Search reveals eight new sources of black hole echoes

In this illustration, a black hole pulls material off a neighboring star and into an accretion disk.
Credits: Aurore Simonnet and NASA’s Goddard Space Flight Center

Scattered across our Milky Way galaxy are tens of millions of black holes — immensely strong gravitational wells of spacetime, from which infalling matter, and even light, can never escape. Black holes are dark by definition, except on the rare occasions when they feed. As a black hole pulls in gas and dust from an orbiting star, it can give off spectacular bursts of X-ray light that bounce and echo off the inspiraling gas, briefly illuminating a black hole’s extreme surroundings.

Now MIT astronomers are looking for flashes and echoes from nearby black hole X-ray binaries — systems with a star orbiting, and occasionally being eaten away by, a black hole. They are analyzing the echoes from such systems to reconstruct a black hole’s immediate, extreme vicinity.

In a study appearing today in the Astrophysical Journal, the researchers report using a new automated search tool, which they’ve coined the “Reverberation Machine,” to comb through satellite data for signs of black hole echoes. In their search, they have discovered eight new echoing black hole binaries in our galaxy. Previously, only two such systems in the Milky Way were known to emit X-ray echoes.

In comparing the echoes across systems, the team has pieced together a general picture of how a black hole evolves during an outburst. Across all systems, they observed that a black hole first undergoes a “hard” state, whipping up a corona of high-energy photons along with a jet of relativistic particles that is launched away at close to the speed of light. The researchers discovered that at a certain point, the black hole gives off one final, high-energy flash, before transitioning to a “soft,” low-energy state.

ESO telescope captures surprising changes in Neptune's temperatures

This composite shows thermal images of Neptune taken between 2006 and 2020. The first three images (2006, 2009, 2018) were taken with the VISIR instrument on ESO’s Very Large Telescope while the 2020 image was captured by the COMICS instrument on the Subaru Telescope (VISIR wasn’t in operation in mid-late 2020 because of the pandemic). After the planet’s gradual cooling, the south pole appears to have become dramatically warmer in the past few years, as shown by a bright spot at the bottom of Neptune in the images from 2018 and 2020. 
Credit: ESO/M. Roman, NAOJ/Subaru/COMICS

An international team of astronomers have used ground-based telescopes, including the European Southern Observatory’s Very Large Telescope (ESO’s VLT), to track Neptune’s atmospheric temperatures over a 17-year period. They found a surprising drop in Neptune’s global temperatures followed by dramatic warming at its south pole.

“This change was unexpected,” says Michael Roman, a postdoctoral research associate at the University of Leicester, UK, and lead author of the study published today in The Planetary Science Journal. “Since we have been observing Neptune during its early southern summer, we expected temperatures to be slowly growing warmer, not colder.”

Like Earth, Neptune experiences seasons as it orbits the Sun. However, a Neptune season lasts around 40 years, with one Neptune year lasting 165 Earth years. It has been summertime in Neptune’s southern hemisphere since 2005, and the astronomers were eager to see how temperatures were changing following the southern summer solstice.

Astronomers looked at nearly 100 thermal-infrared images of Neptune, captured over a 17-year period, to piece together overall trends in the planet’s temperature in greater detail than ever before.

World’s Largest International Dark Sky Reserve Created by McDonald Observatory

The Milky Way soars over the domes of McDonald Observatory's Mount Locke showcasing the region's dark skies.
Credit: Stephen Hummel/McDonald Observatory

The world’s largest International Dark Sky Reserve is coming to Texas and Mexico, thanks to a partnership between The University of Texas at Austin’s McDonald Observatory, The Nature Conservancy, the International Dark-Sky Association (IDA) and many others. The designation, granted by the IDA, recognizes the commitment of organizations, governments, businesses and residents in the region to maintaining dark skies. The move will benefit not only astronomical research, but also wildlife, ecology and tourism.

