The European Southern Observatory's Very Large Telescope is getting an upgrade. ESO signed an agreement with Breakthrough Initiatives, a program created to search for extraterrestrial intelligence, to modify its infrared instrument called VISIR (VLT Imager and Spectrometer for mid-Infrared). Once it's done, the observatory in the Atacama Desert of northern Chile will easily be able to spot exoplanets in the Alpha Centauri. According to ESO, the astronomers' discovery of a habitable planet in our neighboring star system late last year "adds even further impetus to this search."
Exoplanets are hard to spot since the brightness of the massive stars they orbit tend to overwhelm their presence, making them hard to see from our little corner in the universe. While observing them in infrared makes exoplanets easier to detect, the upgrade will give VISIR an even more powerful technique called coronagraphy. It greatly reduces stellar light to make their comparably tinier planets more visible to the telescope.
Breakthrough Initiatives -- backed by Stephen Hawking, Mark Zuckerberg and Russian tech investor Yuri Milner -- will treat any habitable planet VLT finds in the Alpha Centauri as a possible destination for the spacecraft it plans to make. The program aims to develop a "nanocraft" fast enough to travel to the star system, and it wants to reach that goal within one generation.
ESO Views the Glowing Gas Cloud LHA 120-N55
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.
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 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.
ESO's dustbuster reveals hidden stars
In this new image of the nebula Messier 78, young stars cast a bluish pall over their surroundings, while red fledgling stars peer out from their cocoons of cosmic dust. To our eyes, most of these stars would be hidden behind the dust, but ESO's Visible and Infrared Survey Telescope for Astronomy (VISTA) sees near-infrared light, which passes right through dust. The telescope is like a giant dustbuster that lets astronomers probe deep into the heart of the stellar environment.
Messier 78, or M78, is a well-studied example of a reflection nebula. It is located approximately 1600 light-years away in the constellation of Orion (The Hunter), just to the upper left of the three stars that make up the belt of this familiar landmark in the sky. In this image, Messier 78 is the central, bluish haze in the centre; the other reflection nebula towards the right goes by the name of NGC 2071. The French astronomer Pierre Méchain is credited with discovering Messier 78 in 1780. However, it is today more commonly known as the 78th entry in French astronomer Charles Messier's catalogue, added to it in December of 1780.
When observed with visible light instruments, like ESO's Wide Field Imager at the La Silla Observatory, Messier 78 appears as a glowing, azure expanse surrounded by dark ribbons (see eso1105). Cosmic dust reflects and scatters the light streaming from the young, bluish stars in Messier 78's heart, the reason it is known as a reflection nebula.
The dark ribbons are thick clouds of dust that block the visible light originating behind them. These dense, cold regions are prime locations for the formation of new stars. When Messier 78 and its neighbours are observed in the submillimetre light between radio waves and infrared light, for example with the Atacama Pathfinder Experiment (APEX) telescope, they reveal the glow of dust grains in pockets just barely warmer than their extremely cold surroundings (see eso1219). Eventually new stars will form out of these pockets as gravity causes them to shrink and heat up.
In between visible and submillimetre light lies the near-infrared part of the spectrum, where the Visible and Infrared Survey Telescope for Astronomy (VISTA) provides astronomers with crucial information. Beyond dusty reflections and through thinner portions of obscuring material, the luminous stellar sources within Messier 78 are visible to VISTA's eyes. In the centre of this image, two blue supergiant stars, called HD 38563A and HD 38563B, shine brightly. Towards the right of the image, the supergiant star illuminating NGC 2071, called HD 290861, is also seen.
Besides big, blue, hot stars, VISTA can also see many stars that are just forming within the cosmic duststrewn about this region, their reddish and yellow colours shown clearly in this image. These colourful fledgling stars can be found in the dust bands around NGC 2071 and along the trail of dust running towards the left of the image. Some of these are T Tauri stars. Although relatively bright, they are not yet hot enough for nuclear fusion reactions to have commenced in their cores. In several tens of millions of years, they will attain full "starhood," and will take their place alongside their stellar brethren lighting up the Messier 78 region.
