HD141569A: disk dissipation caught in action

International audienceDebris disks are usually thought to be gas-poor, the gas being dissipated by accretion or evaporation during the proto-planetary phases. HD141569 is a 5 Myr old star harbouring a famous debris disk, with multiple rings and spiral features in particular imaged in scattered light. The dust observations also reveal a central cavity of ~130 AU. Despite the apparently evolved status of the disk, large quantities of CO have been detected. Near-infrared observations of gas have revealed that the dust cavity is not devoid of gas, and by consequence that the gas and dust are not co-located. I present here Plateau de Bure Interferometer observations mapping the 12CO(2-1) gas in HD141569 disk. We used the DISKFIT code to analyze the data and model them by fitting power-laws. It confirms that dust and gas are not co-located everywhere in the disk with the gas inner radius inferior to 60 AU and its outer radius being smaller than the dust one. In terms of modeling, the results indicate the gas is still optically thick and more massive than expected for a debris disk. This study tends to show that HD141569 is an hybrid disk with a primordial gas component and secondary-made dust created by planetesimal collisions, and then is an interesting target to better understand the transition between early and evolved phases of the disks which give birth to planetary systems