Alien Solar System Looks Strikingly Like Ours

Astronomers have discovered a group of at least five planets – with hints of two more – circling around a star in an arrangement similar to our own solar system. Confirmation of the extra planets would make this the highest tally of alien worlds ever spotted around a single star.

The planets and their own sun-like star are about 127 light-years from Earth, astronomers with the European Southern Observatory said. It is one of just 15 planetary systems known to have more than three worlds.

The five planets circle their parent star, HD 10180, in a regular pattern like the planets of our solar system, only in a more compact arrangement, the researchers said.

Of the two potential additional planets that may be present, one may have a mass that is the closest to the Earth's yet seen, if it is confirmed, they added. [The Strangest Alien Planets]

"We have found what is most likely the system with the most planets yet discovered," astronomer Christophe Lovis, lead author of the study, said in a statement Tuesday. "This remarkable discovery also highlights the fact that we are now entering a new era in exoplanet research: the study of complex planetary systems and not just of individual planets.

"Studies of planetary motions in the new system reveal complex gravitational interactions between the planets and give us insights into the long-term evolution of the system."

The research was announced at an international colloquium on extrasolar planets at the Observatoire de Haute-Provence, France. It came just days ahead of a scheduled announcement from NASA's Kepler planet-hunting mission to discuss an "intriguing planetary system."

Lovis and his team used the planet-hunting HARPS spectrograph instrument on a 3.6-meter telescope at the European Southern Observatory in La Silla, Chile, to detect the system in the constellation Hydrus.

The instrument allows astronomers to measure the movement, or "wobble," of a star caused by the gravitational pull of planets orbiting around it.

The five strongest wobble signals were caused by planets with masses similar to Neptune, between 13 and 25 times the mass of the Earth.

Though these planets are relatively large, they are located close to their parent star and race around at intervals that range from just six days to 600 days.

The closest planet is not quite 5.6 million miles (9 million km) from HD 10180, compared to the 93 million miles (150 million km) separating Earth from the sun, a distance also known as an astronomical unit. The distance of the farthest one from its star is about 1.4 AU.

When compared to our solar system, all of these planets would fit inside the orbit of Mars and appear to have nearly circular orbits.

The wobble method for detecting alien planets also suggested more worlds are orbiting HD 10180, one of them up close and the other far off.

"We also have good reasons to believe that two other planets are present," Lovis said.

One of these extra planets, if confirmed, would be much like Saturn, with at least 65 times the mass of Earth and year that lasts 2,200 days.

The other potential planet is the most tantalizing for astronomers. If confirmed, it would be the least massive world ever found outside our solar system, with a mass just 1.4 times that of Earth. It is thought to orbit extremely close to the star – just 2 percent of an AU – and completes its circuit in only 1.18 Earth days, researchers said.

"This object causes a wobble of its star of only about 3 km/hour— slower than walking speed — and this motion is very hard to measure," said study team member Damien Segransan.

This planet would probably be a small, rocky world similar to the hellish planet Corot-7b, which orbits close to a different star. There the daytime temperatures can reach 4,000 degrees Fahrenheit (2,200 degrees Celsius), with nighttime lows of minus 350 F (minus 210 C).

The newly found system could set the extrasolar record for most known planets. It currently shares the record with the system around the star 55 Cancri, which has five planets, two of them gas giants.

No gas giants seem to be present in the HD 10180 star system.

"Systems of low-mass planets like the one around HD 10180 appear to be quite common, but their formation history remains a puzzle," Lovis said.

Galactic Plane - Aquila

This image combines data from PACS and SPIRE to form a three-colour image. PACS images at 70 microns (blue), 160microns (green) are combined with the SPIRE 250 microns channel (red). Cooler material is shown in red, while warmer material is blue - but all just 10-50 degreen above absolute zero. This image is taken in constellation of Aquila and shows the entire assembly line of newborn stars. The diffuse glow reveals the widespread cold reservoir of raw material which our Galaxy has in stock for the production of new stars.

Two bright star forming regions are seen on the left and centre, called W43 and G29.9 respectively. Below W43, a cavity can be seen in the interstellar medium. The strong winds from the stars forming in the dense clump are pushing the material out, blowing the bobble.
This image is taken as part of a project called "Hi-GAL", which aims to image a strip across the plane of our Galaxy towards its central regions. This is a section 30 degrees away from the centre of our Galaxy.

Ambitious Survey Spots Stellar Nurseries

Astronomers scanning the skies as part of ESO’s VISTA Magellanic Cloud survey have now obtained a spectacular picture of the Tarantula Nebula in our neighbouring galaxy, the Large Magellanic Cloud. This panoramic near-infrared view captures the nebula itself in great detail as well as the rich surrounding area of sky. The image was obtained at the start of a very ambitious survey of our neighbouring galaxies, the Magellanic Clouds, and their environment.

