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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
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) 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:
FileName Lrecl Records Explanations
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
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
Bytes Format Units Label Explanations
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
Note (1): In original data, HD 27835 is a misprint for HD 27845; corrected at CDS.
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
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)
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%.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
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
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 11-Oct-2010
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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