ESO Archives

November 8, 2012December 23, 2015 by Jason Major

Astronomers Find Tantalizing Hints of a Potentially Habitable Exoplanet

Dwarf star HD 40307 is now thought to host at least 6 exoplanet candidates… one of them well within its habitable zone. (G. Anglada/Celestia)

Located 43 light-years away in the southern constellation Pictor, the orange-colored dwarf star HD 40307 has previously been found to hold three “super-Earth” exoplanets in close orbit. Now, a team of researchers poring over data from ESO’s HARPS planet-hunting instrument are suggesting that there are likely at least six super-Earth exoplanets orbiting HD 40307 — with one of them appearing to be tucked neatly into the star’s water-friendly “Goldilocks” zone.

HARPS (High Accuracy Radial velocity Planet Searcher) on ESO’s La Silla 3.6m telescope is a dedicated exoplanet hunter, able to detect the oh-so-slight wobble of a star caused by the gravitational tug of orbiting planets. Led by Mikko Tuomi of the UK’s University of Hertfordshire Centre for Astrophysics Research, a team of researchers reviewed publicly-available data from HARPS and has identified what seems to be three new exoplanets in the HD 40307 systems. The candidates, designated with the letters e, f, and g, all appear to be “super Earth” worlds… but the last one, HD 40307 g, is what’s getting people excited, as the team has calculated it to be orbiting well within the region where liquid water could exist on its surface — this particular star’s habitable zone.

In addition, HD 40307 g is located far enough away from its star to likely not be tidally locked, according to the team’s paper. This means it wouldn’t have one side subject to constant heat and radiation while its other “far side” remains cold and dark, thus avoiding the intense variations in global climate, weather and winds that would come as a result.

“The star HD 40307, is a perfectly quiet old dwarf star, so there is no reason why such a planet could not sustain an Earth-like climate.”
– Guillem Anglada-Escudé, co-author.

“If the signal corresponding to HD 40307 g is a genuine Doppler signal of planetary origin, this candidate planet might be capable of supporting liquid water on its surface according to the current definition of the liquid water habitable zone around a star and is not likely to suffer from tidal locking.” (Tuomi et al.)

If HD 40307 g is indeed confirmed, it may very well get onto the official short list of potentially habitable worlds outside our Solar System — although those others are quite a bit closer to the mass of our own planet.

UPDATE: HD 40307 g has been added to the Planetary Habitability Laboratory’s Habitable Exoplanets Catalog, maintained by the PHL at the University of Puerto Rico at Arecibo. It’s now in 4th place of top exoplanets of interest based on similarity to Earth. According to Professor Abel Mendez Torres of the PHL, “Average temperatures might be near 9°C (48°F) assuming a similar scaled-up terrestrial atmosphere. It might also experience strong seasonal surface temperature shifts between -17° to 52°C (1.4° to 126°F) due to its orbital eccentricity. Nevertheless, these extremes are tolerable by most complex life, as we know it.” (Read more here.)

While the other planetary candidates in the HD 40307 system are positioned much more closely to the star, with b, c, d, and e within or at the equivalent orbital distance of Mercury, g appears to be in the star’s liquid-water habitable zone, orbiting at 0.6 AU in an approximately 200-day-long orbit. At this distance the estimated 7-Earth-mass exoplanet receives around 62-67% of the radiation that Earth gets from the Sun.

Representation of the liquid water habitable zone around HD 40307 compared to our Solar System (Tuomi et al., from the team’s paper.)

Although news like this is exciting, as we’re always eagerly anticipating the announcement of a true, terrestrial Earthlike world that could be host to life as we know it, it’s important to remember that HD 40307 g is still a candidate — more observations are needed to not only confirm its existence but also to find out exactly what kind of planet it may be.

“A more detailed characterization of this candidate is very unlikely using ground based studies because it is very unlikely [sic] to transit the star, and a direct imaging mission seems the most promising way of learning more about its possible atmosphere and life-hosting capabilities,” the team reports.

Read: How Well Can Astronomers Study Exoplanet Atmospheres?

Still, just finding potential Earth-sized worlds in a system like HD 40307’s is a big deal for planetary scientists. This system is not like ours, yet somewhat similar planets have still formed… that in itself is a clue to what else may be out there.

“The planetary system around HD 40307 has an architecture radically different from that of the solar system… which indicates that a wide variety of formation histories might allow the emergence of roughly Earth-mass objects in the habitable zones of stars.”

