By studying in great detail the ‘ringing’ of a planet-harbouring star, a team of astronomers using ESO’s 3.6-m telescope have shown that it must have drifted away from the metal-rich Hyades cluster. This discovery has implications for theories of star and planet formation, and for the dynamics of our Milky Way.

The yellow-orange star Iota Horologii, located 56 light-years away towards the southern Horologium (”The Clock”) constellation, belongs to the so-called “Hyades stream”, a large number of stars that move in the same direction.

Previously, astronomers using an ESO telescope had shown that the star harbours a planet, more than 2 times as large as Jupiter and orbiting in 320 days (ESO 12/99).

But until now, all studies were unable to pinpoint the exact characteristics of the star, and hence to understand its origin. A team of astronomers, led by Sylvie Vauclair from the University of Toulouse, France, therefore decided to use the technique of ‘asteroseismology’ to unlock the star’s secrets.

“In the same way as geologists monitor how seismic waves generated by earthquakes propagate through the Earth and learn about the inner structure of our planet, it is possible to study sound waves running through a star, which forms a sort of large, spherical bell,” says Vauclair.

The ‘ringing’ from this giant musical instrument provides astronomers with plenty of information about the physical conditions in the star’s interior.

And to ‘listen to the music’, the astronomers used one of the best instruments available. The observations were conducted in November 2006 during 8 consecutive nights with the state-of-the-art HARPS spectrograph mounted on the ESO 3.6-m telescope at La Silla.

Up to 25 ‘notes’ could be identified in the unique dataset, most of them corresponding to waves having a period of about 6.5 minutes.

These observations allowed the astronomers to obtain a very precise portrait of Iota Horologii: its temperature is 6150 K, its mass is 1.25 times that of the Sun, and its age is 625 million years. Moreover, the star is found to be more metal-rich than the Sun by about 50%.

These results show the power of asteroseismology when using a very precise instrument such as HARPS,” says Vauclair. “It also shows that Iota Horologii has the same metal abundance and age as the Hyades cluster and this cannot be a coincidence.”

The Hyades is an ensemble of stars that is seen with the unaided eye in the Northern constellation Taurus (”The Bull”). This open cluster, located 151 light-years away, contains stars that were formed together 625 million years ago.

The star Iota Horologii must have thus formed together with the stars of the Hyades cluster but must have slowly drifted away, being presently more than 130 light-years away from its original birthplace. This is an important result to understand how stars move on the galactic highways of the Milky Way.

This also means that the amount of metals present in the star is due to the original cloud from which it formed and not because it engulfed planetary material. “The chicken and egg question of whether the star got planets because it is metal-rich, or whether it is metal-rich because it made planets that were swallowed up is at least answered in one case,” says Vauclair.

The astronomers’ study is being published as a Letter to the Editor in Astronomy and Astrophysics (”The exoplanet-host star iota Horologii: an evaporated member of the primordial Hyades cluster”, by S. Vauclair et al.). The team is composed of Sylvie Vauclair, Marion Laymand, Gérard Vauclair, Alain Hui Bon Hoa, and Stéphane Charpinet (LATT, Toulouse, France), François Bouchy (IAP, Paris, France), and Michaël Bazot (University of Porto, Portugal).

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“Swinhoe’s soft-shell turtle” was thought to be extinct in nature. Cleveland Metroparks Zoo has just announced the discovery of a critically endangered turtle in northern Vietnam that previously was thought to be extinct in the wild. Experts from the Zoo’s Asian Turtle Program confirmed that they have identified the only known living specimen of a Swinhoe’s soft-shell turtle (Rafetus swinhoei) in nature.

After three years of searching lakes and wetlands along the Red River in northern Vietnam, researchers sponsored by Cleveland Metroparks Zoo and the Cleveland Zoological Society, turned their focus to a lake just west of Hanoi, where local residents claimed to have occasionally seen the gigantic soft-shell turtle. Field biologist Nguyen Xuan Thuan, with Education for Nature in Vietnam, found and photographed the turtle as it basked on the lake’s surface, allowing scientists to confirm the animal was the extremely rare Swinhoe’s turtle.

This is an incredibly important discovery because the Swinhoe’s turtle is one of the most critically endangered species of turtle in the world,” said Doug Hendrie, the Vietnam-based coordinator of Cleveland Metroparks Zoo’s Asian Turtle Program. “This species has legendary status among the people of Vietnam, so this is perhaps an opportunity for the legend to live on.”

Other than the turtle discovered by Cleveland Metroparks Zoo’s Asian Turtle Program, only three of the giant turtles are known to remain. Two of them are at zoos in China, and one is in the Hoan Kiem Lake in Hanoi. The Swinhoe’s soft-shell turtle is considered by many in Vietnam to be a national treasure.