The new Greater Big Bend International Dark Sky Reserve will encompass more than 15,000 square miles in portions of western Texas and northern Mexico. It is the only such reserve to cross an international border.

“This reserve protects both the scientific research and public education missions of McDonald Observatory,” said Taft Armandroff, director of UT Austin’s McDonald Observatory. “Since 1939, the observatory has enabled the study of the cosmos by faculty, students and researchers at UT Austin and other Texas institutions of higher learning, with topics ranging from planets orbiting nearby stars to the accelerating expansion of the universe.”

Scientists Have Spotted the Farthest Galaxy Ever

HD1, object in red, appears at the center of a zoom-in image.
Credit: Harikane et al.
Hi-Res Zoomable Image

An international team of astronomers, including researchers at the Center for Astrophysics | Harvard & Smithsonian, has spotted the most distant astronomical object ever: a galaxy.

Named HD1, the galaxy candidate is some 13.5 billion light-years away and is described today in the Astrophysical Journal. In an accompanying paper published in the Monthly Notices of the Royal Astronomical Society Letters, scientists have begun to speculate exactly what the galaxy is.

The team proposes two ideas: HD1 may be forming stars at an astounding rate and is possibly even home to Population III stars, the universe’s very first stars — which, until now, have never been observed. Alternatively, HD1 may contain a supermassive black hole about 100 million times the mass of our Sun.

“Answering questions about the nature of a source so far away can be challenging,” says Fabio Pacucci, lead author of the MNRAS study, co-author in the discovery paper on ApJ, and an astronomer at the Center for Astrophysics. “It’s like guessing the nationality of a ship from the flag it flies, while being faraway ashore, with the vessel in the middle of a gale and dense fog. One can maybe see some colors and shapes of the flag, but not in their entirety. It’s ultimately a long game of analysis and exclusion of implausible scenarios.”

Finding Planets That Have No Star

 

Most planets orbit a star, but some planets can escape and “go rogue.” But how do astronomers study planets that wander the cold dark of interstellar space?

Join our host, Summer Ash of the National Radio Astronomy Observatory, as she talks about how radio astronomers' study rogue planets.

Source/Credit: National Radio Astronomy Observatory / Amy C. Oliver

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Evidence Shows Violent Collapse Responsible for Formation of Jupiter-Like Protoplanet

This is an artist's illustration of a massive, newly forming exoplanet called AB Aurigae b. Researchers used new and archival data from the Hubble Space Telescope and the Subaru Telescope to confirm this protoplanet is forming through an intense and violent process, called disk instability.
Credits: NASA, ESA, Joseph Olmsted (STScI)

NASA's Hubble Space Telescope has directly photographed evidence of a Jupiter-like protoplanet forming through what researchers describe as an "intense and violent process." This discovery supports a long-debated theory for how planets like Jupiter form, called "disk instability."

The new world under construction is embedded in a protoplanetary disk of dust and gas with distinct spiral structure swirling around, surrounding a young star that's estimated to be around 2 million years old. That's about the age of our solar system when planet formation was underway. (The solar system's age is currently 4.6 billion years.)

"Nature is clever; it can produce planets in a range of different ways," said Thayne Currie of the Subaru Telescope and Eureka Scientific, lead researcher on the study.

The wild years of our Milky Way galaxy

The architectural galaxy: our Milky Way consists of different components. Max Planck researchers have now reconstructed the history of thick and thin discs in particular.
Credit: Stefan Payne-Wardenaar / MPIA

A very long time ago, our Milky Way had a truly eventful life: between about 13 and 8 billion years ago, it lived hard and fast, merging with other galaxies and consuming a lot of hydrogen to form stars. With the help of a new data set, Maosheng Xiang and Hans-Walter Rix from the Max Planck Institute for Astronomy in Heidelberg have reconstructed the turbulent teenage years of our home galaxy. To do this, the researchers had to precisely determine the ages of 250,000 Milky Way stars.

