What we get with yesterday's gravitational wave announcement isn't a breakthrough in itself. After all, this is not the first but the fourth detection of a black hole merger, so as we enter the era of gravitational wave astronomy, we're beginning to build our catalog of exotic objects. But the gravitational wave known as GW170814 is significant because of the addition of the Virgo Gravitational-Wave Observatory to our toolkit. We ramp up our capabilities at locating the objects we detect in the sky when we factor in this new detector. Thus Chad Hanna (Penn State), who served as co-chair of the group within LIGO (Laser Interferometer Gravitational-Wave Observatory) that made all previous detections: "It is our hope to one day detect gravitational waves and to simultaneously observe the source of the gravitational waves with conventional telescopes so that we might learn even more about what causes the gravitational waves. In order to do that, we need to know where to look. LIGO and...

How 'normal' is the Milky Way? It's an interesting question because as we look out into a visible universe filled with perhaps 100 billion galaxies, we base many of our models for their behavior on what we know of our own. That this may not be the best way to proceed is brought home by a much smaller study, the comparison between our Solar System and what we've been finding around other stars. Finding Solar System analogs has proven surprisingly difficult, although older models assumed outer gas giants and inner rocky worlds as a common pattern. Thus I am keeping an eye on a survey called Satellites Around Galactic Analogs (SAGA), which is looking into galaxies with smaller satellite galaxies. We're only in the early days of this survey, with eight galaxies now examined in a new paper from lead author Marla Geha (Yale University). But the goal is 100 galaxies, with 25 of these studied within the next two years. Image: A three-color optical image of a Milky Way sibling. Credit: Sloan...

Andrew Siemion, who heads up the Breakthrough Listen initiative and is director of the Berkeley SETI Research Center, sent out a message to astronomers on August 29 noting recent activity from the radio source FRB 121102. The heightened activity had been noted by Breakthrough Listen postdoctoral researcher Vishal Gajjar. You'll recall that Fast Radio Bursts (FRBs) are powerful but extremely short-duration radio pulses whose sources generally remain unknown. What tags FRB 121102 as especially interesting is that it is the only FRB known to repeat. In fact, more than 150 bursts have been observed coming from the dwarf galaxy 3 billion light years from Earth that is thought to be its place of origin. And now we have heightened activity in the form of 15 new bursts, as the Astronomer's Telegram notes: These are the highest frequency and widest bandwidth detections of bursts from FRB 121102 obtained to-date. Additional fully calibrated full-Stokes analysis employing coherent dedispersion...

Red supergiants are stars more massive than 9 times the mass of the Sun, a late stage of stellar evolution in which the stars' atmospheres become expansive, while lowering in density. Antares, the brightest star in the constellation Scorpius, is about 12 times as massive as the Sun, but its diameter is 700 times larger. Its mass was once thought to be 15 times that of the Sun, with three solar masses of material being shed during its lifetime. If located in our Solar System, its outer edges would reach somewhere between the orbits of Mars and Jupiter. Now we have word that scientists using the European Southern Observatory's Very Large Telescope Interferometer (VLTI) at Paranal Observatory in Chile have been able to map the surface of this star, and to measure the motion of its surface material. What we get out of all this is the best image of the surface and atmosphere of any star other than our own. Image: VLTI reconstructed view of the surface of Antares. Credit: ESO. Lead author...

I often think of brown dwarfs in terms of the planets that might form around them, and the question of whether even these small 'failed stars' may be capable of sustaining life. Have a look, for example, at Luhman 16AB, two brown dwarfs in the Sun's immediate neighborhood. There are some indications of a planet here which, if it were ever confirmed, would make it the second closest known exoplanet to the Earth, at least for now. We can rule out planets of Neptune mass or greater with a period of between one and two years, but future Hubble observations, already approved for August of next year, may tell us more. Image: Luhman 16AB, two brown dwarfs in the Sun's neighborhood. Credit: NASA / JPL / Gemini Observatory / AURA / NSF. But brown dwarfs, incapable of fusing chemical elements, have their own planetary characteristics. It's this intriguing aspect of this population that gives us a kind of bridge to exoplanet systems, because brown dwarfs are often found alone, without a bright...

