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Some intermediate polars show outbursts that are much shorter than thoseobserved in normal dwarf novae, and whose origin has remained unelucidated fora long time. We examine here the case of V1223 Sgr, an intermediate polar thatshowed a short outburst in 1984, and compare the outburst characteristics withthe predictions of the magnetospheric gating model. We use the archival datafrom the AAVSO from which we extract the outburst profiles. We use our code forcomputing the time-dependent evolution of an accretion disc truncated by thewhite dwarf magnetic field, using a simple description of the interactionbetween the disc and the magnetic field, as in D'Antona and Spruit (2010). Wefind that V1223 Sgr underwent a series of short outbursts, with a rise lastingfor typically two to three hours, and a slightly longer decay. When applied tointermediate polars, the model by D'Antona and Spruit (2010) accounts well forthe observed outburst duration and intensity. We confirm, however, that themodel outcome depends sensitively on the rather poorly constrained model'sassumptions. We have also searched the AAVSO database for short outbursts inother IPs, identifying individual short outbursts in FO Aqr, TV Col, NY Lup andEI UMa, but no series as those observed in V1223 Sgr. We also found asuperoutburst, followed by a reflare in CTCV J2056-3014. Although themagnetic-gating accretion instability model is clearly responsible for theseries of V1223 Sgr short outbursts and most probably for similar events inother intermediate polars, the model describing this process needs improving,in particular concerning the interaction of the white-dwarf's magnetic fieldwith the accretion disc. This difficult task might benefit from furthercomparison of the model outcome with additional observations having good timecoverage and time resolution.

Magnetically-gated accretion model: application to short bursts in the intermediate polar V1223 Sgr