The infrared temporal evolution of FG Sagittae

Charles E. Woodward; G. F. Lawrence; R. D. Gehrz; Terry J. Jones; H. A. Kobulnicky; James Cole; Tracy Hodge; Harley A. Thronson

doi:10.1086/186825

The infrared temporal evolution of FG Sagittae

Charles E. Woodward, G. F. Lawrence, R. D. Gehrz, Terry J. Jones, H. A. Kobulnicky, James Cole, Tracy Hodge, Harley A. Thronson

Minnesota Institute for Astrophysics

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Abstract

We present near- and mid-infrared photometry of the post-AGB star FG Sge obtained at two distinct epochs separated by a period of 10 years. Observations of FG Sge taken in 1983 suggest that the 1 to 12 μm energy distribution was produced at that time by a stellar photosphere, with a blackbody temperature of ≈5600 K. In late August of 1992, FG Sge exhibited a marked decline (≈3 mag in V) in its visible light curve. At the same time the 1 to 18.0 μm infrared energy distribution has evolved to become a ≈1000 K blackbody. We propose that this light decline partially is due to the ejection and condensation of a dust shell. We estimate the amount of dust condensed during this episode to be ≈3.3 × 10^-9 M_⊙, with a covering factor (total visual depth) of ≈0.3.

Original language	English (US)
Pages (from-to)	L37-L40
Journal	Astrophysical Journal
Volume	408
Issue number	1 PART 2
DOIs	https://doi.org/10.1086/186825
State	Published - 1993

Keywords

Circumstellar matter
Stars individual: (FG Sagittae)
Stars: Evolution

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title = "The infrared temporal evolution of FG Sagittae",

abstract = "We present near- and mid-infrared photometry of the post-AGB star FG Sge obtained at two distinct epochs separated by a period of 10 years. Observations of FG Sge taken in 1983 suggest that the 1 to 12 μm energy distribution was produced at that time by a stellar photosphere, with a blackbody temperature of ≈5600 K. In late August of 1992, FG Sge exhibited a marked decline (≈3 mag in V) in its visible light curve. At the same time the 1 to 18.0 μm infrared energy distribution has evolved to become a ≈1000 K blackbody. We propose that this light decline partially is due to the ejection and condensation of a dust shell. We estimate the amount of dust condensed during this episode to be ≈3.3 × 10-9 M⊙, with a covering factor (total visual depth) of ≈0.3.",

keywords = "Circumstellar matter, Stars individual: (FG Sagittae), Stars: Evolution",

author = "Woodward, {Charles E.} and Lawrence, {G. F.} and Gehrz, {R. D.} and Jones, {Terry J.} and Kobulnicky, {H. A.} and James Cole and Tracy Hodge and Thronson, {Harley A.}",

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TY - JOUR

T1 - The infrared temporal evolution of FG Sagittae

AU - Woodward, Charles E.

AU - Lawrence, G. F.

AU - Gehrz, R. D.

AU - Jones, Terry J.

AU - Kobulnicky, H. A.

AU - Cole, James

AU - Hodge, Tracy

AU - Thronson, Harley A.

PY - 1993

Y1 - 1993

N2 - We present near- and mid-infrared photometry of the post-AGB star FG Sge obtained at two distinct epochs separated by a period of 10 years. Observations of FG Sge taken in 1983 suggest that the 1 to 12 μm energy distribution was produced at that time by a stellar photosphere, with a blackbody temperature of ≈5600 K. In late August of 1992, FG Sge exhibited a marked decline (≈3 mag in V) in its visible light curve. At the same time the 1 to 18.0 μm infrared energy distribution has evolved to become a ≈1000 K blackbody. We propose that this light decline partially is due to the ejection and condensation of a dust shell. We estimate the amount of dust condensed during this episode to be ≈3.3 × 10-9 M⊙, with a covering factor (total visual depth) of ≈0.3.

AB - We present near- and mid-infrared photometry of the post-AGB star FG Sge obtained at two distinct epochs separated by a period of 10 years. Observations of FG Sge taken in 1983 suggest that the 1 to 12 μm energy distribution was produced at that time by a stellar photosphere, with a blackbody temperature of ≈5600 K. In late August of 1992, FG Sge exhibited a marked decline (≈3 mag in V) in its visible light curve. At the same time the 1 to 18.0 μm infrared energy distribution has evolved to become a ≈1000 K blackbody. We propose that this light decline partially is due to the ejection and condensation of a dust shell. We estimate the amount of dust condensed during this episode to be ≈3.3 × 10-9 M⊙, with a covering factor (total visual depth) of ≈0.3.

KW - Circumstellar matter

KW - Stars individual: (FG Sagittae)

KW - Stars: Evolution

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VL - 408

SP - L37-L40

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1 PART 2

ER -

The infrared temporal evolution of FG Sagittae

Abstract

Keywords

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