Physical characteristics thumb|right|Optical image of Arcturus (DSS2 / MAST / STScI / NASA) Based upon an annual parallax shift of 88.83 milliarcseconds, as measured by the Hipparcos satellite, Arcturus is from Earth. The parallax margin of error is 0.54 milliarcseconds, translating to a distance margin of error of ±. Because of its proximity, Arcturus has a high proper motion, two arcseconds a year, greater than any first magnitude star other than α Centauri. It is [[list of nearest giant stars|the second-closest giant star to Earth, after Pollux.
Physical characteristics thumb|right|Optical image of Arcturus (DSS2 / MAST / STScI / NASA) Based upon an annual parallax shift of 8,8.83 milliarcseconds, as measured by the Hipparcos satellite Arcturus is from Earth. The parallax margin of error is 0.54 milliarcseconds, translating to a distance margin of error of ±. Because of its proximity, Arcturus has a high proper motion, two arcseconds a year, greater than any first magnitude star other than α Centauri. It is [[list of nearest giant stars|the second-closest giant star to Earth, after Pollux.