Understanding the formation history and evolution of our home galaxy is a major goal for astronomy and astrophysics, and one where a flood of high-quality “big data” over the past years has led to impressive progress. The new study by Xiang and Rix constitutes a big step forward by putting much more precise dates onto the different phases of early Milky Way history. This was made possible by a unique analysis that managed to determine the ages of 250,000 stars.

A rough sketch of Milky Way history

In our current understanding, our home galaxy went through several phases. During the “baby phase” (not an official astronomy term), small, gas-rich progenitor galaxies merged to form a conglomerate that subsequently grew into our Milky Way. As those galaxies did not collide head-on, they imparted a spin on the resulting structure, presumably flattening its out into what we now see as the so-called thick disk of our Milky Way: gas and stars in a flat pancake, 100,000 light-years in diameter and 6000 light-years thick.

Nearby star could help explain why our sun didn’t have sunspots for 70 years

This image depicts a typical 11-year cycle on the sun, with the fewest sunspots appearing at its minimum (top left and top right) and the most appearing at its maximum (center).
Credit: NASA

The number of sunspots on our sun typically ebbs and flows in a predictable 11-year cycle, but one unusual 70-year period when sunspots were incredibly rare has mystified scientists for 300 years. Now a nearby sun-like star seems to have paused its own cycles and entered a similar period of rare starspots, according to a team of researchers at Penn State. Continuing to observe this star could help explain what happened to our own sun during this “Maunder Minimum” as well as lend insight into the sun's stellar magnetic activity, which can interfere with satellites and global communications and possibly even affect climate on Earth.

  The star — and a catalog of 5 decades of starspot activity of 58 other sun-like stars — is described in a new paper that appears online in the Astronomical Journal.

  Starspots appear as a dark spot on a star’s surface due to temporary lower temperatures in the area resulting from the star’s dynamo — the process that creates its magnetic field. Astronomers have been documenting changes in starspot frequency on our sun since they were first observed by Galileo and other astronomers in the 1600s, so there is a good record of its 11-year cycle. The exception is the Maunder Minimum, which lasted from the mid-1600s to early 1700s and has perplexed astronomers ever since.

Astronomers Closer to Unlocking Origin of Mysterious Fast Radio Bursts

Artist's conception of fast radio burst reaching Earth.
Credit: Jingchuan Yu, Beijing Planetarium

Nearly 15 years after the discovery of fast radio bursts (FRBs), the origin of the millisecond-long, deep-space cosmic explosions remain a mystery.

That may soon change, thanks to the work of an international team of scientists – including UNLV astrophysicist Bing Zhang – which tracked hundreds of the bursts from five different sources and found clues in FRB polarization patterns that may reveal their origin. The team’s findings were reported in the journal Science.

FRBs produce electromagnetic radio waves, which are essentially oscillations of electric and magnetic fields in space and time. The direction of the oscillating electric field is described as the direction of polarization. By analyzing the frequency of polarization in FRBs observed from various sources, scientists revealed similarities in repeating FRBs that point to a complex environment near the source of the bursts.

“This is a major step towards understanding the physical origin of FRBs,” said Zhang, a UNLV distinguished professor of astrophysics who coauthored the paper and contributed to the theoretical interpretation of the phenomena.

A “hot Jupiter’s” dark side is revealed in detail for first time

An artists’s impression of WASP-121 b.
Credit: Mikal Evans

MIT astronomers have obtained the clearest view yet of the perpetual dark side of an exoplanet that is “tidally locked” to its star. Their observations, combined with measurements of the planet’s permanent day side, provide the first detailed view of an exoplanet’s global atmosphere.

“We’re now moving beyond taking isolated snapshots of specific regions of exoplanet atmospheres, to study them as the 3D systems they truly are,” says Thomas Mikal-Evans, who led the study as a postdoc in MIT’s Kavli Institute for Astrophysics and Space Research.

