An unexpected treat on a star first described more than 400 years ago have spied by the NASA space telescope Galaxy Evolution Explorer (GALEX) as part of a survey of the ultraviolet spectrum of the sky that the telescope began in 2003 and is expected to complete later this year.
The tail- the streak of a 13-light-year-long tail, could provide clues about how celestial bodies are formed from the material spat out by such ageing stars. Tails are sometimes seen on neutron stars as they are spat out at high speed from supernovae explosions, but the phenomena are short-lived.
According to Mark Seibert, an astronomer with the Observatories of the Carnegie Institution of Washington in Pasadena, California, other telescopes missed the special feature of the star — called Mira — because they were either looking in the wrong wavelength of light,or simply peering too closely. “Mira has been studied in every conceivable wavelength by the Hubble Space Telescope,” Seibert says.
Mira is also known as Omicron Ceti. According to astronomers it is actually a binary star system, made up of a large Mira A and a smaller Mira B. It is the standard example in astronomical texts of a class of pulsating stars in a late stage of evolution, when much of its mass is spat out in a dusty wind. Here, Mira happens to be moving quite quickly; its stellar wind streams out behind it in a tail that can be seen in the ultraviolet range.
The team, led by Christopher Martin of the California Institute of Technology in Pasadena, also viewed a ‘bow wake’ in front of Mira. Such a wake has only been seen once before on a star of this type, weakly, in the infrared spectrum around a star called R Hydrae.