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Title: The Shadow Knows: Using Shadows to Investigate the Structure of the Pretransitional Disk of HD 100453

Abstract

We present Gemini Planet Imager polarized intensity imagery of HD 100453 in Y , J , and K 1 bands that reveals an inner gap (9–18 au), an outer disk (18–39 au) with two prominent spiral arms, and two azimuthally localized dark features that are also present in Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) total intensity images. Spectral energy distribution fitting further suggests that the radial gap extends to 1 au. The narrow, wedge-like shape of the dark features appears similar to predictions of shadows cast by an inner disk that is misaligned with respect to the outer disk. Using the Monte Carlo radiative transfer code HOCHUNCK3D, we construct a model of the disk that allows us to determine its physical properties in more detail. From the angular separation of the features, we measure the difference in inclination between the disks (45°) and their major axes, PA = 140° east of north for the outer disk, and 100° for the inner disk. We find an outer-disk inclination of 25° ± 10° from face-on, in broad agreement with the Wagner et al. measurement of 34°. SPHERE data in J and H bands indicate a reddish disk, which indicates that HD 100453 ismore » evolving into a young debris disk.« less

Authors:
; ;  [1];  [2];  [3]; ; ; ;  [4];  [5];  [6];  [7];  [8]; ;  [9];  [10];  [11];  [12];  [13]
  1. Department of Physics, University of Cincinnati, Cincinnati, OH 45221 (United States)
  2. Department of Astronomy/Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
  3. Division of Liberal Arts, Kogakuin University, 1-24-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo, 163-8677 (Japan)
  4. National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan)
  5. Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305 (United States)
  6. Eureka Scientific, 2452 Delmer Street, Suite 100, Oakland CA 96402 (United States)
  7. Division of Particle and Astrophysical Science, Graduate School of Science, Nagoya University, Nagoya (Japan)
  8. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
  9. University of Exeter Astrophysics Group, School of Physics, Stocker Road, Exeter, Devon EX4 4QL (United Kingdom)
  10. Department of Astronomical Science, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193 (Japan)
  11. Exoplanets and Stellar Astrophysics Laboratory, Code 667, NASA’s Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
  12. Department of Astronomy and RESCUE, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033 (Japan)
  13. Homer L. Dodge Department of Physics, University of Oklahoma, Norman, OK 73071 (United States)
Publication Date:
OSTI Identifier:
22661231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 838; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AUGER ELECTRON SPECTROSCOPY; ENERGY SPECTRA; FORECASTING; INCLINATION; INTERACTIONS; MONTE CARLO METHOD; POLARIZATION; PROTOPLANETS; RADIANT HEAT TRANSFER; STARS

Citation Formats

Long, Zachary C., Fernandes, Rachel B., Sitko, Michael, Wagner, Kevin, Muto, Takayuki, Hashimoto, Jun, Oh, Daehyon, Tamura, Motohide, Yang, Yi, Follette, Katherine, Grady, Carol A., Fukagawa, Misato, Hasegawa, Yasuhiro, Kluska, Jacques, Kraus, Stefan, Mayama, Satoshi, McElwain, Michael W., Uyama, Taichi, and Wisniewski, John P. The Shadow Knows: Using Shadows to Investigate the Structure of the Pretransitional Disk of HD 100453. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA64DA.
Long, Zachary C., Fernandes, Rachel B., Sitko, Michael, Wagner, Kevin, Muto, Takayuki, Hashimoto, Jun, Oh, Daehyon, Tamura, Motohide, Yang, Yi, Follette, Katherine, Grady, Carol A., Fukagawa, Misato, Hasegawa, Yasuhiro, Kluska, Jacques, Kraus, Stefan, Mayama, Satoshi, McElwain, Michael W., Uyama, Taichi, & Wisniewski, John P. The Shadow Knows: Using Shadows to Investigate the Structure of the Pretransitional Disk of HD 100453. United States. doi:10.3847/1538-4357/AA64DA.
Long, Zachary C., Fernandes, Rachel B., Sitko, Michael, Wagner, Kevin, Muto, Takayuki, Hashimoto, Jun, Oh, Daehyon, Tamura, Motohide, Yang, Yi, Follette, Katherine, Grady, Carol A., Fukagawa, Misato, Hasegawa, Yasuhiro, Kluska, Jacques, Kraus, Stefan, Mayama, Satoshi, McElwain, Michael W., Uyama, Taichi, and Wisniewski, John P. Mon . "The Shadow Knows: Using Shadows to Investigate the Structure of the Pretransitional Disk of HD 100453". United States. doi:10.3847/1538-4357/AA64DA.
@article{osti_22661231,
title = {The Shadow Knows: Using Shadows to Investigate the Structure of the Pretransitional Disk of HD 100453},
author = {Long, Zachary C. and Fernandes, Rachel B. and Sitko, Michael and Wagner, Kevin and Muto, Takayuki and Hashimoto, Jun and Oh, Daehyon and Tamura, Motohide and Yang, Yi and Follette, Katherine and Grady, Carol A. and Fukagawa, Misato and Hasegawa, Yasuhiro and Kluska, Jacques and Kraus, Stefan and Mayama, Satoshi and McElwain, Michael W. and Uyama, Taichi and Wisniewski, John P.},
abstractNote = {We present Gemini Planet Imager polarized intensity imagery of HD 100453 in Y , J , and K 1 bands that reveals an inner gap (9–18 au), an outer disk (18–39 au) with two prominent spiral arms, and two azimuthally localized dark features that are also present in Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) total intensity images. Spectral energy distribution fitting further suggests that the radial gap extends to 1 au. The narrow, wedge-like shape of the dark features appears similar to predictions of shadows cast by an inner disk that is misaligned with respect to the outer disk. Using the Monte Carlo radiative transfer code HOCHUNCK3D, we construct a model of the disk that allows us to determine its physical properties in more detail. From the angular separation of the features, we measure the difference in inclination between the disks (45°) and their major axes, PA = 140° east of north for the outer disk, and 100° for the inner disk. We find an outer-disk inclination of 25° ± 10° from face-on, in broad agreement with the Wagner et al. measurement of 34°. SPHERE data in J and H bands indicate a reddish disk, which indicates that HD 100453 is evolving into a young debris disk.},
doi = {10.3847/1538-4357/AA64DA},
journal = {Astrophysical Journal},
number = 1,
volume = 838,
place = {United States},
year = {Mon Mar 20 00:00:00 EDT 2017},
month = {Mon Mar 20 00:00:00 EDT 2017}
}
  • Detailed observations of gaps in protoplanetary disks have revealed structures that drive current research on circumstellar disks. One such feature is the two intensity nulls seen along the outer disk of the HD 142527 system, which are particularly well traced in polarized differential imaging. Here we propose that these are shadows cast by the inner disk. The inner and outer disk are thick, in terms of the unit-opacity surface in the H band, so that the shape and orientation of the shadows inform on the three-dimensional structure of the system. Radiative transfer predictions on a parametric disk model allow usmore » to conclude that the relative inclination between the inner and outer disks is 70° ± 5°. This finding taps the potential of high-contrast imaging of circumstellar disks, and bears consequences on the gas dynamics of gapped disks, as well as on the physical conditions in the shadowed regions.« less
  • In order to look for signs of ongoing planet formation in young disks, we carried out the first J -band polarized emission imaging of the Herbig Ae/Be stars HD 150193, HD 163296, and HD 169142 using the Gemini Planet Imager, along with new H band observations of HD 144432. We confirm the complex “double ring” structure for the nearly face-on system HD 169142 first seen in H -band, finding the outer ring to be substantially redder than the inner one in polarized intensity. Using radiative transfer modeling, we developed a physical model that explains the full spectral energy distribution andmore » J - and H -band surface brightness profiles, suggesting that the differential color of the two rings could come from reddened starlight traversing the inner wall and may not require differences in grain properties. In addition, we clearly detect an elongated, off-center ring in HD 163296 (MWC 275), locating the scattering surface to be 18 au above the midplane at a radial distance of 77 au, co-spatial with a ring seen at 1.3 mm by ALMA linked to the CO snow line. Lastly, we report a weak tentative detection of scattered light for HD 150193 (MWC 863) and a non-detection for HD 144432; the stellar companion known for each of these targets has likely disrupted the material in the outer disk of the primary star. For HD 163296 and HD 169142, the prominent outer rings we detect could be evidence for giant planet formation in the outer disk or a manifestation of large-scale dust growth processes possibly related to snow-line chemistry.« less
  • Inner cavities and annular gaps in circumstellar disks are possible signposts of giant planet formation. The young star HD 142527 hosts a massive protoplanetary disk with a large cavity that extends up to 140 AU from the central star, as seen in continuum images at infrared and millimeter wavelengths. Estimates of the survival of gas inside disk cavities are needed to discriminate between clearing scenarios. We present a spatially and spectrally resolved carbon monoxide isotopologue observations of the gas-rich disk HD 142527, in the J = 2-1 line of {sup 12}CO, {sup 13}CO, and C{sup 18}O obtained with the Atacamamore » Large Millimeter/submillimeter Array (ALMA). We detect emission coming from inside the dust-depleted cavity in all three isotopologues. Based on our analysis of the gas in the dust cavity, the {sup 12}CO emission is optically thick, while {sup 13}CO and C{sup 18}O emissions are both optically thin. The total mass of residual gas inside the cavity is ∼1.5-2 M {sub Jup}. We model the gas with an axisymmetric disk model. Our best-fit model shows that the cavity radius is much smaller in CO than it is in millimeter continuum and scattered light observations, with a gas cavity that does not extend beyond 105 AU (at 3σ). The gap wall at its outer edge is diffuse and smooth in the gas distribution, while in dust continuum it is manifestly sharper. The inclination angle, as estimated from the high velocity channel maps, is 28 ± 0.5 deg, higher than in previous estimates, assuming a fix central star mass of 2.2 M {sub ☉}.« less
  • SAO 206462 (HD 135344B) has previously been identified as a Herbig F star with a circumstellar disk with a dip in its infrared excess near 10 {mu}m. In combination with a low accretion rate estimated from Br {gamma}, it may represent a gapped, but otherwise primordial or 'pre-transitional' disk. We test this hypothesis with Hubble Space Telescope coronagraphic imagery, FUV spectroscopy and imagery and archival X-ray data, and spectral energy distribution (SED) modeling constrained by the observed system inclination, disk outer radius, and outer disk radial surface brightness (SB) profile using the Whitney Monte Carlo Radiative Transfer Code. The essentiallymore » face-on (i {approx}< 20{sup 0}) disk is detected in scattered light from 0.''4 to 1.''15 (56-160 AU), with a steep (r {sup -9.6}) radial SB profile from 0.''6 to 0.''93. Fitting the SB data requires a concave upward or anti-flared outer disk, indicating substantial dust grain growth and settling by 8 {+-} 4 Myr. The warm dust component is significantly variable in near to mid-IR excess and in temperature. At its warmest, it appears confined to a narrow belt from 0.08 to 0.2 AU. The steep SED for this dust component is consistent with grains with a{<=} 2.5 {mu}m. For cosmic carbon to silicate dust composition, conspicuous 10 {mu}m silicate emission would be expected and is not observed. This may indicate an elevated carbon to silicate ratio for the warm dust, which is not required to fit the outer disk. At its coolest, the warm dust can be fit with a disk from 0.14 to 0.31 AU, but with a higher inclination than either the outer disk or the gaseous disk, providing confirmation of the high inclination inferred from mid-IR interferometry. In tandem, the compositional and inclination difference between the warm dust and the outer dust disk suggests that the warm dust may be of second-generation origin, rather than a remnant of a primordial disk component. With its near face-on inclination, SAO 206462's disk is a prime location for planet searches.« less
  • We report the first independent, second epoch (re-)detection of a directly imaged protoplanet candidate. Using L' high-contrast imaging of HD 100546 taken with the Near-Infrared Coronagraph and Imager on Gemini South, we recover ''HD 100546 b'' with a position and brightness consistent with the original Very Large Telescope/NAos-COnica detection from Quanz et al., although data obtained after 2013 will be required to decisively demonstrate common proper motion. HD 100546 b may be spatially resolved, up to ≈12-13 AU in diameter, and is embedded in a finger of thermal IR-bright, polarized emission extending inward to at least 0.''3. Standard hot-start models implymore » a mass of ≈15 M{sub J} . However, if HD 100546 b is newly formed or made visible by a circumplanetary disk, both of which are plausible, its mass is significantly lower (e.g., 1-7 M{sub J} ). Additionally, we discover a thermal IR-bright disk feature, possibly a spiral density wave, at roughly the same angular separation as HD 100546 b but 90° away. Our interpretation of this feature as a spiral arm is not decisive, but modeling analyses using spiral density wave theory implies a wave launching point exterior to ≈0.''45 embedded within the visible disk structure: plausibly evidence for a second, hitherto unseen, wide-separation planet. With one confirmed protoplanet candidate and evidence for one to two others, HD 100546 is an important evolutionary precursor to intermediate-mass stars with multiple super-Jovian planets at moderate/wide separations like HR 8799.« less