FOC images Mira binary system

This (top) image of the cool red giant star Mira A (right) and its nearby hot companion (left) was recorded on 11 December 1995 in visible light using ESA's Faint Object Camera (FOC) aboard the Hubble Space Telescope. The stars in this false-colour image are separated by only 0.6 arcsec (equal to 70 times the distance between Earth and the Sun), but clearly resolved by the FOC. Image reconstruction techniques have been used to further enhance the details in the Mira images. In the lower two panels the reconstructed images of Mira are magnified and the companion is out of the field of view to the left from Mira. FOC's visible-light image (lower left) reveals that Mira has an odd, asymmetrical shape. This may be tied to dramatic changes during its expansion-contraction cycles, or to the presence of unresolved spots on its surface. Hubble measurements show the red giant star is 700 times larger than our Sun. In UV light, FOC resolves (lower right) a small hook-like appendage extending from Mira, in the direction of the companion. It could be material from Mira being gravitationally drawn toward the smaller star. Alternately, it could be that material in Mira's upper atmosphere is being heated due to the companion's presence. [Image Date: 11-12-95] [98.06.005-011]