In this image from ESO’s Very Large Telescope (VLT), light from blazing blue stars energises the gas left over from the stars’ recent formation. The result is a strikingly colourful emission nebula, called LHA 120-N55, in which the stars are adorned with a mantle of glowing gas. Astronomers study these beautiful displays to learn about the conditions in places where new stars develop.
In this image from ESO’s Very Large Telescope (VLT), light from blazing blue stars energises the gas left over from the stars’ recent formation. The result is a strikingly colourful emission nebula, called LHA 120-N55, in which the stars are adorned with a mantle of glowing gas. Astronomers study these beautiful displays to learn about the conditions in places where new stars develop.
LHA 120-N55, or N55 as it is usually known, is a glowing gas cloud in the Large Magellanic Cloud (LMC), a satellite galaxy of the Milky Way located about 163 000 light-years away. N55 is situated inside a supergiant shell, or superbubble called LMC 4. Superbubbles, often hundreds of light-years across, are formed when the fierce winds from newly formed stars and shockwaves from supernova explosions work in tandem to blow away most of the gas and dust that originally surrounded them and create huge bubble-shaped cavities.
The material that became N55, however, managed to survive as a small remnant pocket of gas and dust. It is now a standalone nebula inside the superbubble and a grouping of brilliant blue and white stars — known as LH 72 — also managed to form hundreds of millions of years after the events that originally blew up the superbubble. The LH 72 stars are only a few million years old, so they did not play a role in emptying the space around N55. The stars instead represent a second round of stellar birth in the region.
This zoom sequence takes us on a journey of 160 000 light-years to one of our neighbouring galaxies, the Large Magellanic Cloud. In the final image, taken with ESO’s Very Large Telescope (VLT), light from blazing blue stars energises the gas left over from the stars’ recent formation to create a strikingly colourful emission nebula, called LHA 120-N55, in which the stars are adorned with a mantle of glowing gas. Astronomers study these beautiful displays to learn about the conditions in places where new stars develop. Credit: ESO/ Nick Risinger (skysurvey.org)/Robert Gendler (http://www.robgendlerastropics.com/). Music: Johan monell
The recent rise of a new population of stars also explains the evocative colours surrounding the stars in this image. The intense light from the powerful, blue–white stars is stripping nearby hydrogen atoms in N55 of their electrons, causing the gas to glow in a characteristic pinkish colour in visible light. Astronomers recognise this telltale signature of glowing hydrogen gas throughout galaxies as a hallmark of fresh star birth.
While things seem quiet in the star-forming region of N55 for now, major changes lie ahead. Several million years hence, some of the massive and brilliant stars in the LH 72 association will themselves go supernova, scattering N55’s contents. In effect, a bubble will be blown within a superbubble, and the cycle of starry ends and beginnings will carry on in this close neighbour of our home galaxy.
This pan video gives a close-up look at a new image of the strikingly colourful emission nebula, called LHA 120-N55 from ESO’s Very Large Telescope (VLT). Light from blazing blue stars energises the gas left over from the stars’ recent formation to create a mantle of glowing gas. Astronomers study these beautiful displays to learn about the conditions in places where new stars develop. Credit: ESO. Music: Johan Monell
This new image was acquired using the FOcal Reducer and low dispersion Spectrograph (FORS2) instrument attached to ESO’s VLT. It was taken as part of the ESO Cosmic Gems programme, an outreach initiative to produce images of interesting, intriguing or visually attractive objects using ESO telescopes for the purposes of education and public outreach. The programme makes use of telescope time that cannot be used for science observations. All data collected may also be suitable for scientific purposes, and are made available to astronomers through ESO’s science archive.
This chart shows all the naked eye stars in the far-southern constellation of Dorado (The Dolphin Fish) and also indicates the outline of the Large Magellanic Cloud, a small nearby galaxy. The position of the star formation region LHA 120-N55 is marked. This gas cloud is very faint to be seen visually, but the hot young stars with which it is associated are easier to spot. Credit: ESO/IAU and Sky & Telescope
On Monday the planet Mercury will transit across the face of the Sun as seen from earth between about 7:12 am and 2:42 pm EDT : Mercury Enters Spotlight on May 9 – NASA.
This video shows the path that it will take:
Don’t ever look directly at the sun. There are various safe ways to observe the transit such as using a solar filter over a telescope aperature or to project the image onto a white board with a pinhole. The transit will also be webcast from various sites.
