Category: Deep Space

Perseid meteor shower to peak this weekend

Lack of visible Moon will make this the year’s best meteor shower.

Skywatchers will have ideal viewing conditions to watch the annual Perseid meteor shower, which will peak this weekend, between August 10 and 13.

Named for the Perseus constellation from which it originates, this meteor shower is visible every year in August when Earth passes through debris from the comet Swift-Tuttle. A short-period comet, Swift-Tuttle takes 133 years to circle the Sun. Each time it makes its closest approach, the Sun’s heat and tidal forces cause pieces of it to break off, leaving behind a debris field.

The Perseids will be especially bright this year because the meteor shower occurs at the new Moon, when the Moon will not be present to brighten the sky and obscure the meteors. Night skies without a Moon are darker and provide the best opportunities for meteor viewing.

“This year, the Moon will be near new Moon; it will be a crescent, which means it will set before the Perseid show gets underway after midnight. The Moon is very favorable for the Perseids this year, and that’ll make the Perseids probably the best shower of 2018 for people who want to go out and view it,” NASA meteor specialist Bill Cooke told the website Space.com.

On Saturday night August 11, viewers with dark skies should be able to see between 60 and 70 meteors per hour. An online map of areas across the country with the least light pollution, created by a research team at the Cooperative Institute for Research in Environmental Sciences (CIRES) and Chris Elvidge of the National Oceanic and Atmospheric Administration (NOAA) is available to guide viewers to the best locations.

Both the brightness of meteor showers and the number of meteors visible are determined by several factors, including the density of the debris field, the debris field’s relative speed in relation to Earth, the distance between Earth and the debris field, and the degree of light pollution at a viewing site.

Observers should allow approximately 30 minutes for their eyes to adapt to the dark.

While the shower peaks this weekend, Perseid meteors can be seen any clear night between July 17 and August 24.

“Twin” exoplanets formed through very different processes

Identical appearance can hide very different origins.

Two giant exoplanets in separate star systems are practically identical but likely formed through very different processes, according to a team of scientists led by Trent Dupuy of the Gemini Observatory.

Beta Pictoris b and and 2MASS 0249 c, found via direct imaging in 2009 and 2017 respectively, have the same masses–approximately 13 Jupiter masses–as well as the same brightnesses and spectra.

Although the two planets are alike enough for astronomers to refer to the newly-discovered planet as a “doppelganger” of the first, and the two have parent stars that likely formed in the same stellar nursery of gas and dust, scientists believe their origins are very different.

“We have found a gas giant that is a virtual twin of a previously known planet, but it looks like the two objects formed in different ways,” Dupuy said.

Many stars are born in stellar nurseries but subsequently wander away from one another. By observing both planets with the Canada-France-Hawaii Telescope (CFHT), the researchers determined they originated in the same stellar nursery.

However, the stars they orbit as well as their orbital distances are very different from one another. Beta Pictoris b is in a close orbit at approximately nine astronomical units (AU, with one AU equal to the average Earth-Sun distance or 93 million miles) around a star 10 times brighter than the Sun while 2MASS 0249 c circles a pair of brown dwarfs at a distance of 2,000 AU.

Brown dwarfs are the lowest end of the stellar category. Dim and cool, they are not hot enough to fuse hydrogen in their cores although some fuse deuterium, an isotope of hydrogen.

Gas giant planets typically begin their lives as small rocky cores that grow by gathering gas from their parent stars’ protoplanetary disks. Beta Pictoris b likely formed in this manner.

However, this formation process would not have been possible for 2MASS 0249 c because its two brown dwarf parents would not have had a large enough protoplanetary disk to provide the levels of gas needed to form a gas giant. This means the planet absorbed its gas directly from the stellar nursery.

“2MASS 0249 c and Beta Pictoris b show us that nature has more than one way to make very similar looking exoplanets. Beta Pictoris b probably formed like we think most gas giants do, starting from tiny dust grains. In contrast, 2MASS 0249 c looks like an underweight brown dwarf that formed from the collapse of a gas cloud. They’re both considered exoplanets, but 2MASS 0249 c illustrates that such a simple classification can obscure a complicated reality,” explained Kaitlin Kratter of the University of Arizona, who took part in the study.