The planet at the center of the new study, which appears in Nature Astronomy, is WASP-121b, a massive gas giant nearly twice the size of Jupiter. The planet is an ultrahot Jupiter and was discovered in 2015 orbiting a star about 850 light years from Earth. WASP-121b has one of the shortest orbits detected to date, circling its star in just 30 hours. It is also tidally locked, such that its star-facing “day” side is permanently roasting, while its “night” side is turned forever toward space.  

“Hot Jupiters are famous for having very bright day sides, but the night side is a different beast. WASP-121b's night side is about 10 times fainter than its day side,” says Tansu Daylan, a TESS postdoc at MIT who co-authored the study.

Fermi's 12-year View of the Gamma-ray Sky

 

Credit: NASA/EGRET Team and NASA/DOE/Fermi LAT Collaboration
Hi-Res Zoomable Still Image

This animation cycles between images that encapsulate decades of progress in gamma-ray astrophysics. The lower-resolution image shows the sky as seen by the EGRET instrument aboard NASA's Compton Gamma-Ray Observatory (1991 to 2000) using gamma rays above 100 million electron volts. Lighter colors indicate greater numbers of gamma rays. The most prominent feature is the central plane of our galaxy, which runs across the middle of the map, a result of gamma rays produced when accelerated particles strike interstellar gas and starlight. The largest yellow spot on the right side of the galactic plane is the Vela pulsar, one of five new gamma-ray pulsars EGRET discovered. The prominent reddish blob at top right is the blazar 3C 279. The all-sky map produced by Fermi's Large Area Telescope (LAT), using 12 years of data, is sharper, more detailed, and shows gamma rays of much higher energy than EGRET's. In its first five years, the LAT detected more than 10 times the number of gamma-ray sources seen by EGRET and had captured more high-energy gamma rays from a single source, the Vela pulsar, than the total number EGRET detected from all sources.

These all-sky views show how the sky appears at energies greater than 1 billion electron volts (GeV) according to 12 years of data from NASA's Fermi Gamma-ray Space Telescope. (For comparison, the energy of visible light is between 2 and 3 electron volts.) The image contains 144 months of data from Fermi's Large Area Telescope; for better angular resolution, the map shows only gamma rays detected at the front of the instrument's tracker. Lighter colors indicate brighter gamma-ray sources. The images show the entire sky in galactic coordinates, in which the center is the center of our galaxy. The bright midplane of our galaxy runs across the images.

Source/Credit: NASA / GSFC

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Hubble Captures Chameleon Cloud I

Image Credit: NASA, ESA, K. Luhman and T. Esplin (Pennsylvania State University), et al., and ESO; Processing: Gladys Kober (NASA/Catholic University of America)
Hi-Res Zoomable Image

This NASA Hubble Space Telescope image captures one of three segments that comprise a 65-light-year wide star-forming region named the Chamaeleon Cloud Complex. The segment in this Hubble composite image, called Chamaeleon Cloud I (Cha I), reveals dusty-dark clouds where stars are forming, dazzling reflection nebulae glowing by the light of bright-blue young stars, and radiant knots called Herbig-Haro objects.

Herbig-Haro objects are bright clumps and arcs of interstellar gas shocked and energized by jets expelled from infant “protostars” in the process of forming. The white-orange cloud at the bottom of the image hosts one of these protostars at its center. Its brilliant white jets of hot gas are ejected in narrow torrents from the protostar’s poles, creating the Herbig-Haro object HH 909A.

Expanded University of Hawaiʻi asteroid tracking system can monitor entire sky

Left: Sutherland ATLAS station during construction in South Africa.
Credit: Willie Koorts (SAAO)
Right: Chilean engineers and astronomers installing the ATLAS telescope at El Sauce Observatory.

A state-of-the-art asteroid alert system operated by the University of Hawaiʻi Institute for Astronomy (IfA) can now scan the entire dark sky every 24 hours for dangerous bodies that could plummet toward Earth.