Here are some sites with information on webcasts and tips on viewing the transit directly:
The SETI Institute has a fund-raising campaign underway this month with the goal of reaching $50k: SETI.org/give. Donations will go to support the Institute’s research, outreach and education.
One of the events to highlight the campaign was a panel discussion on the question, When Will We Find Life Beyond Earth?
The SETI Institute panelists included:
Nathalie Cabrol, Director of the Carl Sagan Center
Seth Shostak, Senior Astronomer
Mark Showalter, Senior Research Scientist
Fergal Mullaly, Senior Research Scientist
From the caption:
Is this the generation that will discover extraterrestrial life? Some scientists have opined that we’ll find other living beings – whether they be microbes on other planets or intelligent beings in another star system – within two decades. An energetic panel of SETI Institute astrobiologists will discuss why both science and technology give support to the idea that we may soon prove that Earth is not the only world where life has arisen. Audience Q&A follows [the] panelists.
What can you see in the sky this month? Mercury transits the sun and Mars is closer to Earth than it has been in 11 years. Watch to learn how and where to look for them.
This artist’s impression [Full size image] shows an imagined view from the surface one of the three planets orbiting an ultracool dwarf star just 40 light-years from Earth that were discovered using the TRAPPIST telescope at ESO’s La Silla Observatory. These worlds have sizes and temperatures similar to those of Venus and Earth and are the best targets found so far for the search for life outside the Solar System. They are the first planets ever discovered around such a tiny and dim star. In this view one of the inner planets is seen in transit across the disc of its tiny and dim parent star. Credit: ESO/M. KornmesserAstronomers using the TRAPPIST telescope at ESO’s La Silla Observatory have discovered three planets orbiting an ultracool dwarf star just 40 light-years from Earth. These worlds have sizes and temperatures similar to those of Venus and Earth and are the best targets found so far for the search for life outside the Solar System. They are the first planets ever discovered around such a tiny and dim star. The new results will be published in the journal Nature on 2 May 2016.
Astronomers using telescopes at ESO’s observatories in Chile have discovered three planets around a dim dwarf star just 40 light-years from Earth. These worlds have sizes and temperatures similar to those of Venus and the Earth, and they are the best targets so far found in the hunt for life elsewhere in the Universe. Credit: ESO. [More video info & options.]
A team of astronomers led by Michaël Gillon, of the Institut d’Astrophysique et Géophysique at the University of Liège in Belgium, have used the Belgian TRAPPIST telescope [1] to observe the star 2MASS J23062928-0502285, now also known as TRAPPIST-1. They found that this dim and cool star faded slightly at regular intervals, indicating that several objects were passing between the star and the Earth [2]. Detailed analysis showed that three planets with similar sizes to the Earth were present.
This artist’s impression [full size version] shows an imagined view from close to one of the three planets orbiting an ultracool dwarf star just 40 light-years from Earth that were discovered using the TRAPPIST telescope at ESO’s La Silla Observatory. These worlds have sizes and temperatures similar to those of Venus and Earth and are the best targets found so far for the search for life outside the Solar System. They are the first planets ever discovered around such a tiny and dim star. In this view one of the inner planets is seen in transit across the disc of its tiny and dim parent star. Credit: ESO/M. KornmesserTRAPPIST-1 is an ultracool dwarf star — it is much cooler and redder than the Sun and barely larger than Jupiter. Such stars are both very common in the Milky Way and very long-lived, but this is the first time that planets have been found around one of them. Despite being so close to the Earth, this star is too dim and too red to be seen with the naked eye or even visually with a large amateur telescope. It lies in the constellation of Aquarius (The Water Carrier).
Emmanuël Jehin, a co-author of the new study, is excited:
“This really is a paradigm shift with regards to the planet population and the path towards finding life in the Universe. So far, the existence of such ‘red worlds’ orbiting ultra-cool dwarf stars was purely theoretical, but now we have not just one lonely planet around such a faint red star but a complete system of three planets!”