A paper on the findings has been accepted for publication in the Astronomical Journal.

Astronomers observe unique binary asteroid

A binary asteroid known as 2017 YE5 is unlike any other such object on record.

Scientists at Arecibo Observatory in Puerto Rico and the Green Bank Observatory in West Virginia have discovered a pair of similarly-sized asteroids locked in their binary orbit around a mutual center of gravity.

The team first detected the odd object, known as 2017 YE5, in December of last year. At the time, it sat an such an angle that scientists could not determine if it was two distinct objects or two lobes of the same object joined at one point, Science Alert reports.

However, last month the pair came closer to Earth than they had ever been, which then allowed astronomers to get a much better look. They did that by shooting a radar signal out towards the asteroid. The beam then bounced off the object and shot back down towards our planet. Individual observations were made as well.

That revealed the asteroids make one full orbit around each other once every 20 to 24 hours.

Though observations estimate that about 15 percent of all near-Earth asteroids that measure more than larger than 650 feet across are binaries, most of them are made up of one large asteroid and one small one.

YE5 is unique because both objects measure 3,000 feet across, showing that they are roughly the same size. In addition, the rocks each reflected the radar signal differently. That shows they likely have different surface roughness or density.

More research needs to be done on the pair before such questions can be answered, and the team plans to do that the next time the asteroids fly past Earth in roughly four-and-a-half years.

In the meantime, researchers will analyze data taken from recent observations and attempt to discover more about the densities of the object. That could then provide new insight into its structure and composition.

Bright quasar dates back to early universe

Discovery could help scientists better understand how the universe’s first galaxies formed.

The brightest quasar or active galactic nucleus ever detected dates back nearly 13 billion years, meaning it originated in the early universe and could potentially aid scientists in understanding the formation process of the first galaxies.

Quasars are extremely luminous super-massive black holes at the centers of galaxies. These black holes are active, meaning they are devouring large amounts of matter that form an accretion disk spiraling toward their centers. The most luminous, powerful, and remote energy sources in existence, quasars emit as much as one thousand times the energy output of the Milky Way galaxy across the entire electromagnetic spectrum.

A research team led by Eduardo Banadas of the Carnegie Institution for Science discovered the quasar PSO J1352.4034-15.3373 emitting the brightest radio emission ever detected as a result of high-speed jets shooting out of it towards Earth.

His discovery was confirmed by Emmanuel Momjian of the National Radio Astronomy Observatory, who, along with his science team, was able to view the jet emitted by the quasar with an unprecedented level of detail.

The researchers found the jets have been traveling for 13 billion years, making this quasar the first known to have been spewing jets within the first billion years of the universe’s 13.8-billion-year existence.

Unlike most quasars, this one does more than suck matter into its black hole. It also emits jets of plasma that travel at almost the speed of light. This makes the jets appear extremely bright when viewed with radio telescopes.

Approximately 10 percent of quasars are known to emit strong radio jets.

“There is a dearth of known strong radio emitters from the universe’s youth, and this is the brightest radio quasar at that epoch by any order of magnitude,” Banados stated.

Following the Big Bang, the universe was dark as it expanded and cooled into neutral hydrogen gas, with few sources of brightness. Approximately 800 million years after the Big Bang, gravity condensed matter into the first galaxies and stars, which released energy, causing the neutral hydrogen to lose an electronic and become ionized, generating light.

“The jet from this quasar could serve as an important calibration tool to help future projects penetrate the dark ages and perhaps reveal how the earliest galaxies came into being,” Banados emphasized.

Findings of the study have been published in two separate papers in The Astrophysical Journal.

Astronomers capture ghostly particle in Antarctic ice sheet

The new discovery could usher in a new era of neutrino astronomy.

