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Abstract We present Band 6 and Band 7 observations of 10 Lupus disks around M3-K6 stars from the Atacama Large Millimeter/submillimeter Array survey of Gas Evolution in PROtoplanetary disks (AGE-PRO) Large Program. In addition to continuum emission in both bands, our Band 6 setup covers the12CO,13CO, and C18OJ= 2–1 lines, while our Band 7 setup covers the N2H+J= 3–2 line. All of our sources are detected in12CO and13CO; seven out of ten are detected in C18O; and three are detected in N2H+. We find strong correlations between the CO isotopologue line fluxes and the continuum flux densities. With the exception of one disk, we also identify a strong correlation between the C18OJ= 2–1 and N2H+J= 3–2 fluxes, indicating similar CO abundances across this sample. For the two sources with well-resolved continuum and12COJ= 2–1 images, we find that their gas-to-dust size ratio is consistent with the median value of ∼2 inferred from a larger sample of Lupus disks. We derive dust disk masses from continuum flux densities. We estimate gas disk masses by comparing C18OJ= 2–1 line fluxes with those predicted by the limited grid of self-consistent disk models of M. Ruaud et al. A comparison of these mass estimates with those derived by L. Trapman et al., using a combination of CO isotopologue and N2H+line emission, shows that the masses are consistent with each other. Some discrepancies appear for small and faint disks, but they are still within the uncertainties. Both methods find gas disk masses increase with dust disk masses, and gas-to-dust mass ratios are between 10 and 100 in the AGE-PRO Lupus sample.
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This content will become publicly available on November 1, 2026
Discovery of carbon monoxide emission from five debris disks around young A-type stars
Context. Over the past 15 years, surveys mainly at millimeter wavelengths have led to the discovery of ~20 gas-bearing debris disks, most of them surrounding young intermediate-mass stars. Exploring the properties and origin of this gas could be fundamental to better understanding the transition between the protoplanetary and debris disk phases, the evolution of icy planetesimal belts, and the formation of planetary atmospheres. Aims. To expand the list of known CO-bearing debris disks and to improve our knowledge of the environmental conditions under which they can form, we targeted 12 dust-rich debris disks around young (<50 Myr) intermediate-mass stars. Methods. Using the ALMA 12m Array we performed millimeter continuum and CO line observations to search for dust and gas and to measure their quantity and spatial distribution. Results. We discovered CO gas in five disks. Two of them have a low CO content of a few times 10−5M⊕, similar to that ofβPic. The other three disks, however, are CO-rich withMCO> 10−3M⊕. By combining our results with those of other studies we concluded, in agreement with previous findings, that the detection rate of CO gas is significantly higher for disks around stars with 6.5L⊙<L*< 21.9L⊙(~A8–A0 spectral type) than for disks around less luminous stars (0.18L⊙<L*< 6.4L⊙, K7–A9). A comparison of the measured CO masses and the estimated mass loss rates of solids in disks with low CO content (<10−4M⊕) suggests that collisions may play a role in CO gas production in such systems. Interestingly, however, the estimated mass loss rates of CO-rich debris disks are not higher than those of systems with low CO content. In light of this finding, we speculate on what could lead to the formation of CO-rich debris disks.
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- Award ID(s):
- 2307920
- PAR ID:
- 10701560
- Publisher / Repository:
- Astronomy & Astrophysics
- Date Published:
- Journal Name:
- Astronomy & Astrophysics
- Volume:
- 703
- ISSN:
- 0004-6361
- Page Range / eLocation ID:
- A15
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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