ALMA 1.3 Millimeter Map of the HD 95086 System

ALMA 1.3 Millimeter Map of the HD 95086 System

Authors:

Su et al

Abstract:

Planets and minor bodies such as asteroids, Kuiper-belt objects and comets are integral components of a planetary system. Interactions among them leave clues about the formation process of a planetary system. The signature of such interactions is most prominent through observations of its debris disk at millimeter wavelengths where emission is dominated by the population of large grains that stay close to their parent bodies. Here we present ALMA 1.3 mm observations of HD 95086, a young early-type star that hosts a directly imaged giant planet b and a massive debris disk with both asteroid- and Kuiper-belt analogs. The location of the Kuiper-belt analog is resolved for the first time. The system can be depicted as a broad (ΔR/R∼0.84), inclined (30\arcdeg±3\arcdeg) ring with millimeter emission peaked at 200±6 au from the star. The 1.3 mm disk emission is consistent with a broad disk with sharp boundaries from 106±6 to 320±20 au with a surface density distribution described by a power law with an index of --0.5±0.2. Our deep ALMA map also reveals a bright source located near the edge of the ring, whose brightness at 1.3 mm and potential spectral energy distribution are consistent with it being a luminous star-forming galaxy at high redshift. We set constraints on the orbital properties of planet b assuming co-planarity with the observed disk.

Spectroscopic Characterization of Directly Imaged gas Giant HD 95086b

Spectroscopic characterization of HD 95086 b with the Gemini Planet Imager

Authors:

de Rosa et al

Abstract:

We present new H (1.5-1.8 μm) photometric and K1 (1.9-2.2 μm) spectroscopic observations of the young exoplanet HD 95086 b obtained with the Gemini Planet Imager. The H-band magnitude has been significantly improved relative to previous measurements, whereas the low resolution K1 (λ/δλ≈66) spectrum is featureless within the measurement uncertainties, and presents a monotonically increasing pseudo-continuum consistent with a cloudy atmosphere. By combining these new measurements with literature L′ photometry, we compare the spectral energy distribution of the planet to other young planetary-mass companions, field brown dwarfs, and to the predictions of grids of model atmospheres. HD 95086 b is over a magnitude redder in K1−L′ color than 2MASS J12073346-3932539 b and HR 8799 c and d, despite having a similar L′ magnitude. Considering only the near-infrared measurements, HD 95086 b is most analogous to the brown dwarfs 2MASS J2244316+204343 and 2MASS J21481633+4003594, both of which are thought to have dusty atmospheres. Morphologically, the spectral energy distribution of HD 95086 b is best fit by low temperature (Teff= 800-1300 K), low surface gravity spectra from models which simulate high photospheric dust content. This range of effective temperatures is consistent with field L/T transition objects, but the spectral type of HD 95086 b is poorly constrained between early L and late T due to its unusual position the color-magnitude diagram, demonstrating the difficulty in spectral typing young, low surface gravity substellar objects. As one of the reddest such objects, HD 95086 b represents an important empirical benchmark against which our current understanding of the atmospheric properties of young extrasolar planets can be tested.

Debris Distribution in HD 95086

Debris Distribution in HD 95086 - A Young Analog of HR 8799

Authors:

Su et al

Abstract:

HD 95086 is a young early-type star that hosts (1) a 5 MJ planet at the projected distance of 56 AU revealed by direct imaging, and (2) a prominent debris disk. Here we report the detection of 69 um crystalline olivine feature from the disk using the Spitzer/MIPS-SED data covering 55-95 um. Due to the low resolution of MIPS-SED mode, this feature is not spectrally resolved, but is consistent with the emission from crystalline forsterite contributing 5% of the total dust mass. We also present detailed analysis of the disk SED and re-analysis of resolved images obtained by Herschel. Our results suggest that the debris structure around HD 95086 consists of a warm (175 K) belt, a cold (55 K) disk, and an extended disk halo (up to 800 AU), and is very similar to that of HR 8799. We compare the properties of the three debris components, and suggest that HD 95086 is a young analog of HR 8799. We further investigate and constrain single-planet, two-planet, three-planet and four-planet architectures that can account for the observed debris structure and are compatible with dynamical stability constraints. We find that equal-mass four-planet configurations of geometrically spaced orbits, with each planet of mass 5 MJ, could maintain the gap between the warm and cold debris belts, and also be just marginally stable for timescales comparable to the age of the system.

HD 95086b Imaged

Near-Infrared Detection and Characterization of the Exoplanet HD 95086 b with the Gemini Planet Imager

Authors

Galicher et al

Abstract:

HD 95086 is an intermediate-mass debris-disk-bearing star. VLT/NaCo 3.8μm observations revealed it hosts a 5±2MJup companion (HD 95086 b) at ≃56 AU. Follow-up observations at 1.66 and 2.18 μm yielded a null detection, suggesting extremely red colors for the planet and the need for deeper direct-imaging data. In this Letter, we report H- (1.7μm) and K1- (2.05μm) band detections of HD 95086 b from Gemini Planet Imager (GPI) commissioning observations taken by the GPI team. The planet position in both spectral channels is consistent with the NaCo measurements and we confirm it to be comoving. Our photometry yields colors of H-L'= 3.6±1.0 mag and K1-L'=2.4±0.7 mag, consistent with previously reported 5-σ upper limits in H and Ks. The photometry of HD 95086 b best matches that of 2M 1207 b and HR 8799 cde. Comparing its spectral energy distribution with the BT-SETTL and LESIA planet atmospheric models yields Teff∼600-1500 K and log g∼2.1-4.5. Hot-start evolutionary models yield M=5±2 MJup. Warm-start models reproduce the combined absolute fluxes of the object for M=4-14 MJup for a wide range of plausible initial conditions (Sinit=8-13 kB/baryon). The color-magnitude diagram location of HD 95086 b and its estimated Teff and log g suggest that the planet is a peculiar L-T transition object with an enhanced amount of photospheric dust.