A ghostly particle was captured in a patch of ice beneath the South Pole in September of last year by the IceCube Antarctic detector—the orbiting Fermi Gammaray Space Telescope. Astronomers believe that this particle—a neutrino, electrically neutral and almost massless—likely came for a far off blazar, a hugely bright source of radiation powered by a supermassive black hole. The new finding could mark the founding event of neutrino astronomy, writes Daniel Clery in Science.

These particles are known as ultrahigh-energy cosmic rays because they exude a million times more energy than those produced in earthbound particle accelerators. Astronomers have yet to unequivocally pinpoint the source that boosts these particles to massive energies, but have speculated that it could be neutron stars, gamma ray bursts, hypernovae, or radiation-spewing black holes. However, they believe that whatever the source, high energy neutrinos are a likely byproduct. The IceCube neutrino detector captures these elusive particles in a cubic kilometer of Antarctic ice. Based on the location, timing, and brightness of the detected light, researchers can reconstruct the path and energy of the neutrino.

Last September’s ensnared neutrino, called IceCube-170922A, is calculated to have an energy of 290 TeV, and has offered scientists a clear track back into space. Six days after the observation, the Fermi team reported the satellite discovered a blazar, called TXS 0506+056, was especially bright, having started to flare, and less than 0.1° away from the neutrino’s path. Blazars are distant cosmic beacons powered by supermassive black holes that fire jets of particles from their poles. Though it’s not clear whether TXS 0506+056 was flaring when IceCube-170922A started its journey to Earth, Pierre Sokolsky of the University of Utah in Salt Lake City has hope, saying “it’s a very mouthwatering observation and I very much hope it will be confirmed.”

Cosmic rays traced back to massive black hole

For the first time ever researchers have found an origin of the mysterious cosmic rays that come to Earth from outer space.

A team of international scientists have confirmed the source of ultra high-energy cosmic rays that beam to Earth from space, according to a new study published in the journal Science

Occasionally, our planet gets hit with protons and atomic nuclei that shoot out of space with energy so high that scientists cannot replicate it. Researchers first discovered those “cosmic rays” over 100 years ago, but they never knew where they came from until now.

In the new study, the team combined data from light and a single high-energy neutrino particle and found that the rays originate from a blazar — a supermassive black hole at the center of a galaxy.

That discovery could open up new insight into the universe and provide a brand new way to study the cosmos.

“We have been looking for the sources of cosmic rays for more than a century, and we finally found one,” study co-author Francis Halzen, lead scientist at the IceCube Neutrino Observatory and a professor of physics at the University of Wisconsin-Madison, told Space.com.

This finding came about when the IceCube detector at the South Pole spotted a neutrino particle that had an incredible amount of energy. The detector’s computers quickly calculated where it came from and sent the coordinates to astronomers across the globe.

Six days later, the Fermi Large Area Telescope found a distant blazer known as TXS 0506+056 in the same spot.

Further research showed the blazar is able to produce high-energy protons and nuclei, which then creates neutrinos. In that way, it can create the ultra high-energy cosmic rays that have eluded astronomers for the past century.

That is an exciting discovery, but it is just one source. As a result, more research needs to be done to explain all cosmic rays and how they get made.

“We clearly need more data. One source is not enough,” study co-author Spencer Klein, a physicist at Lawrence Berkeley National Lab, told Gizmodo. “Now that we found one accelerator, we’d like to find more and find out how they work.”

Scientists examine Voyager-1 data in search of dark matter particles

Voyager’s pristine cosmic ray data is allowing researchers to form the bounds of the cosmos’ dark matter.

NASA’s Voyager-1 spacecraft is sending back cosmic ray data that has allowed researchers to better understand the cosmos’ exotic dark matter, reports Bruce Dorminey for Forbes Magazine. What they found was that analysis of the spacecraft’s cosmic ray detections beyond the heliopause (where the solar wind’s influence ends and the flux of low energy galactic cosmic rays begins), provided no evidence of dark matter. The researchers theorized that if dark matter was present, they would have found a higher density of lower energy cosmic rays in the data.

