Morpho-kinematics of the wind of AGB star L$_2$ Pup
  Single dish observations of AGB star L$_2$ Pup have revealed exceptionally
low mass loss rate and expansion velocity, challenging interpretations in terms
of standard wind models. Recent VLT and ALMA observations have drawn a detailed
picture of the circumstellar envelope within $\sim$20 au from the centre of the
star: a nearly edge-on rotating disc of gas and dust, probably hosting a
planetary companion near the star. However, these observations provide no
direct information on the wind escaping the gravity of the star. The present
article uses ALMA observations of the $^{12,13}$CO(3-2), $^{29}$SiO(8-7),
$^{12}$CO(2-1) and $^{28}$SiO(5-4) line emissions to shed new light on this
issue. It shows the apparent normality of L$_2$ Pup in terms of the formation
of the nascent wind, with important line broadening within 4 au from the centre
of the star, but no evidence for a wind flowing along the disc axis. At larger
distances, up to some 200 au from the centre of the star, the wind
morpho-kinematics is dominated by a disc, or equatorial enhancement, expanding
isotropically and radially with a velocity not exceeding some 5 km s$^{-1}$ ,
inclined in the north-west/south-east direction with respect to the plane of
the sky. In addition, outflows of lower density are observed on both sides of
the disc, covering large solid angles about the disc axis, contributing about
half the flux of the disc. Such morphology is at strong variance with the
expectation of a pair of back-to-back outflows collimated by the central
gas-and-dust disc.
