Asteroid belts in debris disk twins: Vega and fomalhaut

Kate Y L Su, George H. Rieke, Renu Malhotra, Karl R. Stapelfeldt, A. Meredith Hughes, Amy Bonsor, David J. Wilner, Zoltan Balog, Dan M. Watson, Michael W. Werner, Karl A. Misselt

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Abstract

Vega and Fomalhaut are similar in terms of mass, ages, and global debris disk properties; therefore, they are often referred to as "debris disk twins." We present Spitzer 10-35 μm spectroscopic data centered at both stars and identify warm, unresolved excess emission in the close vicinity of Vega for the first time. The properties of the warm excess in Vega are further characterized with ancillary photometry in the mid-infrared and resolved images in the far-infrared and submillimeter wavelengths. The Vega warm excess shares many similar properties with the one found around Fomalhaut. The emission shortward of 30 μm from both warm components is well described as a blackbody emission of 170 K. Interestingly, two other systems, ε Eri and HR 8799, also show such an unresolved warm dust using the same approach. These warm components may be analogous to the solar system's zodiacal dust cloud, but of far greater mass (fractional luminosity of 10-5 to 10-6 compared to 10-8 to 10-7). The dust temperature and tentative detections in the submillimeter suggest that the warm excess arises from dust associated with a planetesimal ring located near the water-frost line and presumably created by processes occurring at similar locations in other debris systems as well. We also review the properties of the 2 μm hot excess around Vega and Fomalhaut, showing that the dust responsible for the hot excess is not spatially associated with the dust we detected in the warm belt. We suggest it may arise from hot nano grains trapped in the magnetic field of the star. Finally, the separation between the warm and cold belt is rather large with an orbital ratio ≳10 in all four systems. In light of the current upper limits on the masses of planetary objects and the large gap, we discuss the possible implications for their underlying planetary architecture and suggest that multiple, low-mass planets likely reside between the two belts in Vega and Fomalhaut.

Original languageEnglish (US)
Article number118
JournalAstrophysical Journal
Volume763
Issue number2
DOIs
StatePublished - Feb 1 2013

Fingerprint

asteroid belts
debris
asteroid
dust
zodiacal dust
stars
frost
protoplanets
planetesimal
solar system
photometry
planets
luminosity
planet
orbitals
magnetic field
rings
wavelength
magnetic fields
wavelengths

Keywords

  • circumstellar matter
  • infrared: stars
  • planetary systems
  • stars: individual (Vega, Fomalhaut)

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Su, K. Y. L., Rieke, G. H., Malhotra, R., Stapelfeldt, K. R., Hughes, A. M., Bonsor, A., ... Misselt, K. A. (2013). Asteroid belts in debris disk twins: Vega and fomalhaut. Astrophysical Journal, 763(2), [118]. https://doi.org/10.1088/0004-637X/763/2/118

Asteroid belts in debris disk twins : Vega and fomalhaut. / Su, Kate Y L; Rieke, George H.; Malhotra, Renu; Stapelfeldt, Karl R.; Hughes, A. Meredith; Bonsor, Amy; Wilner, David J.; Balog, Zoltan; Watson, Dan M.; Werner, Michael W.; Misselt, Karl A.

In: Astrophysical Journal, Vol. 763, No. 2, 118, 01.02.2013.

Research output: Contribution to journalArticle

Su, KYL, Rieke, GH, Malhotra, R, Stapelfeldt, KR, Hughes, AM, Bonsor, A, Wilner, DJ, Balog, Z, Watson, DM, Werner, MW & Misselt, KA 2013, 'Asteroid belts in debris disk twins: Vega and fomalhaut', Astrophysical Journal, vol. 763, no. 2, 118. https://doi.org/10.1088/0004-637X/763/2/118
Su, Kate Y L ; Rieke, George H. ; Malhotra, Renu ; Stapelfeldt, Karl R. ; Hughes, A. Meredith ; Bonsor, Amy ; Wilner, David J. ; Balog, Zoltan ; Watson, Dan M. ; Werner, Michael W. ; Misselt, Karl A. / Asteroid belts in debris disk twins : Vega and fomalhaut. In: Astrophysical Journal. 2013 ; Vol. 763, No. 2.
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