The NASA-funded Asteroid Terrestrial-impact Last Alert System (ATLAS) has expanded its reach to the southern hemisphere, from two existing northern-hemisphere telescopes on Haleakalā and Maunaloa. Construction is now complete and operations are underway on two additional telescopes in South Africa and Chile.

Telescope unit on Haleakalā, Maui.
Photo credit: Henry Weiland

The Roman Space Telescope's Simulated Ultra-Deep Field Image

This video demonstrates how Roman could expand on Hubble’s iconic Ultra Deep Field image. While a similar Roman observation would be just as sharp as Hubble’s and see equally far back in time, it could reveal an area 300 times larger, offering a much broader view of cosmic ecosystems.

Also on our You Tube channel 

Source/Credit: 
Video: NASA / Goddard Space Flight Center
Music: "Subterranean Secret" and "Expectant Aspect" from Universal Production Music.
Final Editing and Conversion Scientific Frontline

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Newly-discovered planets will be ‘swallowed’ by their stars

Artist’s rendition of what a planetary system similar to the planets discovered might look like. 
Credit: Karen Teramura/IfA

Astronomers at the University of Hawaiʻi Institute for Astronomy (IfA) are part of a team that recently discovered three planets orbiting dangerously close to stars nearing the ends of their lives.

Out of the thousands of extrasolar planets found so far, these three gas giant planets, first detected by the NASA TESS (Transiting Exoplanet Survey Satellite) Mission, have some of the shortest-period orbits around subgiant or giant stars. One of the planets, TOI-2337b, will be consumed by its host star in less than 1 million years, sooner than any other planet currently known.

These discoveries are crucial to understanding a new frontier in exoplanet studies: how planetary systems evolve over time.

Samuel Grunblatt

“These discoveries are crucial to understanding a new frontier in exoplanet studies: how planetary systems evolve over time,” explained lead author Samuel Grunblatt, a postdoctoral fellow at the American Museum of Natural History and the Flatiron Institute in New York City. Grunblatt, who earned his PhD from the IfA, added that “these observations offer new windows into planets nearing the end of their lives, before their host stars swallow them up.”

Astronomers capture red supergiant’s death throes

Artistic illustrations of a red supergiant exploding.
Credit: W.M. Keck Observatory/Adam Makarenko.

For the first time ever, astronomers have imaged in real time the dramatic end to a red supergiant’s life — watching the massive star’s rapid self-destruction and final death throes before collapsing into a type II supernova.

Led by researchers at Northwestern University and the University of California, Berkeley (UC Berkeley), the team observed the red supergiant during its last 130 days leading up to its deadly detonation.

The discovery defies previous ideas of how red supergiant stars evolve right before exploding. Earlier observations showed that red supergiants were relatively quiescent before their deaths — with no evidence of violent eruptions or luminous emissions. The new observations, however, detected bright radiation from a red supergiant in the final year before exploding. This suggests at least some of these stars must undergo significant changes in their internal structure, which then result in the tumultuous ejection of gas moments before they collapse.

“This is a breakthrough in our understanding of what massive stars do moments before they die,” said Wynn Jacobson-Galán, the study’s lead author. “Direct detection of pre-supernova activity in a red supergiant star has never been observed before in an ordinary type II supernova. For the first time, we watched a red supergiant star explode.”

New year's mission to start new phase of exoplanet research

Source: University of Birmingham

A mission to one of the coldest and most remote places on earth will enable a new phase in the search for distant planetary systems.

University of Birmingham PhD researcher Georgina Dransfield has travelled to the Franco-Italian Concordia Research Station in Antarctica, to oversee the installation of a new state-of-the-art camera at the ASTEP (Antarctic Search for Transiting ExoPlanets) telescope.

The new instrument will enable scientists to see a much wider range of planets orbiting suns outside the Solar system, broadening our search for planets capable of hosting life.

The ASTEP telescope detects signals from distant planetary systems using the ‘transit’ method, measuring the slight dips in brightness that occur when a planet passes between Earth and its host star.

