Joel D. Green, Olivia C. Jones, Luke D. Keller, Charles A. Poteet, Yao-Lun Yang, William J. Fischer, Neal J. Evans, Benjamin A. Sargent, Luisa M. Rebull
We present new SOFIA-FORCAST observations obtained in Feburary 2016 of the archetypal outbursting low mass young stellar object FU Orionis, and compare the continuum, solid state, and gas properties with mid-IR data obtained at the same wavelengths in 2004 with Spitzer-IRS. In this study, we conduct the first mid-IR spectroscopic comparison of an FUor over a long time period. Over a 12 year period, UBVR monitoring indicates that FU Orionis has continued its steady decrease in overall brightness by ~ 14%. We find that this decrease in luminosity occurs only at wavelengths < 20 microns. In particular, the continuum short ward of the silicate emission complex at 10 microns exhibits a ~ 12% (~ 3 sigma) drop in flux density, but no apparent change in slope; both the Spitzer and SOFIA spectra are consistent with a 7200 K blackbody. Additionally, the detection of water absorption is consistent with the Spitzer spectrum. The silicate emission feature at 10 microns continues to be consistent with unprocessed grains, unchanged over 12 years. We conclude that either the accretion rate in FU Orionis has decreased by ~ 12-14% over this time baseline, or that the inner disk has cooled, but the accretion disk remains in a superheated state outside of the innermost region.
We have obtained low-resolution optical (0.7-0.98 micron) and near-infrared (1.11-1.34 micron and 0.8-2.5 micron) spectra of twelve isolated planetary-mass candidates (J = 18.2-19.9 mag) of the 3-Myr sigma Orionis star cluster with a view to determining the spectroscopic properties of very young, substellar dwarfs and assembling a complete cluster mass function. We have classified our targets by visual comparison with high- and low-gravity standards and by measuring newly defined spectroscopic indices. We derived L0-L4.5 and M9-L2.5 using high- and low-gravity standards, respectively. Our targ…
Constraining mass ratio and extinction in the FU Orionis binary system with infrared integral field spectroscopy
我们报告低分辨率近红外光谱观测的爆发星FU猎户座使用积分场摄谱仪项目1640安装在Palomar黑尔望远镜。这项工作的重点是阐明位于FU Ori以南0.5”的微弱源的性质，并于2003年被确定为FU Ori S。我们首先使用我们的观察与已公布的数据相结合，以证明这两颗恒星确实是物理相关的，并形成一个真正的双星对。然后，我们继续使用阻尼LOCI算法提取J和H波段分光光度法，这是一种为IFS的高对比度科学量身定制的还原方法。这是第一次报告这种技术的高精度的通信，由项目1640团队开创，在一个微弱的天文来源。我们使用我们的低分辨率近红外光谱结合10.2微米干涉数据来限制FU Ori S的红外过量。然后，我们专注于估计FU Ori S的体物理性质。我们的模型导致严重红化的对象的估计，A_V =8-12，有效温度为~ 4000-6500 K。最后，我们把这些结果放在FU Ori N-S系统的背景下，认为我们的分析提供了证据，FU Ori S可能是这个双星系统中更大的组成部分
During their formation phase stars gain most of their mass in violent episodic accretion events, such as observed in FU Orionis (FUor) and EXor stars. V346 Normae is a well-studied FUor that underwent a strong outburst beginning in $\sim1980$. Here, we report photometric and spectroscopic observations which show that the visual/near-infrared brightness has decreased dramatically between the 1990s and 2010 ($ΔR\approx10.9^{\rm m}$, $ΔJ\approx7.8^{\rm m}$, $ΔK\approx5.8^{\rm m}$). The spectral properties of this fading event cannot be explained with variable extinction alone, but indicate a drop…
