Tag: Telescopes

The Most Detailed Observations of Material Orbiting Close to a Black Hole

ESO’s GRAVITY instrument on the Very Large Telescope (VLT) Interferometer has been used by scientists from a consortium of European institutions, including ESO, to observe flares of infrared radiation coming from the accretion disc around Sagittarius A*, the massive object at the heart of the Milky Way.

The observed flares provide long-awaited confirmation that the object in the centre of our galaxy is, as has long been assumed, a supermassive black hole.

The flares originate from material orbiting very close to the black hole’s event horizon — making these the most detailed observations yet of material orbiting this close to a black hole.

While some matter in the accretion disc — the belt of gas orbiting Sagittarius A* at relativistic speeds — can orbit the black hole safely, anything that gets too close is doomed to be pulled beyond the event horizon.

The closest point to a black hole that material can orbit without being irresistibly drawn inwards by the immense mass is known as the innermost stable orbit, and it is from here that the observed flares originate.

These measurements were only possible thanks to international collaboration and state-of-the-art instrumentation.

The GRAVITY instrument which made this work possible combines the light from four telescopes of ESO’s VLT to create a virtual super-telescope 130 metres in diameter, and has already been used to probe the nature of Sagittarius A*.

Earlier this year, GRAVITY and SINFONI, another instrument on the VLT, allowed the same team to accurately measure the close fly-by of the star S2 as it passed through the extreme gravitational field near Sagittarius A*, and for the first time revealed the effects predicted by Einstein’s general relativity in such an extreme environment.

During S2’s close fly-by, strong infrared emission was also observed.

This emission, from highly energetic electrons very close to the black hole, was visible as three prominent bright flares, and exactly matches theoretical predictions for hot spots orbiting close to a black hole of four million solar masses.

The flares are thought to originate from magnetic interactions in the very hot gas orbiting very close to Sagittarius A*.

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Pass it on: New Scientist

Astronomers May Have Discovered The First Moon Ever Found Outside Our Solar System

An artistic rendering of the Kepler-1625b planetary system.

A pair of astronomers believes they’ve found a moon orbiting a planet outside our Solar System — something that has never before been confirmed to exist.

Though they aren’t totally certain of their discovery yet, the find opens up the possibility that more distant moons are out there. And that could change our understanding of how the Universe is structured.

The astronomy team from Columbia University found this distant satellite, known as an exomoon, using two of NASA’s space telescopes.

They first spotted a signal from the object in data collected by the planet-hunting telescope Kepler, and then they followed up with the Hubble Space Telescope, which is in orbit around Earth.

Thanks to the observations from these two spacecraft, the team suspect this moon orbits around a Jupiter-sized planet located about 4,000 light-years from Earth. And this planet, dubbed Kepler-1625b, orbits around a star similar to our Sun.

Scientists have strongly believed for decades that moons exist outside our Solar System, but these objects have remained elusive for scientists up until now.

There have been just a couple of candidates that astronomers have speculated about in the past, but nothing has been confirmed.

That’s because moons are thought to be too small and too faint to pick up from Earth. However, this suspected exomoon, detailed today in the journal Science Advances, is particularly large, about the size of Neptune, making it one of the few targets that our telescopes can detect.

You can make the argument that this is the lowest hanging fruit,” Alex Teachey, an astronomy graduate student at Columbia University and one of the lead authors on the paper said.

“Because it is so large, in some ways, this is the first thing we should detect because it is the easiest.”

Teachey argues that finding more moons outside our Solar System will change our understanding of how planetary systems formed thousands of light-years away.

Our cosmic neighborhood is filled with moons, and they explain a lot about how our planets came to be. Exomoons could tell similar tales.

NASA’s Hubble Space Telescope.

However, none of our moons come close to the size of this one, which creates a puzzle for astronomers.

Because it is so unusual, or at least has not been anticipated largely by the community, this poses new challenges to explain it,” says Teachey. “How do you get something like this?

It was only a few decades ago — in the late 1980s and early 1990s — that astronomers confirmed the existence of planets outside our Solar System.

Since then, thousands of these distant worlds, known as exoplanets, have been confirmed by spacecraft like Kepler and other telescopes.

Perhaps the most popular way to find exoplanets is by staring at stars, waiting for them to flicker. When a planet crosses “in front” of its host star, it dims the stars’ light ever so slightly.

These dips in brightness can be used to determine how big a planet is and the kind of orbit it’s on.

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Over The Past Nineteen Years, This Man Has Dedicated His Work To The Study Of Our Solar System

Dr. Franck Marchis is a senior planetary astronomer and chair of the exoplanet group at the Carl Sagan Center of the SETI Institute and Chief Scientific Officer and Founder at Unistellar.

He began full-time work at the Institute in June 2011 after leaving a joint position with Institute and the department of astronomy at University of California, Berkeley.