According to folklore, the rare turtle has emerged at key points in Vietnam’s history. The legend says that in the 15th century, the giant turtle rose from Hoan Kiem Lake to reclaim a magical sword that was given to Emperor Le Loi to expel the Chinese army from Vietnam. Some people believe that the single, large soft-shell turtle that occupies the lake today is the very same turtle that retrieved the sword from the Emperor and returned it to God.

Hanoi residents often line the banks of Hoan Kiem Lake in hopes of spotting the legendary turtle, which some believe brings good fortune to those who see it.

“This is one of those mythical species that people always talked about but no one ever saw, so it’s hugely significant that we found this lone turtle in the wild,” said Geoff Hall, General Curator of Cleveland Metroparks Zoo. “It gives us some hope for a species that truly is on the verge of extinction.”

The demise of this revered species is largely due to hunters who captured and killed them for food or to make traditional medicine from their bones. Loss of nesting habitats along major rivers and pollution also are to blame. And while the recent discovery of another specimen of the Swinhoe’s turtle is promising, the future of the species remains uncertain.

“Our hopes are set on finding other turtles that have somehow been overlooked by hunters or were preserved in lakes and wetlands along the Red River,” Hendrie said. “However, without evidence of reproduction, the future of the legendary Hoan Kiem turtle and its three surviving cohorts looks bleak.”

Efforts are underway to unite the male and female soft-shell turtles at the two separate Chinese zoos in hopes they may reproduce and ensure another generation of the species.

The largest freshwater turtle in the world, the Swinhoe’s soft-shell turtle also is referred to as the Shanghai soft-shell turtle or the Yangtze soft-shell turtle. The giant turtles can weigh up to 300 pounds and measure up to 3_ feet with some living to more than 100 years old. The species historically could be found in the Red River basin of northern Vietnam, extending north into southern China and along the Yangtze River in eastern China.

Before announcing their big discovery, the team of Zoo-supported researchers notified senior government officials and took measures to protect the turtle in its natural habitat. The Swinhoe’s turtle remains in the lake where it was found.

The Asian Turtle Program is a special conservation program of Cleveland Metroparks Zoo and the Cleveland Zoological Society, with all work in Vietnam being carried out in partnership with Education for Nature — Vietnam (ENV). Additional funding and support for the Asian Turtle Program comes from Conservation International, the Turtle Survival Alliance, the Wildlife Conservation Society, Melbourne Zoo, the Turtle Conservation Fund, the Wade Foundation and the Bachelor Foundation.

Cleveland Metroparks Zoo is home to 3,000 animals representing 600 species from six continents. Committed to improving the future for wildlife, the Zoo runs conservation initiatives both locally and abroad, supporting field scientists and conservation efforts in Asia, Latin America and Africa.

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WA researchers investigating how blood vessel growth keeps cancers alive have made a world-first discovery that could boost the chances of successfully treating life-threatening tumours.

Western Australian Institute for Medical Research (WAIMR) Associate Professor Ruth Ganss and her team have found that a gene called RGS5 can reverse angiogenesis — the growth of blood vessels inside the tumour. The discovery was recentlly published in the journal Nature.

“It’s the uncontrolled growth of blood vessels and the formation of abnormal blood vessels inside tumours that ‘feed’ them, allowing them to grow and stopping the immune system from wiping out the tumour,” said Associate Professor Ganss.

“What we’ve shown is that RGS5 is a master gene in angiogenesis and that when it is removed, angiogenesis reverses and the blood vessels in tumours appear more normal.

“Importantly, this normalisation changes the tumour environment in a way that improves immune cell entry, meaning tumours can be destroyed and improving survival rates in laboratory tests.”

Reversing abnormal vessel growth represents a fresh approach to tackling angiogenesis, with most current research focusing on how to block or kill tumour-feeding blood vessels.

“We’ve long-suspected this research would deliver advances in knowledge about what impacts tumour growth and this publication recognises the innovation and importance of our work,” said Associate Professor Ganss.

“By understanding what is actually going on in the tumour itself, the ultimate hope is that we’ll be able to work on making current therapeutic approaches even more successful and reducing side effects of them.”

Associate Professor Ganss’ breakthrough comes after joining WAIMR from Heidelberg where she worked at the German Cancer Research Center.

The majority of the discovery was funded by the National Health and Medical Research Council and part of the work was achieved using facilities at The University of WA based Centre for Microscopy, Characterisation and Analysis.

Earlier this month, a second paper by Associate Professor Ganss’ and her team was published in The Journal of Clinical Investigation which describes how tumours can be attacked by the immune system with fewer side-effects.

“This discovery involves targeting tumours with inflammatory substances that change the environment, so immune cells can attack the tumour through blood vessels more effectively and lessen the amount of toxins going elsewhere in the body,” Associate Professor Ganss said.

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