We present the results of high-resolution (R $\ge$ 30,000) optical and near-infrared spectroscopic monitoring observations of a FU Orionis-type object, V960 Mon, which underwent an outburst in 2014 November. We have monitored this object with the Bohyunsan Optical Echelle Spectrograph (BOES) and the Immersion GRating INfrared Spectrograph (IGRINS) since 2014 December. Various features produced by a wind, disk, and outflow/jet were detected. The wind features varied over time and continually weakened after the outburst. We detected double-peaked line profiles in the optical and near-infrared, a…
V7995 Sgr: A New FU Orionis Accretion Outburst Near NGC 6589/6590
California Institute of Technology（加州理工学院）；Columbia University（哥伦比亚大学）；Center for Computational Astrophysics, Flatiron Institute（平顿研究所计算天体物理中心）；Harvard University（哈佛大学）；Jet Propulsion Laboratory, California Institute of Technology（加州理工学院喷气推进实验室）
本文报告了 V7995 Sgr 在 2024 年底达到峰值亮度的一次 FU Orionis 型爆发，基于多波段光变曲线和光谱观测，确认其由吸积盘驱动并伴有强风。
Multi-color characterization of optically invisible FU Orionis-type outbursts: Demonstration and prospects for the WINTER survey
Harvard & Smithsonian（哈佛-史密森天体物理中心）；Columbia University（哥伦比亚大学）；Flatiron Institute（平顿研究所）；California Institute of Technology（加州理工学院）；Massachusetts Institute of Technology（麻省理工学院）
A SCUBA-2 850-$μ$m survey of circumstellar disks in the $λ$ Orionis cluster
我们目前的结果，从850- $μ$米调查的$\sim$ 500万年的老$λ$猎户座恒星形成区。我们使用詹姆斯·克拉克·麦克斯韦望远镜上的SCUBA-2相机来测量$\sim$ 0.5直径的圆形区域，该区域包含36个（59个中的）星团成员，这些成员具有指示拱星盘的红外过量。我们只探测到一个具有$>3σ$意义的天体，即赫比格Ae星HD 245185，其通量密度为$\sim74$ mJy光束$^{-1}$，对应的尘埃质量为$\sim150$ M $_{\oplus}$。堆积个别未检测到的来源没有产生显着的平均信号，但给出了一个上限的平均尘埃质量$λ$猎户座磁盘的$\sim3$ M $_{\oplus}$。我们用亚毫米波天线阵对HD 245185进行的后续观测发现了微弱的CO2--1谱线发射，其积分通量为$\sim170$ mJy km s $^{-1}$，但在30 mJy km s $^{-1}$灵敏度下没有$^{13}$ CO或C $^{18}$ O同位素体发射，这表明$\lesssim1$ M $_{\rm Jup}$的气体质量。因此，隐含的气尘比是标准星际介质值的$\gtrsim50$倍，使HD 245185与其他年龄相近的赫比格Ae盘区分开来，这些盘被发现富含气体;由于HD 245185也显示出吸积的迹象，我们可能在盘清理的最后阶段捕捉到它。我们对$λ$ Orionis星团的研究对…
We report Spitzer Space Telescope IRAC 3.6, 4.5, 5.8 and 8 um and MIPS 24 and 70 um observations of the 32 Ori Group, a recently discovered nearby stellar association situated towards northern Orion. The proximity of the group (~93 pc) has enabled a sensitive search for circumstellar dust around group members, and its age (~20 Myr) corresponds roughly to an epoch thought to be important for terrestrial planet formation in our own solar system. We quantify infrared excess emission due to circumstellar dust among group members, utilizing available optical (e.g. Hipparcos, Tycho) and near-IR (2MA…
Context. FU Orionis is the archetypal FUor star, a subclass of young stellar object (YSO) that undergo rapid brightening events, often gaining 4-6 magnitudes on timescales of days. This brightening is often associated with a massive increase in accretion; one of the most ubiquitous processes in astrophysics from planets and stars to super-massive black holes. We present multi-band interferometric observations of the FU Ori circumstellar environment, including the first J-band interferometric observations of a YSO. Aims. We investigate the morphology and temperature gradient of the inner-most r…
We present the mid-infrared (mid-IR) period$-$luminosity relations (PLRs) using over 1000 Mira variables in the Large Magellanic Cloud (LMC), for the four Wide-Field Infrared Survey Explorer (WISE) and the four Spitzer bands. These PLRs cover a mid-IR wavelength range from $3.4$ $μ$m to $22$ $μ$m and are presented separately for the oxygen-rich (O-rich) and carbon-rich (C-rich) Miras. These relations can be used to measure distances to individual O-rich and/or C-rich Mira stars with the accuracy of $5\%$ and $12\%$, respectively. They are the most accurate Mira PLRs in the mid-IR to date.