Marchis moved to the United States in October 2000 shortly after getting a Ph.D. from the University of Toulouse in France that he acquired while traveling around the world for his research and for the sake of exploration.

Over the past nineteen years, he has dedicated his work to the study of our solar system, specifically the search for asteroids with moons, using mainly ground-based telescopes equipped with adaptive optics (AO).

More recently he has been also involved in the definition of new generation of AOs for 8 -10 m class telescopes and future Extremely Large Telescopes.

He has also developed algorithms to process and enhance the quality of astronomical and biological images.

He is currently the collaboration manager of the Gemini Planet Imager Exoplanet Survey, which consists in imaging and characterizing Jupiter-like exoplanets using an extreme AO system designed for the Gemini South telescope.

Today, Marchis dedicates most of his energy to instruments capable of imaging and characterizing Earth-like exoplanets by being involved in education, public outreach, technology, and scientific investigations related to those ambitious projects both in the United States and in Europe.

Marchis is also involved in startups related to astronomy so he joined Unistellar as a Chief Scientific Officer and VR2Planets as a scientific advisor in 2017.

Marchis is a member of numerous science committees including the SETI Science council, the GPI steering Committee, the TMT Science Definition Team, PLOS One editor board, the Project Blue and the PLANETS Foundation Advisory board.

He has co-authored more than 380 scientific publications, trained numerous students, and served as a science consultant and interviewee for numerous documentaries and movies in English, French, and Spanish.

The asteroid (6639) was named Marchis in honor of his discovery of the first triple-asteroid system in 2007. He has been an affiliated Astronomer at Observatoire de Paris since 2003.

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NASA’s Planet-Hunting TESS Telescope Launches Today Aboard A SpaceX Rocket

Some of the most exciting space news of the past few years has been about Earth-like exoplanets that could one day (or perhaps already do) support life. TESS, a space telescope set to launch today aboard a SpaceX Falcon 9 rocket.

It will scan the sky for exoplanets faster and better than any existing platforms, expanding our knowledge of the universe and perhaps finding a friendly neighborhood to move to.

The Transit Exoplanet Survey Satellite has been in the works for years and in a way could be considered a sort of direct successor to the Kepler, the incredibly fruitful mission that has located thousands of exoplanets over nearly a decade.

But if Kepler was a telephoto aimed at dim targets far in the distance, TESS is an ultra-wide-angle lens that will watch nearly the entire visible sky.

They both work on the same principle, which is really quite simple: when a planet (or anything else) passes between us and a star (a “transit”), the brightness of that star temporarily dims.

By tracking how much dimmer and for how long over multiple transits, scientists can determine the size, speed, and other characteristics of the body that passed by.

It may seem like looking for a needle in a haystack, watching the sky hoping a planet will pass by at just the right moment.

But when you think about the sheer number of stars in the sky — and by the way, planets outnumber them — it’s not so crazy.

As evidence of this fact, in 2016 Kepler confirmed the presence of 1,284 new planets just in the tiny patch of sky it was looking at.

TESS will watch for the same thing with a much, much broader perspective.

Its camera array has four 16.4-megapixel imaging units, each covering a square of sky 24 degrees across, making for a tall “segment” of the sky like a long Tetris block.

The satellite will spend full 13.7-day orbits observing a segment, then move on to the next one.

There are 13 such segments in the sky’s Northern hemisphere and 13 in the southern; by the time TESS has focused on them all, it will have checked 85 percent of the visible sky.

It will be focusing on the brightest stars in our neighborhood: less than 300 light-years away and 30 to 100 times as bright as the ones Kepler was looking at.

The more light, the more data, and often the less noise — researchers will be able to tell more about stars that are observed, and if necessary dedicate other ground or space resources towards observing them.

Of course, with such close and continuous scrutiny of hundreds of thousands of stars, other interesting behaviors may be observed and passed on to the right mission or observatory.

Stars flaring or going supernova, bursts of interesting radiation, and other events could very well occur.

In fact, an overlapping area of observation above each of Earth’s poles will be seen for a whole year straight, increasing the likelihood of catching some rare phenomenon.

SpaceX is the launch partner, and the Falcon 9 rocket on which it will ride into orbit has already been test fired. TESS is packaged up and ready to go, as you see at right.

Currently the launch is planned for a 30-second window at 6:32 Florida time; if for some reason they miss that window, they’ll have to wait until the moon comes round again — a March 20 launch was already canceled.

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Launch Of NASA’s Most Anticipated Webb Space Telescope Delayed Until 2020

The James Webb space telescope is certainly one of the most anticipated projects coming out of NASA, both because of its grand scale and its interminable gestation time.

