gas weighing the equivalent of millions of suns, which now billows above and below our galaxy’s center.

The immense structures, dubbed the Fermi Bubbles, were first discovered in 2010 by NASA’s Fermi Gamma-ray Space Telescope. But recent Hubble observations of the northern bubble have helped astronomers determine a more accurate age for the bubbles and how they came to be.

a galaxy with red-white-blue bubbles above and below, insets
The light of several distant quasars pierces the northern half of the Fermi Bubbles – an outflow of gas expelled by our Milky Way galaxy’s hefty black hole. Bottom left: the measurement of gas moving toward and away from Earth, indicating the material is traveling at a high velocity. Hubble also observed light from quasars that passed outside the northern bubble. Upper right: the gas in one such quasar’s light path is not moving toward or away from Earth. This gas is in the disk of the Milky Way and does not share the same characteristics as the material probed inside the bubble.
Credits: NASA, ESA, and Z. Levy (STScI)

“For the first time, we have traced the motion of cool gas throughout one of the bubbles, which allowed us to map the velocity of the gas and calculate when the bubbles formed,” said lead researcher Rongmon Bordoloi of the Massachusetts Institute of Technology in Cambridge. “What we find is that a very strong, energetic event happened 6 million to 9 million years ago. It may have been a cloud of gas flowing into the black hole, which fired off jets of matter, forming the twin lobes of hot gas seen in X-ray and gamma-ray observations. Ever since then, the black hole has just been eating snacks.”

The new study is a follow-on to previous Hubble observations that placed the age of the bubbles at 2 million years old.

A black hole is a dense, compact region of space with a gravitational field so intense that neither matter nor light can escape. The super-massive black hole at the center of our galaxy has compressed the mass of 4.5 million sun-like stars into a very small region of space.

Material that gets too close to a black hole is caught in its powerful gravity and swirls around the compact powerhouse until it eventually falls in. Some of the matter, however, gets so hot it escapes along the black hole’s spin axis, creating an outflow that extends far above and below the plane of a galaxy.

The team’s conclusions are based on observations by Hubble’s Cosmic Origins Spectrograph (COS), which analyzed ultraviolet light from 47 distant quasars. Quasars are bright cores of distant active galaxies.

Imprinted on the quasars’ light as it passes through the Milky Way bubble is information about the speed, composition, and temperature of the gas inside the expanding bubble.

The COS observations measured the temperature of the gas in the bubble at approximately 17,700 degrees Fahrenheit. Even at those sizzling temperatures, this gas is much cooler than most of the super-hot gas in the outflow, which is 18 million degrees Fahrenheit, seen in gamma rays. The cooler gas seen by COS could be interstellar gas from our galaxy’s disk that is being swept up and entrained into the super-hot outflow. COS also identified silicon and carbon as two of the elements being swept up in the gaseous cloud. These common elements are found in most galaxies and represent the fossil remnants of stellar evolution.

The cool gas is racing through the bubble at 2 million miles per hour. By mapping the motion of the gas throughout the structure, the astronomers estimated that the minimum mass of the entrained cool gas in both bubbles is equivalent to 2 million suns. The edge of the northern bubble extends 23,000 light-years above the galaxy.

“We have traced the outflows of other galaxies, but we have never been able to actually map the motion of the gas,” Bordoloi said. “The only reason we could do it here is because we are inside the Milky Way. This vantage point gives us a front-row seat to map out the kinematic structure of the Milky Way outflow.”

The new COS observations build and expand on the findings of a 2015 Hubble study by the same team, in which astronomers analyzed the light from one quasar that pierced the base of the bubble.

“The Hubble data open a whole new window on the Fermi Bubbles,” said study co-author Andrew Fox of the Space Telescope Science Institute in Baltimore, Maryland. “Before, we knew how big they were and how much radiation they emitted; now we know how fast they are moving and which chemical elements they contain. That’s an important step forward.”

The Hubble study also provides an independent verification of the bubbles and their origin, as detected by X-ray and gamma-ray observations.

“This observation would be almost impossible to do from the ground because you need ultraviolet spectroscopy to detect the fingerprints of these elements, which can only be done from space,” Bordoloi said. “Only with COS do you have the wavelength coverage, the sensitivity, and the spectral resolution coverage to make this observation.”

The Hubble results appeared in the January 10, 2017, edition of The Astrophysical Journal.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

For the related feature, Hubble Discovers Milky Way Core Drives Wind at 2 Million Miles per hour:
https://www.nasa.gov/content/goddard/hubble-discovers-that-milky-way-core-drives-wind-at-2-million-miles-per-hour

For images and more information about the Fermi Bubbles and Hubble, visit:
http://www.nasa.gov/hubble
http://hubblesite.org/news_release/news/2017-10

Felicia Chou
NASA Headquarters, Washington, D.C.
felicia.chou@nasa.gov
202-358-0257

Donna Weaver / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4493 / 410-338-4514
dweaver@stsci.edu / villard@stsci.edu

Rongmon Bordoloi
Massachusetts Institute of Technology, Cambridge, Massachusetts
617-252-1736
bordoloi@mit.edu

Editor: Karl Hille

Photo Credit: NASA

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The Dawn of a New Era for Supernova 1987a

Three decades ago, astronomers spotted one of the brightest exploding stars in more than 400 years. The titanic supernova, called Supernova 1987A (SN 1987A), blazed with the power of 100 million suns for several months following its discovery on Feb. 23, 1987.

Since that first sighting, SN 1987A has continued to fascinate astronomers with its spectacular light show. Located in the nearby Large Magellanic Cloud, it is the nearest supernova explosion observed in hundreds of years and the best opportunity yet for astronomers to study the phases before, during, and after the death of a star.

The video begins with a nighttime view of the Small and Large Magellanic clouds, satellite galaxies of our Milky Way. It then zooms into a rich star-birth region in the Large Magellanic Cloud. Nestled between mountains of red-colored gas is the odd-looking structure of Supernova 1987A, the remnant of an exploded star that was first observed in February 1987. The site of the supernova is surrounded by a ring of material that is illuminated by a wave of energy from the outburst. Two faint outer rings are also visible. All three rings existed before the explosion as fossil relics of the doomed star’s activity in its final days.
Credits: NASA, ESA, and G. Bacon (STScI)

To commemorate the 30th anniversary of SN 1987A, new images, time-lapse movies, a data-based animation based on work led by Salvatore Orlando at INAF-Osservatorio Astronomico di Palermo, Italy, and a three-dimensional model are being released. By combining data from NASA’s Hubble Space Telescope and Chandra X-ray Observatory, as well as the international Atacama Large Millimeter/submillimeter Array (ALMA), astronomers — and the public — can explore SN 1987A like never before.

red nebula and stars
This Hubble Space Telescope image shows Supernova 1987A within the Large Magellanic Cloud, a neighboring galaxy to our Milky Way.
Credits: NASA, ESA, R. Kirshner (Harvard-Smithsonian Center for Astrophysics and Gordon and Betty Moore Foundation), and M. Mutchler and R. Avila (STScI)
This time-lapse video sequence of Hubble Space Telescope images reveals dramatic changes in a ring of material around the exploded star Supernova 1987A. The images, taken from 1994 to 2016, show the effects of a shock wave from the supernova blast smashing into the ring. The ring begins to brighten as the shock wave hits it. The ring is about one light-year across.
Credits: NASA, ESA, and R. Kirshner (Harvard-Smithsonian Center for Astrophysics and Gordon and Betty Moore Foundation), and P. Challis (Harvard-Smithsonian Center for Astrophysics)
Hubble has repeatedly observed SN 1987A since 1990, accumulating hundreds of images, and Chandra began observing SN 1987A shortly after its deployment in 1999. ALMA, a powerful array of 66 antennas, has been gathering high-resolution millimeter and submillimeter data on SN 1987A since its inception.

“The 30 years’ worth of observations of SN 1987A are important because they provide insight into the last stages of stellar evolution,” said Robert Kirshner of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and the Gordon and Betty Moore Foundation in Palo Alto, California.

The latest data from these powerful telescopes indicate that SN 1987A has passed an important threshold. The supernova shock wave is moving beyond the dense ring of gas produced late in the life of the pre-supernova star when a fast outflow or wind from the star collided with a slower wind generated in an earlier red giant phase of the star’s evolution. What lies beyond the ring is poorly known at present, and depends on the details of the evolution of the star when it was a red giant.

“The details of this transition will give astronomers a better understanding of the life of the doomed star, and how it ended,” said Kari Frank of Penn State University who led the latest Chandra study of SN 1987A.

Supernovas such as SN 1987A can stir up the surrounding gas and trigger the formation of new stars and planets. The gas from which these stars and planets form will be enriched with elements such as carbon, nitrogen, oxygen and iron, which are the basic components of all known life. These elements are forged inside the pre-supernova star and during the supernova explosion itself, and then dispersed into their host galaxy by expanding supernova remnants. Continued studies of SN 1987A should give a unique insight into the early stages of this dispersal.

Some highlights from studies involving these telescopes include:

Hubble studies have revealed that the dense ring of gas around the supernova is glowing in an optical light, and has a diameter of about a light-year. The ring was there at least 20,000 years before the star exploded. A flash of ultraviolet light from the explosion energized the gas in the ring, making it glow for decades.

The central structure visible inside the ring in the Hubble image has now grown to roughly half a light-year across. Most noticeable are two blobs of debris in the center of the supernova remnant racing away from each other at roughly 20 million miles an hour.

From 1999 until 2013, Chandra data showed an expanding ring of X-ray emission that had been steadily getting brighter. The blast wave from the original explosion has been bursting through and heating the ring of gas surrounding the supernova, producing X-ray emission.

In the past few years, the ring has stopped getting brighter in X-rays. From about February 2013 until the last Chandra observation analyzed in September 2015 the total amount of low-energy X-rays has remained constant. Also, the bottom left part of the ring has started to fade. These changes provide evidence that the explosion’s blast wave has moved beyond the ring into a region with less dense gas. This represents the end of an era for SN 1987A.

Beginning in 2012, astronomers used ALMA to observe the glowing remains of the supernova, studying how the remnant is actually forging vast amounts of new dust from the new elements created in the progenitor star. A portion of this dust will make its way into interstellar space and may become the building blocks of future stars and planets in another system.

These observations also suggest that dust in the early universe likely formed from similar supernova explosions.

Astronomers also are still looking for evidence of a black hole or a neutron star left behind by the blast. They observed a flash of neutrinos from the star just as it erupted. This detection makes astronomers quite certain a compact object formed as the center of the star collapsed — either a neutron star or a black hole — but no telescope has uncovered any evidence for one yet.

These latest visuals were made possible by combining several sources of information including simulations by Salvatore Orlando and collaborators that appear in this paper: https://arxiv.org/abs/1508.02275. The Chandra study by Frank et al. can be found online at http://lanl.arxiv.org/abs/1608.02160. Recent ALMA results on SN 87A are available at https://arxiv.org/abs/1312.4086.

The Chandra program is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington.

ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), NSC and ASIAA (Taiwan), and KASI (Republic of South Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ.

For visuals and more information about SN 1987A, visit:

http://hubblesite.org/news_release/news/2017-08

http://www.nasa.gov/hubble

http://www.nasa.gov/chandra

Donna Weaver / Ray Villard
Space Telescope Science Institute, Baltimore, Md.
dweaver@stsci.edu / villard@stsci.edu
410-338-4493 / 410-338-4514

Megan Watzke
Chandra X-ray Center, Cambridge, Mass.
mwatzke@cfa.harvard.edu
617-496-7998

Rob Gutro
NASA’s Goddard Space Flight Center, Greenbelt, Md.
robert.j.gutro@nasa.gov
301-286-4044

Editor: Karl Hille

Photo Credit: NASA

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Newly discovered planets could have water on their surfaces

An international team of astronomers has found a system of seven potentially habitable planets orbiting a star 39 light years away three of which could have water on their surfaces raising the possibility they could host life. Using ground and space telescopes, the team identified the planets as they passed in front of the ultracool dwarf star known as TRAPPIST-1. The star is around eight per cent of the mass of the Sun and is no bigger than Jupiter.

The team has been using the TRAPPIST–South telescope at the European Space Observatory’s (ESO) La Silla Observatory, the Very Large Telescope (VLT) at Paranal, the NASA Spitzer Space Telescope as well as two other telescopes supported by the UK’s STFC, the William Herschel Telescope and the Liverpool Telescope. All the planets, labelled TRAPPIST-1b, c, d, e, f, g and h in order of increasing distance from their parent star, have sizes comparable to Earth.

The astronomers identified the planets thanks to periodic drops in the brightness of the central star. As the planets passed in front of the star, they cast a shadow, events known as transits, from which the team could measure the planet’s orbital periods and calculate their sizes and masses. They found that the inner six planets were comparable in size, mass and temperature to the Earth raising the possibility that they host liquid water on their surface.

With just 8% the mass of the Sun, TRAPPIST-1 is very small in stellar terms, only marginally bigger than the planet Jupiter — and though nearby in the constellation Aquarius, it is invisible visually with anything less than powerful telescopes. Astronomers expected that such dwarf stars might host many Earth-sized planets in tight orbits, making them promising targets in the hunt for extraterrestrial life. TRAPPIST-1 is the first such system to be discovered.

Co-author Dr Amaury Triaud, of the University of Cambridge’s Institute of Astronomy, explains: “Stars like TRAPPIST-1 belong to the most common type of stars that exist within our Galaxy. The planets that we found are likely representative of the most common sort of planets in the Universe.

“That the planets are so similar to Earth bodes well for the search for life elsewhere. Planets orbiting ultra-cool dwarfs, like TRAPPIST-1, likely represent the largest habitable real estate in the Milky Way!”

The team determined that all the planets in the system were similar in size to Earth and Venus in our Solar System, or slightly smaller. The density measurements suggest that at least the innermost six are probably rocky in composition.

The planetary orbits are not much longer than that of Jupiter’s Galilean moon system, and much smaller than the orbit of Mercury in the Solar System. However, TRAPPIST-1’s small size and low temperature means that the energy input to its planets is similar to that received by the inner planets in our Solar System; TRAPPIST-1c, d and f receive similar energy inputs to Venus, Earth and Mars, respectively.

All seven planets discovered in the system could potentially have liquid water on their surfaces, though their orbital distances make some of them more likely candidates than others. Climate models suggest the innermost planets, TRAPPIST-1b, c and d, are probably too hot to support liquid water, except maybe on a small fraction of their surfaces. The orbital distance of the system’s outermost planet, TRAPPIST-1h, is unconfirmed, though it is likely to be too distant and cold to harbour liquid water — assuming no alternative heating processes are occurring. TRAPPIST-1e, f, and g, however, are of more interest for planet-hunting astronomers, as they orbit in the star’s habitable zone and could host oceans of surface water.

These new discoveries make the TRAPPIST-1 system an even more important target in the search for extra-terrestrial life. Team member Didier Queloz, from the University of Cambridge’s Cavendish Laboratory, is excited about the future possibilities: “Thanks to future facilities like ESO’ Extremely Large Telescope, or NASA/ESA’s soon-to-be-launched James Webb Space telescope, we will be capable to measure the structure of the planets’ atmospheres, as well as their chemical composition. We are about to start the remote exploration of terrestrial climates beyond our Solar system.”

The discovery is described in Nature, which also includes a science fiction short story, written by Laurence Suhner. Amaury Triaud comments: “We were thrilled at the idea of having artists be inspired by our discoveries right away. We hope this helps convey the sense of awe and excitement that we all have within the team about the TRAPPIST-1 system.”

The star draws its name from the TRAPPIST-South telescope, which made the initial discovery. TRAPPIST is the forerunner of a more ambitious facility called “SPECULOOS” that includes Cambridge as core partner, conducted by researchers of the “Cambridge Centre for Exoplanet Research” in the broad research context related to “Universal Life”. SPECULOOS is currently under construction at ESO’ Observatory of Cerro Paranal. SPECULOOS will survey 10 times more stars for planets, than TRAPPIST could do. We expect to detect dozens of additional terrestrial planets.

 

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Photo credit: European Southern Observatory

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This article was originally published by the University of Cambridge.

 

After 15 Years, SABER on TIMED Still Breaks Ground from Space

James Russell III
James Russell III, SABER principal investigator and co-director of the Center for Atmospheric Sciences at Hampton University, said, “We broke new ground on the coupling of high and low atmosphere, and on the long-term change in carbon dioxide, water, and other gases.” Credits: NASA/David C. Bowman

About 21 years ago, team members started building and testing the Sounding of the Atmosphere using Broadband Emission Radiometry, or SABER instrument. Back then, they dreamed of how great two years of data from an unexplored region of the upper atmosphere would be.

Now, 15 years later, SABER aboard the Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics, or TIMED, spacecraft has more than delivered on that dream as it continues to provide a wealth of fundamental knowledge about the radiation budget, chemistry, and dynamics of the upper atmosphere.

Marty Mlynczak
Marty Mlynczak, SABER associate principal investigator and senior research scientist at NASA Langley, spoke during the 15th-anniversary celebration. Credits: NASA/David C. Bowman

On Jan. 31, 2017, SABER team members gathered at NASA’s Langley Research Center to acknowledge and celebrate 15 years of atmospheric discovery.

“SABER, which marked 15 years of on-orbit operation on Jan. 22, 2017, has provided a never-before-seen view of the atmosphere and paved the way for new avenues of scientific study,” said NASA Langley’s Deputy Director Clayton Turner. “Fifteen years of SABER data has deepened our knowledge of the planet’s radiation budget — the balance between Earth’s incoming and outgoing energy. That’s an important achievement.”

Earth’s heat engine does more than simply move heat from one part of the surface to another; it also moves heat from Earth’s surface and the lower atmosphere back to space. This flow of incoming and outgoing energy is Earth’s energy budget.

Built by Utah State University Space Dynamics Laboratory and managed by NASA Langley and Hampton University in Hampton, Virginia, SABER is one of four instruments on the TIMED spacecraft.

“SABER has scanned the horizon more than 8 million times since launch,” said Joann Haysbert, Chancellor and Provost of Hampton University. “And without that good home (TIMED) to carry SABER, we would not be where we are today.”

As Dave Grant, TIMED Project Manager from Johns Hopkins University – Applied Physics Laboratory, explained, TIMED was given a two-year baseline plan. “No one was thinking 15 years,” he said. “But here we are with more than 15,000 contacts with the spacecraft and 98 percent of all SABER data recovered.”

A Series of Scientific “Firsts”

The Earth’s atmospheric limb known as the MLTI region — Mesosphere and Lower Thermosphere/Ionosphere — is home to the International Space Station and hundreds of satellites in Low Earth Orbit. It is also where the sun’s energy first impacts Earth’s atmosphere. Although it is the first shield from the sun’s ultraviolet radiation and contains important gases such as ozone, water vapor, and carbon dioxide, very little was known about this thin, outer layer between 10 and 110 miles in altitude.

Fifteen years ago, the MLTI was considered one of the least explored regions of Earth. But thanks to SABER on TIMED there is a new wealth of comprehensive global measurements of the MLTI.

The SABER dataset is the first global, long-term, and continuous record of the thermosphere, or upper atmospheric, emissions of nitric oxide and carbon dioxide (— molecules that, in this region of the atmosphere, serve as atmospheric thermostats that send upper atmospheric heat back into space.

Clayton Turner
“In the ‘90s when we were building SABER, it had a specific focus,” said NASA Langley Deputy Director Clayton Turner. “But today, it has an even greater focus to understand Earth and other planets by leveraging the knowledge and expertise of the SABER instrument and team.” Credits: NASA/David C. Bowman

One well-documented occurrence of this transfer of heat was in 2012 when over just three days, solar storms dumped enough energy in Earth’s upper atmosphere to power every residence in New York City for two years. SABER data revealed that the nitric oxide and carbon dioxide in the thermosphere re-radiated 95 percent of that energy back into space.

Data from that event, as well as other more recent solar events, continue to be analyzed to determine the effect on Earth’s upper atmosphere.

As Marty Mlynczak, SABER associate principal investigator and senior research scientist at NASA Langley explained, in order to understand Earth’s atmosphere, we must understand all of its layers.

“This climate record of the upper atmosphere is our first chance to have the other side of the equation,” Mlynczak said.

James Russell III, SABER principal investigator and co-director of the Center for Atmospheric Sciences at Hampton University adds, “We broke new ground on the coupling of high and low atmosphere, and on the long-term change in carbon dioxide, water, and other gasses.”

The usefulness of SABER’s unprecedented data is evident by the more than 1,350 journal articles in peer-reviewed literature that use SABER data.

SABER continues to exceed expectations and find a new purpose. The SABER data are now also being considered as a guide in the search for life on exoplanets. As Mlynczak explained, SABER detects elements through radiative signals from Earth’s atmosphere. Similar signals can be sought from Earth-like planets residing in habitable zones around sun-like stars. This knowledge can be utilized by NASA’s James Webb Telescope in the search for new planets that may harbor life.

“In the ‘90s when we were building SABER, it had a specific focus,” Turner said. “But today, it has an even greater focus to understand Earth and other planets by leveraging the knowledge and expertise of the SABER instrument and team.”

SABER’s atmospheric scanning has marked a series of “firsts” for the scientific community, and with no end in sight, that series continues.

According to the Deputy Director of NASA’s Heliophysics Division Peg Luce, SABER’s advancement in our understanding of the waves and dynamics that shape our upper atmosphere and ionosphere come into increased focus as NASA prepares for the launch of the Ionospheric Connection, or ICON, explorer and The Global-scale Observations of the Limb and Disk, or GOLD, missions later this year, and anticipates significant collaboration potential between the three missions.

“The SABER story is not over yet,“ Grant said. “We have a long way to go.”

Denise Lineberry
NASA Langley Research Center

Editor: Joe Atkinson

Photo Credit: NASA

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NASA’s OSIRIS-REx Begins Earth-Trojan Asteroid Search

A NASA spacecraft begins its search Thursday for an enigmatic class of near-Earth objects known as Earth-Trojan asteroids. OSIRIS-REx, currently on a two-year outbound journey to the asteroid Bennu, will spend almost two weeks searching for evidence of these small bodies.

Trojan asteroids are trapped in stable gravity wells, called Lagrange points, which precede or follow a planet. OSIRIS-REx is currently traveling through Earth’s fourth Lagrange point, which is located 60 degrees ahead in Earth’s orbit around the sun, about 90 million miles (150 million kilometers) from our planet. The mission team will use this opportunity to take multiple images of the area with the spacecraft’s MapCam camera in the hope of identifying Earth-Trojan asteroids in the region.

Trojan asteroids are common at the L4 and L5 Lagrange points of other planets, leading or following the planet in its orbit. But detecting our own Trojan asteroids from Earth is difficult since they appear close to the sun from our perspective.
Credits: NASA’s Goddard Space Flight Center/Dan Gallagher, producer

 

Although scientists have discovered thousands of Trojan asteroids accompanying other planets, only one Earth-Trojan has been identified to date, asteroid 2010 TK7. Scientists predict that there should be more Trojans sharing Earth’s orbit, but they are difficult to detect from Earth as they appear near the sun on the Earth’s horizon.

“Because the Earth’s fourth Lagrange point is relatively stable, it is possible that remnants of the material that built Earth are trapped within it,” said Dante Lauretta. “So this search gives us a unique opportunity to explore the primordial building blocks of Earth.”

The search commences today and continues through Feb. 20. On each observation day, the spacecraft’s MapCam camera will take 135 survey images that will be processed and examined by the mission’s imaging scientists at the University of Arizona, Tucson. The study plan also includes opportunities for MapCam to image Jupiter, several galaxies, and the main belt asteroids 55 Pandora, 47 Aglaja and 12 Victoria.

Whether or not the team discovers any new asteroids, the search is a beneficial exercise. The operations involved in searching for Earth-Trojan asteroids closely resemble those required to search for natural satellites and other potential hazards around Bennu when the spacecraft approaches its target in 2018. Being able to practice these mission-critical operations in advance will help the OSIRIS-REx team reduce mission risk once the spacecraft arrives at Bennu.

NASA’s Goddard Space Flight Center provides overall mission management, systems engineering and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s observation planning and processing. Lockheed Martin Space Systems in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the agency’s New Frontiers Program for its Science Mission Directorate in Washington.

For more information on OSIRIS-Rex, visit:

www.nasa.gov/osirisrex  and www.asteroidmission.org

Erin Morton
University of Arizona, Tucson

Nancy Neal Jones
NASA’s Goddard Space Flight Center in Greenbelt, Maryland

Editor: Karl Hille

 

Photo Credit: Nasa

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Hubble Witnesses Massive Comet-Like Object Pollute Atmosphere of a White Dwarf

For the first time, scientists using NASA’s Hubble Space Telescope have witnessed a massive object with the makeup of a comet being ripped apart and scattered in the atmosphere of a white dwarf, the burned-out remains of a compact star. The object has a chemical composition similar to Halley’s Comet, but it is 100,000 times more massive and has a much higher amount of water. It is also rich in the elements essential for life, including nitrogen, carbon, oxygen, and sulfur.

These findings are evidence for a belt of comet-like bodies orbiting the white dwarf, similar to our solar system’s Kuiper Belt. These icy bodies apparently survived the star’s evolution as it became a bloated red giant and then collapsed to a small, dense white dwarf.

As many as 25 to 50 percent of white dwarfs are known to be polluted with infalling debris from rocky, asteroid-like objects, but this is the first time a body made of icy, comet-like material has been seen polluting a white dwarf’s atmosphere.

The results also suggest the presence of unseen, surviving planets which may have perturbed the belt and worked as a “bucket brigade” to draw the icy objects into the white dwarf. The burned-out star also has a companion star, which may disturb the belt, causing objects from the belt to travel toward the burned-out star.

Siyi Xu of the European Southern Observatory in Garching, Germany, led the team that made the discovery. According to Xu, this was the first time that nitrogen was detected in the planetary debris that falls onto a white dwarf. “Nitrogen is a very important element for life as we know it,” Xu explained. “This particular object is quite rich in nitrogen, more so than any object observed in our solar system.”

Our own Kuiper Belt, which extends outward from Neptune’s orbit, is home to many dwarf planets, comets, and other small bodies left over from the formation of the solar system. Comets from the Kuiper Belt may have been responsible for delivering water and the basic building blocks of life to Earth billions of years ago.

The new findings are observational evidence supporting the idea that icy bodies are also present in other planetary systems, and have survived throughout the history of the star’s evolution.

To study the white dwarf’s atmosphere, the team used both Hubble and the W. M. Keck Observatory. The measurements of nitrogen, carbon, oxygen, silicon, sulfur, iron, nickel, and hydrogen all come from Hubble, while Keck provides the calcium, magnesium, and hydrogen. The ultraviolet vision of Hubble’s Cosmic Origins Spectrograph (COS) allowed the team to make measurements that are very difficult to do from the ground.

This is the first object found outside our solar system that is akin to Halley’s Comet in composition. The team used the famous comet for comparison because it has been so well studied.

The white dwarf is roughly 170 light-years from Earth in the constellation Bootes, the Herdsman. It was first recorded in 1974 and is part of a wide binary system, with a companion star separated by 2,000 times the distance that the Earth is from the sun.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA Goddard manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

For images and more information about the exocomets and Hubble, visit:

http://hubblesite.org/news_release/news/2017-09

www.nasa.gov/hubble

For additional information, contact:

Ann Jenkins / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4488 / 410-338-4514
jenkins@stsci.edu / villard@stsci.edu

Siyi Xu
European Southern Observatory
011-49-89-3200-6298
sxu@eso.org

Editor: Karl Hille

Photo Credit: NASA

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