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تسجيل مستخدم جديد$beta$ Pictoris inner disk in polarized light and new orbital parameters for $beta$ Pictoris b
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We present $H$-band observations of $beta$ Pic with the Gemini Planet Imagers (GPIs) polarimetry mode that reveal the debris disk between ~0.3 (~6 AU) and ~1.7 (~33 AU), while simultaneously detecting $beta$ Pic $b$. The polarized disk image was fit with a dust density model combined with a Henyey-Greenstein scattering phase function. The best fit model indicates a disk inclined to the line of sight ($phi=85.27{deg}^{+0.26}_{-0.19}$) with a position angle $theta_{PA}=30.35{deg}^{+0.29}_{-0.28}$ (slightly offset from the main outer disk, $theta_{PA}approx29{deg}$), that extends from an inner disk radius of $23.6^{+0.9}_{-0.6}$ AU to well outside GPIs field of view. In addition, we present an updated orbit for $beta$ Pic $b$ based on new astrometric measurements taken in GPIs spectroscopic mode spanning 14 months. The planet has a semi-major axis of $a=9.2^{+1.5}_{-0.4}$AU, with an eccentricity $eleq 0.26$. The position angle of the ascending node is $Omega=31.75{deg}pm0.15$, offset from both the outer main disk and the inner disk seen in the GPI image. The orbital fit constrains the stellar mass of $beta$ Pic to $1.60pm0.05 M_{odot}$. Dynamical sculpting by $beta$ Pic $b$ cannot easily account for the following three aspects of the inferred disk properties: 1) the modeled inner radius of the disk is farther out than expected if caused by $beta$ Pic b; 2) the mutual inclination of the inner disk and $beta$ Pic $b$ is $4{deg}$, when it is expected to be closer to zero; and 3) the aspect ratio of the disk ($h_0 = 0.137^{+0.005}_{-0.006}$) is larger than expected from interactions with $beta$ Pic $b$ or self-stirring by the disks parent bodies.
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The intermediate-mass star Beta Pictoris is known to be surrounded by a structured edge-on debris disk within which a gas giant planet was discovered orbiting at 8-10 AU. The physical properties of Beta Pic b were previously inferred from broad and n
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Context. {beta} Pictoris b is one of the most studied objects nowadays since it was identified with VLT/NaCo as a bona-fide exoplanet with a mass of about 9 times that of Jupiter at an orbital separation of 8-9 AU. The link between the planet and the
dusty disk is unambiguously attested and this system provides an opportunity to study the disk/planet interactions and to constrain formation and evolutionary models of gas giant planets. Still, {beta} Pictoris b had never been confirmed with other telescopes so far. Aims. We aimed at an independent confirmation using a different instrument. Methods. We retrieved archive images from Gemini South obtained with the instrument NICI, which is designed for high contrast imaging. The observations combine coronagraphy and angular differential imaging and were obtained at three epochs in Nov. 2008, Dec. 2009 and Dec. 2010. Results. We report the detection with NICI of the planet {beta} Pictoris b in Dec. 2010 images at a separation of 404 pm 10 mas and P A = 212.1 pm 0.7{deg} . It is the first time this planet is observed with a telescope different than the VLT.
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lthough the dominant gas production mechanism is so far not identified. The origin of the observed overabundance of C and O compared to solar abundances of metallic elements, e.g. Na and Fe, is also unclear. Aims: Our goal is to constrain the spatial distribution of C in the disk, and thereby the gas origin and its abundance pattern. Methods: We used the HIFI instrument onboard Herschel to observe and spectrally resolve CII emission at 158 $mu$m from the {beta} Pic debris disk. Assuming Keplerian rotation, we use the spectrally resolved line profile to constrain the spatial distribution of the gas. Results: We show that most of the gas is located around $sim$100 AU or beyond. We estimate a total C gas mass of $1.3times10^{-2}$ M$_oplus$. The data suggest that more gas is located on the southwest side of the disk than on the northeast side. The data are consistent with the hypothesis of a well-mixed gas (constant C/Fe ratio throughout the disk). Assuming instead a spatial profile expected from a simplified accretion disk model, we found it to give a significantly worse fit to the observations. Conclusions: Since the bulk of the gas is found outside 30 AU, we argue that the cometary objects known as falling evaporating bodies are unlikely to be the dominant source of gas; production from grain-grain collisions or photodesorption seems more likely. The incompatibility of the observations with a simplified accretion disk model could favour a preferential depletion explanation for the overabundance of C and O. More stringent constraints on the spatial distribution will be available from ALMA observations of CI at 609 $mu$m.
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