Stellar lab in Sagittarius
Messier 18 was discovered and catalogued in 1764 by Charles Messier—for whom the Messier Objects are named—during his search for comet-like objects. It lies within the Milky Way, approximately 4600 light-years away in the constellation of Sagittarius, and consists of many sibling stars loosely bound together in what is known as an open cluster.
There are over 1000 known open star clusters within the Milky Way, with a wide range of properties, such as size and age, that provide astronomers with clues to how stars form, evolve and die. The main appeal of these clusters is that all of their stars are born together out of the same material.
In Messier 18 the blue and white colours of the stellar population indicate that the cluster's stars are very young, probably only around 30 million years old. Being siblings means that any differences between the stars will only be due to their masses, and not their distance from Earth or the composition of the material they formed from. This makes clusters very useful in refining theories ofstar formation and evolution.
Astronomers now know that most stars do form in groups, forged from the same cloud of gas that collapsed in on itself due to the attractive force of gravity. The cloud of leftover gas and dust—or molecular cloud—that envelops the new stars is often blown away by their strong stellar winds, weakening the gravitational shackles that bind them. Over time, loosely bound stellar siblings like those pictured here will often go their separate ways as interactions with other neighbouring stars or massive gas clouds nudge, or pull, the stars apart. Our own star, the Sun, was most likely once part of a cluster very much like Messier 18 until its companions were gradually distributed across the Milky Way.
The dark lanes that snake through this image are murky filaments of cosmic dust, blocking out the light from distant stars. The contrasting faint reddish clouds that seem to weave between the stars are composed of ionised hydrogen gas. The gas glows because young, extremely hot stars like these are emitting intense ultraviolet light which strips the surrounding gas of its electrons and causes it to emit the faint glow seen in this image. Given the right conditions, this material could one day collapse in on itself and provide the Milky Way with yet another brood of stars—a star formation process that may continue indefinitely.
This mammoth 30 577 x 20 108 pixel image was captured using the OmegaCAM camera, which is attached to the VLT Survey Telescope (VST) at ESO's Paranal Observatory in Chile.
A cosmic rose with many names
This new image of the rose-colored star forming region Messier 17 was captured by the Wide Field Imager on the MPG/ESO 2.2-meter telescope at ESO's La Silla Observatory in Chile. It is one of the sharpest images showing the entire nebula and not only reveals its full size but also retains fine detail throughout the cosmic landscape of gas clouds, dust and newborn stars.
The nebula pictured here may have had more names bestowed upon it over the ages than any other object of its kind. Although officially known as Messier 17, its nicknames include: the Omega Nebula, the Swan Nebula, the Checkmark Nebula, the Horseshoe Nebula and—lest those with more of a more marine bent miss out—the Lobster Nebula.
Messier 17 is located about 5500 light-years from Earth near the plane of the Milky Way and in the constellation of Sagittarius (The Archer). The object spans a big section of the sky—its gas and dust clouds measure about 15 light-years across. This material is fueling the birth of new stars and the wide field of view of the new picture reveals many stars in front of, in, or behind Messier 17.
The nebula appears as a complex red structure with some graduation to pink. Its colouring is a signature of glowing hydrogen gas. The short-lived blue stars that recently formed in Messier 17 emit enough ultraviolet light to heat up surrounding gas to the extent that it begins to glow brightly. In the central region the colours are lighter, and some parts appear white. This white colour is real—it arises as a result of mixing the light from the hottest gas with the starlight reflected by dust.
The gas in the nebula is estimated to have more than 30 000 times the mass of the Sun. Messier 17 also contains an open star cluster of 35 stars, which is known as NGC 6618. The total number of stars in the nebula, however, is much higher—there are almost 800 stars in the centre with even more forming in its outer regions.
Throughout this rosy glow, the nebula shows a web of darker regions of dust that obscure the light. This obscuring material is also glowing and—although these areas are dark in this visible-light image—they look bright when observed using infrared cameras.
The nebula owes its official name to the French comet hunter Charles Messier who included the nebula as the seventeenth object in his famous astronomical catalogue in 1764. But even with a name as bland as Messier 17, this flowery nebula still looks dazzling.
This picture comes from the ESO Cosmic Gems programme.