3I/Atlas 正离开太阳系并返回星际空间，但其掠过期间留下的资料仍在分析中。一篇仍在审查中的研究指出，ALMA 对智利阿塔卡马沙漠的观测显示，这颗彗星的彗发中甲醇异常富集。相较于太阳系彗星的典型水准，3I/Atlas 的甲醇含量最高可达 4 倍，这使它成为迄今量测到甲醇最丰富的第 2 颗彗星。

研究还发现二氧化碳、铁与氮等成分也偏高，显示 3I/Atlas 的化学组成明显异常。过量甲醇、以二氧化碳为主的彗发，以及其他非典型化学比值，共同支持一项推论：3I/Atlas 形成于比太阳系彗星诞生区域更寒冷、受辐照更强，或化学条件不同的环境。这些比例与丰度趋势，使它看起来像一个形成条件显著不同的天体。

论文同时提出，3I/Atlas 可能属于高活性彗星，其水蒸气产量高于表面本身所能解释的程度。在这类天体中，部分气体来自脱离彗核、漂浮于彗发中的冰粒升华；研究者认为，甲醇、水与二氧化碳都可能同时来自彗核与这些冰粒。这一机制有助于解释其异常比例，也进一步排除人造起源猜测。3I/Atlas 目前正以 60 km/s 远离太阳系，并且是历来仅第 3 个已确认的星际天体。

3I/Atlas is leaving the solar system and returning to interstellar space, but data from its passage are still being analyzed. A study still under review reports that ALMA observations from Chile's Atacama Desert show an anomalously methanol-rich coma. Relative to typical levels in solar system comets, 3I/Atlas contained up to 4 times as much methanol, making it the 2nd most methanol-rich comet ever measured.

The study also found elevated carbon dioxide, iron, and nitrogen, indicating that 3I/Atlas has a strongly unusual chemical composition. Excess methanol, a carbon-dioxide-dominated coma, and other atypical chemical ratios together support the inference that 3I/Atlas formed in an environment colder, more irradiated, or chemically different than the regions where solar system comets formed. These ratios and abundance patterns make it look like an object shaped by markedly different formation conditions.

The paper further suggests that 3I/Atlas may be a hyperactive comet, meaning its water vapor output exceeds what its surface alone can explain. In such bodies, some gas comes from ice grains detached from the nucleus and sublimating in the coma; the researchers argue that methanol, water, and carbon dioxide likely came from both the nucleus and these grains. That mechanism helps explain the anomalous ratios and further weakens speculation about an artificial origin. 3I/Atlas is now receding from the solar system at 60 km/s and is only the 3rd confirmed interstellar object in history.