The team’s paper will be published in the journal Astronomy & Astrophysics. http://arxiv.org/pdf/1211.1617v1.pdf

Another researcher on the team, Guillem Anglada-Escudé of Germany’s Universität Göttingen, assembled this tour of the HD 40307 system (not including g) via Celestia.

Inset image: current potentially habitable exoplanets. Credit: PHL @ UPR Arecibo.

October 31, 2012December 23, 2015 by Nancy Atkinson

Beautiful Star Cluster Looks Surprisingly Youthful

This view of the globular cluster NGC 6362 was captured by the Wide Field Imager attached to the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile. Credit: ESO/J. Emerson/VISTA. Acknowledgment: Cambridge Astronomical Survey Unit

Past observations of globular star clusters have revealed that they are some of the oldest objects in the Universe, with most of the stars originating around the same time — some are more than 10 billion years old. And this new image of NGC 6362, a ball of stars found in the constellation of Ara, definitely shows its age, with many yellowish stars in the cluster that have already run through much of their lives and become red giant stars. But astronomers are seeing some curious stellar activities in this cluster that appears to indicate younger, bluer stars are part of the mix, too.

So how can this be, since all the stars in a cluster formed at the same time from the same cloud of gas?

NGC 6362 is home to many blue stragglers — old stars that succeed in passing for a younger age. Blue stragglers are bluer and more luminous — and hence more massive — than they should be after ten billion years of stellar evolution. Blue stars are hot and consume their fuel quickly, so if these stars had formed about ten billion years ago, then they should have fizzled out long ago. How did they survive?

Right now astronomers have two main theories about blue stragglers and how they maintain their youthful appearance: stars colliding and merging, and a transfer of material between two companion stars. The basic idea behind both of these options is that the stars were not born as big as we see them today, but that they received an injection of extra material at some point during their lifetimes and this then gave them a new lease of life.

This new image shows the entire cluster against a rich background of the carpet of stars in the Milky Way. It can be easily seen by amateur astronomers with a small telescope.

This video zooms into the cluster, starting with views from the La Silla Observatory and ending with a detailed view of the center from the Hubble Space Telescope:

Source: ESO

October 24, 2012December 23, 2015 by Nancy Atkinson

Zoom Through 84 Million Stars in Gigantic New 9-Gigapixel Image

The image above is a portion of a new gigantic nine-gigapixel image from the VISTA infrared survey telescope at ESO’s Paranal Observatory of the central portion of the Milky Way Galaxy. The resolution of this image is so great, that if it was printed out in the resolution of a typical book, it would be 9 meters long and 7 meters tall! Click on the image to have access to an interactive, zoomable view of the more than 84 million stars that astronomers have now catalogued from this image. The huge dataset contains more than ten times more stars than previous studies and astronomers say it is a major step forward for the understanding of our home galaxy.

“By observing in detail the myriads of stars surrounding the centre of the Milky Way we can learn a lot more about the formation and evolution of not only our galaxy, but also spiral galaxies in general,” said Roberto Saito from Pontificia Universidad Católica de Chile, Universidad de Valparaíso, lead author of the study.

UPDATE: The image is also available on Gigapan, which provides a very smooth interface in which to explore and zoom around the image.

The dataset contains a treasure trove of information about the structure and content of the Milky Way. One interesting result revealed in the new data is the large number of faint red dwarf stars, which are prime candidates to search for small exoplanets using the transit method. Using this dataset, astronomers can also study the different physical properties of stars such as their temperatures, masses and ages.

To help analyze this huge catalogue, the brightness of each star is plotted against its color for about 84 million stars to create a color–magnitude diagram. This plot contains more than ten times more stars than any previous study and it is the first time that this has been done for the entire bulge.

This infrared view of the central part of the Milky Way from the VVV VISTA survey has been labelled to show a selection of the many nebulae and clusters in this part of the sky. Credit: ESO/VVV Consortium, Acknowledgement: Ignacio Toledo, Martin Kornmesser

“Each star occupies a particular spot in this diagram at any moment during its lifetime,” said Dante Minniti, also from Pontificia Universidad Catolica de Chile, Chile, co-author of the study. “Where it falls depends on how bright it is and how hot it is. Since the new data gives us a snapshot of all the stars in one go, we can now make a census of all the stars in this part of the Milky Way.”

