Polish scientists have proof of destruction of a planet by a star

<P>After billions of years of evolution, star such as the Sun begins to grow, and its dimensions may even reach Earth\'s orbit. Astronomers call stars in this phase red giants. The Sun will enter this phase in about 5 billion years, which will have a significant influence on the final fate of planets such as Mercury, Venus, and maybe even Earth.</P> <P></P> <P>Studies of astronomers from Poland, Spain and the United States provided evidence of the process of planet destruction by the red giant BD+48 740. This star is older than the Sun and has 11 times greater diameter. The researchers conducted observations with 9.2-meter telescope HET in Texas (U.S.).</P> <P></P> <P>"Our detailed spectroscopic analysis indicates that the red giant BD+48 740 contains an unusually large amount of lithium, rare element, originally created 14 billion years ago in the Big Bang" - said Monika Adamów from Toruń Centre for Astronomy of the Nicolaus Copernicus University.</P> <P></P> <P>Lithium is easily destroyed in stars, and older objects usually contain small amounts. "Theorists have identified only a few very specific conditions, other than the Big Bang, in which Lithium can form in stars. In the case of BD+48 740, it is probable that the production of lithium was initiated by a planet-size mass, which was approaching the star in a spiral movement, being more and more heated until it was destroyed" - explained Aleksander Wolszczan of Pennsylvania State University.</P> <P></P> <P>The second clue pointing to such a scenario is a very elongated elliptical orbit of a planet discovered in the BD+48 740 system. This planet has a mass at least 1.6 times larger than Jupiter. "We discovered that the planet orbits the star on an orbit that in the nearest section is a little wider than the orbit of Mars, but it is much more stretched at the farthest point" - said Andrzej Niedzielski of Toruń Centre for Astronomy.</P> <P></P> <P>The scientists believe that such an unusual orbit is the result of gravitational interactions between planets. The planet, which was approaching the red giant, could pass part of its energy to the second planet (which survived), pushing it into a more elliptical orbit.</P> <P></P> <P>The main author of the paper published in the Astrophysical Journal Letters is Monika Adamów from Toruń Centre for Astronomy of the Nicolaus Copernicus University. Other team members include Andrzej Niedzielski (Toruń Centre for Astronomy, Nicolaus Copernicus University), Eva Villaver (Universidad Autonoma de Madrid, Spain), Gregory Smith (Toruń Centre for Astronomy, Nicolaus Copernicus University) and Aleksander Wolszczan (Pennsylvania State University, U.S.).</P> <P></P> <P>PAP - Science and Scholarship in Poland</P> <P></P> <P>cza/ agt/ mrt/</P> <P></P> <P>tr. RL</P>