The setting Sun dips below the horizon of the Pacific Ocean, bathing the Paranal platform in light in this amazing aerial image from the Atacama Desert in northern Chile. The Cerro Paranal mountain top is home to the world’s most advanced ground-based facility for astronomy, hosting the four 8.2-metre Unit Telescopes of the Very Large Telescope, four 1.8-metre Auxiliary Telescopes and the VLT Survey Telescope (VST) — all of which are visible in this image. The 4.1-metre Visible and Infrared Survey Telescope for Astronomy (VISTA), also housed at Cerro Paranal, is hidden out of frame.
When it comes to telescopes, bigger really is better. A larger telescope brings with it the ability to see fainter objects and also to be able to see more detail. Typically we have relied upon larger and larger single aperture telescopes in our attempts to distinguish exoplanets around other stars. Space telescopes have also been employed but all that may be about to change. A new paper suggests that multiple telescopes working together as interferometers are what’s needed.
Ever since the advent of space exploration we have seen some amazing images of the planets. New technology often brings with it a new perspective and we have been reminded of this again just recently with images from the Hubble Space Telescope (HST) and New Horizons spacecraft. The two objects simultaneously imaged Uranus from different perspectives in an attempt to predict what astronomers would see when they look at exoplanets orbiting other stars.
Artist rendition of exoplanet, Beta Pictoris b, whose partial orbit was recently featured in a time-lapsed video. (Credit: ESO L. Calçada/N. Risinger)
Searching for exoplanets is incredibly difficult given their literal astronomical distances from Earth, which is why a myriad of methods have been created to find them. These include transit, redial velocity, astrometry, gravitational microlensing, and direct imaging. It is this last method that was used to recently create a time-lapse video that compresses a mind-blowing 17 years of the partial orbit of exoplanet, Beta Pictoris b, into 10 seconds. The data to create the video was collected between 2003 and 2020, it encompasses approximately 75 percent of the total orbit, and marks the longest time-lapse video of an exoplanet ever produced.
One of the best things about the sheer number of exoplanets that astronomers are currently finding is how some are just very different. Those differences can sometimes undermine standing theories, and prompt scientists to start considering new theories that account for the new information. That is undoubtedly what will happen to accommodate a new massive planet found by a team led by Dutch scientists. This planet is unique in one very special way – it is about 110 times farther away from its star than the Earth is from the sun.
This image, captured by the SPHERE instrument on ESO’s Very Large Telescope, shows the star TYC 8998-760-1 accompanied by two giant exoplanets. This is the first time astronomers have directly observed more than one planet orbiting a star similar to the Sun.
The image was captured by blocking the light from the young, Sun-like star (on the top left corner) using a coronagraph, which allows for the fainter planets to be detected. The bright and dark rings we see on the star’s image are optical artefacts. The two planets are visible as two bright dots in the centre and bottom right of the frame. Image Credit: ESO/Bohn et al, 2020
We’ve detected thousands of exoplanets, but for the most part, nobody’s ever seen them. They’re really just data, and graphs of light curves. The exoplanet images you see here at Universe Today and other space websites are the creations of very skilled illustrators, equal parts data and creative license. But that’s starting to change.
The European Southern Observatory’s Very Large Telescope (VLT) has captured images of two exoplanets orbiting a young, Sun-like star.
Just. Wow. The motion of an alien world, reduced to a looping .gif. We truly live in an amazing age. A joint press release out of the Gemini Observatory and the University of Toronto demonstrates a stunning first: a sequence of direct images showing an exoplanet… in motion.
The world imaged is Beta Pictoris b, about 19 parsecs (63 light years) distant in the southern hemisphere constellation Pictor the Painter’s Easel. The Gemini Planet Imager (GPI), working in concert with the Gemini South telescope based in Chile captured the sequence.
The images span an amazing period of a year and a half, starting in November 2013 and running through April of earlier this year. Beta Pictoris b has an estimated 22 year orbital period… hey, in the year 2035 or so, we’ll have a complete animation of its orbit!
Current estimates place Beta Pictoris b in the 7x Jupiter mass range, about plus or minus 4 Jupiter masses… and yes, the high end of that range is flirting with the lower boundary for a sub-stellar brown dwarf. Several exoplanet candidates blur this line, and we suspect that the ‘what is a planet debate?’ that has plagued low mass worlds will one day soon extend into the high end of the mass spectrum as well.
An annotated diagram of the Beta Pictoris system. Image credit: ESO/A.-M Lagrange et al.
Beta Pictoris has long been a target for exoplanetary research, as it is known to host a large and dynamic debris disk spanning 4,000 astronomical units across. The host star Beta Pictoris is 1.8 times as massive as our Sun, and 9 times as luminous. Beta Pic is also a very young star, at an estimated age of only 8-20 million years old. Clearly, we’re seeing a very young solar system in the act of formation.
Orbiting its host star 9 astronomical units distant, Beta Pictoris b has an orbit similar to Saturn’s. Place Beta Pictoris b in our own solar system, and it would easily be the brightest planet in the sky.
The Heavyweight world B Pictoris b vs planets in our solar system… note the rapid rotation rate! Image credit: ESO/I. Snellen (Leiden University)
“The images in the series represent the most accurate measurements of a planet’s position ever made,” says astronomer Maxwell Millar-Blanchaer of the Department of Astronomy and Astrophysics at the University of Toronto in a recent press release. ‘With the GPI, we’re able to see both the disk and the planet at the exact same time. With our combined knowledge of the disk and the planet we’re really able to get a sense of the planetary system’s architecture and how everything interacts.”
A recent paper released in the Astrophysical Journal described observations of Beta Pictoris b made with the Gemini Planet Imager. As with bodies in our own solar system, refinements in the orbit of Beta Pictoris b will enable astronomers to understand the dynamic relationship it has with its local environment. Already, the orbit of Beta Pictoris b appears inclined out of our line of sight in such a way that a transit of the stellar disk is unlikely to occur. This is the case with most exoplanets, which elude the detection hunters such as the Kepler space telescope. As a matter of fact, watching the animation, it looks like Beta Pictoris b will pass behind the occluding disk and out of view of the Gemini Planet Imager in the next few years.
The location of Beta Pictoris in the southern hemisphere sky. Image credit: Stellarium
“It’s remarkable that Gemini is not only able to directly image exoplanets but is also capable of effectively making movies of them orbiting their parent star,” Says National Science Foundation astronomy division program director Chris Davis in Monday’s press release. The NSF is one of five international partners that funds the Gemini telescope program. “Beta Pic is a special target. The disk of gas and dust from which planets are currently forming was one of the first observed and is a famous laboratory for the study of young solar systems.”
The Gemini Planet Imager is part of the GPI Exoplanet Survey (GPIES), which discovered its first exoplanet 51 Eridani b just last month. The survey will target 600 stars over the next three years. The current tally of known exoplanets currently sits at 1,958 and counting, with thousands more in the queue courtesy of Kepler awaiting confirmation.
And as new spacecraft such as the Transiting Exoplanet Survey Satellite (TESS) take to orbit in 2018, we wouldn’t be surprised if the tally of exoplanets hits five digits by the end of this decade.
An amazing view of a brave new world in motion. It’s truly a golden age of exoplanetary science, with more exciting discoveries to come!
