Deep Thermal Infrared Imaging of HR 8799 bcde: New Atmospheric Constraints and Limits on a Fifth Planet
Deep Thermal Infrared Imaging of HR 8799 bcde: New Atmospheric Constraints and Limits on a Fifth Planet
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HR 8799 bcde 的深热红外成像：第五颗行星上的新大气约束和限制
DOI：
10.1088/0004-637x/795/2/133
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发表时间：
2014
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通讯作者：
Tae-Soo
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作者：
Currie;Thayne; Burrows;Adam; Girard;Julien H.; Cloutier;Ryan; Fukagawa;Misato; Sorahana;Satoko; Kuchner;Marc; Kenyon;Scott J.; Madhusudhan;Nikku; Itoh;Yoichi; Jayawardhana;Ray; Matsumura;Soko; Pyo;Tae-Soo
我们展示了用 Keck/NIRC2、VLT/NaCo 和 Subaru/IRCS 获得的年轻行星宿主恒星 HR 8799 的新 L'（3.8 μm）和 Brα（4.05 μm）数据以及重新处理的档案 L'数据。我们以中等到高信噪比 (S/N≳ 6–15) 检测每个数据集中的所有四颗 HR 8799 行星。我们未能在 5σ 置信水平下识别出第五颗行星“HR 8799 f”，r< 15 AU：0 Farcs 2 处的一个暗示性的、略微显着的残差很可能是点扩散函数伪影。假设伴星年龄为 30 Myr 和 Baraffe 行星冷却模型，我们排除了 HR 8799 f，其质量分别为 5 M J (7 M J)、7 M J (10 M J) 或 12 M J (13 M J)，r proj∼ 12 AU、9 AU 和 5 AU。所有四颗 HR 8799 行星都具有类似早期 T 矮星的红色 L'−[4.05] 颜色，表明它们的光谱能量分布在 L' 和 M' 宽带滤光片之间达到峰值。我们发现 HR 8799 cde 的颜色没有统计学上的显着差异。假设厚的、斑驳的云层的大气模型似乎比假设均匀云层的模型更符合 HR 8799 bcde 的光度测量。虽然需要非平衡碳化学来解释 HR 8799 b 和 c 的光度测定/光谱，但 HR 8799 d 和 e 的光度测定的证据较弱。未来，使用双子座行星成像仪、SCExAO/CHARIS 和其他设施进行的深红外光谱/分光光度测量可能会澄清行星的化学性质是否相似或异质。
We present new L'(3.8 μm) and Brα (4.05 μm) data and reprocessed archival L'data for the young, planet-hosting star HR 8799 obtained with Keck/NIRC2, VLT/NaCo, and Subaru/IRCS. We detect all four HR 8799 planets in each data set at a moderate to high signal-to-noise ratio (S/N≳ 6–15). We fail to identify a fifth planet," HR 8799 f," at r< 15 AU at a 5σ confidence level: one suggestive, marginally significant residual at 0 farcs 2 is most likely a point-spread function artifact. Assuming companion ages of 30 Myr and the Baraffe planet cooling models, we rule out an HR 8799 f with a mass of 5 M J (7 M J), 7 M J (10 M J), or 12 M J (13 M J) at r proj∼ 12 AU, 9 AU, and 5 AU, respectively. All four HR 8799 planets have red early T dwarf-like L'−[4.05] colors, suggesting that their spectral energy distributions peak in between the L'and M'broadband filters. We find no statistically significant difference in HR 8799 cde's color. Atmosphere models assuming thick, patchy clouds appear to better match HR 8799 bcde's photometry than models assuming a uniform cloud layer. While non-equilibrium carbon chemistry is required to explain HR 8799 b and c's photometry/spectra, evidence for it from HR 8799 d and e's photometry is weaker. Future, deep-IR spectroscopy/spectrophotometry with the Gemini Planet Imager, SCExAO/CHARIS, and other facilities may clarify whether the planets are chemically similar or heterogeneous.