The leader of the survey team, Maria-Rosa Cioni (University of Hertfordshire, UK) explains: "This view is of one of the most important regions of star formation in the local Universe — the spectacular 30 Doradus star-forming region, also called the Tarantula Nebula. At its core is a large cluster of stars called RMC 136, in which some of the most massive stars known are located."

ESO’s VISTA telescope [1] is a new survey telescope at the Paranal Observatory in Chile (eso0949). VISTA is equipped with a huge camera that detects light in the near-infrared part of the spectrum, revealing a wealth of detail about astronomical objects that gives us insight into the inner workings of astronomical phenomena. Near-infrared light has a longer wavelength than visible light and so we cannot see it directly for ourselves, but it can pass through much of the dust that would normally obscure our view. This makes it particularly useful for studying objects such as young stars that are still enshrouded in the gas and dust clouds from which they formed. Another powerful aspect of VISTA is the large area of the sky that its camera can capture in each shot.

This image is the latest view from the VISTA Magellanic Cloud Survey (VMC). The project will scan a vast area — 184 square degrees of the sky (corresponding to almost one thousand times the apparent area of the full Moon) including our neighbouring galaxies the Large and Small Magellanic Clouds. The end result will be a detailed study of the star formation history and three-dimensional geometry of the Magellanic system.

Chris Evans from the VMC team adds: “The VISTA images will allow us to extend our studies beyond the inner regions of the Tarantula into the multitude of smaller stellar nurseries nearby, which also harbour a rich population of young and massive stars. Armed with the new, exquisite infrared images, we will be able to probe the cocoons in which massive stars are still forming today, while also looking at their interaction with older stars in the wider region.”

The wide-field image shows a host of different objects. The bright area above the centre is the Tarantula Nebula itself, with the RMC 136 cluster of massive stars in its core. To the left is the NGC 2100 star cluster. To the right is the tiny remnant of the supernova SN1987A (eso1032). Below the centre are a series of star-forming regions including NGC 2080 — nicknamed the “Ghost Head Nebula” — and the NGC 2083 star cluster.

The VISTA Magellanic Cloud Survey is one of six huge near-infrared surveys of the southern sky that will take up most of the first five years of operations of VISTA.
Notes

[1] VISTA ― the Visible and Infrared Survey Telescope for Astronomy ― is the newest telescope at ESO’s Paranal Observatory in northern Chile. VISTA is a survey telescope working at near-infrared wavelengths and is the world’s largest survey telescope. Its large mirror, wide field of view and very sensitive detectors will reveal a completely new view of the southern sky.

The telescope is housed on the peak adjacent to the one hosting ESO’s Very Large Telescope (VLT) and shares the same exceptional observing conditions. VISTA has a main mirror that is 4.1 m across. In photographic terms it can be thought of as a 67-megapixel digital camera with a 13 000 mm f/3.25 mirror lens.
More information

ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and VISTA, the world’s largest survey telescope. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 42-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

A Galactic Spectacle

A beautiful new image of two colliding galaxies has been released by NASA's Great Observatories. The Antennae galaxies, located about 62 million light-years from Earth, are shown in this composite image from the Chandra X-ray Observatory (blue), the Hubble Space Telescope (gold and brown), and the Spitzer Space Telescope (red). The Antennae galaxies take their name from the long antenna-like "arms," seen in wide-angle views of the system. These features were produced by tidal forces generated in the collision.

The collision, which began more than 100 million years ago and is still occurring, has triggered the formation of millions of stars in clouds of dust and gas in the galaxies. The most massive of these young stars have already sped through their evolution in a few million years and exploded as supernovas.

The X-ray image from Chandra shows huge clouds of hot, interstellar gas that have been injected with rich deposits of elements from supernova explosions. This enriched gas, which includes elements such as oxygen, iron, magnesium, and silicon, will be incorporated into new generations of stars and planets. The bright, point-like sources in the image are produced by material falling onto black holes and neutron stars that are remnants of the massive stars. Some of these black holes may have masses that are almost one hundred times that of the Sun.

The Spitzer data show infrared light from warm dust clouds that have been heated by newborn stars, with the brightest clouds lying in the overlapping region between the two galaxies.

The Hubble data reveal old stars and star-forming regions in gold and white, while filaments of dust appear in brown. Many of the fainter objects in the optical image are clusters containing thousands of stars.

The Chandra image was taken in December 1999. The Spitzer image was taken in December 2003. The Hubble image was taken in July 2004 and February 2005.