تقرير
Atmospheric Characterization and Further Orbital Modeling of $\kappa$ And b
| العنوان: | Atmospheric Characterization and Further Orbital Modeling of $\kappa$ And b |
|---|---|
| المؤلفون: | Uyama, Taichi, Currie, Thayne, Hori, Yasunori, De Rosa, Robert J., Mede, Kyle, Brandt, Timothy D., Kwon, Jungmi, Guyon, Olivier, Lozi, Julien, Jovanovic, Nemanja, Martinache, Frantz, Kudo, Tomoyuki, Tamura, Motohide, Groff, Tyler, Chilcote, Jeffrey, Hayashi, Masahiko, McElwain, Michael W., Asensio-Torres, Ruben, Janson, Markus, Knapp, Gillian R., Serabyn, Eugene |
| سنة النشر: | 2019 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics |
| الوصف: | We present $\kappa$ Andromeda b's photometry and astrometry taken with Subaru/SCExAO+HiCIAO and Keck/NIRC2, combined with recently published SCExAO/CHARIS low-resolution spectroscopy and published thermal infrared photometry to further constrain the companion's atmospheric properties and orbit. $\kappa$ And b's Y/Y-K colors are redder than field dwarfs, consistent with its youth and lower gravity. Empirical comparisons of its Y-band photometry and CHARIS spectrum to a large spectral library of isolated field dwarfs reaffirm the conclusion from Currie et al. (2018) that it likely has a low gravity but admit a wider range of most plausible spectral types (L0-L2). Our gravitational classification also suggests that the best-fit objects for $\kappa$ And b may have lower gravity than those previously reported. Atmospheric models lacking dust/clouds fail to reproduce its entire 1--4.7 $\mu m$ spectral energy distribution, cloudy atmosphere models with temperatures of $\sim$ 1700--2000 $K$ better match $\kappa$ And b data. Most well-fitting model comparisons favor 1700--1900 $K$, a surface gravity of log(g) $\sim$ 4--4.5, and a radius of 1.3--1.6\,$R_{\rm Jup}$; the best-fit model (DRIFT-Phoenix) yields the coolest and lowest-gravity values: $T_{\rm eff}$=1700 K and $\log g$=4.0. An update to $\kappa$ And b's orbit with ExoSOFT using new astrometry spanning seven years reaffirms its high eccentricity ($0.77\pm0.08$). We consider a scenario where unseen companions are responsible for scattering $\kappa$ And b to a wide separation and high eccentricity. If three planets, including $\kappa$ And b, were born with coplanar orbits and one of them was ejected by gravitational scattering, a potential inner companion with mass $\gtrsim10M_{\rm Jup}$ could be located at $\lesssim$ 25 au. Comment: accepted for publication in AJ, typo fixed in ver.2 |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.3847/1538-3881/ab5afa |
| URL الوصول: | http://arxiv.org/abs/1911.09758 |
| رقم الأكسشن: | edsarx.1911.09758 |
| قاعدة البيانات: | arXiv |
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