skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A Resolved and Asymmetric Ring of PAHs within the Young Circumstellar Disk of IRS 48

Abstract

For one decade, the spectral type and age of the ρ Oph object IRS-48 were subject to debate and mystery. Modeling its disk with mid-infrared to millimeter observations led to various explanations to account for the complex intricacy of dust holes and gas-depleted regions. We present multi-epoch high-angular-resolution interferometric near-infrared data of spatially resolved emissions in the first 15 au of IRS-48, known to have very strong polycyclic aromatic hydrocarbon (PAH) emissions within this dust-depleted region. We make use of new Sparse-Aperture-Masking data to instruct a revised radiative-transfer model, where spectral energy distribution fluxes and interferometry are jointly fitted. Neutral and ionized PAH, very small grains (VSG), and classical silicates are incorporated into the model; new stellar parameters and extinction laws are explored. A bright (42 L {sub ⊙}) and hence large (2.5 R {sub ⊙}) central star with A {sub v} = 12.5 mag and R {sub v} = 6.5 requires less near-infrared excess: the inner-most disk at ≈1 au is incompatible with the interferometric data. The revised stellar parameters place this system on a 4 Myr evolutionary track, four times younger than the previous estimations, which is in better agreement with the surrounding ρ Oph region and disk-lifetimemore » observations. The disk-structure solution converges to a classical-grain outer disk from 55 au combined with an unsettled and fully resolved VSG and PAH ring, between 11 and 26 au. We find two overluminosities in the PAH ring at color-temperatures consistent with the radiative transfer simulations; one follows a Keplerian circular orbit at 14 au. We show a depletion of a factor of ≈5 of classical dust grains up to 0.3 mm compared to very small particles: the IRS-48 disk is nearly void of dust grains in the first 55 au. A 3.5 M {sub Jup} planet on a 40 au orbit can qualitatively explain the new disk structure.« less

Authors:
; ;  [1];  [2]; ;  [3];  [4];  [5];  [6]
  1. LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universits, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité (France)
  2. Dpto. Astrofísica, Centro de Astrobiología (INTA-CSIC), ESAC Campus, P.O. Box 78, E-28691, Villanueva de la Cañada (Spain)
  3. Univ. Grenoble Alpes, IPAG, F-38000 Grenoble, France CNRS, IPAG, F-38000 Grenoble (France)
  4. Observatoire de l’Université de Genève, 51 chemin des Maillettes, 1290 Versoix (Switzerland)
  5. European Southern Observatory, Alonso de Cordova 3107, Casilla 19001 Vitacura, Santiago 19 (Chile)
  6. Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006 (Australia)
Publication Date:
OSTI Identifier:
22663496
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 842; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; APERTURES; ASYMMETRY; COMPARATIVE EVALUATIONS; DUSTS; EMISSION; ENERGY SPECTRA; INTERFEROMETRY; INTERSTELLAR SPACE; LIFETIME; ORBITS; PLANETS; POLYCYCLIC AROMATIC HYDROCARBONS; PROTOPLANETS; RADIANT HEAT TRANSFER; RESOLUTION; RINGS; SIMULATION; STARS

Citation Formats

Schworer, Guillaume, Lacour, Sylvestre, Du Foresto, Vincent Coudé, Huélamo, Nuria, Pinte, Christophe, Chauvin, Gaël, Ehrenreich, David, Girard, Julien, and Tuthill, Peter. A Resolved and Asymmetric Ring of PAHs within the Young Circumstellar Disk of IRS 48. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA74B7.
Schworer, Guillaume, Lacour, Sylvestre, Du Foresto, Vincent Coudé, Huélamo, Nuria, Pinte, Christophe, Chauvin, Gaël, Ehrenreich, David, Girard, Julien, & Tuthill, Peter. A Resolved and Asymmetric Ring of PAHs within the Young Circumstellar Disk of IRS 48. United States. doi:10.3847/1538-4357/AA74B7.
Schworer, Guillaume, Lacour, Sylvestre, Du Foresto, Vincent Coudé, Huélamo, Nuria, Pinte, Christophe, Chauvin, Gaël, Ehrenreich, David, Girard, Julien, and Tuthill, Peter. Tue . "A Resolved and Asymmetric Ring of PAHs within the Young Circumstellar Disk of IRS 48". United States. doi:10.3847/1538-4357/AA74B7.
@article{osti_22663496,
title = {A Resolved and Asymmetric Ring of PAHs within the Young Circumstellar Disk of IRS 48},
author = {Schworer, Guillaume and Lacour, Sylvestre and Du Foresto, Vincent Coudé and Huélamo, Nuria and Pinte, Christophe and Chauvin, Gaël and Ehrenreich, David and Girard, Julien and Tuthill, Peter},
abstractNote = {For one decade, the spectral type and age of the ρ Oph object IRS-48 were subject to debate and mystery. Modeling its disk with mid-infrared to millimeter observations led to various explanations to account for the complex intricacy of dust holes and gas-depleted regions. We present multi-epoch high-angular-resolution interferometric near-infrared data of spatially resolved emissions in the first 15 au of IRS-48, known to have very strong polycyclic aromatic hydrocarbon (PAH) emissions within this dust-depleted region. We make use of new Sparse-Aperture-Masking data to instruct a revised radiative-transfer model, where spectral energy distribution fluxes and interferometry are jointly fitted. Neutral and ionized PAH, very small grains (VSG), and classical silicates are incorporated into the model; new stellar parameters and extinction laws are explored. A bright (42 L {sub ⊙}) and hence large (2.5 R {sub ⊙}) central star with A {sub v} = 12.5 mag and R {sub v} = 6.5 requires less near-infrared excess: the inner-most disk at ≈1 au is incompatible with the interferometric data. The revised stellar parameters place this system on a 4 Myr evolutionary track, four times younger than the previous estimations, which is in better agreement with the surrounding ρ Oph region and disk-lifetime observations. The disk-structure solution converges to a classical-grain outer disk from 55 au combined with an unsettled and fully resolved VSG and PAH ring, between 11 and 26 au. We find two overluminosities in the PAH ring at color-temperatures consistent with the radiative transfer simulations; one follows a Keplerian circular orbit at 14 au. We show a depletion of a factor of ≈5 of classical dust grains up to 0.3 mm compared to very small particles: the IRS-48 disk is nearly void of dust grains in the first 55 au. A 3.5 M {sub Jup} planet on a 40 au orbit can qualitatively explain the new disk structure.},
doi = {10.3847/1538-4357/AA74B7},
journal = {Astrophysical Journal},
number = 2,
volume = 842,
place = {United States},
year = {Tue Jun 20 00:00:00 EDT 2017},
month = {Tue Jun 20 00:00:00 EDT 2017}
}