we present the discovery of a previously unknown member of the immediate solar neighbourhood , DENIS-P J104814.7 - 395606.1 ( hereafter DENIS 1048 - 39 ) , identified while mining the DENIS database for new nearby stars .
A HIRES echelle spectrum obtained with the 10-m Keck telescope shows that it is an M9 dwarf .
DENIS 1048 - 39 has a very bright apparent magnitude ( I = 12.67 ) for its spectral type and colour ( I - J = 3.07 ) , and is therefore very nearby .
If it is single its distance is only 4.1 \pm 0.6 pc , ranking it as between our 12 ^ { th } and 40 ^ { th } closest neighbour .
It is also the closest star or brown dwarf with a spectral type later than M7V .
Its proper motion was determined through comparison of Sky atlas Schmidt plates , scanned by the MAMA microdensitometer , with the DENIS images .
At 1.52 " yr ^ { -1 } it primarily attests the closeness of DENIS 1048 - 39 and hence its dwarf status .
These characteristics make it an obvious target for further detailed studies .