A New Map For A Birthplace Of Stars

A Yale-led research group has created the most detailed maps yet of a vast seedbed of stars similar to Earth’s Sun.

The maps provide unprecedented detail of the structure of the Orion A molecular cloud, the closest star-forming region of high-mass stars. Orion A hosts a variety of star-forming environments, including dense star clusters similar to the one where Earth’s Sun is believed to have formed.

“Our maps probe a wide range of physical scales needed to study how stars form in molecular clouds, and how young stars impact their parent cloud,” said Yale postdoctoral associate Shuo Kong, first author of a study about the group’s research that appears in the Astrophysical Journal Supplement.

The research team includes astronomers from institutions in the U.S., Chile, Japan, France, Germany, Spain, and the U.K. The team’s principal investigators are Yale astronomy professor Héctor G. Arce, ALMA Observatory scientist John Carpenter, and Caltech astronomy professor Anneila Sargent.

Kong said the team constructed its maps of the Orion A cloud by combining data from a single-dish telescope and an interferometer. The Yale Center for Research Computing assisted in handling the large dataset and producing the images.

The dataset and maps are collectively known as the CARMA-NRO Orion Survey. The name refers to the Combined Array for Research in Millimeter Astronomy (CARMA), an interferometer that was located in California, and the Nobeyama Radio Observatory (NRO) telescope, in Japan.

“Our survey is a unique combination of data from two very different telescopes,” said Yale graduate student Jesse Feddersen, a co-author of the study. “We have combined the zoom of CARMA with the wide-angle of NRO to simultaneously capture the details of individual forming stars and the overall shape and motions of the giant molecular cloud.”

In addition, the maps will help researchers calibrate star formation models for extragalactic studies. “The data we provide here will benefit research on a broad range of evolutionary stages of the star formation process and on the environment stars form,” Arce said.

Yale graduate student María José Maureira is also a co-author of the study.

“The combined observations are a great help for astronomers seeking to understand how fast and efficiently stars form. For example, their maps show the energy released by high-mass stars has a strong impact on the cloud environment,” said Glen Langston, program director at the National Science Foundation. The research was supported by the National Science Foundation.

Unusual Laser Emission From The Ant Nebula

An international team of astronomers have discovered an unusual laser emission that suggests the presence of a double star system hidden at the heart of the “spectacular” Ant Nebula.

The extremely rare phenomenon is connected to the death of a star and was discovered in observations made by European Space Agency’s (ESA) Herschel space observatory.

When low- to middleweight stars like our Sun approach the end of their lives they eventually become dense, white dwarf stars. In the process, they cast off their outer layers of gas and dust into space, creating a kaleidoscope of intricate patterns known as a planetary nebula. Our Sun is expected to one day form such a planetary nebula.

A nebula is an interstellar cloud of dust, hydrogen, helium and other ionized gases. The Ant Nebula earns its nickname from the twin lobes that resemble the head and body of an ant.

The recent Herschel observations have shown that the dramatic demise of the central star in the core of the Ant Nebula is even more theatrical than implied by its colourful appearance in visible images — such as those taken by the NASA/ESA Hubble Space Telescope.

The new data shows that the Ant Nebula also beams intense laser emission from its core. Lasers are well-known down on earth in everyday life, from special visual effects in music concerts to health care and communications. In space, laser emission is detected at very different wavelengths and only under certain conditions. Only a few of these infrared space lasers are known.

By coincidence, astronomer Donald Menzel who first observed and classified this particular planetary nebula in the 1920s (it is officially known as Menzel 3 after him) was also one of the first to suggest that in certain conditions natural ‘light amplification by stimulated emission of radiation’ — from which the acronym ‘laser’ derives — could occur in nebulae in space. This was well before the discovery of lasers in laboratories.

Dr Isabel Aleman, lead author of a paper describing the new results, said “We detected a very rare type of emission called hydrogen recombination laser emission, which is only produced in a narrow range of physical conditions.

“Such emission has only been identified in a handful of objects before and it is a happy coincidence that we detected the kind of emission that Menzel suggested, in one of the planetary nebulae that he discovered.”

