Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
A submillimetre search for cold extended debris disks in the β Pictoris moving group
Stockholm University, Faculty of Science, Department of Astronomy.
Stockholm University, Faculty of Science, Department of Astronomy.
Stockholm University, Faculty of Science, Department of Astronomy.
Show others and affiliations
2009 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 508, no 2, 1057-1065 p.Article in journal (Refereed) Published
Abstract [en]

Context. Previous observations with the Infrared Astronomical Satellite and the Infrared Space Observatory, and ongoing observations with Spitzer and AKARI, have led to the discovery of over 200 debris disks, based on detected mid-and far infrared excess emission, indicating warm circumstellar dust. To constrain the properties of these systems, e.g., to more accurately determine the dust mass, temperature and radial extent, follow-up observations in the submillimetre wavelength region are needed.

Aims. The beta Pictoris moving group is a nearby stellar association of young (similar to 12 Myr) co-moving stars including the classical debris disk star beta Pictoris. Due to their proximity and youth, they are excellent targets when searching for submillimetre emission from cold, extended, dust components produced by collisions in Kuiper-Belt-like disks. They also allow an age independent study of debris disk properties as a function of other stellar parameters.

Methods. We observed 7 infrared-excess stars in the beta Pictoris moving group with the LABOCA bolometer array, operating at a central wavelength of 870 mu m at the 12-m submillimetre telescope APEX. The main emission at these wavelengths comes from large, cold dust grains, which constitute the main part of the total dust mass, and hence, for an optically thin case, make better estimates on the total dust mass than earlier infrared observations. Fitting the spectral energy distribution with combined optical and infrared photometry gives information on the temperature and radial extent of the disk.

Results. From our sample, beta Pic, HD181327, and HD172555 were detected with at least 3 sigma certainty, while all others are below 2 sigma and considered non-detections. The image of beta Pic shows an offset flux density peak located near the south-west extension of the disk, similar to the one previously found by SCUBA at the JCMT. We present SED fits for detected sources and give an upper limit on the dust mass for undetected ones.

Conclusions. We find a mean fractional dust luminosity (f) over bar (dust) = 1.1 x 10(-3) at t approximate to 12 Myr, which together with recent data at 100 Myr suggests an f(dust) proportional to t(-alpha) a decline of the emitting dust, with alpha > 0.8.

Place, publisher, year, edition, pages
2009. Vol. 508, no 2, 1057-1065 p.
Keyword [en]
circumstellar matter, planetary systems, planetary systems: formation
National Category
Astronomy, Astrophysics and Cosmology
Research subject
Astronomy
Identifiers
URN: urn:nbn:se:su:diva-30820DOI: 10.1051/0004-6361/200912010ISI: 000273296700052OAI: oai:DiVA.org:su-30820DiVA: diva2:274244
Note
Based on observations with APEX, Llano Chajnantor, Chile (ESO programmes 079.F-9307(A) and 079.F-9308(A))Available from: 2010-01-15 Created: 2009-10-27 Last updated: 2017-12-12Bibliographically approved
In thesis
1. Circumstellar Debris Disks: Observational Studies of Cold Dust and Gas Emission in Planetary Nurseries
Open this publication in new window or tab >>Circumstellar Debris Disks: Observational Studies of Cold Dust and Gas Emission in Planetary Nurseries
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Planetary systems form in disks of gas and dust surrounding newborn stars. The young circumstellar environment is characterized by frequent collisions between rocky bodies, leading to a continuous production of small dust grains. Such collisional processing persists in leftover debris disks or belts akin to the Solar System's asteroid and Kuiper belts, during the star's entire main-sequence lifetime. This thesis presents observations of thermal emission from cold dust in extended debris disks, in addition to spatially resolved observations of dust scattered light and gas emission in nearby debris disk systems. A total of 30 debris disk candidates identified from infrared excess were observed at submillimeter (submm) wavelengths with the Atacama Pathfinder EXperiment (APEX) telescope in search for dust at radial distances corresponding to the Kuiper belt or beyond. Two observing campaigns with the PolCor instrument at the Nordic Optical Telescope (NOT), performing optical polarimetric coronagraphy to resolve scattered light from nearby disks were also carried out. The edge-on debris disk surrounding the star β Pictoris was explored using integral-field spectroscopy with the Very Large Telescope (VLT) in an attempt to map the spatial distribution of previously detected gas. The APEX observations detected 14 exo-Kuiper belts, out of which 7 were new discoveries in the submm region. Modeling of the spectral energy distribution from available photometry and detected submm fluxes allowed us to study the dependence of the fractional dust luminosity and characteristic radial dust distance on stellar spectral type and age. The results indicate a decrease in fractional dust luminosity as t-α, where t is the age of the system and α = 0.8–2.0. From the VLT data we retrieved the first complete image of Ca II and Fe I emission in the disk of β Pictoris. Subsequent modeling demonstrated that the anomalous vertical structure of the observed Ca II emission can be explained by an optically thick disk midplane.

Place, publisher, year, edition, pages
Stockholm: Department of Astronomy, Stockholm University, 2012. 84 p.
Keyword
circumstellar disks, debris disks, Kuiper belts, planet formation, submillimeter imaging, photometry, coronagraphy, integral-field spectroscopy
National Category
Astronomy, Astrophysics and Cosmology
Research subject
Astronomy
Identifiers
urn:nbn:se:su:diva-74460 (URN)978-91-7447-470-1 (ISBN)
Public defence
2012-04-20, FB52, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 10:00 (English)
Opponent
Supervisors
Note
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Submitted. Paper 5: Submitted.Available from: 2012-03-29 Created: 2012-03-13 Last updated: 2012-04-03Bibliographically approved

Open Access in DiVA

fulltext(287 kB)140 downloads
File information
File name FULLTEXT02.pdfFile size 287 kBChecksum SHA-512
b3883e940757c77aee804c50c530a3e09b9e2edb145772eb6d112b39781b69db97000eeff0b50f6418d34ecf24291cf8852ea5e18347e58f6354c850eb577c4b
Type fulltextMimetype application/pdf

Other links

Publisher's full text

Search in DiVA

By author/editor
Nilsson, RickyBrandeker, AlexisOlofsson, Göran
By organisation
Department of Astronomy
In the same journal
Astronomy and Astrophysics
Astronomy, Astrophysics and Cosmology

Search outside of DiVA

GoogleGoogle Scholar
Total: 154 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 110 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf