Herschel Observations of Protoplanetary Disks in Lynds 1641*

2018/06/18 by Sierra L. Grant, Catherine C. Espaillat, S. Thomas Megeath +7
Physics and Astronomy · #Accretion (finance) #Accretion disc #Astro and Planetary Science #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Circumstellar disk #Photometry (optics) #Planetesimal #Protoplanetary disk #Protostar #Spectral energy distribution #Spectral index #astro-ph.GA #astro-ph.SR

paper · pdf · doi:10.3847/1538-4357/aacda7

51 pages, 13 figures

arxiv created 2018/06/18 · openalex created_date 2018/06/21 · openalex publication_date 2018/08/06 · arxiv updated 2018/08/15 · openalex updated_date 2026/08/06

Abstract

Abstract We analyze Herschel Space Observatory observations of 104 young stellar objects with protoplanetary disks in the ∼1.5 Myr star-forming region Lynds 1641 (L1641) within the Orion A Molecular Cloud. We present spectral energy distributions from the optical to the far-infrared including new photometry from the Herschel Photodetector Array Camera and Spectrometer at 70 μ m. Our sample, taken as part of the Herschel Orion Protostar Survey, contains 24 transitional disks, 8 of which we identify for the first time in this work. We analyze the full disks (FDs) with irradiated accretion disk models to infer dust settling properties. Using forward modeling to reproduce the observed <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>n</mml:mi> </mml:mrow> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>K</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>S</mml:mi> </mml:mrow> </mml:msub> <mml:mo>−</mml:mo> <mml:mo stretchy="false">[</mml:mo> <mml:mn>70</mml:mn> <mml:mo stretchy="false">]</mml:mo> </mml:mrow> </mml:msub> </mml:math> index for the FD sample, we find the observed disk indices are consistent with models that have depletion of dust in the upper layers of the disk relative to the midplane, indicating significant dust settling. We perform the same analysis on FDs in Taurus with Herschel data and find that Taurus is slightly more evolved, although both samples show signs of dust settling. These results add to the growing literature that significant dust evolution can occur in disks by ∼1.5 Myr.

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