This kind of laser emission needs very dense gas close to the star. Comparison of the observations with models found that the density of the gas emitting the lasers is around ten thousand times denser than the gas seen in typical planetary nebulae and in the lobes of the Ant Nebula itself.

Normally, the region close to the dead star — close in this case being about the distance of Saturn from the Sun — is quite empty, because its material is ejected outwards. Any lingering gas would soon fall back onto it.

Co-author Prof Albert Zijlstra, from the Jodrell Bank Centre for Astrophysics at University of Manchester, added: “The only way to keep such dense gas close to the star is if it is orbiting around it in a disc. In this nebula, we have actually observed a dense disc in the very centre that is seen approximately edge-on. This orientation helps to amplify the laser signal.

“The disc suggests there is a binary companion, because it is hard to get the ejected gas to go into orbit unless a companion star deflects it in the right direction. The laser gives us a unique way to probe the disc around the dying star, deep inside the planetary nebula.”

Astronomers have not yet seen the expected second star, hidden in the heart of the Ant nebula.

Göran Pilbratt, ESA’s Herschel project scientist, added: “It is a nice conclusion that it took the Herschel mission to connect together Menzel’s two discoveries from almost a century ago.”

The paper’s publication coincides with the first UNESCO International Day of Light, and celebrates the anniversary of the first successful operation of the laser in 1960 by physicist and engineer, Theodore Maiman.

Scientists Just Found the Fastest-Growing Black Hole

Researchers have spotted the fastest-growing black hole ever found — and have seen the (thankfully) distant devourer consume a mass equivalent to Earth’s sun every two days.

Researchers used newly released data from the European Space Agency’s Gaia satellite to confirm that the brightly shining object is a black hole, which appears to have been the mass of about 20 billion suns when the light was released and was growing by 1 percent every million years, researchers said in a statement released today (May 15).

“This black hole is growing so rapidly that it’s shining thousands of times more brightly than an entire galaxy, due to all the gases it sucks in daily that cause lots of friction and heat,” Christian Wolf, an astronomer at the Australian National University and first author on the new research, said in the statement. [The Strangest Black Holes in the Universe]

“If we had this monster sitting at the center of our Milky Way galaxy, it would appear 10 times brighter than a full moon. It would appear as an incredibly bright, pinpoint star that would almost wash out all of the stars in the sky,” he added.

Luckily, though, the black hole is far enough away that it likely released its light more than 12 billion years ago, the researchers said. The energy it emits is mostly ultraviolet light, but it also releases X-rays. “Again, if this monster was at the center of the Milky Way, it would likely make life on Earth impossible with the huge amounts of X-rays emanating from it,” Wolf said.

Because of its distance and the expansion of space, that light had shifted into the near-infrared during its billions-of-years journey. Wolf and his colleagues spotted the light with the SkyMapper telescope at the ANU Siding Spring Observatory. They then used the Gaia satellite to measure that the object was sitting still, thereby also confirming that it was incredibly distant and likely a supermassive black hole, the researchers said. Then, another ANU telescope measured the wavelengths released from the object to verify its composition.

“We don’t know how this one grew so large, so quickly in the early days of the universe,” Wolf said. “The hunt is on to find even faster-growing black holes.”

Wolf added that distant black holes like this one can help scientists study the early universe. Researchers can spot the shadows of other objects in front of the black holes, and their radiation also helps clear away obscuring gas.

With giant new ground-based telescopes currently under construction, scientists will also be able to use bright, distant objects like this voracious black hole to measure the universe’s expansion, the researchers said.

The new work was accepted to the journal Publications of the Astronomical Society of Australia.

Orbital Variations Can Trigger ‘Snowball’ States In Habitable Zones Around Sunlike Stars

Aspects of an otherwise Earthlike planet’s tilt and orbital dynamics can severely affect its potential habitability — even triggering abrupt “snowball states” where oceans freeze and surface life is impossible, according to new research from astronomers at the University of Washington.

The research indicates that locating a planet in its host star’s “habitable zone” — that swath of space just right to allow liquid water on an orbiting rocky planet’s surface — isn’t always enough evidence to judge potential habitability.

Russell Deitrick, lead author of a paper to be published in the Astronomical Journal, said he and co-authors set out to learn, through computer modeling, how two features — a planet’s obliquity or its orbital eccentricity — might affect its potential for life. They limited their study to planets orbiting in the habitable zones of “G dwarf” stars, or those like the sun.

A planet’s obliquity is its tilt relative to the orbital axis, which controls a planet’s seasons; orbital eccentricity is the shape, and how circular or elliptical — oval — the orbit is. With elliptical orbits, the distance to the host star changes as the planet comes closer to, then travels away from, its host star.

Deitrick, who did the work while with the UW, is now a post-doctoral researcher at the University of Bern. His UW co-authors are atmospheric sciences professor Cecilia Bitz, astronomy professors Rory Barnes, Victoria Meadows and Thomas Quinn and graduate student David Fleming, with help from undergraduate researcher Caitlyn Wilhelm.

The Earth hosts life successfully enough as it circles the sun at an axial tilt of about 23.5 degrees, wiggling only a very little over the millennia. But, Deitrick and co-authors asked in their modeling, what if those wiggles were greater on an Earthlike planet orbiting a similar star?

Previous research indicated that a more severe axial tilt, or a tilting orbit, for a planet in a sunlike star’s habitable zone — given the same distance from its star — would make a world warmer. So Deitrick and team were surprised to find, through their modeling, that the opposite reaction appears true.

“We found that planets in the habitable zone could abruptly enter ‘snowball’ states if the eccentricity or the semi-major axis variations — changes in the distance between a planet and star over an orbit — were large or if the planet’s obliquity increased beyond 35 degrees,” Deitrick said.

The new study helps sort out conflicting ideas proposed in the past. It used a sophisticated treatment of ice sheet growth and retreat in the planetary modeling, which is a significant improvement over several previous studies, co-author Barnes said.

“While past investigations found that high obliquity and obliquity variations tended to warm planets, using this new approach, the team finds that large obliquity variations are more likely to freeze the planetary surface,” he said. “Only a fraction of the time can the obliquity cycles increase habitable planet temperatures.”

Barnes said Deitrick “has essentially shown that ice ages on exoplanets can be much more severe than on Earth, that orbital dynamics can be a major driver of habitability and that the habitable zone is insufficient to characterize a planet’s habitability.” The research also indicates, he added, “that the Earth may be a relatively calm planet, climate-wise.”

This kind of modeling can help astronomers decide which planets are worthy of precious telescope time, Deitrick said: “If we have a planet that looks like it might be Earth-like, for example, but modeling shows that its orbit and obliquity oscillate like crazy, another planet might be better for follow-up” with telescopes of the future.”

The main takeaway of the research, he added, is that “We shouldn’t neglect orbital dynamics in habitability studies.”

‘Lost’ Asteroid 2010 WC9 Makes an Unusually Close Flyby of Earth

A jumbo-jet-size asteroid gave Earth a close shave today (May 15), whizzing past our planet at a safe distance of 126,000 miles (203,000 kilometers) — or about half the distance between Earth and the moon.
The asteroid, which is officially designated 2010 WC9, made its closest approach at 6:05 p.m. EDT (2205 GMT) while traveling at a speed of 28,655 mph (46,116 km/h), according to the Minor Planet Center.

Astronomers estimate that the asteroid measures 125 to 390 feet (38 to 119 meters) in diameter. That means it’s about as big as New York City’s Statue of Liberty, though it could be even longer than a football field.

While this isn’t exceptionally large for a near-Earth asteroid, it is rare for asteroids this big to venture so close to Earth. According to EarthSky.org, this was “one of the closest approaches ever observed of an asteroid of this size.”

Asteroid 2010 WC9 was first spotted by the Catalina Sky Survey in 2010, but astronomers lost track of it once it became too faint to see. The “lost” asteroid was rediscovered on May 8, and astronomers have been tracking its approach ever since.

The asteroid isn’t visible to the naked eye, but it can be spotted through some telescopes. Astronomers with The Virtual Telescope Project in Italy and Tenagra Observatories in Arizona captured a view of the asteroid today at 2:46 a.m. EDT (0646 GMT). At the time, the asteroid was about 454,000 miles (730,000 km) from Earth.

The Slooh community observatory has also been tracking the asteroid, and yesterday (May 14), the observatory showed a live webcast of the asteroid as seen from its telescopes at the Institute of Astrophysics of the Canary Islands.

Astronomers Have Discovered How Earth’s Magnetic Field Survives Intense Solar Storms

NASA’s Magnetospheric Multiscale (MMS) space weather mission has helped solve one of astrophysics’ biggest questions – when a solar storm strikes our planet, where does its intense rain of energy go?

The discovery explains the behaviour of a chaotic zone at the edge of Earth’s protective magnetic shell when it is showered with charged particles. In turn, the discovery lays fresh foundations for understanding similar turbulent hot-spots such as the one surrounding the Sun.

Astronomers found that there are sub-atomic scale shifts in the turbulent swirl of electrons far above our planet’s surface that effectively dissipates the energy that gets caught up in its writhing mess of magnetism.

While most of us are familiar with the old-school diagram of a spherical cage of magnetic lines neatly surrounding our planet, a hairy scribble of magnetic fields also wraps around this calm bubble.

This messy zone of magnetism – called a magnetosheath – is somewhat like the white-capped swell of waves outside of the smooth currents of a lagoon, stretching out a distance equivalent to the diameter of the Earth several times over.

Further out still is a region called the bow shock, where the stream of solar wind slows down and bunches up as it enters our magnetic space.

Astronomers have studied the calmer ‘lagoon’ waters of our magnetosphere for decades, and have a fairly good understanding of how its magnetic lines carry charged particles.

But the wild waters in front of the bow shock have been far too choppy to get a good handle on, making it hard to accurately model how they channel the charged winds of plasma that blow in from the Sun.

“We know that magnetic energy in churning, turbulent systems cascades to smaller and smaller scales. At some point that energy is fully dissipated,” says physicist James Drake from the University of Maryland.

“The big question is how that happens, and what role magnetic reconnection plays at such small scales.”

Magnetic reconnection is the dramatic breaking and joining of opposing lines in a magnetic field, which releases showers of charged particles being channelled down their invisible pipelines.

Explosive surges of protons and electrons are known to release huge amounts of energy, putting any delicate electronic technologies in their path at risk.

It would make sense that similar surges play a role in soaking up a significant portion of the solar wind’s energy as it spills from the bow shock.

Studying such reconnections in the magnetosphere is relatively easy thanks in part to the fact they produce long ‘ion jets’ involving chunky particles like hydrogen ions.

That wild west of a magnetosheath is not only chaotic, its snapping fields is awash with electrons, which are virtually impossible to directly measure from down here thanks to their vastly shorter range.

That’s where MMS comes in.

The mission’s four satellites orbit in a close-knit pyramid formation, mapping the zone’s electron density on a millisecond timescale and providing a detailed description of their behaviour.

Sure enough, among the tightly knotted weaves of magnetic lines there was a whole lot of snapping and reconnecting, clearly evident in the movements of electrons.

“MMS discovered electron magnetic reconnection, a new process much different from the standard magnetic reconnection that happens in calmer areas around Earth,” says the study’s lead author Tai Phan, a space scientist from the University of California, Berkeley.

This clip below explains the research with some great visuals.

Having solid evidence of magnetic reconnection on this scale not only helps us understand our own surrounding space and better protect our technology (not to mention our astronauts’ health), it can be applied to a whole array of astronomical phenomena.

“Turbulence occurs everywhere in space: on the Sun, in the solar wind, interstellar medium, dynamos, accretion disks around stars, in active galactic nuclei jets, supernova remnant shocks and more,” says physicist Michael Shay of the University of Delaware.

The Sun’s corona is hundreds of times hotter than the visible surface beneath, and so far nobody has come up with a convincing explanation. One possibility is explosive eruptions called ‘nanoflares’.

Knowing more about how magnetic fields reconnect in this ultrahot zone might fill in the missing pieces that lead to a satisfactory answer.

NASA’s upcoming Solar Probe mission intends to collect crucial data by sweeping through the star’s corona.

Why Does The Sun’s Corona Sizzle At One Million Degrees Fahrenheit?

The Sun’s corona, invisible to the human eye except when it appears briefly as a fiery halo of plasma during a solar eclipse, remains a puzzle even to scientists who study it closely. Located 1,300 miles from the star’s surface, it is more than a hundred times hotter than lower layers much closer to the fusion reactor at the Sun’s core.

A team of physicists, led by NJIT’s Gregory Fleishman, has recently discovered a phenomenon that may begin to untangle what they call “one of the greatest challenges for solar modeling” — determining the physical mechanisms that heat the upper atmosphere to 1 million degrees Fahrenheit and higher. Their findings, which account for previously undetected thermal energy in the corona, were recently published in the 123-year-old Astrophysical Journal, whose editors have included foundational space scientists such as Edwin Hubble.

“We knew that something really intriguing happens at the interface between the photosphere — the Sun’s surface — and the corona, given the noticeable disparities in the chemical composition between the two layers and the sharp rise in plasma temperatures at this junction,” notes Fleishman, a distinguished research professor of physics.

With a series of observations from NASA’s space-based Solar Dynamics Observatory (SDO), the team has revealed regions in the corona with elevated levels of heavy metal ions contained in magnetic flux tubes — concentrations of magnetic fields — which carry an electrical current. Their vivid images, captured in the extreme (short wave) ultraviolet (EUV) band, reveal disproportionally large — by a factor of five or more — concentrations of multiply charged metals compared to single-electron ions of hydrogen, than exist in the photosphere.

The iron ions reside in what the team calls “ion traps” located at the base of coronal loops, arcs of electrified plasma directed by magnetic field lines. The existence of these traps, they say, implies that there are highly energetic coronal loops, depleted of iron ions, which have thus far eluded detection in the EUV range. Only metal ions, with their fluctuating electrons, produce emissions which make them visible.

“These observations suggest that the corona may contain even more thermal energy than is directly observed in the EUV range and that we have not yet accounted for,” he says. “This energy is visible in other wavelengths, however, and we hope to combine our data with scientists who view it through microwaves and X-rays, such as scientists at NJIT’s Expanded Owens Valley Solar Array, for example, to clarify mismatches in energy that we’ve been able to quantify so far.”

There are various theories, none yet conclusive, that explain the sizzling heat of the corona: magnetic energy lines that reconnect in the upper atmosphere and release explosive energy and energy waves dumped in the corona, where they are converted to thermal energy, among others.

“Before we can address how energy is generated in the corona, we must first map and quantify its thermal structure,” Fleishman notes.

“What we know of the corona’s temperature comes from measuring EUV emissions produced by heavy ions in various states of ionization, which depends on their concentrations, as well as plasma temperature and density,” he adds. “The non-uniform distribution of these ions in space and time appears to affect the temperature of the corona.”

The metal ions enter the corona when variously sized solar flares destroy the traps, and they are evaporated into flux loops in the upper atmosphere.

Energy releases in solar flares and associated forms of eruptions occur when magnetic field lines, with their powerful underlying electric currents, are twisted beyond a critical point that can be measured by the number of turns in the twist. The largest of these eruptions cause what is known as space weather — the radiation, energetic particles and magnetic field releases from the Sun powerful enough to cause severe effects in Earth’s near environment, such as the disruption of communications, power lines and navigation systems.

It is only through recent advances in imaging capabilities that solar scientists can now take routine measurements of photospheric magnetic field vectors from which to compute the vertical component of electric currents, and, simultaneously, quantify the EUV emissions produced by heavy ions.

“Prior to these observations, we have only accounted for the coronal loops filled with heavy ions, but we could not account for flux tubes depleted of them,” Fleishman says. “Now all of these poorly understood phenomena have a solid physical foundation that we can observe. We are able to better quantify the corona’s thermal structure and gain a clearer understanding of why ion distribution in the solar atmosphere is non-uniform in space and variable in time.”

Scientists at NJIT’s Big Bear Solar Observatory (BBSO) have captured the first high-resolution images of magnetic fields and plasma flows originating deep below the Sun’s surface, tracing the evolution of sunspots and magnetic flux ropes through the chromosphere before their dramatic appearance in the corona as flaring loops.

EUV emissions, however, can only be observed from space. The SDO, aboard a spacecraft launched in 2010, measures both magnetic field and EUV emissions from the whole Sun. The implications of the corona’s temperature structure, and whether it allows the Sun to transfer more heat into the solar system, “is the subject of future study,” Fleishman says.