Caltech physicist Alan Cummings, who is part of the Voyager science team, explains that Voyager’s cosmic ray detector was designed specifically to look for galactic cosmic rays—low-energy cosmic rays that can only be detected outside our solar system. While most scientists believe cosmic rays originate within supernova remnants, some are thought to be related to dark matter. These rays—charged elemental particles that sometimes move at velocities approaching that of light—are helping researchers understand dark matter’s lower mass limits. The idea is that at least some dark matter particles present in the galaxy will annihilate into particle-antiparticle pairs, Dorminey writes—however, this is rare.

Scientists have proposed that dark matter could be made of microscopic black holes. A microscopic black hole would be no bigger than a nucleus of the element Xenon, explains Pierre Salati, a physicist at France’s Laboratoire d’Annecy-le-Vieux de Physique théorique. Researchers hoped that analyzing the new Voyager data to look for the evaporation of black holes emitting cosmic rays would be observable. But it wasn’t, leading Salati to conclude that these cosmic rays may not exist. “The idea is that the black holes evaporate and that evaporation emits cosmic rays,” he said. Despite the lack of evidence, researchers still plan to analyze data sent back from Voyager as long as possible.

Nearby rocky exoplanet could be habitable

Chemical composition of host star can inform scientists about the nature of orbiting planets.

A rocky exoplanet 11 light years away may not be an Earth twin but likely has a temperate climate that could sustain liquid water on its surface.

Known as Ross 128 b, the planet was discovered last fall by researchers who used the Sloan Digital Sky Survey’s (SDSS) APOGEE spectroscopic instrument. It orbits a red dwarf star, Ross 128, that is smaller, cooler, and dimmer than our Sun.

Scientists estimate 70 percent of stars in the galaxy are red dwarfs, most of which likely have at least one orbiting planet.

Now, a group of researchers led by Diogo Souto of Brazil’s Observatorio Nacional and by Johanna Teske of the Carnegie Institution for Science measured the chemical composition the star using APOGEE in the near-infrared and found signs of carbon, oxygen, magnesium, aluminum, potassium, calcium, titanium, and iron.

Knowing which elements are present in a star helps researchers predict the type of exoplanets that might be orbiting that star and whether any of those planets could be habitable.

“Until recently, it was difficult to obtain detailed chemical abundances for this type of star,” explained Souto, who last year pioneered a new technique to obtain this information.

“The ability of APOGEE to measure near-infrared light, where Ross 128 is brightest, was key for this study. It allowed us to address some fundamental questions about Ross 128 b’s ‘Earth-like-ness,'” Teske explained.

A star’s chemical content influences the protoplanetary disk of gas and dust that rotates around it in its early days. Planets form within these disks, and a star’s chemistry therefore influences its interior structure, mineraology, mass, and layering.

Ross 128 was found to have an iron level similar to that of our Sun. Based on its ratio of iron to magnesium, the researchers believe Ross 128 b has a larger core than the Earth has.

Once they had a good estimate of the planet’s mass and chemical abundance, the scientists were able to come up with a range for its radius.

Knowing a planet’s mass and radius enables scientists to calculate its bulk density.

Planets with 1.7 or more Earth radii are not considered habitable, as they are likely surrounded by a layer of gas, meaning they resemble our solar system’s ice giants.

In contrast, planets with lower radii, as Ross 128 b appears to have, are expected to be more rocky than gaseous.

The researchers also measured the exoplanet’s temperature and estimated how much of the star’s light reflects off its surface, which indicated it has a temperate climate.

“It’s exciting what we can learn about another planet by determining what the light from its host star tells us about the system’s chemistry,” Souto  noted. “Although Ross 128 b is not Earth’s twin, and there is still much we don’t know about its potential geologic activity, we were able to strengthen the argument that it’s a temperate planet that could potentially have liquid water on its surface.”

A paper detailing these findings has been published in The Astrophysical Journal Letters.