Longest-Lasting Stellar Eclipse: Three-And-A-Half Year Eclipses In Binary System

Imagine living on a world where, every 69 years, the sun disappears in a near-total eclipse that lasts for three and a half years.

That is just what happens in an unnamed binary star system nearly 10,000 light years from Earth. The newly discovered system, known only by its astronomical catalog number TYC 2505-672-1, sets a new record for both the longest duration stellar eclipse and the longest period between eclipses in a binary system.


Discovery of the system’s extraordinary properties was made by a team of astronomers from Vanderbilt and Harvard with the assistance of colleagues at Lehigh, Ohio State and Pennsylvania State universities, Las Cumbres Observatory Global Telescope Network and the American Association of Variable Star Observers and is described in a paper accepted for publication in the Astronomical Journal.

“It’s the longest duration stellar eclipse and the longest orbit for an eclipsing binary ever found…by far,” said the paper’s first author Vanderbilt doctoral student Joey Rodriguez.

The previous record holder is Epsilon Aurigae, a giant star that is eclipsed by its companion every 27 years for periods ranging from 640 to 730 days.

“Epsilon Aurigae is much closer — about 2,200 light years from Earth — and brighter, which has allowed astronomers to study it extensively,” said Rodriguez. The leading explanation is that Epsilon Aurigae consists of a yellow giant star orbited by a normal star slightly bigger than the sun embedded in a thick disk of dust and gas oriented nearly edge on when viewed from Earth.

“One of the great challenges in astronomy is that some of the most important phenomena occur on astronomical timescales, yet astronomers are generally limited to much shorter human timescales,” said co-author Keivan Stassun, professor of physics and astronomy at Vanderbilt. “Here we have a rare opportunity to study a phenomenon that plays out over many decades and provides a window into the types of environments around stars that could represent planetary building blocks at the very end of a star system’s life.”

Two unique astronomical resources made the discovery possible: observations by the American Association of Variable Star Observers (AAVSO) network and the Digital Access to a Sky Century @ Harvard (DASCH) program.

AAVSO is a non-profit organization of professional and amateur astronomers dedicated to understanding variable stars. It provided a few hundred observations of TYC 2505-672-1’s most recent eclipse.

The DASCH survey is based on thousands of photographic plates taken by Harvard astronomers between 1890 and 1989 as part of a regular survey of the northern sky. In recent years the university has begun digitizing these plates. In the process TYC 2505-672-1 caught the eye of Sumin Tang at the Harvard-Smithsonian Center for Astrophysics.

Rodriguez attended a conference where Tang presented her results on TYC 2505-672-1 and the system piqued his interest as well. He is a member of the survey team for the low-cost Kilodegree Extremely Little Telescope (KELT) system that consists of a pair of robotic telescopes designed to find exoplanets around bright stars operated by astronomers at Ohio State University, Vanderbilt University, Lehigh University and the South African Astronomical Observatory. KELT has an extremely wide field of view (26 degrees by 26 degrees) and he thought it was likely that the KELT database contained a number of recent images of the distant binary system.

After the lecture Rodriguez contacted Tang and they agreed to collaborate. When he searched the KELT database, Rodriguez found about 9,000 images of the obscure system taken in the last eight years that they could combine with the 1,432 images taken over the last century at Harvard. Rodriquez also contacted the AAVSO network and obtained several hundred more observations of the system’s most recent eclipse to help fill in the picture. When she became busy with some other projects, Tang agreed to let Rodriguez take the lead.

The resulting analysis revealed a system similar to the one at Epsilon Aurigae, with some important differences. It appears to consist of a pair of red giant stars, one of which has been stripped down to a relatively small core and surrounded by an extremely large disk of material that produces the extended eclipse.

“About the only way to get these really long eclipse times is with an extended disk of opaque material. Nothing else is big enough to block out a star for months at a time,” Rodriguez said.

TYC-2505-672-1 is so distant that the amount of data the astronomers could extract from the images was limited. However, they were able to estimate the surface temperature of the companion star and found that it is about 2,000 degrees Celsius hotter than the surface of the sun. Combined with the observation that it appears to be less than half the diameter of the sun has led them to propose that it is a red giant that has had its outer layers stripped away and that this stripped material may account for the obscuring disk. However, they don’t know that for certain.

In order to produce the 69-year interval between eclipses, the astronomers calculate that they must be orbiting at an extremely large distance, about 20 astronomical units, which is approximately the distance between the Sun and Uranus.

“Right now even our most powerful telescopes can’t independently resolve the two objects,” said Rodriguez. “Hopefully, technological advances will make that possible by 2080 when the next eclipse occurs.”

