Herschel discovery of a new class of cold, faint debris discs
Journal article, 2011
We present Herschel PACS 100 and 160 mu m observations of the solar-type stars alpha Men, HD 88230 and HD 210277, which form part of the FGK stars sample of the Herschel open time key programme (OTKP) DUNES (DUst around NEarby S tars). Our observations show small infrared excesses at 160 mu m for all three stars. HD 210277 also shows a small excess at 100 mu m, while the 100 mu m fluxes of alpha Men and HD 88230 agree with the stellar photospheric predictions. We attribute these infrared excesses to a new class of cold, faint debris discs. Both alpha Men and HD 88230 are spatially resolved in the PACS 160 mu m images, while HD 210277 is point-like at that wavelength. The projected linear sizes of the extended emission lie in the range from similar to 115 to <= 250 AU. The estimated black body temperatures from the 100 and 160 mu m fluxes are less than or similar to 22 K, and the fractional luminosity of the cold dust is L(dust)/L(*) similar to 10(-6), close to the luminosity of the solar-system's Kuiper belt. These debris discs are the coldest and faintest discs discovered so far around mature stars, so they cannot be explained easily invoking "classical" debris disc models.
pacs
planetary systems
HD 210277 (HIP 109378)
circumstellar matter
main-sequence stars
(HIP 29271)
stars: individual:
stars: individual: alpha Men
planets
stars: individual: HD 88230 (HIP 49908)
images
disks
Author
C. Eiroa
Universidad Autonoma de Madrid
J. P. Marshall
Universidad Autonoma de Madrid
A. Mora
European Space Astronomy Centre
A. Krivov
Friedrich Schiller Universitat Jena
B. Montesinos
CSIC-INTA - Centro de Astrobiologia (CAB)
O. Absil
Universite de Liege
D. R. Ardila
California Institute of Technology
M. Arevalo
CSIC-INTA - Centro de Astrobiologia (CAB)
J. C. Augereau
Universite Grenoble Alpes
A. Bayo
European Space Observatory
W. Danchi
NASA Goddard Space Flight Center
C. del Burgo
UNINOVA-CA3
S. Ertel
Christian-Albrechts-Universitat zu Kiel
M. Fridlund
ESTEC/SRE-SA
B. M. Gonzalez-Garcia
European Space Astronomy Centre
A. Heras
ESTEC/SRE-SA
J. Lebreton
Universite Grenoble Alpes
René Liseau
Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics
J. Maldonado
Universidad Autonoma de Madrid
G. Meeus
Universidad Autonoma de Madrid
D. Montes
Universidad Complutense de Madrid
G.L. Pilbratt
ESTEC/SRE-SA
A. Roberge
NASA Goddard Space Flight Center
J. Sanz-Forcada
CSIC-INTA - Centro de Astrobiologia (CAB)
K. R. Stapelfeldt
Jet Propulsion Laboratory, California Institute of Technology
P. Thebault
GEPI - Galaxies, Etoiles, Physique, Instrumentation
G. J. White
Open University
Rutherford Appleton Laboratory
S. Wolf
Christian-Albrechts-Universitat zu Kiel
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 536 L4Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
DOI
10.1051/0004-6361/201117797