Fig7_5 Proxima Centauri

Fig7_5 Proxima Centauri

Fig. 7.5 . The red star centered in this image is the nearest star to the Earth, other than the Sun; it is at a distance of 4.24 light-years from us. Despite its closeness, the star has an absolute luminosity of just two thousandths, or 0.002 times, the Sunís luminosity, and is too faint to be seen with the unaided eye. Named Proxima Centauri, because of its proximity, the star is close enough for its angular diameter to be measured by interferometric techniques, yielding a radius of one-seventh the radius of the Sun. Proxima Centauri orbits the bright double star Alpha Centauri (see Fig. 7.9) at a distance of about 0.24 light-years and an angular separation of 2.2 degrees. All three stars are located in the southern sky, and cannot be seen from the northern hemisphere of the Earth. (Courtesy of David Malin/UK Schmidt Telescope/DSS/AAO.)

Copyright 2010, Professor Kenneth R. Lang, Tufts University