Michael B. Lund and Kyle Conroy at Vanderbilt University; Joshua Pepper at Lehigh University; Robert Siverd at Las Cumbres Observatory Global Telescope Network; Stella Kafka at the American Association of Variable Star Observers; Scott Gaudi and Daniel Stevens at Ohio State University; and Thomas Beatty at Pennsylvania State University also contributed to the study.

The research was funded by National Science Foundation grants NNG040G070G, AST-1056524, AST-1358862, AST-0407380, AST-0909073, AST-1313370, AST-0909182 and AST-1313422 and National Aeronautics and Space Administration grant NNG05GF22G.

First Detection Of Gases At Super-Earth Show A Light-Weight, Dry Atmosphere – With A Hint Of Carbon Too?

The first successful detection of gases in the atmosphere of a super-Earth reveals the presence of hydrogen and helium, but no water vapour. The exotic exoplanet, 55 Cancri e, is over eight times the mass of Earth and has previously been dubbed the ‘diamond planet’ because models based on its mass and radius have led some astronomers to speculate that its interior is carbon-rich. Now, using new processing techniques on data from the NASA/ESA Hubble Space Telescope, a UCL-led team of European researchers has been able to examine the atmosphere of 55 Cancri e, also known as ‘Janssen’, in unprecedented detail. The results will be published in the Astrophysical Journal.


“This is a very exciting result because it’s the first time that we have been able to find the spectral fingerprints that show the gases present in the atmosphere of a super-Earth,” said Angelos Tsiaras, a PhD student at UCL, who developed the analysis technique along with colleagues Dr Ingo Waldmann and Marco Rocchetto in UCL Physics & Astronomy. “Our analysis of 55 Cancri e’s atmosphere suggests that the planet has managed to cling on to a significant amount of hydrogen and helium from the nebula from which it formed.”

Super-Earths are thought to be the most common planetary type in our galaxy and are so-called because they have a mass larger than Earth but are still much smaller than the gas giants in the Solar System. The Wide Field Camera 3 (WFC3) on Hubble has already been used to probe the atmosphere of two super-Earths, but no spectral features were found in these previous studies.

55 Cancri e has a year that lasts 18 hours and temperatures on the surface are thought to reach around 2000 degrees Celsius. The planet is located in a solar system around 55 Cancri, also known as ‘Copernicus’, a star in the Cancer constellation that is around 40 light-years from Earth. Because 55 Cancri is such a bright star, the team were able to use new analysis techniques to extract information about its planetary companion.

Observations were made by scanning WFC3 very quickly across the star to create a number of spectra. By combining these observations and processing through computer analytic ‘pipeline’ software, the researchers were able to retrieve the spectral fingerprints of 55 Cancri e embedded in the starlight.

“This result gives a first insight into the atmosphere of a super-Earth. We now have clues as to what the planet is currently like, how it might have formed and evolved, and this has important implications for 55 Cancri e and other super-Earths,” said Professor Giovanna Tinetti, also from UCL.

Intriguingly, the data also hinted at a signature for hydrogen cyanide, a marker for carbon-rich atmospheres.

“Such an amount of hydrogen cyanide would indicate an atmosphere with a very high ratio of carbon to oxygen,” said Dr Olivia Venot, KU Leuven, Belgium, who developed an atmospheric chemical model of 55 Cancri e that supported the analysis of the observations.

“If the presence of hydrogen cyanide and other molecules is confirmed in a few years time by the next generation of infrared telescopes, it would support the theory that this planet is indeed carbon rich and a very exotic place,” said Professor Jonathan Tennyson, UCL. “Although, hydrogen cyanide or prussic acid is highly poisonous, so it is perhaps not a planet I would like to live on!”

Gravitational Waves Offer Glimpse Into The Past – But Will We Ever Catch Ripples From The Big Bang?

Einstein was right – changes in gravity do spread as waves through space. The LIGO experiment detected such waves from a collision between two black holes with masses of about 36 and 29 times that of the sun (described as 36 and 29 “solar masses”). But the merger of these 65 solar masses in total created a remnant of just 62 – so what happened to the other three? These were used to power the burst of gravitational waves, in a spectacular demonstration of Einstein’s famous formula, E=Mc2, where mass and energy are equivalent.


This is only the beginning. Now that we know how to measure gravitational waves, we can use experiments like LIGO to learn about events in the cosmos that we have never been able to see before, such as mergers of supermassive black holes in the early universe. But how far back can we go? What about “primordial” gravitational waves from the birth of the universe itself – will LIGO’s discovery help us catch those?

