Kuiper belts around nearby stars
Artikel i vetenskaplig tidskrift, 2010

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 µm, as part of a large programme with the LABOCA bolometer at the APEX telescope. Dust masses (or upper limits) were calculated from integrated 870 µm fluxes, and fits to the SED of detected sources revealed the fractional dust luminosities f_dust, dust temperatures T_dust, and power-law exponents β of the opacity law. Results: A total of 10 detections with at least 3σ significance were made, out of which five (HD 95086, HD 131835, HD 161868, HD 170773, and HD 207129) have previously never been detected at submillimetre wavelengths. Three additional sources are marginally detected with \gt 2.5σ significance. The best-fit β 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 \prop t^-α, with α ~ 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. Based on observations with APEX, Llano Chajnantor, Chile (OSO programme 081.F-9330(A)).

planets and satellites: formation

circumstellar matter

planetary systems

Kuiper belt: general

submillimeter: planetary systems

Författare

R. Nilsson

Stockholms universitet

René Liseau

Chalmers, Institutionen för radio- och rymdvetenskap, Radioastronomi och astrofysik

A. Brandeker

Stockholms universitet

G. Olofsson

Stockholms universitet

G.L. Pilbratt

ESTEC

C. Risacher

Netherlands Institute for Space Research (SRON)

J. Rodmann

ESTEC

J. C. Augereau

Université Grenoble Alpes

Per Bergman

Chalmers, Institutionen för radio- och rymdvetenskap, Nationella anläggningen för radioastronomi

C. Eiroa

Universidad Autonoma de Madrid (UAM)

M. Fridlund

ESTEC

P. Thébault

Stockholms universitet

Observatoire de Paris-Meudon

G. J. White

Open University

Rutherford Appleton Laboratory

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 518 A40- A40

Ämneskategorier

Astronomi, astrofysik och kosmologi

Fundament

Grundläggande vetenskaper

DOI

10.1051/0004-6361/201014444