EF Cha: Warm Dust Orbiting a Nearby 10 Myr Old Star

Abstract

Most Vega-like stars have far-infrared excess (60micron or longward in IRAS, ISO, or Spitzer MIPS bands) and contain cold dust (<~150K) analogous to the Sun's Kuiper-Belt region. However, dust in a region more akin to our asteroid belt and thus relevant to the terrestrial planet building process is warm and produces excess emission in mid-infrared wavelengths. By cross-correlating Hipparcos dwarfs with the MSX catalog, we found that EF Cha, a member of the recently identified, ~10 Myr old, ``Cha-Near'' Moving Group, possesses prominent mid-infrared excess. N-band spectroscopy reveals a strong emission feature characterized by a mixture of small, warm, amorphous and possibly crystalline silicate grains. Survival time of warm dust grains around this A9 star is <~ 1E5 yrs, much less than the age of the star. Thus, grains in this extra-solar terrestrial planetary zone must be of "second generation" and not a remnant of primodial dust and are suggestive of substantial planet formation activity. Such second generation warm excess occurs around ~ 13% of the early-type stars in nearby young stellar associations.

New Spitzer MIPS data added; 14 pages, 1 figure, ApJ in press

References in corpus (7)

• Spitzer IRS Spectroscopy of IRAS-Discovered Debris Disks
• Formation and Evolution of Planetary Systems: Upper Limits to the Gas Mass in Disks Around Sun-like Stars
• On the Nature of the Dust in the Debris Disk Around HD69830
• HD 98800: A 10-Myr-Old Transition Disk
• IRS Spectra of Solar-Type Stars: \break A Search for Asteroid Belt Analogs
• Spitzer 24 micron Survey of Debris Disks in the Pleiades
• Spitzer Far-Infrared Detections of Cold Circumstellar Disks

Cited by in corpus (13)

• Five steps in the evolution from protoplanetary to debris disk
• Warm dust in the terrestrial planet zone of a sun-like Pleiad: collisions between planetary embryos?
• Circumstellar Dust Created by Terrestrial Planet Formation in HD 113766
• CO mass upper limits in the Fomalhaut ring - the importance of NLTE excitation in debris discs and future prospects with ALMA
• A Sensitive Identification of Warm Debris Disks in the Solar Neighborhood Through Precise Calibration of Saturated WISE Photometry
• A CO survey in planet-forming disks: characterizing the gas content in the epoch of planet formation
• A Spitzer Study of Debris Disks In The Young Nearby Cluster NGC 2232: Icy Planets Are Common Around ~ 1.5--3 Solar-Mass Stars
• A Deep Spitzer Survey of Circumstellar Disks in the Young Double Cluster, h and chi Persei
• Probing the Terrestrial Regions of Planetary Systems: Warm Debris Disks with Emission Features
• Burn Out or Fade Away? On the X-ray and Magnetic Death of Intermediate Mass Stars
• A kinematically unbiased, all-sky search for nearby, young, low-mass stars
• A GLIMPSE into the Nature of Galactic Mid-IR Excesses
• V488 Per revisited: no strong mid-infrared emission features and no evidence for stellar/sub-stellar companions