Looking back in time

Although the masses involved in this event are large by stellar standards, they are dwarfed by the supermassive black holes that astronomers believe are present at the centre of almost every galaxy. Our own galaxy, the Milky Way, hosts a hole of about 4m sun masses, detected through the motions of stars orbiting it. Even this is fairly insignificant compared with the holes of up to tens of billions of sun masses thought to be at the centre of the largest galaxies.

There are many things astronomers want to know about these supermassive black holes. We currently see them through the vast amounts of electromagnetic radiation, like visible light and X-rays, produced as gas falls into them. We know that this process helps them grow but it is nevertheless mysterious – most of the gas in galaxies moves too fast or is too far away for the black holes to capture it. So how could they get so big?

It could be that collisions between these supermassive holes helped to grow them, especially when they were relatively young and had not yet gained much gas. However, a collision between two supermassive black holes can probably only happen if the two galaxies hosting them collide and merge too. This is an inherently rare event in the nearby universe, as galaxies are far away from each other. But it must have been much more common soon after the universe was born in the Big Bang, when galaxies were much closer together.

So detecting gravitational waves from such collisions means looking back in time – observing the most distant galaxies. Light from these galaxies set off on its journey to us only a relatively short time after the Big Bang. This could give us direct clues about how important these events were in growing supermassive black holes early in their lives. This is relevant to our own existence – the electromagnetic radiation thrown out as black holes grow has had a major effect on shaping the galaxies in which stars and planets, including our own, live peaceful lives.

To make such observations will require detectors with sizes far larger than the 4km arms of LIGO. The proposed eLISA experiment will put three satellites into orbit as an equilateral triangle with sides longer than the distance from the Earth to the moon.

The problem with primordial waves

But even supermassive black hole collisions are not the ultimate goal. The Big Bang, and particularly the epoch of very rapid expansion dubbed inflation – which many experts believe took place very soon after – must have involved enormous masses moving with almost light speed. This means that they must have produced powerful gravitational waves. However, the most powerful signal comes from masses whose size is comparable to the scale of the universe itself. Since gravitational radiation has a typical wavelength larger than the masses emitting it, the “wavelength” of this radiation is itself similar to the entire size of the universe. So LIGO, or any other experiment that is smaller than the universe, will not be able to detect it.

Detecting these waves must probably be done indirectly by observing their effects on cosmic microwave background radiation (CMB) – the radiation left over from the Big Bang.

When light waves vibrate in a certain direction, we say that the light has a specific polarisation. If gravitational waves were present at the time when the CMB was born, they should leave behind a unique swirly pattern –- a curling in the polarisation of the light –- dubbed “B modes”. A result based on B modes was claimed a few years ago, but it turned out the signal had just been caused by cosmic dust. This is just one of the many competing effects that can distort the CMB polarisation, showing just how hard it will be to detect the true signal.

The stakes are incredibly high. A positive result could give evidence for the popular inflation theory, and offer explanations for several puzzling features of the universe, such as why the distribution of matter is so homogeneous. Although finding such a signal is an enormous challenge, so was the direct detection of gravitational waves when first proposed half a century ago.

BREAKING NEWS: New Discovery of Over 800 Galaxies Behind Milky Way

Lead author Professor Lister Staveley-Smith, from The University of Western Australia node of the International Centre for Radio Astronomy Research (ICRAR), said the team found 883 galaxies, a third of which had never been seen before. “Scientists have been trying to get to the bottom of the mysterious Great Attractor since major deviations from universal expansion were first discovered in the 1970s and 1980s. We don’t actually understand what’s causing this gravitational acceleration on the Milky Way or where it’s coming from.”


Using CSIRO’s Parkes radio telescope equipped with an innovative receiver, an international team of scientists were able to see through the stars and dust of the Milky Way, into a previously unexplored region of space. The discovery may help to explain the Great Attractor region, which appears to be drawing the Milky Way and hundreds of thousands of other galaxies towards it with a gravitational force equivalent to a million billion Suns.


“An average galaxy contains 100 billion stars, so finding hundreds of new galaxies hidden behind the Milky Way points to a lot of mass we didn’t know about until now,” said University of Cape Town astronomer Professor Renée Kraan-Korteweg. Dr. Bärbel Koribalski from CSIRO Astronomy and Space Science said, “With the 21-cm multibeam receiver on Parkes we’re able to map the sky 13 times faster than we could before and make new discoveries at a much greater rate.”


