Ross 248 ranks as the 10th closest star to Earth. The star lies about 10.3 light-years away. One light-year equals the distance light travels in a vacuum in a year, about 9.46 trillion kilometers. As seen from Earth, Ross 248 appears in the constellation Andromeda. The star takes its name from the American astronomer Frank E. Ross, who first cataloged it in 1925. Ross 248 shines too faintly to be seen with the unaided eye.
Astronomers classify Ross 248 as a type of small, faint star called a red dwarf. Ross 248 has about 1/10 the sun’s mass (amount of matter). Its diameter measures about 1/5 that of the sun. Ross 248’s reddish color results from its relatively low surface temperature, around 2500 K. One kelvin (K) equals one Celsius degree above absolute zero (–273.15 °C). This star gives off about 1/1,000 as much light as does the sun.
Ross 248 exhibits sudden, intense increases in brightness called flares that fade within a few minutes. These flares probably resemble solar flares on the sun. But because Ross 248 is much smaller than the sun, the flares have a much more pronounced effect on its overall brightness. For this reason, astronomers refer to Ross 248 as a flare star.
See also Star (table: The 10 known stars nearest Earth) .
