Two-dimensional Radiative Transfer in Protostellar Envelopes. II. An Evolutionary Sequence

By B. Whitney, K. Wood, J. Bjorkman, Marvin L. Cohen. 2003

349 citations recorded by the source corpus.

We present model spectral energy distributions (SEDs), colors, polarization, and images for an evolutionary sequence of a low-mass protostar from the early collapse stage (Class 0) to the remnant disk stage (Class III). We find a substantial overlap in colors and SEDs between protostars embedded in envelopes (Class 0-I) and T Tauri disks (Class II), especially at mid-IR wavelengths. Edge-on Class I-II sources show double-peaked SEDs, with a short-wavelength hump due to scattered light and a long-wavelength hump due to thermal emission. These are the bluest sources in mid-IR color-color diagrams. Since Class 0 and I sources are diffuse, the size of the aperture over which fluxes are integrated has a substantial effect on the computed colors, with larger aperture results showing significantly bluer colors. Viewed through large apertures, the Class 0 colors fall in the same regions of mid-IR color-color diagrams as Class I sources and are even bluer than Class II-III sources in some colors. It is important to take this into account when comparing color-color diagrams of star formation regions at different distances or different sets of observations of the same region. However, the near-IR polarization of the Class 0 sources is much higher than the Class I-II sources, providing a means to separate these evolutionary states. We varied the grain properties in the circumstellar envelope, allowing for larger grains in the disk midplane and smaller grains in the envelope. In comparing with models with the same grain properties throughout, we find that the SED of the Class 0 source is sensitive to the grain properties of the envelope only—that is, grain growth in the disk in Class 0 sources cannot be detected from the SED. Grain growth in disks of Class I sources can be detected at wavelengths greater than 100 μm. Our image calculations predict that the diffuse emission from edge-on Class I and II sources should be detectable in the mid-IR with the Space Infrared Telescope Facility (SIRTF) in nearby star-forming regions (out to several hundred parsecs).

Subfields: Astronomy and Astrophysics, Atmospheric Science, Spectroscopy

View Paper: https://www.semanticscholar.org/paper/27a263df3ad13cb9292b6e42741c1a81e21afb21

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The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. N. Evans II
2. P. Myers
3. K. Luhman
4. Mark R. Krumholz
5. L. Hartmann
6. L. Allen
7. N. Calvet
8. R. Gutermuth