Purchased with support from the Science and Technology Facilities Council and from the European Research Council, the telescope’s new camera is sensitive to the reddest wavelengths in the spectrum. This means it can spot the smallest stars in our galaxy, which are colder, fainter and therefore redder.

“It is easier to detect smaller planets orbiting these small stars, so we have a good chance of being able to detect planets of a similar size and temperature to the Earth, thanks to this new camera,” explained Georgina.

The camera also has a ‘blue’ channel, so can see in two colors at once. This will enable astronomers to distinguish planetary signals from parasitic signals produced by other astrophysical phenomena, enabling new planets to be confirmed more rapidly and efficiently.

Scientists, students will utilize newly launched James Webb Space Telescope for solar system research

The flight mirrors for the James Webb Space Telescope undergo cryogenic testing at NASA Marshall. Credit: Ball Aerospace

In one of the most exciting developments in astronomy in the 21st century, NASA is launching the James Webb Space Telescope (JWST) today—and Northern Arizona University astronomers, planetary astronomers and their students will use the massive observatory to expand their research and advance our understanding of the solar system.

“Webb is NASA’s newest premier space science observatory—destined to be a household name, like its predecessor, Hubble,” NASA announced. “This is an Apollo moment for NASA science—Webb will fundamentally alter our understanding of the universe. It can observe all of the cosmos, from planets to stars to nebulae to galaxies and beyond—helping scientists uncover secrets of the distant universe as well as exoplanets closer to home. Webb can explore our own solar system’s residents with exquisite new detail and search for faint signals from the first galaxies ever made. From new forming stars to devouring black holes, Webb will reveal all this and more.”

The JWST, which NASA calls “a feat of human ingenuity,” is being launched in a global partnership with the European Space Agency and Canadian Space Agency. The mission has evolved over the past 20 years with contributions from thousands of scientists, engineers and other professionals from more than 14 countries and 29 U.S. states, including professor David Trilling, professor Josh Emery and assistant professor Cristina Thomas of NAU’s Department of Astronomy and Planetary Science.

ESO telescopes help uncover largest group of rogue planets

This artist’s impression shows an example of a rogue planet with the Rho Ophiuchi cloud complex visible in the background. Rogue planets have masses comparable to those of the planets in our Solar System but do not orbit a star, instead roaming freely on their own. 
Credit: ESO/M. Kornmesser

Rogue planets are elusive cosmic objects that have masses comparable to those of the planets in our Solar System but do not orbit a star, instead roaming freely on their own. Not many were known until now, but a team of astronomers, using data from several European Southern Observatory (ESO) telescopes and other facilities, have just discovered at least 70 new rogue planets in our galaxy. This is the largest group of rogue planets ever discovered, an important step towards understanding the origins and features of these mysterious galactic nomads.

New class of galac­tic nebulae disco­vered

Image: Discovery image of the nebula. For this image, 120 individual exposures had to be combined to obtain a total exposure time of 20 hours. The images were taken over several months from Brazil. Credit: Maicon Germiniani

An international team of astronomers led by Stefan Kimeswenger from the Department of Astro and Particle Physics, together with scientific amateurs, has identified a new class of galactic nebulae. This provides an important building block in the understanding of stellar evolution and shows the importance of international collaboration between university research and community science.

For the first time, scientists, starting from a discovery by scientific amateurs, have succeeded in providing evidence for a fully developed shell of a common-envelope-system (CE) – the phase of the common envelope of a binary star system. “Toward the end of their lives, normal stars inflate into red giant stars. Since a very large fraction of stars are in binary stars, this affects the evolution at the end of their lives. In close binary systems, the inflating outer part of a star merges as a common envelope around both stars. However, inside this gas envelope the cores of the two stars are practically undisturbed and follow their evolution like independent single stars,” explains astrophysicist Stefan Kimeswenger. The researchers have now published their results in the journal Astronomy & Astrophysics.