Getting such a detailed view of the central region of our galaxy is not an easy task.

“Observations of the bulge of the Milky Way are very hard because it is obscured by dust,” said Minniti. “To peer into the heart of the galaxy, we need to observe in infrared light, which is less affected by the dust.”

The team used ESO’s 4.1-metre Visible and Infrared Survey Telescope for Astronomy (VISTA), which has a wide field of view. This new image is just one of six public surveys carried out with VISTA.

“One of the other great things about the VVV survey is that it’s one of the ESO VISTA public surveys. This means that we’re making all the data publicly available through the ESO data archive, so we expect many other exciting results to come out of this great resource,” said Saito.

Source: ESO

October 16, 2012December 23, 2015 by Nancy Atkinson

Next Door Neighbors? Earth-Sized Planet Discovered in Nearest Star System to Us

Artist’s impression of the planet around Alpha Centauri B. Credit: ESO

Artist’s impression of the planet around Alpha Centauri B. Credit: ESO

Astronomers have discovered an enticing new planet that could be considered our next-door neighbor. The planet is orbiting a star in the Alpha Centauri system — the closest system to our own, just 4.3 light years away — and the planet has a mass about the same as Earth. It is also the lightest exoplanet ever discovered around a sun-like star. While this planet is likely too hot to contain life as we know it, the star system could possibly host other worlds that could be habitable, researchers from the European Southern Observatory at La Silla say.

“This result represents a major step towards the detection of Earth twins in the immediate vicinity of the Sun,” the team wrote in their paper.

“This is the first planet with a mass similar to Earth ever found around a star like the Sun. Its orbit is very close to its star and it must be much too hot for life as we know it,” said Stéphane Udry from the Geneva Observatory, a co-author of the paper that will be published in Nature on Oct. 17, and member of the team that used the HARPS instrument to find the planet. “But it may well be just one planet in a system of several. Our other HARPS results, and new findings from Kepler, both show clearly that the majority of low-mass planets are found in such systems.”

The planet is called Alpha Centauri Bb and it whips around its star every 3.2 days, orbiting at a distance of just 6 million kilometers (3.6 million miles), closer than Mercury’s orbit around the Sun. (Earth orbits at a comfortable 150 million kilometers (93 million miles) from the Sun.) So it is likely very hot and covered with molten rock, the researchers say.

Many astronomers have thought that the Alpha Centauri system would be a perfect candidate to host Earth-sized worlds. In fact, in 2008, a team of astronomers ran computer simulations of the system’s first 200 million years, and in each instance, despite different parameters, multiple terrestrial planets formed around the star. In every case, at least one planet turned up similar in size to the Earth, and in many cases this planet fell within the star’s habitable zone.

But while astronomers have looked for years, previous searches of planets in the Alpha Centauri system came up empty.

Until now.

“Our observations extended over more than four years using the HARPS instrument and have revealed a tiny, but real, signal from a planet orbiting Alpha Centauri B every 3.2 days,” says Xavier Dumusque (Geneva Observatory, Switzerland and Centro de Astrofisica da Universidade do Porto, Portugal), lead author of the paper. “It’s an extraordinary discovery and it has pushed our technique to the limit!”

The European team detected the planet by using the radial velocity method — by picking up the tiny wobbles in the motion of the star Alpha Centauri B created by the gravitational pull of the orbiting planet. The effect is extremely small, as it causes the star to move back and forth by no more than 51 centimeters per second (1.8 km/hour). The team said this is the highest precision ever achieved using this method.

Alpha Centauri is one of the brightest stars in the southern skies and is actually a triple star — a system consisting of two stars similar to the Sun orbiting close to each other, designated Alpha Centauri A and B, and a more distant and faint red component known as Proxima Centauri.

Alpha Centauri B is very similar to the Sun but slightly smaller and less bright. The orbit of Alpha Centauri A is hundreds of times further away from the planet, but it would still be a very brilliant object in the planet’s skies.

A wide-field view of the sky around Alpha Centauri was created from photographic images forming part of the Digitized Sky Survey 2. The star appears so big just because of the scattering of light by the telescope’s optics as well as in the photographic emulsion. Credit: ESO

The first exoplanet around a Sun-like star was found by the same team back in 1995 and there are now 843 Exoplanets with the addition of Alpha Centauri Bb. Most are much bigger than Earth, and many are as big as Jupiter. The previous closest exoplanet was Epsilon Eridani b, 10.4 light years away.

