A Pathway to the Confirmation and Characterisation of Habitable Alien Worlds

确认和描述宜居外星世界的途径

• 批准号: MR/Y011759/1
• 负责人: Heather Cegla
• 金额: $ 75.76万
• 依托单位: University of Warwick
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2025
• 资助国家: 英国
• 起止时间: 2025 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FY011759%2F1
• 关键词: Pathway; Confirmation; Characterisation; Habitable; Alien

Are we alone in the Universe? Since the confirmation of the first planets outside our solar system in the 1990s, we have made tremendous progress towards answering this question. Yet, the confirmation of a true Earth-analogue still evades us. On top of this, if we are truly to understand the origins of life in the cosmos, we must also create a complete picture of planetary formation, evolution, and habitability.However, each of these aspects necessitates a detailed knowledge of solar-type stars. This is because we study exoplanets indirectly by analysing their much more luminous host stars. For example, most planet confirmation relies on the Doppler wobble of the host star, induced by the planet. Moreover, we can learn about a planet's dynamical history from mapping its projected orbit as it transits its host star. Hence, stellar surface inhomogeneities can impact planetary interpretations, and can completely swamp the signals from rocky worlds. My research aims to overcome these hurdles. For this, my team studies stellar surfaces from a two-pronged approach: with state-of-the-art 3D simulations and using transiting planets to empirically probe stellar surfaces.I aim to understand and disentangle a fundamental barrier on the pathway to confirming other Earths: the stellar surface inhomogeneities from convection. Planet confirmation requires a mass measurement, which can be determined from the Doppler shift of the absorption lines in the stellar atmosphere. However, all Sun-like stars are enveloped in boiling plasma, causing hot bubbles of plasma to rise to the surface (inducing blueshifts), where they cool and fall down into the surrounding regions (inducing redshifts). The net result is spurious velocity shifts up to a m/s - completely swamping the tiny signal of an Earth- twin, which is a mere 9 cm/s. These shifts can be even larger if regions of magnetic field concentrate and inhibit the convection. As the next generation spectrographs continue to come online, we are entering an era where it is technologically feasible to confirm Earth-twins. With the launch of the PLATO mission in 2026, primed to provide such candidates, and the Terra Hunting Survey commencing late 2024, equipped to confirm such worlds, this work is extremely time critical.The Sun has shown us convection does not easily average out; we must disentangle its signature to find Earth-like worlds. To do this, my team uses 3D magnetohydrodynamic simulations to create realistic model stars. With these, we study precisely how convection alters stellar lines, and work to optimise stellar noise reduction techniques. My present work on Solar- analogues indicates we can use the curvature of the stellar lines to remove this noise, but will this work for hotter or cooler stars? How do noise diagnostics behave if a star has a patchy distribution of magnetic field? Which lines are most sensitive to the convection and magnetic fields? These are some of the questions my research aims to answer.Of course, these diagnostics are only as reliable as their underlying simulations. I have pioneered a new technique, using transiting planets as probes, to validate these for the first time for main-sequence stars other than the Sun. By subtracting in- from out-of-transit observations, we isolate the starlight behind the planet. With this, we can study the convection behaviour, stellar differential rotation, and determine the 3D trajectory of a planet's orbit - a key feature in understanding its formation and evolution. By applying this technique to a range of systems are able to validate the simulations, quantify the impact of convection on planetary dynamic measurements, and contribute to a more global understanding of planet formation and evolution.With this 2-pronged approach, I aim to push the frontiers of astronomy towards the future confirmation and characterisation of habitable alien worlds, and help answer whether or not we are truly alone in the Universe.

我们一个人在宇宙中吗？自从1990年代在太阳系以外的第一行星确认以来，我们在回答这个问题方面取得了巨大的进步。然而，对真正的地球 - 征服的确认仍然使我们逃避了我们。最重要的是，如果我们真正了解宇宙中生命的起源，我们还必须完整地描绘行星形成，进化和宜居性。但是，这些方面的每个方面都必须对太阳能型星星有详细的了解。这是因为我们通过分析其更发光的宿主恒星间接研究系外行星。例如，大多数行星确认都依赖于行星引起的宿主恒星的多普勒摇摆。此外，我们可以通过绘制其经过托管恒星时的投影轨道来了解星球的动态历史。因此，出色的表面不均匀性会影响行星解释，并可以完全淹没来自岩石世界的信号。我的研究旨在克服这些障碍。为此，我的团队从两管齐下的方法中研究出色的表面：使用最新的3D模拟，并使用过境行星在经验上探测出色的表面。行星确认需要进行质量测量，可以从恒星大气中吸收线的多普勒移位确定。然而，所有类似太阳状的恒星都被沸腾的血浆包裹，导致血浆的热气泡升至表面（诱导蓝光），在那里它们冷却并落入周围区域（引起红移）。最终结果是虚假速度转移到m/s-完全淹没了地球双胞胎的微小信号，这是一个仅9 cm/s。如果磁场浓缩区域并抑制对流的区域，这些变化可能会更大。随着下一代光谱仪继续上网，我们进入了一个在技术上可行的时代以确认地球圈。随着2026年柏拉图任务的启动，准备提供此类候选人，而Terra狩猎调查开始于2024年末，配备了确认此类世界，这项工作极为至关重要。太阳向我们表明对流并不容易平均；我们必须解开其签名，以找到类似地球的世界。为此，我的团队使用3D磁水动力模拟来创建逼真的模型星。通过这些，我们精确地研究了对流如何改变恒星线，并致力于优化恒星降噪技术。我目前在太阳能方面的工作表明我们可以使用恒星线的曲率来消除这种噪音，但是这种噪音是否适用于较热或凉爽的恒星？噪声诊断如何表现，如果恒星的磁场分布分布？哪些线对对流和磁场最敏感？这些是我的研究旨在回答的一些问题。当然，这些诊断仅与它们的基础模拟一样可靠。我先开创了一种新技术，使用过境行星作为探针，以首次验证它们以验证太阳以外的主要序列恒星。通过从传输外观测中减去进口，我们隔离了地球背后的星光。这样，我们可以研究对流行为，出色的差异旋转，并确定行星轨道的3D轨迹 - 理解其形成和进化的关键特征。通过将该技术应用于一系列系统，能够验证模拟，量化对流对行星动态测量的影响，并有助于对行星形成和进化的全球了解。使用这种2个备受关系的方法，我旨在将天文学的边界推向未来的Alien Alien Worlds的未来确认和表征，并没有回答我们是否真正地回答了我们是否真正地回答了我们是否可以予以掌握。