Studying the Evolution of Warm Dust Encircling BD +20 307 Using SOFIA

Abstract

The small class of known stars with unusually warm, dusty debris disks is a key sample to probe in order to understand cascade models and extreme collisions that likely lead to the final configurations of planetary systems. Because of its extreme dustiness and small radius, the disk of BD +20 307 has a short predicted collision time and is therefore an interesting target in which to look for changes in dust quantity and composition over time. To compare with previous ground and Spitzer Space Telescope data, SOFIA photometry and spectroscopy were obtained. The system's 8.8-12.5 $\mu$m infrared emission increased by $10\pm 2\%$ over nine years between the SOFIA and earlier Spitzer measurements. In addition to an overall increase in infrared excess, there is a suggestion of a greater increase in flux at shorter wavelengths (less than 10.6 $\mu$m) compared to longer wavelengths (greater than 10.6 $\mu$m). Steady-state collisional cascade models cannot explain the increase in BD +20 307's disk flux over such short timescales. A catastrophic collision between planetary-scale bodies is still the most likely origin for the system's extreme dust; however, the cause for its recent variation requires further investigation.

13 pages, 7 Figures, Accepted to ApJ

References in corpus (10)

• The Dartmouth Stellar Evolution Database
• Transience of hot dust around sun-like stars
• Steady-State Size Distributions for Collisional Populations: Analytical Solution with Size-Dependent Strength
• Collisional dust avalanches in debris discs
• Variability of the Infrared Excess of Extreme Debris Disks
• Planetary Collisions outside the Solar System: Time Domain Characterization of Extreme Debris Disks
• The effect of dust composition and shape on radiation-pressure forces and blowout sizes of particles in debris disks
• Planetary systems around close binary stars: the case of the very dusty, Sun-like, spectroscopic binary BD+20 307
• Herschel Observations of Dusty Debris Disks
• On the Binary Nature of Dust-encircled BD+20 307

Cited by in corpus (1)

• Mid-infrared Studies of HD 113766 and HD 172555: Assessing Variability in the Terrestrial Zone of Young Exoplanetary Systems