J/ApJ/679/720 Spitzer observations of the Hyades (Cieza+, 2008)
Spitzer observations of the Hyades: circumstellar debris disks at 625 Myr
of age.
Cieza L.A., Cochran W.D., Augereau J.-C.
<Astrophys. J., 679, 720-731 (2008)>
=2008ApJ...679..720C 2008ApJ...679..720C
ADC_Keywords: Clusters, open ; Photometry, infrared ; Stars, late-type ;
Stars, dwarfs ; Photometry, millimetric/submm
Keywords: circumstellar matter -
open clusters and associations: individual (Hyades)
Abstract:
We use the Spitzer Space Telescope to search for infrared excess at
24, 70, and 160um due to debris disks around a sample of 45 FGK-type
members of the Hyades. We supplement our observations with archival
24 and 70um Spitzer data of an additional 22 FGK-type and 11 A-type
Hyades members in order to provide robust statistics on the incidence
of debris disks at 625Myr of age, an era corresponding to the late
heavy bombardment in the solar system. We find that none of the 67
FGK-type stars in our sample show evidence for a debris disk, while
2 out of the 11 A-type stars do. This difference in debris disk
detection rate is likely to be due to a sensitivity bias in favor of
early-type stars. The fractional disk luminosity, Ldust/L*, of the
disks around the two A-type stars is ∼4x10-5, a level that is below
the sensitivity of our observations toward the FGK-type stars.
However, our sensitivity limits for FGK-type stars are able to
exclude, at the 2σ level, frequencies higher than 12% and 5%
of disks with Ldust/L*>1x10-4 and Ldust/L*>5x10-4,
respectively. We also use our sensitivity limits and debris disk
models to constrain the maximum mass of dust, as a function of
distance from the stars, that could remain undetected around our
targets.
Description:
The majority of the 78 targets discussed in this paper were observed
at 3.6, 4.5, 5.8, and 8.0um with the Infrared Array Camera (IRAC) and
at 24, 70, and 160um with MIPS as part of our General Observer (GO)
program 3371. This program contains 45 FGK-type Hyades members from
the high-precision radial velocity (RV) survey discussed by Cochran
et al. (2002AJ....124..565C 2002AJ....124..565C) and Paulson et al. (2004, Cat.
J/AJ/127/3579). We have also included MIPS 24 and 70um observations of
Hyades members from the Formation and Evolution of Planetary Systems
Spitzer Legacy Project (program ID 148; 21 FGK-type stars) and two
Guaranteed Time Observation (GTO) programs (program ID 40, 11 A-type
stars; and program ID 71, 1 K0 star).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 68 78 Hyades Stars
table2.dat 44 43 IRAC Photometry
table3.dat 65 78 MIPS photometry and photospheric predictions
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See also:
J/A+A/481/661 : Hyades brown dwarfs and very low mass stars (Bouvier+, 2008)
J/AJ/132/111 : BV(RI)Cphotometry of 77 Hyades stars (Joner+, 2006)
J/AJ/127/3579 : Radial velocities of Hyades stars (Paulson+, 2004)
J/A+A/331/81 : Hyades membership (Perryman+ 1998)
J/ApJ/448/683 : Hyades RASS observations (Stern+ 1995)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name HD, BD or HIP star designation (1)
11- 18 F8.5 deg RAdeg Right Ascension in decimal degrees (J2000)
20- 27 F8.5 deg DEdeg Declination in decimal degrees (J2000)
29- 36 I8 --- MIPS-AOR Spitzer/MIPS Astronomical Observation Request ID
38- 45 I8 --- IRAC-AOR ? Spitzer/IRAC Astronomical Observation Request ID
47- 50 I4 --- PID Spitzer Program ID
52- 53 A2 --- SpT MK Spectral type from the literature
55- 58 F4.2 mag Jmag 2MASS J band magnitude
60- 63 F4.2 mag Hmag 2MASS H band magnitude
65- 68 F4.2 mag Ksmag 2MASS Ks band magnitude
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Note (1): In original data, HD 27835 is a misprint for HD 27845; corrected
at CDS.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name HD, BD or HIP star designation
11- 18 F8.5 deg RAdeg Right Ascension in decimal degrees (J2000)
20- 27 F8.5 deg DEdeg Declination in decimal degrees (J2000)
29- 32 I4 mJy F3.6 ? Spitzer/IRAC 3.6 micron flux (1)
34- 36 I3 mJy F4.5 ? Spitzer/IRAC 4.5 micron flux (1)
38- 40 I3 mJy F5.8 ? Spitzer/IRAC 5.8 micron flux (1)
42- 44 I3 mJy F8.0 ? Spitzer/IRAC 8.0 micron flux (1)
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Note (1): A 5% error should be adopted for all IRAC fluxes. As discussed in
Section 3.1, even thought the formal errors in our IRAC measurements
are typically <1%, there is a random error floor to the best
uncertainty possible with our IRAC observing techniques and data
reduction process of ∼5%.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name HD, DM or HIP star designation
11- 16 F6.2 mJy F24 Spitzer/MIPS 24 micron flux
18- 23 F6.4 mJy e_F24 Uncertainty in F24
24- 29 F6.2 mJy F24p Predicted stellar 24 micron photospheric flux
31- 36 F6.2 mJy F70 Spitzer/MIPS 70 micron flux
38- 41 F4.2 mJy e_F70 Uncertainty of Spitzer MIPS 70 micron flux
43- 47 F5.2 mJy F70p Predicted stellar 70 micron photospheric flux
49- 54 F6.1 mJy F160 ? Spitzer/MIPS 160 micron flux
56- 60 F5.2 mJy e_F160 ? Uncertainty of Spitzer MIPS 160 micron flux
62- 65 F4.2 mJy F160p ? Predicted stellar 160 micron photospheric flux
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 11-Oct-2010