New Equation:
Increase Charged Particles and Decreased Magnetic Field → Increase Outer Core Convection → Increase of Mantle Plumes → Increase in Earthquake and Volcanoes → Cools Mantle and Outer Core → Return of Outer Core Convection (Mitch Battros – July 2012)

The research identified several new structures that could help to explain the movement of the Milky Way, including three galaxy concentrations (named NW1, NW2 and NW3) and two new clusters (named CW1 and CW2). The study involved researchers from Australia, South Africa, the US and the Netherlands, and was published today in the Astronomical Journal.

Revolutionary Discovery: Scientists Find Gravitational Waves Einstein Predicted

In a discovery that promises to revolutionize astronomy, scientists have made the first direct observations of gravitational waves – bizarre ripples in space-time foreseen by Albert Einstein a century ago.


The find is a triumph for Einstein’s celebrated general theory of relativity, the basis of his 1916 prediction that the fabric of the universe is perturbed by gravitational energy. The find is also a triumph for the mammoth scientific apparatus – the Laser Interferometer Gravitational-wave Observatory (LIGO) – that was the first to pick up the stealthy advance of these waves, in this case created by the violent union of two black holes 1.3 billion years ago.

Other scientists hailed the find as the kind of advance that comes along only once or twice in a lifetime. Because gravitational waves carry information about their source, the ability to detect these weird undulations will allow researchers to study distant and elusive features of the universe. Black holes too far way to study using today’s techniques, for example, should become easy scientific prey with the help of gravitational waves.

Study of the universe via gravitational waves “will be the astronomy of the 21st century,” predicted Arizona State University’s Lawrence Krauss, who is not part of the LIGO team. “This is a whole new window on the universe.”

As far back as the 1970s, scientists garnered indirect evidence for such waves, spawned by the movements of massive objects in space, such as spinning supernovae or whirling pairs of neutron stars. The $1 billion LIGO directly captured the wave itself, which, if confirmed, would be “a monumental extra step,” said Cole Miller of the University of Maryland, who is not affiliated with LIGO either.

LIGO’s twin detectors, one in Hanford, Wash., the other in Livingston, La., picked up the wave on Sept. 14, 2015 – several days before official data collection was scheduled to resume after a five-year renovation of the equipment. Each of LIGO’s outposts consists of an L-shaped tunnel, the arm of each L stretching 2½ miles. When a gravitational wave hits, the length of the arms changes ever so slightly. The detectors are sensitive enough to pick up a length change of only one ten-thousandth the diameter of a proton, which is one of the particles making up an atom.

The gravitational waves detected by LIGO came from the final moments before the collision of two black holes somewhere in the Southern Hemisphere. The two had been spiraling closer and closer toward one another for billions of years, spitting out gravitational waves as they approached.

In the last, cataclysmic instant before they crashed together and merged into one, they generated waves with more energy than the entire visible universe. The waves rippled outward at the speed of light, eventually arriving at – and passing through — Earth.

Many such cosmic spectacles have been invisible to science until now.

“We’re missing some of the most violent, dynamic and exciting things in the universe,” Miller said, but gravitational waves are “going to give us a remarkable view into a universe that has largely been denied us.”

Scientists have never gotten a peep at the very edge of a black hole, for instance. But studying gravitational waves, which are born at that edge, will “allow us to see almost into the heart of a black hole,” Krauss said. The waves will allow researchers to probe “realms we’ve only thought about, realms of science-fiction movies.”

Researchers had long worried that the first sign of gravitational waves would be ambiguous or fuzzy. Instead “the data are spectacular,” said Scott Ransom of the National Radio Astronomy Observatory, adding that the data prompted one of his colleagues to shed tears of happiness.

Assuming the detection is confirmed, Miller says, his reaction is “unalloyed joy. … This is fantastic.”

Gravitational waves confirmed

Astrophysicists have announced the discovery of gravitational waves, ripples that travel at the speed of light through the fabric of space-time. A 1916 theory of Albert Einstein’s predicted their existence.


The ripples can be unleashed by movements of massive objects in space, such as a spinning neutron star or a pair of black holes orbiting each other.


Two black holes swinging around each other create gravitational waves as they spiral closer together.

The ‘Glitching’ Of The Vela Pulsar

A team of Australian astronomers has conducted an intensive observation of a curious young pulsar to investigate changes in its rotation frequency known as ‘glitching’.


Located about 910 light years from the Earth, the Vela pulsar is very young in astronomical terms, only 11,300 years old, and has captured astronomers’ attention with its ‘glitching’ nature. In a paper published online on Feb. 5 on arXiv.org, Jim Palfreyman of the University of Tasmania, together with his teammates, try to provide more insights on the pulsar’s violent behavior.

