Kuiper belts around nearby starsShow others and affiliations
2010 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 518, p. A40-Article in journal (Refereed) Published
Abstract [en]
Context. The existence of dusty debris disks around a large fraction of solar type main-sequence stars, inferred from excess far-IR and submillimetre emission compared to that expected from stellar photospheres, suggests that leftover planetesimal belts analogous to the asteroid-and comet reservoirs of the solar system are common.
Aims. Sensitive submillimetre observations are essential to detect and characterise cold extended dust originating from collisions of small bodies in disks, belts, or rings at Kuiper-belt distances (30-50 AU or beyond). Measurements of the flux densities at these wavelengths will extend existing IR photometry and permit more detailed modelling of the Rayleigh-Jeans tail of the disks spectral energy distribution (SED), effectively constraining dust properties and disk extensions. By observing stars spanning from a few up to several hundred Myr, the evolution of debris disks during crucial phases of planet formation can be studied.
Methods. We observed 22 exo-Kuiper-belt candidates at 870 mu m, as part of a large programme with the LABOCA bolometer at the APEX telescope. Dust masses (or upper limits) were calculated from integrated 870 mu m fluxes, and fits to the SED of detected sources revealed the fractional dust luminosities f(dust), dust temperatures T(dust), and power-law exponents beta of the opacity law.
Results. A total of 10 detections with at least 3 sigma significance were made, out of which five (HD95086, HD131835, HD161868, HD170773, and HD207129) have previously never been detected at submillimetre wavelengths. Three additional sources are marginally detected with > 2.5 sigma significance. The best-fit beta parameters all lie between 0.1 and 0.8, in agreement with previous results indicating the presence of significantly larger grains than those in the ISM. From our relatively small sample we estimate f(dust) proportional to t(-alpha), with a similar to 0.8-2.0, and identify an evolution of the characteristic radial dust distance R(dust) that is consistent with the t(1/3) increase predicted from models of self-stirred collisions in debris disks.
Place, publisher, year, edition, pages
2010. Vol. 518, p. A40-
Keywords [en]
circumstellar matter, planetary systems, planet formation, Kuiper belt, submillimeter observations
National Category
Astronomy, Astrophysics and Cosmology
Research subject
Astronomy
Identifiers
URN: urn:nbn:se:su:diva-74265DOI: 10.1051/0004-6361/201014444ISI: 000285342500058OAI: oai:DiVA.org:su-74265DiVA, id: diva2:507366
Note
authorCount :13
2012-03-092012-03-042022-02-24Bibliographically approved
In thesis