The Mira Binary System: A Red Giant Star and Its Hot Companion

 The Mira Binary System: A Red Giant Star and Its Hot Companion

[TOP] This is a NASA Hubble Space Telescope image of the cool red giant star Mira A (right), officially called Omicron Ceti in the constellation Cetus, and its nearby hot companion (left) taken on December 11, 1995 in visible light using the European Space Agency's Faint Object Camera (FOC). The stars in this false-color picture are separated by an angular size of only 0.6 arcseconds (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.

[LOWER LEFT] Hubble's visible-light image of the disk of Mira reveals it has an odd, asymmetrical shape resembling a football. This may be tied to dramatic changes occurring 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.

[LOWER RIGHT] In UV light, Hubble resolves a small hook-like appendage extending from Mira, in the direction of the companion that 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.

In this magnified image of Mira, displayed on a log scale to show better the extension toward the companion, the companion is out of the field of view - to the left of Mira.

Credits

Margarita Karovska (Harvard-Smithsonian Center for Astrophysics) and NASA

About The Object
Object Name Mira A, Omicron Ceti
R.A. Position 02h 19m 20.79s
Dec. Position -2° 58' 39.51"
About The Object
Object Name A name or catalog number that astronomers use to identify an astronomical object.
Object Description The type of astronomical object.
R.A. Position Right ascension – analogous to longitude – is one component of an object's position.
Dec. Position Declination – analogous to latitude – is one component of an object's position.
Constellation One of 88 recognized regions of the celestial sphere in which the object appears.
Distance The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs.
Dimensions The physical size of the object or the apparent angle it subtends on the sky.
About The Data
Data Description
  • Proposal: A description of the observations, their scientific justification, and the links to the data available in the science archive.
  • Science Team: The astronomers who planned the observations and analyzed the data. "PI" refers to the Principal Investigator.
Instrument The science instrument used to produce the data.
Exposure Dates The date(s) that the telescope made its observations and the total exposure time.
Filters The camera filters that were used in the science observations.
About The Image
Image Credit The primary individuals and institutions responsible for the content.
Publication Date The date and time the release content became public.
Color Info A brief description of the methods used to convert telescope data into the color image being presented.
Orientation The rotation of the image on the sky with respect to the north pole of the celestial sphere.