HD 152384: A 5-megayear-old debris disk system showing a gaseous ring of refractory elements at the dust sublimation radius
Year: 2026
Type: article
Abstract: Circumstellar gas around young stars provides key insights into planet formation and disk evolution. HD,152384, a young (5 Myr) A0,V star in Sco-Cen, exhibits hybrid disk characteristics with a modest infrared excess due to small dust grains and atomic emission lines dominated by refractory elements, but the disk's structure and origin remain unclear. We aim to characterise the kinematics and excitation of the circumstellar gas around HD,152384, and to constrain the physical properties of the emitting region. We used new optical and near-infrared high spectral resolution data from the Ultraviolet and Visual Echelle Spectrograph (UVES) and CRyogenic high-resolution InfraRed Echelle Spectrograph (CRIRES) instruments at the Very Large Telescope to revisit the circumstellar environment of HD,152384. Earlier studies suggested the presence of a broad, gas-rich circumstellar disk; here, we re-examine this scenario. -1 $ peak separation. Modelling of gas in Keplerian rotation indicates that the gas is confined to a geometrically thin ring at a radial distance of 0.09--0.12 au from the central star, close to the dust sublimation radius (0.10--0.14 au, assuming a dust sublimation temperature of ∼1500 K). The detected Fe, i emission comes from an optically thick region. However, the Mg, i lines are optically thin, allowing us to derive a mass of 2.2 times 10^22 kg (or 3.6 times 10^-3 M$_⊕) in magnesium gas confined to the geometrically thin ring. The inferred mass and composition of circumstellar dust and gas in the HD,152384 system are consistent with a secondary origin related to rocky planetesimal collisions. We suggest that the atomic gas seen in our observations is due to the sublimation of small dust grains created in such collisions, spiralling inwards to the dust sublimation radius, creating an accumulation of atomic gas at this location. We conclude that HD,152384 represents a young analogue of gas-bearing debris disk systems such as β Pictoris and of the gaseous debris disks around metal-polluted white dwarfs (in which a similar phenomenology is observed), offering a new window into the early violent phase of rocky planetesimal processing.
Source: Astronomy and Astrophysics
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
OpenAlex ID: W7223287819