Michaël Gillon, lead author of the paper presenting the discovery, explains the significance of the new findings:
“Why are we trying to detect Earth-like planets around the smallest and coolest stars in the solar neighbourhood? The reason is simple: systems around these tiny stars are the only places where we can detect life on an Earth-sized exoplanet with our current technology. So if we want to find life elsewhere in the Universe, this is where we should start to look.“
Astronomers will search for signs of life by studying the effect that the atmosphere of a transiting planet has on the light reaching Earth. For Earth-sized planets orbiting most stars this tiny effect is swamped by the brilliance of the starlight. Only for the case of faint red ultra-cool dwarf stars — like TRAPPIST-1 — is this effect big enough to be detected.
This picture [Larger versions] shows the Sun and the ultracool dwarf star TRAPPIST-1 to scale. The faint star has only 11% of the diameter of the sun and is much redder in colour. Credit: ESOFollow-up observations with larger telescopes, including the HAWK-I instrument on ESO’s 8-metre Very Large Telescope in Chile, have shown that the planets orbiting TRAPPIST-1 have sizes very similar to that of Earth. Two of the planets have orbital periods of about 1.5 days and 2.4 days respectively, and the third planet has a less well determined period in the range 4.5 to 73 days.
“With such short orbital periods, the planets are between 20 and 100 times closer to their star than the Earth to the Sun. The structure of this planetary system is much more similar in scale to the system of Jupiter’s moons than to that of the Solar System,”
explains Michaël Gillon.
This artist’s impression video shows an imagined view from close to one of the three planets orbiting an ultracool dwarf star just 40 light-years from Earth that were discovered using the TRAPPIST telescope at ESO’s La Silla Observatory. These worlds have sizes and temperatures similar to those of Venus and Earth and are the best targets found so far for the search for life outside the Solar System. They are the first planets ever discovered around such a tiny and dim star.
In this view one of the inner planets is seen in transit across the disc of its tiny and dim parent star. Credit: ESO/M. Kornmesser
Although they orbit very close to their host dwarf star, the inner two planets only receive four times and twice, respectively, the amount of radiation received by the Earth, because their star is much fainter than the Sun. That puts them closer to the star than the habitable zone for this system, although it is still possible that they possess habitable regions on their surfaces. The third, outer, planet’s orbit is not yet well known, but it probably receives less radiation than the Earth does, but maybe still enough to lie within the habitable zone.
“Thanks to several giant telescopes currently under construction, including ESO’s E-ELT and the NASA/ESA/CSA James Webb Space Telescope due to launch for 2018, we will soon be able to study the atmospheric composition of these planets and to explore them first for water, then for traces of biological activity. That’s a giant step in the search for life in the Universe,”
concludes Julien de Wit, a co-author from the Massachusetts Institute of Technology (MIT) in the USA.
This work opens up a new direction for exoplanet hunting, as around 15% of the stars near to the Sun are ultra-cool dwarf stars, and it also serves to highlight that the search for exoplanets has now entered the realm of potentially habitable cousins of the Earth. The TRAPPIST survey is a prototype for a more ambitious project called SPECULOOS that will be installed at ESO’s Paranal Observatory [3].
This chart shows the naked eye stars visible on a clear dark night in the sprawling constellation of Aquarius (The Water Carrier). The position of the faint and very red ultracool dwarf star TRAPPIST-1 is marked. Although it is relatively close to the Sun it is very faint and not visible in small telescopes. Credit: ESO/IAU and Sky & TelescopeNotes [1] TRAPPIST (the TRAnsiting Planets and PlanetesImals Small Telescope) is a Belgian robotic 0.6-metre telescope operated from the University of Liège and based at ESO’s La Silla Observatory in Chile. It spends much of its time monitoring the light from around 60 of the nearest ultracool dwarf stars and brown dwarfs (“stars” which are not quite massive enough to initiate sustained nuclear fusion in their cores), looking for evidence of planetary transits.The target in this case, TRAPPIST-1, is an ultracool dwarf, with about 0.05% of the Sun’s luminosity and a mass of about 8% that of the Sun.
[2] This is one of the main methods that astronomers use to identify the presence of a planet around a star. They look at the light coming from the star, to see if some of the light is blocked as the planet passes in front of its host star on the line of sight to Earth — transits the star, as astronomers say. As the planet orbits around its star, we expect to see regular small dips in the light coming from the star as the planet moves in front of it.
[3] SPECULOOS is mostly funded by the European Research Council and led also by the University of Liège. Four 1-metre robotic telescopes will be installed at the Paranal Observatory to search for habitable planets around 500 ultra-cool stars over the next five years.
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