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Anaemia reveals star's great age

Article Abstract:

Stellar models present ways to measure the age of the Universe by measuring the ages of old stellar systems. The age of a very old star, CS22892-052, was estimated through a method called nucleocosmochronology where the abundance of a long-lived radioactive element is compared with its predicted initial value. When the abundances of stable r-process elements in the said star were plotted against scaled Solar System abundances, a perfect match of patterns resulted. This implies that the thorium in the Solar System was synthesized just before the formation of the Sun, which means that the age of CS22892-052 is greater than the initial estimate of 15Gyr.

Stellar age

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One of our planets is missing

Article Abstract:

New findings by David Gray undermine the planetary companion hypothesis of Michel Mayor and Didier Queloz. In 1995, Mayor and Queloz reported the detection of a four-day cycle in the radial velocity of the star 51 Pegasi. They proposed that the cycle is a reflex motion caused by a giant planet orbiting very near the star. Gray's findings indicate the occurrence of a four-day variation in the shape of the star's spectral lines, with sufficient amplitude to give the impression of a reflex motion. These observations imply that a planet need not be present to cause changes in the shape of the spectral lines.

Research, Stellar oscillations

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On the wings of Pegasus

Article Abstract:

There have been several studies dealing with the existence of planets with similar characteristics as Jupiter. One such study was made by Michel Mayor and Didier Queloz which involved the discovery of the star 51 Pegasi whose mass was half that of Jupiter. However, the effort to discover other extrasolar planets is fraught with difficulty because of their great distance and consequent invisibility.

Observations

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