Binary stars are more common than we thought

Credit: ESO/WFI (Optical); MPIfR/ESO/APEX/A. Weiss et al. (Submillimetre); NASA/CXC/CfA/R. Kraft et al. (X-ray)1 / 16

High-mass stars are rarely solitary. This is what Bochum's astronomers found out at the Ruhr-Universität's (RUB's) observatory in Chile.

For several years, they observed 800 celestial objects that are up to one hundred times heavier than our sun.

More than 90 per cent have turned out to be multiple systems. These data support the theory that heavy stars are already formed as twins.

University observatory as key to success
Even with the world's largest telescopes, binary stars cannot generally be distinguished as two discrete points.

To prove their existence nevertheless, the team headed by Prof Dr Rolf Chini from the RUB Institute of Astronomy used a trick.

They watched the celestial bodies over a period of many weeks and months and detected that their spectra and their brightness oscillated.

Regular brightness variations occur if two or more stars pass each other again and again.

These long-term measurements were possible only because the Ruhr-Universität operates its own observatory in the best place for astronomical observations worldwide: the Atacama Desert in Chile.

Twins that weigh the same
The statistical analysis of the data revealed that stars in multiple systems usually have a partner with the same mass.

According to Rolf Chini, this is no coincidence: "Why should a star of 50 solar masses capture, of all stars, a partner of likewise 50 solar masses in its surroundings?"

"It would be much easier to attract a star of only one solar mass. Surely, the stars' formation process is what provides the explanation."

The celestial objects originate from gas and dust clouds which then become dense. In the final stage, the cloud apparently splits into two parts of similar size.

Rolf Chini, today Head of the university observatory, spent the first money he's ever earned on a telescope. 

Credit: RUBIN, photo: Nelle

You can find the complete article about the research conducted by Prof Dr Rolf Chini's team at the RUB Institute of Astronomy in the online magazine RUBIN.

Our Earth and its Moon Have a Common Water Source

The Moon's water did not come from comets but was already present on Earth 4.5 billion years ago, when a giant collision sent material from Earth to form the Moon, new research shows. 

Credit: NASA/JPL

Researchers used a multicollector ion microprobe to study hydrogen-deuterium ratios in lunar rock and on Earth.

Their conclusion: The Moon's water did not come from comets but was already present on Earth 4.5 billion years ago, when a giant collision sent material from Earth to form the Moon.

Water inside the Moon's mantle came from primitive meteorites, new research finds, the same source thought to have supplied most of the water on Earth. The findings raise new questions about the process that formed the Moon.

By showing that water on the Moon and on Earth came from the same source, this new study offers yet more evidence that the Moon's water has been there all along.

Alberto Saal

"The simplest explanation for what we found is that there was water on the proto-Earth at the time of the giant impact," said Alberto Saal, associate professor of Geological Sciences at Brown University and the study's lead author.

"Some of that water survived the impact, and that's what we see in the Moon."

Erik Hauri

The research was co-authored by Erik Hauri of the Carnegie Institution of Washington, James Van Orman of Case Western Reserve University, and Malcolm Rutherford from Brown and published online in Science Express.

Journal Reference:

1. Alberto E. Saal, Erik H. Hauri, James A. Van Orman, and Malcolm J. Rutherford. Hydrogen Isotopes in Lunar Volcanic Glasses and Melt Inclusions Reveal a Carbonaceous Chondrite Heritage. Science, 9 May 2013 DOI: 10.1126/science.1235142

Hydrogen Peroxide: Ingredient for Life Common on Europa, Jupiter's Icy Moon

A potential energy source for life appears to be common on Jupiter's icy moon Europa, a new study suggests.

An analysis of infrared observations of Europa revealed that hydrogen peroxide is abundant on the ice-covered Jovian moon. If the hydrogen peroxide finds a way beneath Europa's surface and mixes with the moon's liquid water ocean, it could be a vital energy source for any life that might exist there, scientists said.

Kevin Hand

"Life as we know it needs liquid water, elements like carbon, nitrogen, phosphorus and sulfur, and it needs some form of chemical or light energy to get the business of life done," study leader Kevin Hand, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., said in a statement.

 "Europa has the liquid water and elements, and we think that compounds like peroxide might be an important part of the energy requirement. The availability of oxidants like peroxide on Earth was a critical part of the rise of complex, multicellular life."

Planetary scientist Mike Brown of the California Institute of Technology in Pasadena co-authored the new study, which analyzied near-infrared observations of Europa collected in September 2011 by the Keck II telescope atop the Mauna Kea volcano in Hawaii.