Interesting news this morning that begins with the Very Large Array in New Mexico, which a team of astronomers has been using to look at star formation. Their target: The Perseus molecular cloud, a stellar nursery about 600 light years from Earth. Clouds like this are sufficiently large (this one is about 50 light years in length) and dense to permit molecules to form, with molecular hydrogen (H2) being the most common, along with carbon monoxide (CO). Although we can't see into them in visible light (they appear as holes in the starry background because dust and gas obscure the stars forming inside, as well as background stars), such molecular clouds are ideally suited for study with radio telescopes. The VLA survey, called VANDAM (VLA Nascent Disk and Multiplicity) surveyed all the young stars in the Perseus cloud, including both single and multiple stars at separations down to < 20 AU. And now a duo of astronomers has supplemented the VLA data with observations from the James...

The ongoing dimming of Boyajian’s Star will result in a flood of new data from a wide variety of instruments worldwide, excellent news for those trying to piece together what is happening here. I hope you saw Tabetha Boyajian’s interview with David Kipping over the weekend, but if not, you can see it archived here. I tracked the story on Twitter all weekend, and as I did so, I was reminded of the recent news about Fomalhaut, where massive comets may explain what we are seeing in the star’s debris disk. You’ll recall that early in the work on Boyajian’s Star, comets were one explanation for its anomalous light curves, and it will be interesting to see whether the cometary hypothesis can stand up to the influx of new information. Interesting as well to look at the new data in terms of Kepler’s, asking whether this is a periodic dimming, and hence not the result of intervening material between us and the star. Latest photometry from last night; this event seems to have ended, but...

Our catalog of distant, highly energetic events continues to grow. On the Fast Radio Burst (FRB) front, we have the welcome news that the Molonglo radio telescope some 40 kilometers from Canberra, Australia has undergone extensive re-engineering, a project that is paying off with the detection of three new FRBs. The telescope's collecting area of 18,000 square meters and an eight square degree field of view make it ideal for such work. Image: Artist's impression shows three bright red flashes depicting Fast Radio Bursts far beyond the Milky Way, appearing in the constellations Puppis and Hydra. Credit: James Josephides/Mike Dalley. You'll recall that Fast Radio Bursts are millisecond long, intense pulses that can appear out of nowhere with a luminosity a billion times greater than anything we have observed in the Milky Way. The phenomenon was noted for the first time a decade ago at the Parkes radio telescope in New South Wales. The sources remain enigmatic, but Manisha Caleb, a PhD...

When I was growing up, there was a small outbuilding between my house and the stand of woods behind our property. The previous owner had built it as a little house in its own right, everything on a miniature scale, so that while it looked like an actual house -- with front door, nice windows, even a porch and small deck on the back -- it was comprised of only one room inside. This man's kids had used it as a playhouse, but when I got my hands on it, I turned it into what a young boy thought of as his 'lab,' with microscope, chemistry set and telescope. On the walls I put photographs I had bought at Chicago's Adler Planetarium, and I can still see those blurry images of Saturn, Jupiter and the Milky Way, all taken at the Palomar Observatory, and almost as breathtaking for what they didn't reveal as what they did. I gradually augmented these photos with sky charts and other imagery, and would use these to plan my observing sessions with the 3-inch reflector I would take out into the...

Unexpected things can happen when you’re looking for exoplanets. Ask Kevin Luhman (Penn State), whose search for free-floating planets in the Orion Nebula is now telling us something interesting about star formation in general. In a small region dominated by young stars called the Kleinmann-Low Nebula, some 1300 light years from Earth near the center of the Orion Nebula complex, Luhman and team have come across evidence of a multiple star system whose members have flown rapidly apart due to gravitational interactions with their peers. Luhman’s team was using the Hubble instrument’s Wide Field Camera 3 to run the planet-hunting survey, working with Massimo Robberto (Space Telescope Science Institute) and a group of international colleagues. A star referenced only as ‘source x’ turned up in a comparison between 2015 imagery in the infrared and infrared observations made in 1998 with the Hubble telescope’s Near Infrared Camera and Multi-Object Spectrometer. The surprise: ‘Source x’ had...