The challenge astronomers now face is to detect and characterize a planet of mass comparable to the Earth that is orbiting in the habitable zone around another star. The first step has now been taken, the team says.

“This result represents a major step,” said Dumusque. “We live in exciting times!”

So, how long would it take for us to get to this planet? Using current technology, our slowest mode of space transportation, ion drive propulsion, it would take 81,000 years. Using the speeds of one of the fastest spacecraft (Helios 2) and traveling at a constant speed of 240,000 km/hr, it would take about 19,000 years (or over 600 generations) to travel the 4.3 light years.

Read the team’s paper (PDF)

Source: ESO

October 1, 2012December 23, 2015 by Nancy Atkinson

Watch Live: A Day in the Life of the Very Large Telescope

Ever wonder what takes place on a daily basis at one of the premier ground-based observatories? The European Southern Observatory (ESO) is celebrating its 50th anniversary, and on October 5, 2012, they will host a free, live event on the web, “A Day in the Life of ESO.” There will be live observations from ESO’s flagship observatory, the Very Large Telescope (VLT), on Cerro Paranal in Chile’s Atacama Desert, as well as talks from astronomers at ESO’s Headquarters in Germany. Members of the public are invited to ask questions in advance of the event, or during the stream, by Facebook, Twitter, and email.

The webcast will be streamed through Livestream.

For the first time in ESO’s history, the VLT will be pointed towards an object in the sky selected by members of the public — the Thor’s Helmet Nebula (NGC 2359). This striking nebula was selected as part of the Choose What the VLT Observes competition. Brigitte Bailleul, from France, won the Tweet Your Way to the VLT! competition, and will travel to the Paranal Observatory in Chile to help make the observations. The live link to Paranal will show the observations and the telescopes on the mountaintop, in the stunning landscape of the Atacama Desert, letting viewers join Brigitte on her trip of a lifetime.

The webcast will run from 9:00 to 15:00 UTC on October 5. It will be hosted by astronomer — and host of the ESOcasts — “Dr J” — Dr. Joe Liske, from ESO. There will also be talks from astronomers at ESO’s Headquarters in Germany, on topics ranging from ESO’s state-of-the-art telescopes, via the latest news from the frontiers of astronomy, to what the life of an astronomer is like. Throughout the day there will be question and answer sessions, and the chance to test your ESO knowledge in a quiz to win some astronomical prizes.

Members of the public are invited to ask questions about the activities at the Paranal Observatory, the talks of the day, or general questions about ESO. You can send us your questions before the event, or during the webcast, in English in the following ways:

Send a tweet @ESO, also using the hashtag #ESO50years.

Write a question on your Facebook wall in which you tag ESO’s Facebook page.

Send an email to [email protected] with the subject ESO50years. Optionally, please include your name and country.

See this ESO webpage for more info and schedule of the webcast.

September 26, 2012December 23, 2015 by Jason Major

Take a Gander at a Cosmic Gull

The head and “eye” of the Seagull Nebula (ESO)

This colorful new image from ESO’s La Silla Observatory highlights the heart of a shining stellar nursery located between the constellations Monoceros and Canis Major. Officially named Sharpless 2-292, the cloud of gas and dust forms the “head” of the Seagull Nebula (IC 2177) and gets its glow from the energy emitted by the young, bright star within its “eye”.

A wide-angle image of the Seagull Nebula shows the soaring birdlike shape that gives it its nickname. The cloud seen above forms the gull’s head.

A wide-field view of the Seagull Nebula from the ESO’s Digitized Sky Survey 2 (ESO/Digitized Sky Survey 2. Acknowledgement: Davide De Martin)

The wings of this gull span an impressive 100 light-years from tip to tip. A birthplace for new stars, the nebula is located within our galaxy about 3,700 light-years away.

For an idea of how far that is, if the distance between the Sun and Earth were scaled down to 1 inch (2.5 cm) and you were standing in New York City, the stars in the Seagull Nebula would be in Paris, France (considering the most direct flight route.)

Powerful radiation from young stars causes the surrounding hydrogen gas to glow with a red color. Light from the hot blue-white stars also gets scattered off tiny dust particles in the nebula to create a blue haze.

Celestial Dreaming in a Bit of Pipe Smoke

Zoom into the Pipe Nebula by using the zoom slider, or pan around the image by using the arrow icons on the toolbar or by click-dragging the image. You can also zoom into a particular area by double-clicking on your area of interest. Image credit: ESO. Zoomify by John Williams.