The astronomers conducted a long-term and single pulse study of Vela, using a 26 m radio telescope at the Mount Pleasant Radio Observatory, located near Hobart, Australia. The observation campaign, lasting 18 months, began in March 2014 and collected over 6,000 hours of single-pulse data. A total of 1.5 petabytes of data were collected, describing about 237 million single pulses.

It is known from previous studies that Vela regularly speeds up in rotation frequency, approximately every three years and also experiences ‘micro-glitches’ a number of times per year. The new research showed Vela’s pulse width change over time, as it changes sharply after a micro-glitch, and that the rate of bright pulse activity also changes with micro-glitches.

“What is affecting pulse width is affecting the entire pulse shape. Our observations show that after the second and larger micro-glitch, the pulse has decreased in width,” the scientists wrote in the paper.

What puzzled Palfreyman’s team is that the first micro-glitch coincides with a sudden increase in bright pulse rates, with no change in pulse width, while the second micro-glitch coincides with a reverse situation, showing sudden decrease in pulse width with no change in bright pulse rate.

“Our data shows a pattern of pulse width increase and then decrease following the small micro-glitch. After the much larger micro-glitch, we see a sharp decrease in pulse width followed by a steady increase,” the researchers noted.

To explain this phenomenon, the scientists suggest that the pulsar’s emission zones might be mathematically chaotic in nature and note that width changes could also be caused by a change in the width of the emission cone. However, this theory relies on the emission zones occurring in the cone, whereas young pulsars like Vela should have main core emission rather than conal emission.

The astronomers also found out that secular changes in Vela’s pulse width have three possible cyclic periods that match with X-ray periodicities of a helical jet, implying free precession. The helical X-ray jet streaming from the rotational axis of the pulsar, potentially caused by precession, has periods of 122, 73 and 91 days, what was revealed in previous research papers.

“We see three definite periods in our pulse width data and the ranges of these fall within the ranges of the ‘acceptable’ periods,” the paper reads.

The researchers concluded that their study is crucial for the understanding of Vela’s daily integrated pulse profile width, which is changing both slowly over time and has a discontinuity after a micro-glitch. According to the new findings, these micro-glitches also affect bright-pulse rates, but in an inconsistent manner.

Palfreyman and his colleagues hope that their results might shed some new light on the pulsar emission and glitching process. They also intend to produce further research papers from the large data set acquired during the 18-month intensive observing campaign.

Scientists Discover Hidden Galaxies Behind The Milky Way

Hundreds of hidden nearby galaxies have been studied for the first time, shedding light on a mysterious gravitational anomaly dubbed the Great Attractor.

milky way

Despite being just 250 million light years from Earth—very close in astronomical terms—the new galaxies had been hidden from view until now by our own galaxy, the Milky Way.

Using CSIRO’s Parkes radio telescope equipped with an innovative receiver, an international team of scientists were able to see through the stars and dust of the Milky Way, into a previously unexplored region of space.

The discovery may help to explain the Great Attractor region, which appears to be drawing the Milky Way and hundreds of thousands of other galaxies towards it with a gravitational force equivalent to a million billion Suns.

Lead author Professor Lister Staveley-Smith, from The University of Western Australia node of the International Centre for Radio Astronomy Research (ICRAR), said the team found 883 galaxies, a third of which had never been seen before.

“The Milky Way is very beautiful of course and it’s very interesting to study our own galaxy but it completely blocks out the view of the more distant galaxies behind it,” he said.

Professor Staveley-Smith said scientists have been trying to get to the bottom of the mysterious Great Attractor since major deviations from universal expansion were first discovered in the 1970s and 1980s.

“We don’t actually understand what’s causing this gravitational acceleration on the Milky Way or where it’s coming from,” he said.

“We know that in this region there are a few very large collections of galaxies we call clusters or superclusters, and our whole Milky Way is moving towards them at more than two million kilometres per hour.”

The research identified several new structures that could help to explain the movement of the Milky Way, including three galaxy concentrations (named NW1, NW2 and NW3) and two new clusters (named CW1 and CW2).

University of Cape Town astronomer Professor Renée Kraan-Korteweg said astronomers have been trying to map the galaxy distribution hidden behind the Milky Way for decades.

“We’ve used a range of techniques but only radio observations have really succeeded in allowing us to see through the thickest foreground layer of dust and stars,” she said.

“An average galaxy contains 100 billion stars, so finding hundreds of new galaxies hidden behind the Milky Way points to a lot of mass we didn’t know about until now.”

Dr. Bärbel Koribalski from CSIRO Astronomy and Space Science said innovative technologies on the Parkes Radio telescope had made it possible to survey large areas of the sky very quickly.