Well, the latter just got a little longer: The launch of the Webb, expected previously in mid-2019 (and before that in October 2018), has been delayed to at least May of 2020.

NASA acting administrator Robert Lightfoot and others from the organization announced the news in a conference call.

All the observatory’s flight hardware is now complete,” Lightfoot said.

“However, the issues brought to light with the spacecraft element are prompting us to take the necessary steps to refocus our efforts on the completion of this ambitious and complex observatory.”

The Webb is essentially the successor to the Hubble, which has done yeoman duty and by far exceeded its mission parameters — but all the same is coming to the end of its time.

Conceived more than 20 years ago, it has faced repeated delays, as any project of this scale can expect to.

The $8 billion telescope will be the best eye in the sky and the most in demand, but once it goes up, it can’t be serviced or visited.

That means everything in one of the most complex imaging devices ever created must work perfectly in outer space for decades, with no chance of physical intervention.

So you can understand when its creators say they’d like to take a few extra months to quadruple-check some things.

Various small issues have arisen during testing and a Government Accountability Office report, like a cabling mishap that created a tear in the immense folding sun shield.

“Those are avoidable errors, but in developing very complex systems, those things do happen.”

If you read between the lines, though, it seems that primary partner Northrup Grumman is getting the stink eye here; the company seems to have contributed more than its fair share of mistakes.

A consequence of the delays and new tests is that the project will now likely go over its $8 billion pre-launch budget cap and will need to be re-authorized by Congress.

Considering the ballooning budget on something like the California high speed rail project, the Webb seems like an example of extreme fiduciary responsibility, and Congress knows to haggle, delay further or cut corners will merely cost it more in the long run.

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Unprecedented Image Of A Supernova 80 Million Light Years Away Is Captured For The First Time By An Amateur Astronomer

The first burst of light given off by an exploding star has been captured for the first time by an amateur astronomer in Argentina.

Observations of a dying star 80 million light-years away, taken by Víctor Buso, 60, has given scientists their first view of the initial flash given off by a supernova.

To date, no one has been able to capture the ‘first optical light’ from a supernova, since stars explode seemingly at random in the sky, and the burst is fleeting.

Most are only spotted a long time after the initial blast, making Mr Buso’s one-in-ten-million observations ‘unprecedented‘, scientists said.

The new data provide important clues to the physical structure of the star just before its catastrophic demise and to the nature of the explosion itself.

Professional astronomers have long been searching for such an event,” said University of California at Berkeley astronomer Dr Alex Filippenko, who followed up the lucky discovery with scientific observations of the explosion, called SN 2016gkg.

Observations of stars in the first moments they begin exploding provide information that cannot be directly obtained in any other way.”

It’s like winning the cosmic lottery.”

During tests of a new camera, Mr. Buso snapped images through his 16-inch telescope of the galaxy NGC 613, which is 80 million light-years from Earth.

He took a series of short-exposure photographs of the spiral galaxy, accidentally capturing it before and after the supernova’s ‘shock breakout’.

This is when a pressure wave from the star’s exploding core hits and heats gas at the star’s surface to a very high temperature, causing it to flash and rapidly brighten.

Upon examining the images, Mr. Buso, of Rosario, Argentina, noticed a faint point of light quickly brightening near the end of a spiral arm that was visible in his second set of images but not his first.

Astronomer Dr Melina Bersten and her colleagues at the Instituto de Astrofísica de La Plata in Argentina soon learned of the serendipitous discovery.

They realized that Mr. Buso had caught a rare event; part of the first hour after light emerges from a massive exploding star.

She estimated Mr Buso’s chances of such a discovery, his first supernova, at one in 10 million or perhaps even as low as one in 100 million.

Dr Bersten contacted an international group of astronomers to help conduct additional frequent observations of SN 2016gkg.

A series of subsequent studies have revealed more about the type of star that exploded and the nature of the explosion.

Mr. Buso’s discovery, snapped in September 2016, and results of follow-up observations have now been published in the journal Nature.

Buso’s data are exceptional,” Dr. Filippenko added.

This is an outstanding example of a partnership between amateur and professional astronomers.

The astronomer and his colleagues obtained a series of seven spectra, where the light is broken up into its component colors, as in a rainbow.

They used the Shane 3-meter telescope at the University of California’s Lick Observatory near San Jose, California, and the twin 10-meter telescopes of the W. M. Keck Observatory on Maunakea, Hawaii.

This allowed the international team to determine that the explosion was a Type IIb supernova: The explosion of a massive star that had previously lost most of its hydrogen envelope.

Combining the data with theoretical models, the team estimated that the initial mass of the star was about 20 times the mass of our Sun.

They suggest it lost most of its mass to a companion star and slimmed down to about five solar masses prior to exploding.

Further analyses of the signal could provide further information on the star’s structure and uncover more secrets about supernovas.

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