Gas detection around main sequence stars is becoming more common with around 20 systems showing the presence of CO. However, more detections are needed, especially around later spectral type stars to better understand the origin of this gas and refine our models. To do so, we carried out a survey of 10 stars with predicted high likelihoods of secondary CO detection using ALMA in band 6. We looked for continuum emission of mm-dust as well as gas emission (CO and CN transitions). The continuum emission was detected in 9/10 systems for which we derived the discs' dust masses and geometrical properties, providing the first mm-wave detection of the disc around HD 106906, the first mm-wave radius for HD 114082, 117214, HD 15745, HD 191089 and the first radius at all for HD 121191. A crucial finding of our paper is that we detect CO for the first time around the young 10-16 Myr old G1V star HD 129590, similar to our early Sun. The gas seems colocated with its planetesimal belt and its total mass is likely between $2-10 \times 10^{-5}$ M$_\oplus$. This first gas detection around a G-type main-sequence star raises questions as to whether gas may have been released in the Solar System as well in its youth, which could potentially have affected planet formation. We also detected CO gas around HD 121191 at a higher S/N than previously and find that the CO lies much closer-in than the planetesimals in the system, which could be evidence for the previously suspected CO viscous spreading owing to shielding preventing its photodissociation. Finally, we make estimates for the CO content in planetesimals and the HCN/CO outgassing rate (from CN upper limits), which we find are below the level seen in Solar System comets in some systems.

中文翻译：

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用 ALMA 调查行星带：在类太阳恒星 HD 129590 周围检测到气体

围绕主序星的气体探测变得越来越普遍，大约有 20 个系统显示 CO 的存在。 然而，需要更多的探测，尤其是在后期光谱类型的恒星周围，以更好地了解这种气体的起源并完善我们的模型。为此，我们使用 ALMA 在波段 6 中对 10 颗预测二次 CO 探测的可能性很高的恒星进行了调查。我们寻找毫米尘的连续发射以及气体发射（CO 和 CN 跃迁）。在 9/10 系统中检测到连续发射，我们从中导出了圆盘的尘埃质量和几何特性，提供了围绕 HD 106906 的圆盘的第一个毫米波检测，HD 114082、117214、HD 的第一个毫米波半径15745、HD 191089 和 HD 121191 的第一个半径。我们论文的一个重要发现是，我们首次在年轻的 10-16 Myr 老 G1V 恒星 HD 129590 周围探测到 CO，类似于我们早期的太阳。该气体似乎与其星子带位于同一位置，其总质量可能在 $2-10 \times 10^{-5}$ M$_\oplus$ 之间。围绕 G 型主序星的首次气体探测引发了关于气体是否可能在太阳系及其年轻时释放的问题，这可能会影响行星的形成。我们还检测到 HD 121191 周围的 CO 气体的信噪比比以前更高，并且发现 CO 比系统中的星子更近，这可能是先前怀疑的 CO 粘性扩散的证据，因为屏蔽阻止了它的光解. 最后，