We present the results of an observational campaign which obtained high time cadence, high precision, simultaneous optical and IR photometric observations of three M dwarf flare stars for 47 hours. The campaign was designed to characterize the behavior of energetic flare events, which routinely occur on M dwarfs, at IR wavelengths to milli-magnitude precision, and quantify to what extent such events might influence current and future efforts to detect and characterize extrasolar planets surrounding these stars. We detected and characterized four highly energetic optical flares having U-band total energies of ~7.8x10^30 to ~1.3x10^32 ergs, and found no corresponding response in the J, H, or Ks bandpasses at the precision of our data. For active dM3e stars, we find that a ~1.3x10^32 erg U-band flare (delta Umax ~1.5 mag) will induce <8.3 (J), <8.5 (H), and <11.7 (Ks) milli-mags of a response. A flare of this energy or greater should occur less than once per 18 hours. For active dM4.5e stars, we find that a ~5.1x10^31 erg U-band flare (delta Umax ~1.6 mag) will induce <7.8 (J), <8.8 (H), and <5.1 (Ks) milli-mags of a response. A flare of this energy or greater should occur less than once per 10 hours. No evidence of stellar variability not associated with discrete flare events was observed at the level of ~3.9 milli-mags over 1 hour time-scales and at the level of ~5.6 milli-mags over 7.5 hour time-scales. We therefore demonstrate that most M dwarf stellar activity and flares will not influence IR detection and characterization studies of M dwarf exoplanets above the level of ~5-11 milli-mags, depending on the filter and spectral type. We speculate that the most energetic megaflares on M dwarfs, which occur at rates of once per month, are likely to be easily detected in IR observations with sensitivity of tens of milli-mags.
Infrared Flares from M Dwarfs: a Hinderance to Future Transiting Exoplanet Studies
许多当前和未来的系外行星任务正在推动红外(IR)波长,行星和恒星之间的通量对比更有利(Deming et al. 2009),恒星磁活动的影响减少。事实上,最近对恒星黑子和光斑的分析发现,这些形式的恒星活动不会对具有JWST的FGKM恒星的凌日特征或科学潜力产生实质性影响(Zellem et al. 2017)。然而,在耀斑的情况下,这是不正确的,我证明这可能是一个障碍,过境研究在这份说明。
Stellar flares with Ariel: detection prospects and impacts on exoplanet spectroscopy
Konkoly Observatory(孔科利天文台);HUN-REN Research Centre for Astronomy and Earth Sciences(匈牙利研究网络地球与天文学研究中心);HUN-REN CSFK MTA Centre of Excellence(匈牙利研究网络 CSFK 马塔科学院卓越中心);SRON Space Research Organisation Netherlands(荷兰空间研究组织 SRON)
Young M dwarfs flare activity model: Towards better exoplanetary atmospheric characterisation
University of Oslo(奥斯陆大学);National Solar Observatory, University of Colorado Boulder(美国国家太阳天文台,科罗拉多大学博尔德分校);Department of Astrophysical and Planetary Sciences, University of Colorado(科罗拉多大学天体物理与行星科学系);Laboratory for Atmospheric and Space Physics, University of Colorado Boulder(科罗拉多大学博尔德分校大气与空间物理实验室);Rosseland Centre for Solar Physics, University of Oslo(奥斯陆大学罗斯兰太阳物理中心);Institute of Theoretical Astrophysics, University of Oslo(奥斯陆大学理论天体物理研究所)
Can the Long-Term Impact of Stellar M-Dwarf Flares Alter the Spectral Features of a Giant Gaseous Exoplanet?
SRON, Netherlands Institute for Space Research(荷兰空间研究所);Institute of Astronomy and Astrophysics, Academia Sinica(中央研究院天文及天文物理研究所);Leiden Observatory, Leiden University(莱顿大学莱顿天文台)
A Multiwavelength Survey of Nearby M dwarfs: Optical and Near-Ultraviolet Flares and Activity with Contemporaneous TESS, Kepler/K2, \textit{Swift}, and HST Observations
High-Time-Cadence Spectroscopy and Photometry of Stellar Flares on M-dwarf YZ Canis Minoris with Seimei Telescope and TESS. II. Statistical Properties of Blue/Red Asymmetries in the H$α$ Line
The 5 GHz Arecibo Search for Radio Flares from Ultracool Dwarfs
我们提出了一个4.75 GHz的调查结果33褐矮星和一个年轻的系外行星系统的耀斑无线电发射,进行了305米阿雷西博射电望远镜。该计划的目标是探测和表征比光谱类型L3.5更冷的物体的磁场,这是我们调查之前探测到的最冷的棕矮星。我们还试图探测HR 8799行星系统的耀斑无线电发射,理论工作表明,热,大质量的系外行星可能具有强大的磁场,能够产生GHz频率的无线电发射。我们已经探测到并确认了来自T6.5矮星2 MASS J10475385+2124234的射电耀斑。这一发现极大地扩展了褐矮星似乎至少是零星的无线电发射体的温度范围,从~1900 K(L3.5)下降到~900 K(T6.5)。它还表明,无线电探测作为一种独特的工具,研究亚恒星物体的磁场的实用性延伸到最冷的矮星,并可能延伸到热的大质量系外行星。我们还从L1矮星2 MASS J1439284+192915中发现了一个3.6 σ的耀斑。这一发现是暂时的,需要通过额外的监测观察加以确认。
Stellar flare-driven evolution of primordial early exo-Earth atmospheres: Insights from a Young M Dwarf Flare model
University of Oslo(奥斯陆大学);National Solar Observatory, University of Colorado Boulder(美国国家太阳天文台,科罗拉多大学博尔德分校);Department of Astrophysical and Planetary Sciences, University of Colorado(科罗拉多大学天体物理与行星科学系);Laboratory for Atmospheric and Space Physics, University of Colorado Boulder(科罗拉多大学博尔德分校大气与空间物理实验室);Rosseland Centre for Solar Physics, University of Oslo(奥斯陆大学罗森兰太阳物理中心);Institute of Theoretical Astrophysics, University of Oslo(奥斯陆大学理论天体物理研究所)
The Effect of a Strong Stellar Flare on the Atmospheric Chemistry of an Earth-like Planet Orbiting an M dwarf
主序星M对天体生物学提出了一个有趣的问题:它们在我们银河系中的丰度使它们成为寻找可居住行星的目标,但它们强烈的色球活动产生高能辐射和带电粒子,可能对生命有害。我们研究了1985年4月12日耀斑的影响,从M矮星,AD狮子座(AD狮子座),模拟紫外线辐射和质子对大气化学的影响,一个假设的,类似地球的行星位于其宜居带。根据对太阳质子事件的观测和Neupert效应,我们估计了能量大于10 MeV的粒子的与$5.9\times 10^{8}$质子耀斑有关的质子通量cm $^{-2}$ sr $^{-1}$ s $^{-1}$。然后,我们计算了由耀斑产生的氮氧化合物的丰度,通过缩放这些化合物在一个大型太阳质子事件称为"卡林顿事件"的生产。使用1-D光化学模型耦合到1-D辐射/对流模型进行模拟。我们的研究结果表明,在耀斑期间发出的紫外线辐射并没有产生显着的变化,在臭氧柱深度的行星。当质子的作用包括在内时,对于一个没有磁场的行星,在耀斑爆发两年后臭氧消耗达到了94%的最大值。在耀斑的高峰期,计算出的到达地表的紫外线通量,在对生命有害的波长范围内,超过了地球在不到100秒内接收到的紫外线通量。因此,耀斑可能不会对轨道上的可居住行星表面的生命构成直接危险。由于狮子座AD是已知的磁活动最活跃的M矮星之一,这个结论应该适用于其他色球活动水平较低的M矮星周围的行星。
Astrometric planet search around southern ultracool dwarfs: V. Discovery of the exoplanet candidate PALTA-1 b
European Space Agency(欧洲空间局);Main Astronomical Observatory, National Academy of Sciences of the Ukraine(乌克兰国家科学院主天文台);Instituto de Astrofísica de Canarias(加那利群岛天体物理研究所);Université de Genève(日内瓦大学)
The Unrealised Interdisciplinary Advantage of Observing High Mass Transiting Exoplanets and Brown Dwarfs -- Strategic Exoplanet Initiatives with HST and JWST White Paper
The Polar Vortex Hypothesis: Evolving, Spectrally Distinct Polar Regions Explain Short- and Long-term Light Curve Evolution and Color-Inclination Trends in Brown Dwarfs and Giant Exoplanets
APO & SMARTS flare star campaign observations I. Blue wing asymmetries in chromospheric lines during mid M dwarf flares from simultaneous spectroscopic and photometric observation data
本文通过对三颗中期 M 矮星的同时光谱与测光观测,发现 7 次耀发在 Hα 等色球谱线中呈现蓝翼不对称性,并据此估计了可能的暗条爆发质量及其与 CME 的关系。
The Second Arecibo Search for 5 GHz Radio Flares from Ultracool Dwarfs
我们描述了我们的第二部分的4.75 GHz的超冷矮星(UCD)的调查进行的阿雷西博射电望远镜,它已经观察到27个这样的对象,并导致在检测到零星的耀斑从T6矮星,WISEPC J112254.73+255021.5。我们还介绍了第一个无线电发射的T矮星,2 MASS J10475385+2124234,一个暂时确定的无线电发射的L1矮星,2 MASS J1439284+192915,和已知的无线电耀斑源,2 MASS J13142039+132011 AB的后续观测。我们的新数据表明,2 MASS J1439284+192915不是一个射电耀斑源。我们对射电闪烁UCD的无偏调查的总体检测率为~5%,对于新来源,每个光谱类别的检测率为~5- 10%。很明显,UCD的射电光度并没有随着光谱类型从M7矮星到巨行星而单调下降,这与这些天体的磁场产生和内部结构的理论相矛盾。与其他最近发表的结果一起,我们的数据证明了使用射电观测来揭示和研究星下磁活动特性的独特价值。