Quantifying the composition of the material in protoplanetary disks is essential to determining the potential for exoplanetary systems to produce and support habitable environments. When considering potential habitability, complex organic molecules are relevant, key among which is methanol (CH₃OH). Methanol primarily forms at low temperatures via the hydrogenation of CO ice on the surface of icy dust grains and is a necessary basis for the formation of more complex species such as amino acids and proteins. We report the detection of CH₃OH in a disk around a young, luminous A-type star, HD 100546. This disk is warm and therefore does not host an abundant reservoir of CO ice. We argue that the CH₃OH cannot form in situ, and hence that this disk has probably inherited complex-organic-molecule-rich ice from an earlier cold dark cloud phase. This is strong evidence that at least some interstellar organic material survives the disk-formation process and can then be incorporated into forming planets, moons and comets. Therefore, crucial pre-biotic chemical evolution already takes place in dark star-forming clouds.

量化原行星盘中材料的成分对于确定系外行星系统产生和支持宜居环境的潜力至关重要。在考虑潜在的可居住性时，复杂的有机分子是相关的，其中关键是甲醇（CH ₃ OH）。甲醇主要在低温下通过冰尘颗粒表面的 CO 冰加氢形成，并且是形成更复杂物质（如氨基酸和蛋白质）的必要基础。我们报告了在年轻、明亮的 A 型恒星 HD 100546 周围的圆盘中检测到 CH ₃ OH。这个圆盘是温暖的，因此没有丰富的 CO 冰库。我们认为 CH ₃OH 不能在原地形成，因此这个圆盘可能从早期的冷暗云阶段继承了富含复杂有机分子的冰。这是强有力的证据，表明至少有一些星际有机物质在圆盘形成过程中幸存下来，然后可以融入形成行星、卫星和彗星的过程。因此，关键的前生物化学演化已经发生在黑暗的恒星形成云中。