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

1859 年，地球遭受太阳风暴袭击，电报站中断，南至古巴都可见极光。如果今天发生同样的风暴，将会对世界电网和通信技术造成数万亿美元的损失。就在该事件发生之前，英国天文学家理查德·卡林顿观察到太阳表面突然变亮——这是对太阳耀斑的首次观察。卡林顿观测到的耀斑并非太阳独有，其他恒星也可能发生，尤其是那些温度低于太阳且质量较小的恒星。它们在能量、温度、持续时间和亮度范围内各不相同。通过测量耀斑的特性，我们可以更深入地了解它们的工作原理以及它们如何影响行星维持生命的能力。特别是，测量耀斑的温度可以告诉我们它们对绕其他恒星运行的行星大气层的威胁程度。遗产时空巡天 (LSST) 将在其 10 年的任务中观测到数百万次恒星耀斑。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。该项目还将赞助林肯大学的一名学生从事鲁宾数据的“可听化”工作。该技术通过声音来表示数据，以便盲人和视力障碍者 (BVI) 能够获取结果。即将建成的维拉·C·鲁宾天文台通过其遗留的时空巡天 (LSST) 提供了一个机会，可以收集天空中数百万颗恒星的大量耀斑测量数据。由于耀斑持续时间短且调查节奏短，不太可能通过多个数据点检测到耀斑。该计划旨在开发一种方法，以实现恒星耀斑的 LSST 研究，重点是耀斑温度和温度演化，与耀斑的光度形态相比，这些问题仍然受到很少的限制。利用 Rubin 系统所期望的精致图像质量和灵敏度，差分色折射可用于限制单历元检测中的耀斑温度。将折射效应建模为大气柱密度、光度滤光片和耀斑温度的函数，考虑到 LSST 单次访问绝对天体测量精度的最低指定要求，10,000K 或以上的耀斑温度可以通过气团低至 X=1.2 的单个 g 波段观测来限制。在 Rubin LSST 10 年调查中，预计将在高于 X=1.2 的大气质量处收集近 100,000 张 g 波段图像。该项目将开发一个管道来处理 LSST 数据并表征大量稀疏观测到的耀斑温度样本，这将限制耀斑发射背后的物理过程模型以及耀斑参数（例如温度、持续时间、能量）和恒星参数（例如光谱类型、旋转、磁场）之间的关系。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力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.