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Register a new userSubaru/SCExAO First-Light Direct Imaging of a Young Debris Disk around HD 36546
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We present $H$-band scattered light imaging of a bright debris disk around the A0 star HD 36546 obtained from the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system with data recorded by the HiCIAO camera using the vector vortex coronagraph. SCExAO traces the disk from $r$ $sim$ 0.3 to $r$ $sim$ 1 (34--114 au). The disk is oriented in a near east-west direction (PA $sim$ 75$^{o}$), is inclined by $i$ $sim$ 70--75$^{o}$ and is strongly forward-scattering ($g$ $>$ 0.5). It is an extended disk rather than a sharp ring; a second, diffuse dust population extends from the disks eastern side. While HD 36546 intrinsic properties are consistent with a wide age range ($t$ $sim$ 1--250 $Myr$), its kinematics and analysis of coeval stars suggest a young age (3--10 $Myr$) and a possible connection to Taurus-Aurigas star formation history. SCExAOs planet-to-star contrast ratios are comparable to the first-light Gemini Planet Imager contrasts; for an age of 10 $Myr$, we rule out planets with masses comparable to HR 8799 b beyond a projected separation of 23 au. A massive icy planetesimal disk or an unseen superjovian planet at $r$ $>$ 20 au may explain the disks visibility. The HD 36546 debris disk may be the youngest debris disk yet imaged, is the first newly-identified object from the now-operational SCExAO extreme AO system, is ideally suited for spectroscopic follow up with SCExAO/CHARIS in 2017, and may be a key probe of icy planet formation and planet-disk interactions.
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We present new, near-infrared (1.1--2.4 $mu m$) high-contrast imaging of the bright debris disk surrounding HIP 79977 with the Subaru Coronagraphic Extreme Adaptive Optics system (SCExAO) coupled with the CHARIS integral field spectrograph. SCExAO/CHARIS resolves the disk down to smaller angular separations of (0.11; $r sim 14$ au) and at a higher significance than previously achieved at the same wavelengths. The disk exhibits a marginally significant east-west brightness asymmetry in $H$ band that requires confirmation. Geometrical modeling suggests a nearly edge-on disk viewed at a position angle of $sim$ 114.6$^{o}$ east of north. The disk is best-fit by scattered-light models assuming strongly forward-scattering grains ($g$ $sim$ 0.5--0.65) confined to a torus with a peak density at $r_{0}$ $sim$ 53--75 au. We find that a shallow outer density power law of $alpha_{out}=$-1-- -3 and flare index of $beta = 1$ are preferred. Other disk parameters (e.g.~inner density power law and vertical scale height) are more poorly constrained. The disk has a slightly blue intrinsic color and its profile is broadly consistent with predictions from birth ring models applied to other debris disks. While HIP 79977s disk appears to be more strongly forward-scattering than most resolved disks surrounding 5--30 Myr-old stars, this difference may be due to observational biases favoring forward-scattering models for inclined disks vs. lower inclination, ostensibly neutral-scattering disks like HR 4796As. Deeper, higher signal-to-noise SCExAO/CHARIS data can better constrain the disks dust composition.
We present SCExAO/CHARIS high-contrast imaging/$JHK$ integral field spectroscopy of $kappa$ And b, a directly-imaged low-mass companion orbiting a nearby B9V star. We detect $kappa$ And b at a high signal-to-noise and extract high precision spectrophotometry using a new forward-modeling algorithm for (A-)LOCI complementary to KLIP-FM developed by Pueyo (2016). $kappa$ And bs spectrum best resembles that of a low-gravity L0--L1 dwarf (L0--L1$gamma$). Its spectrum and luminosity are very well matched by 2MASSJ0141-4633 and several other 12.5--15 $M_{rm J}$ free floating members of the 40 $Myr$-old Tuc-Hor Association, consistent with a system age derived from recent interferometric results for the primary, a companion mass at/near the deuterium-burning limit (13$^{+12}_{-2}$ M$_{rm J}$), and a companion-to-primary mass ratio characteristic of other directly-imaged planets ($q$ $sim$ 0.005$^{+0.005}_{-0.001}$). We did not unambiguously identify additional, more closely-orbiting companions brighter and more massive than $kappa$ And b down to $rho$ $sim$ 0.3 (15 au). SCExAO/CHARIS and complementary Keck/NIRC2 astrometric points reveal clockwise orbital motion. Modeling points towards a likely eccentric orbit: a subset of acceptable orbits include those that are aligned with the stars rotation axis. However, $kappa$ And bs semimajor axis is plausibly larger than 75 au and in a region where disk instability could form massive companions. Deeper $kappa$ And high-contrast imaging and low-resolution spectroscopy from extreme AO systems like SCExAO/CHARIS and higher resolution spectroscopy from Keck/OSIRIS or, later, IRIS on the Thirty Meter Telescope could help clarify $kappa$ And bs chemistry and whether its spectrum provides an insight into its formation environment.
We present the first scattered-light image of the debris disk around HD 131835 in $H$ band using the Gemini Planet Imager. HD 131835 is a $sim$15 Myr old A2IV star at a distance of $sim$120 pc in the Sco-Cen OB association. We detect the disk only in polarized light and place an upper limit on the peak total intensity. No point sources resembling exoplanets were identified. Compared to its mid-infrared thermal emission, the disk in scattered light shows similar orientation but different morphology. The scattered-light disk extends from $sim$75 to $sim$210 AU in the disk plane with roughly flat surface density. Our Monte Carlo radiative transfer model can well describe the observations with a model disk composed of a mixture of silicates and amorphous carbon. In addition to the obvious brightness asymmetry due to stronger forward scattering, we discover a weak brightness asymmetry along the major axis with the northeast side being 1.3 times brighter than the southwest side at a 3-{sigma} level.
We present the first scattered light image of the debris disk around HD 129590, a ~1.3 M$_odot$ G1V member of the Scorpius Centaurus association with age ~10-16 Myr. The debris disk is imaged with the high contrast imaging instrument SPHERE at the Very Large Telescope, and is revealed by both the IRDIS and IFS subsytems, operating in the H and YJ bands respectively. The disk has a high infrared luminosity of $L_{textrm{IR}}/L_{textrm{star}}$~5$times$10$^{-3}$, and has been resolved in other studies using ALMA. We detect a nearly edge on ring, with evidence of an inner clearing. We fit the debris disk using a model characterized by a single bright ring, with radius ~60-70 AU, in broad agreement with previous analysis of the target SED. The disk is vertically thin, and has an inclination angle of ~75$^circ$. Along with other previously imaged edge-on disks in the Sco-Cen association such as HD 110058, HD 115600, and HD 111520, this disk image will allow of the structure and morphology of very young debris disks, shortly after the epoch of planet formation has ceased.
We present current status of H$alpha$ high-contrast imaging observations with Subaru/SCExAO+VAMPIRES. Our adaptive optics correction at optical wavelengths in combination with (double) spectral differential imaging (SDI) and angular differential imaging (ADI) was capable of detecting a ring-like feature around omi Cet and the H$alpha$ counterpart of jet around RY Tau. We tested the post-processing by changing the order of ADI and SDI and both of the contrast limits achieved $sim10^{-3}-5times10^{-4}$ at $0.3^{primeprime}$, which is comparable to other H$alpha$ high-contrast imaging instruments in the southern hemisphere such as VLT/SPHERE, VLT/MUSE, and MagAO. Subaru/VAMPIRES provides great opportunities for H$alpha$ high-contrast imaging for northern hemisphere targets.
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