Related topics: orbit · stars · planets · solar system

Chemical element potassium detected in an exoplanet atmosphere

A team of astronomers led by AIP Ph.D. student Engin Keles detected the chemical element potassium in the atmosphere of an exoplanet, for the first time with overwhelming significance and applying high-resolution spectroscopy. ...

Earth is an exoplanet to aliens: This is what they'd see

The study of exoplanets has matured considerably in the last 10 years. During this time, the majority of the over 4000 exoplanets currently known were discovered. It was also during this time that the process has started ...

Fluorescent glow may reveal hidden life in the cosmos

Astronomers have uncovered a new way of searching for life in the cosmos. Harsh ultraviolet radiation flares from red suns, once thought to destroy surface life on planets, might help uncover hidden biospheres. Their radiation ...

The uncertainty of detecting planets

Uncertainty in science is a good thing. Because here's how the scientific model works: you observe a phenomenon, then form a hypothesis about why that phenomenon is taking place, then test the hypothesis, which leads you ...

New exoplanet is smallest to be precisely measured

Earthlings have long daydreamed about faraway planets, but only recently have scientists been able to identify thousands of new exoplanets—and to learn more and more about what they look like.

New space discovery sheds light on how planets form

Researchers at Dartmouth College have discovered a planet orbiting one of the brightest young stars known, according to a study published in the journal The Astrophysical Journal Letters. Aged at approximately 45 million ...

Exoplanet evolution: Astronomers expand cosmic 'cheat sheet'

Cornell astronomers have reached into nature's color palette from early Earth to create a cosmic "cheat sheet" for looking at distant worlds. By correlating tints and hues, researchers aim to understand where discovered exoplanets ...

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Extrasolar planet

An extrasolar planet, or exoplanet, is a planet beyond our Solar System, orbiting a star other than our Sun. As of June 2009[update], 353 exoplanets are listed in the Extrasolar Planets Encyclopaedia. The vast majority have been detected through radial velocity observations and other indirect methods rather than actual imaging. Most announced exoplanets are massive gas giant planets thought to resemble Jupiter, but this is a selection effect (bias) due to limitations in detection technology. Projections based on recent detections of much smaller worlds suggest that lightweight, rocky planets will eventually be found to outnumber extrasolar gas giants.

Extrasolar planets became a subject of scientific investigation in the mid-19th century. Many astronomers supposed that such planets existed, but they had no way of knowing how common they were or how similar they might be to the planets of our Solar System. The first confirmed radial velocity detection was made in 1995, revealing a gas giant planet in a four-day orbit around the nearby G-type star 51 Pegasi. The frequency of detections has tended to increase on an annual basis since then. It is estimated that at least 10% of sun-like stars have planets, and the true proportion may be much higher. The discovery of extrasolar planets sharpens the question of whether some might support extraterrestrial life.

Currently Gliese 581 d, the fourth planet of the red dwarf star Gliese 581 (approximately 20 light years from Earth), appears to be the best example yet discovered of a possible terrestrial exoplanet that orbits within the habitable zone surrounding its star. Although initial measurements suggested that Gliese 581 d resided outside the so-called "Goldilocks Zone", additional measurements place it firmly within.

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