J/A+A/365/545 Remnant disks around main-sequence stars IR flux (Habing+, 2001)
Incidence and survival of remnant disks around main-sequence stars
Habing H.J., Dominik C., Jourdain de Muizon M., Laureijs R.J., Kessler M.F.,
Leech K., Metcalfe L., Siebenmorgen R., Trams N., Bouchet P.
<Astron. Astrophys. 365, 545 (2001)>
=2001A&A...365..545H 2001A&A...365..545H
ADC_Keywords: Stars, dwarfs ; Infrared sources ; Photometry, UBV
Keywords: stars: planetary systems - infrared: stars
Abstract:
We present photometric ISO 60 and 170µm measurements, complemented
by some IRAS data at 60µm, of a sample of 84 nearby main-sequence
stars of spectral class A, F, G and K in order to determine the
incidence of dust disks around such main-sequence stars. Fifty stars
were detected at 60µm; 36 of these emit a flux expected from their
photosphere while 14 emit significantly more. The excess emission we
attribute to a circumstellar disk like the ones around Vega and β
Pictoris. Thirty four stars were not detected at all; the expected
photospheric flux, however, is so close to the detection limit that
the stars cannot have an excess stronger than the photospheric flux
density at 60µm. Of the stars younger than 400Myr one in two has a
disk; for the older stars this is true for only one in ten. We
conclude that most stars arrive on the main sequence surrounded by a
disk; this disk then decays in about 400Myr. Because (i) the dust
particles disappear and must be replenished on a much shorter time
scale and (ii) the collision of planetesimals is a good source of new
dust, we suggest that the rapid decay of the disks is caused by the
destruction and escape of planetesimals. We suggest that the
dissipation of the disk is related to the heavy bombardment phase in
our Solar System. Whether all stars arrive on the main sequence
surrounded by a disk cannot be established: some very young stars do
not have a disk. And not all stars destroy their disk in a similar
way: some stars as old as the Sun still have significant disks.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 68 84 Basic data on all stars
table3.dat 102 84 60 micron flux densities
table4.dat 55 52 170 micron flux densities
tables.tex 117 304 LaTeX version of the tables
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See also:
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
III/135 : Henry Draper Catalogue and Extension (Cannon+ 1918-1924; ADC 1989)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- HD Star number in the Henry Draper Catalogue
(Cat. III/135)
9- 14 I6 --- HIP ? Star number in the HIPPARCOS catalogue
(Cat. I/239)
16- 30 A15 --- Name Stellar name
32- 36 F5.2 mag Vmag V-magnitude taken from the Geneva photometric
catalogue
38- 42 F5.2 mag B-V B-V colour taken from the Geneva photometric
catalogue
44- 47 F4.1 pc Dist Stellar distance, taken from the Hipparcos
catalogue (I/239)
49- 57 A9 --- SpType Spectral type taken from the Hipparcos
catalogue (I/239)
59- 63 F5.2 Gyr Age ? Stellar age
65- 68 I4 K Teff Effective temperature
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Byte-by-byte Description of file: table3.dat table4.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- HD Star number in the Henry Draper Catalogue
9- 16 I8 --- ISO-ID ? Identification number of the measurement
used in the ISO archive
18- 22 I5 mJy Fnu Flux density corrected for bandwidth
effects (4) (1)
24- 26 I3 mJy e_Fnu Error on Fnu (4) (2)
28- 31 I4 mJy Fnup ? Flux expected from the stellar photosphere
(see the text) (4)
33- 37 I5 mJy EFnu Excess flux (Fnu - Fnup) (4) (5)
39 A1 --- lEFnu/eFnu Limit flag on EFnu/e_Fnu
40- 43 F4.1 --- EFnu/e_Fnu Ratio of the excess flux compared to the
measurement error
45- 49 I5 mJy Fnud ? Monochromatic excess flux density (3)
51 A1 --- l_log(tau)d Limit flag on log(tau)d
52- 55 F4.1 --- log(tau)d ? An estimate of the optical depth of the
disk at visual wavelengths, but estimated
from the flux density at 60 micron
57-111 A55 --- Ref Mode of observation reference (table3 only)
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Note (1): Flux density corrected for bandwidth effects under the assumption
that the spectrum is characterized by the Rayleigh-Jeans equation and
for the fact that the stellar flux extended over more than 1 pixel.
Note (2): Error estimate assigned by the ISOPHOT software to the flux
measurement in the previous column; for IRAS measurements the error
has been put at 100mJy.
Note (3): Monochromatic excess flux density recalculated by assuming a flat
spectrum within the ISOPHOT 60µm bandwidth; this is our estimate
of the monochromatic flux density from the disk.
Note (4): In table4.dat, fluxes are corrected for point spread function and
Rayleigh-Jeans colour-correction, i.e. the inband flux has been
divided by 0.64 (psf) and by 1.2 (cc).
Note (5): In table4.dat, "de-colour-corrected" excess from Fnu.
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Acknowledgements: Harm Habing
(End) Patricia Bauer CDS 24-Nov-2000