Beyond their obvious value in advancing our knowledge, astronomical discoveries can be thought of as exercises for the imagination, making us think about what we would see if we were actually near the phenomenon being observed. The view from a planet deep in a globular cluster can only be spectacular, and has been the subject of my own musings for many years. But this morning's topic, a white dwarf star in a fantastically tight orbit around a black hole, leaves my imagination reeling. Just what would a scenario like the one playing out in the globular cluster 47 Tucanae, some 14,800 light years from Earth, look like up close? Here we find, thanks to the space-based Chandra X-Ray Observatory and NuSTAR (Nuclear Spectroscopic Telescope Array), as well as the Australia Telescope Compact Array, a binary that consists of an apparent white dwarf orbiting a black hole every 28 minutes. The presence of large amounts of oxygen in the system gives weight to the idea that the companion is...

Discovered as recently as 1994, the Sagittarius dwarf spheroidal galaxy is a satellite of the Milky Way, and one with an interesting history. One of the nearest of the dwarf galaxies, the Sagittarius dwarf lies 25 kiloparsecs (roughly 82,000 light years) from the center of the Milky Way, and has passed through the disk of the parent galaxy more than once. The result: We see what a new paper on this object calls a ‘stream of tidally stripped stars’ that wraps completely around the celestial sphere. Our own Sun, in fact, is close enough to the Sgr galaxy’s orbital plane that it lies within the width of what can be called the debris tail. What astronomers would like to do is to reconstruct the orbital history of this interesting dwarf galaxy, something Marion Dierickx (Harvard-Smithsonian Center for Astrophysics), working with her PhD advisor Avi Loeb (Harvard) have now managed through computer simulations. Dierickx and Loeb simulated the movements of the Sgr dwarf for the past 8...

Fast Radio Bursts (FRBs) are problematic. Since their discovery about a decade ago, the question has been their place of origin. These transient pulses last no more than milliseconds, yet they emit enormous energies, and we've had only the sketchiest idea where they came from. Now we learn, from an announcement at the 229th meeting of the American Astronomical Society in Grapevine, Texas, that a repeating source of FRBs has been spotted. That makes tracing the burst back to its source and characterizing it an ongoing proposition. "We now know that this particular burst comes from a dwarf galaxy more than three billion light-years from Earth," says Shami Chatterjee, of Cornell University. "That simple fact is a huge advance in our understanding of these events." Papers on the work are being presented in Nature as well as Astrophysical Journal Letters. Research behind the investigation of FRB 121102 has been mounted by an international team of astronomers, representing a spread of...

When Vera Rubin went to Cornell University to earn a master's degree, she quickly found herself immersed in galaxy dynamics, lured to the topic by Martha Stahr Carpenter. The interest, though, was a natural one; it drew on Rubin's childhood fascination with the motion of stars across the sky. You could say that motion captivated her from her earliest days. At Cornell, she studied physics from such luminaries as Richard Feynman, Philip Morrison and Hans Bethe. She would complete the degree in 1951 and head on to Georgetown. Rubin, who died on Christmas day, was possessed of a curiosity that made her ask questions others hadn't thought of. In Bright Galaxies, Dark Matters (1997), a collection of her papers, the astronomer recalls writing to Milton Humason in 1949, asking him about the redshifts he and his colleagues were compiling. Rubin had heard that many had yet to be published, and she would use those she had to look for systematic motion among the galaxies, motion that would show...

A 1.8 meter telescope at the summit of Haleakal? on Maui is the first instrument in use at the Pan-STARRS (Panoramic Survey Telescope & Rapid Response System) observatory. Pan-STARRS recently completed a digital survey of the sky in visible and infrared wavelengths that began in May of 2010, a project that surveyed the entire sky visible from Hawaii over a period of four years, scanning it 12 times in each of five filters. The result is a collection of 3 billion separate sources, including not just stars and galaxies but numerous transient, moving and variable objects. All told, we’re dealing with about 2 petabytes of data. Now we learn that data from the survey is being made available worldwide. Ken Chambers, director of the Pan-STARRS observatories, comments: "The Pan-STARRS1 Surveys allow anyone to access millions of images and use the database and catalogs containing precision measurements of billions of stars and galaxies. Pan-STARRS has made discoveries from Near Earth Objects...

