According to the article announcing its discovery, at only 7.50 light years, HPMS is the third star in order of distance from the Sun, ranking between Barnard's Star and Wolf 359.
It appears to be a red dwarf, a class of low temperature and low luminosity stars. This would explain why it was not discovered earlier, since it has an apparent magnitude of only 15.4 (and an absolute magnitude of 18.5).
See also: