Every Datapoint Counts: Atmosphere-aided Flare Studies in the Rubin era

1859年，一场太阳风暴袭击了地球，扰乱了电报站，南至古巴都出现了可见的极光。如果同样的风暴发生在今天，它将给世界电网和通信技术造成数万亿美元的损失。就在事件发生之前，英国天文学家理查德·卡灵顿观测到太阳表面突然变亮——这是第一次观测到太阳耀斑。像卡灵顿观测到的这种耀斑并不是太阳所特有的，也会发生在其他恒星上，尤其是那些比太阳更冷、质量更小的恒星。它们在能量、温度、持续时间和亮度的范围内变化。通过测量耀斑的特性，我们更接近于理解它们是如何工作的，以及它们是如何影响行星维持生命的能力的。特别是，测量耀斑的温度可以告诉我们它们对围绕其他恒星运行的行星的大气层的威胁程度。“时空遗产调查”（LSST）将在其10年的任务中观测数百万颗恒星耀斑。研究人员正在开发一种技术，利用地球大气层来测量耀斑的颜色，从而测量耀斑的温度。该项目还将资助林肯大学的一名学生研究鲁宾数据的“声音化”。这种技术是通过声音表示数据，使盲人和视障人士（BVI）能够获得结果。即将到来的Vera C. Rubin天文台通过其遗留的空间和时间调查（LSST）提供了一个收集来自天空中数百万颗恒星的耀斑测量的大集合的机会。由于耀斑持续时间短和测量的节奏，用一个以上的数据点来探测耀斑是不可能的。该项目旨在开发一种方法，使恒星耀斑的LSST研究成为可能，重点是耀斑的温度和温度演变，与耀斑的光度形态相比，这些研究仍然缺乏约束。利用鲁宾系统所期望的精美图像质量和灵敏度，差色光折射可以用来约束单历元检测的耀斑温度。将折射效应建模为大气柱密度、光度滤光器和耀斑温度的函数，考虑到LSST单次访问绝对天文测量精度的最低规定要求，在低至X=1.2的空气质量下，单次g波段观测可以约束10000 k或以上的耀斑温度。在鲁宾LSST的10年调查中，预计将在高于X=1.2的空气质量处收集近10万张g波段图像。该项目将开发一个管道来处理LSST数据，并对大量稀疏观测到的耀斑温度进行表征，这将约束耀斑发射背后的物理过程模型，以及耀斑参数（如温度、持续时间、能量）和恒星参数（如光谱类型、自转、磁场）之间的关系。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In 1859, the Earth was struck by a solar storm that disrupted telegraph stations and created visible aurorae as far south as Cuba. If the same storm were to happen today, it would cause trillions of dollars in damage to the world’s power grids and communication technology. Just before the event, English astronomer Richard Carrington observed a sudden brightening of the Sun’s surface - the first observation of a solar flare. Flares such as the one Carrington observed are not unique to the Sun, but also occur on other stars, especially those cooler and less massive than the Sun. They vary across a range of energies, temperatures, durations, and brightness. By measuring the properties of flares, we come closer to understanding how they work and how they affect a planet’s ability to sustain life. In particular, measuring the temperature of flares can tell us the extent to which they threaten the atmospheres of planets orbiting other stars. The Legacy Survey of Space and Time (LSST) will observe millions of stellar flares over its 10-year mission. The investigators are developing a technique to use the Earth’s atmosphere to measure the color, and thus the temperature, of the flares. This project will also sponsor a student at Lincoln University to work on “sonification” of Rubin data. This technique is the representation of data through sound, to make the results accessible to Blind and Visually Impaired (BVI) persons. The upcoming Vera C. Rubin Observatory through its Legacy Survey of Space and Time (LSST) provides an opportunity to collect a large ensemble of flare measurements from millions of stars across the sky. Because of the short flare duration and the survey cadence, it is unlikely that flares will be detected with more than one data point. This program aims to develop a methodology to enable LSST studies of stellar flares, with a focus on flare temperature and temperature evolution, which remain poorly constrained compared to the photometric morphology of flares. Leveraging the exquisite image quality and sensitivity expected from the Rubin system, Differential Chromatic Refraction can be used to constrain flare temperature from a single-epoch detection. Modeling the refraction effect as a function of the atmospheric column density, photometric filter, and temperature of the flare, flare temperatures at or above 10,000K can be constrained by a single g-band observation at airmass as low as X=1.2, given the minimum specified requirement on single-visit absolute astrometric accuracy of LSST. Nearly 100,000 g-band images are expected to be collected at higher airmass than X=1.2 in the Rubin LSST 10-year survey. This project will develop a pipeline to process LSST data and characterize a large sample of sparsely observed flare temperatures, which will constrain models of the physical processes behind flare emission as well as the relationship between flare parameters (e.g. temperature, duration, energy) and stellar parameters (e.g. spectral type, rotation, magnetic field).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.