The supernova considered to be the brightest ever recorded may have been evidence of something even more exotic. The explosion was caught by the All Sky Automated Survey for SuperNovae (ASAS-SN), the event itself dubbed ASASSN-15h. Yesterday we looked at what happens to a star roughly as massive as the Sun as it goes through a red giant phase and becomes a white dwarf, but stars significantly more massive than the Sun take no such route. A star a minimum of 8 times the mass of the Sun can explode as a Type II supernova. But is that what ASASSN-15h really was? Detected in 2015 in a galaxy about 4 billion light years from Earth, the event has now been the subject of new work by an international team led by Giorgos Leloudas (Weizmann Institute of Science, Israel) and the Dark Cosmology Centre (Denmark). From this we get a new explanation: ASASSN-15h may have been the result of a rapidly spinning supermassive black hole tearing a relatively low mass star apart. The passing star, in other...

The star L2 Puppis (HD 56096), a red giant in the direction of the southern constellation Puppis (the Poop Deck), is the subject of interesting new investigations using data from the ALMA array in Chile. The star appears to belong on the asymptotic giant branch of the Hertzsprung-Russell diagram, a category dominated by highly evolved cool stars. The new study sees L2 Puppis as an analog for what our own Sun will become in billions of years. Thus Ward Homan (KU Leuven Institute of Astronomy, Belgium): "We discovered that L2 Puppis is about 10 billion years old. Five billion years ago, the star was an almost perfect twin of our Sun as it is today, with the same mass. One third of this mass was lost during the evolution of the star. The same will happen with our Sun in the very distant future." Image: Composite view of L2 Puppis in visible light | © P. Kervella et al. (CNRS/U. de Chile/Observatoire de Paris/LESIA/ESO/ALMA). But L2 Puppis is more than just an interesting glimpse at what...

Could laser light be used to shape and polish an asteroid to high optical standards? That's the question raised in an imaginative essay in Physics Today that posits the creation, a century from now, of the Asteroid Belt Astronomical Telescope (ABAT). It's science fiction today, part of the series of speculations that the magazine has been running to explore possible futures, but what a concept for an SF novel, and perhaps someday real astronomy (thanks to Centauri Dreams reader Klaus Seidensticker for sending me the link). Author Robert Austin (Florida Polytechnic University) creates a backstory involving a "self-described over-the-hill assistant professor at Purdue University" who uses a research grant to polish a 1-centimeter sphere of pyrolytic carbon magnetically levitated in a vacuum. He achieves the needed flat optical surface along with a reflective hemispherical 'bump' on the object's backside that can be used to reorient the mirror by photon pressure. Soon the idea of using...

One of the brightest Fast Radio Bursts seen since the phenomena were first detected in 2001 has been observed by the Parkes radio telescope in New South Wales. Maybe it should come as no surprise that Parkes was involved, given that most of the 18 FRBs that have so far been detected have been found there, including the so-called 'Lorimer' burst of 2001, which launched researchers' interest in these mysterious processes. This one is thought to be particularly helpful in constraining magnetic fields and gases in intergalactic space, for observed distortions produced by an FRB's travel yield data about the medium. Ryan Shannon (ICRAR-Curtin University), a co-author of the paper, refers to the region between the galaxies as the 'cosmic web,' a region of all but invisible gases and plasma particles that is extremely hard to map. FRBs are short but intense pulses of radio waves -- each lasts about a millisecond -- that are usually discovered by accident, and no two look the same. Radio...

A newly discovered brown dwarf dubbed OGLE-2015-BLG-1319 is significant on several fronts, not the least of which is how it was found. Not only are we dealing here with another instance of gravitational microlensing, where the light of a background star is affected by a foreground object in ways that give us information about the closer star, but this instance of microlensing saw two space telescopes working together to make sense of the event, the first time a microlensing event has been observed by two space telescopes and from the ground. The space-based instruments in question are the Spitzer and Swift telescopes, whose combined observations give us different magnification patterns rising from the same event. Spitzer observed the binary system containing the brown dwarf in July of 2015 from its perch about 1 AU away from the Earth. Swift, in low Earth orbit, also saw the system in late June of that year, marking its first microlensing observation. The first notification of the...