A new classification scheme for exoplanet sizes

There are about 4433 exoplanets in the latest catalogs. Their radii have generally been measured by knowing the radius of their host star and then closely fitting the lightcurves as the planet transits across the face of ...

Planet formation starts before star reaches maturity

A European team of astronomers has discovered that dust particles around a star already coagulate before the star is fully grown. Dust particle growth is the first step in the formation of planets. The researchers from the ...

Donor star breathes life into zombie companion

ESA's Integral space observatory has witnessed a rare event: the moment that winds emitted by a swollen red giant star revived its slow-spinning companion, the core of a dead star, bringing it back to life in a flash of X-rays.

Scientist proposes new definition of a planet

Pluto hogs the spotlight in the continuing scientific debate over what is and what is not a planet, but a less conspicuous argument rages on about the planetary status of massive objects outside our solar system. The dispute ...

Giant bubbles on red giant star's surface

Astronomers using ESO's Very Large Telescope have for the first time directly observed granulation patterns on the surface of a star outside the solar system—the aging red giant π1 Gruis. This remarkable new image from ...

The initial mass function

The gas and dust in giant molecular clouds gradually come together under the influence of gravity to form stars. Precisely how this occurs, however, is incompletely understood. The mass of a star, for example, is by far the ...

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