With the help ofESA Herschel space telescope, an international team of astrophysicists has discoveredthe first carbon-rich red giant with water vapor in its atmosphere. It is calledLeo W., is located in the constellation of Leo, 500 light years from Earth, and with a radius of 500 suns it is the brightest extrasolar object in the sky in the infrared. Details are published today in the magazineNature.
Leo W.It belongs to a type of evolved stars that have used up most of the fuel in their nucleus, reach enormous sizes and are typically reddish in color, which is why they are known as red giants.The Sun will reach this red giant phase in about 5 billion yearsgetting to expand until engulfing all the planets with orbits more internal than Jupiter.
In particular, the researchers have detected hot water vapor, with a temperature around 700 degrees Celsius, in the regions close to the surface of the red giant star. CW Leo. According to the Spanish Marcelino Agúndez, co-author of the discovery, “in these regions the presence of water is not something to be expected because the star has a carbon-rich character where molecules with oxygen such as water should have a negligible abundance”.
To explain the unexpected detection of hot water vapor, several hypotheses have been developed. The main one is that the structure of the gas and dust cloud that surrounds the central red giant star allows thepenetration of ultraviolet radiation, coming from the local interstellar medium, to the regions closest to the star, promoting the formation of water vapor through various chemical reactions.
