We present the results of a high temporal resolution spectroscopic monitoring of the flare (UV Cet type) star V1054 Oph (Wolf
630AB), classified as a dM3.5e visual binary system. Intermediate resolution spectra have been taken during four nights (2–5
April 2001) using the IDS spectrograph of the 2.5 m Isaac Newton Telescope (INT) (La Palma, Canary Islands, Spain). The V1054
Oph spectra show very strong emission lines even in its quiescent state. The analysis of the temporal evolution of the observed
emission lines (from H
β to H
11 and the Ca II H and K lines) reveals four strong flares and several weak flares. We have studied in detail the behaviour
of the chromospheric lines during the different phases (pre-flare, impulsive and gradual decay) of these flares. The observed
flares last from ∼25 to 95 min. The equivalent width of the H
β line changes by a factor up to ∼2.3. Broad wings and asymmetric (red-shifted) lines are observed as well.
stars: V1054 Oph - stars: flares: spectroscopic - stars: activity - stars: late-type
This revised version was published online in July 2006 with corrections to the Cover Date.