In Atmospheric Science

1. N. Evans II
2. B. Whitney
3. P. Myers
4. M. Dunham
5. Zhaohuan Zhu
6. R. Dong
7. Y. Chu
8. Robert A. Gruendl

In Spectroscopy

1. N. Evans II
2. P. Myers
3. K. Luhman
4. L. Allen
5. C. Dullemond
6. L. Hartmann
7. R. Gutermuth
8. J. Muzerolle

Citations in the corpus

• Methanol Masers: Reliable Tracers of the Early Stages of High-Mass Star Formation (2005, background): “For example the models of Whitney et al. (2003) show that the colors of the GLIMPSE sources associated with methanol masers are very similar to those predicted for class 0 YSO.”
• Initial Results from the Spitzer Young Stellar Cluster Survey (2004, methodology): “These colors can be reproduced by models of disks around young, low-mass stars (Allen et al. 2004; Whitney et al. 2003).”
• Interpreting Spectral Energy Distributions from Young Stellar Objects. I. A Grid of 200,000 YSO Model SEDs (2006, methodology): “The main effect of varying the aperture is a bluing of the colors of Stage I sources with larger aperture, as discussed in Whitney et al. (2003b).”
• HIGH- AND INTERMEDIATE-MASS YOUNG STELLAR OBJECTS IN THE LARGE MAGELLANIC CLOUD (2009, methodology): “The SAGE YSOs are initially identified using a complex set of color and magnitude criteria based on the predictions from a grid of radiative transfer models that attempt to simulate the emission from YSOs (Whitney et al. 2003a, 2003b; Robitaille et al. 2006).”
• EVOLUTIONARY SIGNATURES IN THE FORMATION OF LOW-MASS PROTOSTARS. II. TOWARD RECONCILING MODELS AND OBSERVATIONS (2005, methodology): “D models of embedded protostars that include disks (e.g., Whitney et al. 2003a; Whitney et al. 2003b; Robitaille et al. 2006; Crapsi et al. 2008).”
• On the Evolutionary Status of Class I Stars and Herbig-Haro Energy Sources in Taurus-Auriga (2004, background): “…transfer models of still-forming stars predict that edgeon systems will have optical, near- and mid-infrared characteristics similar to less evolved, more embedded stars (Kenyon et al. 1993a, 1993b; Yorke et al. 1993; Sonnhalter et al. 1995; Men’shchikov & Henning 1997; Whitney et al. 2003).”
• THE HERSCHEL ORION PROTOSTAR SURVEY: SPECTRAL ENERGY DISTRIBUTIONS AND FITS USING A GRID OF PROTOSTELLAR MODELS (2016, background): “It influences the near- to farIR slope, the depth of the silicate feature, the emission peak, and the fraction of light emitted at the longest wavelengths (see, e.g., Whitney et al. 2003a).”
• STAR FORMATION IN THE CENTRAL 400 PC OF THE MILKY WAY: EVIDENCE FOR A POPULATION OF MASSIVE YOUNG STELLAR OBJECTS (2009, methodology): “YSOs are also known to have excess emission in infrared wavelengths and are characterized by dusty envelopes and disks that absorb the radiation from the central protostar (Whitney et al. 2003a; Adams et al. 1987).”
• PROPERTIES OF THE YOUNGEST PROTOSTARS IN PERSEUS, SERPENS, AND OPHIUCHUS (2008, methodology): “Whitney et al. (2003) begin with a set geometry for each stage, including some combination of accreting protostar, flared protostellar disk, infalling envelope, bipolar outflow, and grain models for each region, then use radiative transfer modeling to predict protostellar spectra.”
• SPITZER SAGE SURVEY OF THE LARGE MAGELLANIC CLOUD. III. STAR FORMATION AND ∼1000 NEW CANDIDATE YOUNG STELLAR OBJECTS (2008, methodology): “The models accurately compute scattered and thermal emission from dust in a physically plausible geometry, which consists of a stellar source that illuminates a dusty disk, envelope, and bipolar cavity (Whitney et al. 2003a, 2003b).”
• Identifying the Low-Luminosity Population of Embedded Protostars in the c2d Observations of Clouds and Cores (2007, methodology): “D models of sources (e.g., Whitney et al. 2003a; Whitney et al. 2003b; Robitaille et al. 2006) shows that, even at the most extreme pole-on inclinations, the effects of outflow cavities are unlikely to result in an observed SED more luminous in the near-infrared than at 24 and 70 µm.”
• The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. IX. The Serpens YSO Population as Observed with IRAC and MIPS (2007, background): “Recently, Robitaille et al. (2007) have computed a very large grid of models to extend the predictions from those of Whitney et al. (2003) to a much larger parameter space.”
• Infrared Array Camera (IRAC) Colors of Young Stellar Objects (2004, background): “For example, Whitney et al. (2003) predicted IRAC colors for a range of protostellar (Class 0 and I ) and T Tauri objects (Class II).”
• DUST FILTRATION BY PLANET-INDUCED GAP EDGES: IMPLICATIONS FOR TRANSITIONAL DISKS (2012, methodology): “Monte-Carlo radiative transfer set-up The Monte Carlo radiative transfer code was developed by Whitney et al. (2003a,b), Robitaille et al. (2006), and Whitney et al. (2012), while for the disk structure see Whitney et al. (2003b) for references.”
• Observational Signatures of Planets in Protoplanetary Disks I: Gaps Opened by Single and Multiple Young Planets in Disks (2014, methodology): “Monte Carlo Radiative Transfer Simulations We carry out 3D MCRT simulations using the code developed by Whitney et al. (2013, see also Whitney et al. 2003a,b).”
• Few Skewed Disks Found in First Closure-Phase Survey of Herbig Ae/Be Stars (2006, methodology): “…disk theorists routinely produce models for fitting to spectral energy distributions and the results of radiative transfer models are suitable for comparing to interferometry data (e.g., Malbet & Bertout 1995; D’Alessio et al. 1998; Whitney et al. 2003; Lachaume et al. 2003; Akeson et al. 2005a).”
• Clustered and Triggered Star Formation in W5: Observations with Spitzer (2008, methodology): “Schemes developed in Whitney et al. (2003), Allen et al. (2004), Megeath et al. (2004) and Muzerolle et al. (2004) and tested by (for example) Hartmann et al. (2005) have demonstrated the power of this technique for classifying young stellar objects using Spitzer IRAC and MIPS photometry.”