Images like this of the Pipe Nebula from the European Southern Observatory’s La Silla Observatory help me dream about the grandeur of the night sky and the richness of the star lanes that make up the Milky Way.

Continue reading “Celestial Dreaming in a Bit of Pipe Smoke”

August 1, 2012December 23, 2015 by Nancy Atkinson

Tranquil Galaxy is Home to Violent Events

This beautiful spiral galaxy looks peaceful, with its swirling white and blue arms appearing like they could be home to countless solar systems similar to ours. But NGC 1187 has hosted two supernova explosions during the last thirty years, and these violent stellar explosions are the result of the powerful death of either a massive star or a white dwarf in a binary system. Astronomers are keeping an eye on this galaxy for more outbursts.

This lovely new image of NGC 1187 was taken with ESO’s Very Large Telescope, and is the most detailed image of this galaxy. This impressive spiral lies about 60 million light-years away in the constellation of Eridanus (The River).

The galaxy is seen almost face-on, which provides a good view of its spiral structure. About half a dozen prominent spiral arms can be seen, each containing large amounts of gas and dust. The bluish feature in the spiral arms indicate the presence of young stars born out of clouds of interstellar gas.

Looking towards the central regions, we see the bulge of the galaxy glowing yellow. This part of the galaxy is mostly made up of old stars, gas and dust. In the case of NGC 1187, rather than a round bulge, there is a subtle central bar structure. Such bar features are thought to act as mechanisms that channel gas from the spiral arms to the center, enhancing star formation there.

Around the outside of the galaxy many much fainter and more distant galaxies can also be seen. Some even shine right through the disc of NGC 1187 itself. Their mostly reddish hues contrast with the pale blue star clusters of the much closer object.

In October 1982, the first supernova detected in NGC 1187 took place, SN 1982R, and more recently, in 2007, SN 2007Y made an appearance, and was initially discovered by an amateur astronomer Berto Monard in South Africa, and was monitored by other astronomers for almost a year. This new image of NGC 1187 was created from observations taken as part of this study and the supernova can be seen, long after the time of maximum brightness, near the bottom of the image.

These data were acquired using the FORS1 instrument attached to the ESO’s Very Large Telescope at the Paranal Observatory in Chile.

Lead image caption: Spiral galaxy NGC 1187 Credit: ESO

Source: ESO

July 18, 2012December 23, 2015 by Nancy Atkinson

Looking Into the Heart of a Quasar

Caption: Artist’s impression of the quasar 3C 279. Credit: ESO/M. Kornmesser

From an ESO press release:

An international team of astronomers has observed the heart of a distant quasar with unprecedented sharpness, two million times finer than human vision. The observations, made by connecting the Atacama Pathfinder Experiment (APEX) telescope to two others on different continents for the first time, is a crucial step towards the dramatic scientific goal of the “Event Horizon Telescope” project: imaging the supermassive black holes at the centre of our own galaxy and others.

Astronomers connected APEX, in Chile, to the Submillimeter Array (SMA) in Hawaii, USA, and the Submillimeter Telescope (SMT) in Arizona, USA. They were able to make the sharpest direct observation ever of the center of a distant galaxy, the bright quasar 3C 279, which contains a supermassive black hole with a mass about one billion times that of the Sun, and is so far from Earth that its light has taken more than 5 billion years to reach us. APEX is a collaboration between the Max Planck Institute for Radio Astronomy (MPIfR), the Onsala Space Observatory (OSO) and ESO. APEX is operated by ESO.

The telescopes were linked using a technique known as Very Long Baseline Interferometry (VLBI). Larger telescopes can make sharper observations, and interferometry allows multiple telescopes to act like a single telescope as large as the separation — or “baseline” — between them. Using VLBI, the sharpest observations can be achieved by making the separation between telescopes as large as possible. For their quasar observations, the team used the three telescopes to create an interferometer with transcontinental baseline lengths of 9447 km from Chile to Hawaii, 7174 km from Chile to Arizona and 4627 km from Arizona to Hawaii. Connecting APEX in Chile to the network was crucial, as it contributed the longest baselines.

The observations were made in radio waves with a wavelength of 1.3 millimetres. This is the first time observations at a wavelength as short as this have been made using such long baselines. The observations achieved a sharpness, or angular resolution, of just 28 microarcseconds — about 8 billionths of a degree. This represents the ability to distinguish details an amazing two million times sharper than human vision. Observations this sharp can probe scales of less than a light-year across the quasar — a remarkable achievement for a target that is billions of light-years away.

The observations represent a new milestone towards imaging supermassive black holes and the regions around them. In future it is planned to connect even more telescopes in this way to create the so-called Event Horizon Telescope. The Event Horizon Telescope will be able to image the shadow of the supermassive black hole in the centre of our Milky Way galaxy, as well as others in nearby galaxies. The shadow — a dark region seen against a brighter background — is caused by the bending of light by the black hole, and would be the first direct observational evidence for the existence of a black hole’s event horizon, the boundary from within which not even light can escape.

The experiment marks the first time that APEX has taken part in VLBI observations, and is the culmination of three years hard work at APEX’s high altitude site on the 5000-metre plateau of Chajnantor in the Chilean Andes, where the atmospheric pressure is only about half that at sea level. To make APEX ready for VLBI, scientists from Germany and Sweden installed new digital data acquisition systems, a very precise atomic clock, and pressurized data recorders capable of recording 4 gigabits per second for many hours under challenging environmental conditions. The data — 4 terabytes from each telescope — were shipped to Germany on hard drives and processed at the Max Planck Institute for Radio Astronomy in Bonn.

The successful addition of APEX is also important for another reason. It shares its location and many aspects of its technology with the new Atacama Large Millimeter/submillimeter Array (ALMA) telescope. ALMA is currently under construction and will finally consist of 54 dishes with the same 12-metre diameter as APEX, plus 12 smaller dishes with a diameter of 7 metres. The possibility of connecting ALMA to the network is currently being studied. With the vastly increased collecting area of ALMA’s dishes, the observations could achieve 10 times better sensitivity than these initial tests. This would put the shadow of the Milky Way’s supermassive black hole within reach for future observations.

June 27, 2012December 23, 2015 by Jason Major

How to Measure a Hot Jupiter

An international team of astronomers has figured out a way to determine details of an exoplanet’s atmosphere from 50 light-years away… even though the planet doesn’t transit the face of its star as seen from Earth.

Tau Boötis b is a “hot Jupiter” type of exoplanet, 6 times more massive than Jupiter. It was the first planet to be identified orbiting its parent star, Tau Boötis, located 50 light-years away. It’s also one of the first exoplanets we’ve known about, discovered in 1996 via the radial velocity method — that is, Tau Boötis b exerts a slight tug on its star, shifting its position enough to be detectable from Earth. But the exoplanet doesn’t pass in front of its star like some others do, which until now made measurements of its atmosphere impossible.

Today, an international team of scientists working with the Very Large Telescope (VLT) at ESO’s Paranal Observatory in Chile have announced the success of a “clever new trick” of examining such non-transiting exoplanet atmospheres. By gathering high-quality infrared observations of the Tau Boötis system with the VLT’s CRIRES instrument the researchers were able to differentiate the radiation coming from the planet versus that emitted by its star, allowing the velocity and mass of Tau Boötis b to be determined.

“Thanks to the high quality observations provided by the VLT and CRIRES we were able to study the spectrum of the system in much more detail than has been possible before,” said Ignas Snellen with Leiden Observatory in the Netherlands, co-author of the research paper. “Only about 0.01% of the light we see comes from the planet, and the rest from the star, so this was not easy.”

Using this technique, the researchers determined that Tau Boötis b’s thick atmosphere contains carbon monoxide and, curiously, exhibits cooler temperatures at higher altitudes — the opposite of what’s been found on other hot Jupiter exoplanets.

“Maybe one day we may even find evidence for biological activity on Earth-like planets in this way.”

– Ignas Snellen, Leiden Observatory, the Netherlands

In addition to atmospheric details, the team was also able to use the new method to determine Tau Boötis b’s mass and orbital angle — 44 degrees, another detail not previously identifiable.

“The new technique also means that we can now study the atmospheres of exoplanets that don’t transit their stars, as well as measuring their masses accurately, which was impossible before,” said Snellen. “This is a big step forward.

“Maybe one day we may even find evidence for biological activity on Earth-like planets in this way.”

This research was presented in a paper “The signature of orbital motion from the dayside of the planet Tau Boötis b”, to appear in the journal Nature on June 28, 2012.