J/ApJ/750/98 24um observations of AFGKM stars of 3 clusters (Urban+, 2012)
The incidence of debris disks at 24 µm and 670 Myr.
Urban L.E., Rieke G., Su K., Trilling D.E.
<Astrophys. J., 750, 98 (2012)>
=2012ApJ...750...98U 2012ApJ...750...98U
ADC_Keywords: Photometry, infrared ; Clusters, open ; Spectral types
Keywords: circumstellar matter - infrared: stars - planetary systems -
open clusters and associations: individual (Hyades, Coma Ber,
Praesepe)
Abstract:
We use Spitzer Space Telescope 24 µm data to search for debris
disks among 122 AFGKM stars from the ∼670 Myr clusters Hyades,
Coma Ber, and Praesepe, utilizing a number of advances in data
reduction and determining the intrinsic colors of main-sequence stars.
For our sample, the 1σ dispersion about the main-sequence
V-KS, KS-[24] locus is approximately 3.1%. We identify seven
debris disks at 10% or more ( ≥3σ confidence level) above the
expected KS-[24] for purely photospheric emission. The incidence of
excesses of 10% or greater in our sample at this age is
5.7+3.1-1.7%. Combining with results from the literature, the rate
is 7.8+4.2-2.1% for early-type (B9-F4) stars and 2.7+3.3-1.7%
for solar-like (F5-K9) stars. Our primary sample has strict criteria
for inclusion to allow comparison with other work; when we relax these
criteria, three additional debris disks are detected. They are all
around stars of solar-like type and hence reinforce our conclusion
that disks around such stars are still relatively common at 670Myr
and are similar to the rate around early-type stars. The apparently
small difference in decay rates between early-type and solar-like
stars is inconsistent with the first-order theoretical predictions
that the later type stellar disks would decay an order of magnitude
more quickly than the earlier type ones.
Description:
We searched the Spitzer archive for observations of stars in published
membership lists for the Hyades (Paulson et al. 2004, Cat. J/AJ/127/3579),
Coma Ber (Abad & Vicente 1999, Cat. J/A+AS/136/307), and Praesepe
(Gaspar et al. 2009, Cat. J/ApJ/697/1578). Our work is the first
analysis of the Spitzer MIPS data for Coma Ber; however, the
observations of the Hyades have been analyzed previously by Cieza et
al. (2008, Cat. J/ApJ/679/720) and Stauffer et al. (2010ApJ...719.1859S 2010ApJ...719.1859S),
while a paper on Praesepe has been published by Gaspar et al. (2009,
Cat. J/ApJ/697/1578).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 88 355 Cluster stars considered in the Hyades, Coma Ber
or Praesepe
--------------------------------------------------------------------------------
See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
J/A+A/544/A111 : Low-mass stars in Coma Ber (Melnikov+, 2012)
J/MNRAS/426/3419 : UKIDSS GCS Praesepe members (Boudreault+, 2012)
J/A+A/531/A92 : Deep all-sky census of the Hyades (Roeser+, 2011)
J/ApJ/697/1578 : A debris disk study of Praesepe (Gaspar+, 2009)
J/ApJ/679/720 : Spitzer observations of the Hyades (Cieza+, 2008)
J/MNRAS/365/447 : Stellar members of Coma Berenices cluster (Casewell+, 2006)
J/AJ/127/3579 : Radial velocities of Hyades stars (Paulson+, 2004)
J/AJ/124/1570 : JHKs photometry in Praesepe (Adams+, 2002)
J/A+A/375/989 : JHK photometry of Praesepe low-mass stars (Bouvier+, 2001)
J/A+AS/136/307 : Coma Berenices astrometric catalogue (Abad+ 1999)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 23 A23 --- Name Star name
25- 29 A5 --- SpT MK spectral type
31- 36 F6.3 mag Vmag [4/15]? V-band magnitude (1)
38- 43 F6.3 mag Ksmag [3/12] 2MASS Ks-band magnitude
45- 49 F5.3 mag e_Ksmag [0.01/10] Ksmag uncertainty
51- 57 F7.3 mJy F24 [0.2/396]? Spitzer/MIPS 24um flux density
59- 64 F6.3 mag [24] [3/12]? 24um magnitude
66- 70 F5.3 mag e_[24] [0.01/0.4]? [24] uncertainty
72- 76 F5.3 mag K-[24]e [0.02/10]? K-[24] error
78 A1 --- Inc [y/n] Included in analysis? (122 "y")
80- 86 A7 --- Excl [1-7, ] Exclusion reason(s) (2)
88 A1 --- Cl Cluster (h=Hyades, c=Coma Ber, p=Praesepe)
--------------------------------------------------------------------------------
Note (1): For stars in the Hipparcos catalog (Perryman et al. 1997, Cat.
I/239), we adopted the listed Johnson V photometry. For stars that
are not in Hipparcos but are in Praesepe we adopted the V magnitudes
gathered by Gaspar et al. (2009, Cat. J/ApJ/697/1578); we collected
additional V magnitudes from the SIMBAD database. A total of eight
stars have no available V magnitudes, noted as "5" in "n_Inc" column;
these stars are not included in our analysis.
Note (2): Column is blank for the stars included in our analysis;
the reasons for exclusion are as follows:
1 = contamination from nearby stars,
2 = FWHM much greater or much less than 5.5 arcsec,
3 = signal-to-noise ratio <3,
4 = K-[24] error greater than 0.05,
5 = no Vmag,
6 = no 24um counterpart within 1.5" search radius,
7 = giant stars.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 06-Dec-2013