Thermal Emission in the Southwest Clump of VY CMa

Michael S. Gordon, Terry J. Jones, Roberta M. Humphreys, Steve Ertel, Philip M Hinz, William F. Hoffmann, Jordan Stone, Eckhart Spalding, Amali Vaz

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We present high spatial resolution LBTI/NOMIC 9-12 μm images of VY CMa and its massive outflow feature, the Southwest (SW) Clump. Combined with high-resolution imaging from the Hubble Space Telescope (0.4-1 μm) and LBT/LMIRCam (1-5μm), we isolate the spectral energy distribution (SED) of the clump from the star itself. Using radiative-transfer code DUSTY, we model both the scattered light from VY CMa and the thermal emission from the dust in the clump to estimate the optical depth, mass, and temperature of the SW Clump. The SW Clump is optically thick at 8.9 μm with a brightness temperature of ∼200 K. With a dust chemistry of equal parts silicates and metallic iron, as well as assumptions on grain size distribution, we estimate a dust mass of 5.4 × 10 -5 M o . For a gas-to-dust ratio of 100, this implies a total mass of 5.4 × 10 -3 M o . Compared to the typical mass-loss rate of VY CMa, the SW Clump represents an extreme, localized mass-loss event from ≲300 yr ago.

Original languageEnglish (US)
Article number57
JournalAstronomical Journal
Volume157
Issue number2
DOIs
StatePublished - Feb 1 2019

Fingerprint

clumps
thermal emission
dust
brightness temperature
high resolution
optical depth
radiative transfer
estimates
spectral energy distribution
Hubble Space Telescope
spatial resolution
outflow
grain size
optical thickness
silicate
silicates
iron
chemistry
stars
gas

Keywords

  • stars: individual (VY CMa)
  • stars: mass-loss
  • stars: winds, outflows
  • supergiants

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Gordon, M. S., Jones, T. J., Humphreys, R. M., Ertel, S., Hinz, P. M., Hoffmann, W. F., ... Vaz, A. (2019). Thermal Emission in the Southwest Clump of VY CMa. Astronomical Journal, 157(2), [57]. https://doi.org/10.3847/1538-3881/aaf5cb

Thermal Emission in the Southwest Clump of VY CMa. / Gordon, Michael S.; Jones, Terry J.; Humphreys, Roberta M.; Ertel, Steve; Hinz, Philip M; Hoffmann, William F.; Stone, Jordan; Spalding, Eckhart; Vaz, Amali.

In: Astronomical Journal, Vol. 157, No. 2, 57, 01.02.2019.

Research output: Contribution to journalArticle

Gordon, MS, Jones, TJ, Humphreys, RM, Ertel, S, Hinz, PM, Hoffmann, WF, Stone, J, Spalding, E & Vaz, A 2019, 'Thermal Emission in the Southwest Clump of VY CMa', Astronomical Journal, vol. 157, no. 2, 57. https://doi.org/10.3847/1538-3881/aaf5cb
Gordon MS, Jones TJ, Humphreys RM, Ertel S, Hinz PM, Hoffmann WF et al. Thermal Emission in the Southwest Clump of VY CMa. Astronomical Journal. 2019 Feb 1;157(2). 57. https://doi.org/10.3847/1538-3881/aaf5cb
Gordon, Michael S. ; Jones, Terry J. ; Humphreys, Roberta M. ; Ertel, Steve ; Hinz, Philip M ; Hoffmann, William F. ; Stone, Jordan ; Spalding, Eckhart ; Vaz, Amali. / Thermal Emission in the Southwest Clump of VY CMa. In: Astronomical Journal. 2019 ; Vol. 157, No. 2.
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