J/ApJ/756/133 ScoCen debris disks around B- and A-type stars (Chen+, 2012)
A Spitzer MIPS study of 2.5-2.0M☉ stars in Scorpius-Centaurus.
Chen C.H., Pecaut M., Mamajek E.E., Su K.Y.L., Bitner M.
<Astrophys. J., 756, 133 (2012)>
=2012ApJ...756..133C 2012ApJ...756..133C
ADC_Keywords: Associations, stellar ; Photometry, infrared ; Stars, B-type;
Stars, A-type
Keywords: circumstellar matter - infrared, planetary systems - infrared, stars -
open clusters and associations, individual (Upper Scorpius,
Lower Centaurus Crux, Upper Centaurus Lupus) - planetary systems -
planets and satellites: formation
Abstract:
We have obtained Spitzer Space Telescope Multiband Imaging Photometer
for Spitzer (MIPS) 24 micron and 70 micron observations of 215 nearby,
Hipparcos B- and A-type common proper-motion single and binary systems
in the nearest OB association, Scorpius-Centaurus. Combining our MIPS
observations with those of other ScoCen stars in the literature, we
estimate 24 micron B+A-type disk fractions of 17/67 (25+6-5%),
36/131 (27+4-5%), and 23/95 (24+5-4%) for Upper Scorpius
(∼11Myr), Upper Centaurus Lupus (∼15Myr), and Lower Centaurus Crux
(∼17Myr), respectively, somewhat smaller disk fractions than
previously obtained for F- and G-type members. We confirm previous
IRAS excess detections and present new discoveries of 51
protoplanetary and debris disk systems, with fractional infrared
luminosities ranging from LIR/L*=10-6 to 10-2 and grain
temperatures ranging from Tgr=40 to 300K. In addition, we confirm that
the 24 micron and 70 micron excesses (or fractional infrared
luminosities) around B+A-type stars are smaller than those measured
toward F+G-type stars and hypothesize that the observed disk property
dependence on stellar mass may be the result of a higher stellar
companion fraction around B- and A-type stars at 10-200AU. Finally, we
note that the majority of the ScoCen 24 micron excess sources also
possess 12 micron excess, indicating that Earth-like planets may be
forming via collisions in the terrestrial planet zone at ∼10-100Myr.
Description:
We present (1) stellar spectral types, distances, extinctions,
subgroup membership, and binary properties based on the literature,
(2) 24 and 70 micron photometry measured from Spitzer MIPS images and
used to identify members with dusty disks (Table 2), and (3) debris
disk properties estimated from our estimated stellar properties and
far-infrared excesses (Table 3).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 137 216 Stellar Properties
table2.dat 73 215 Spitzer MIPS 24 and 70 micron fluxes
table3.dat 89 50 Single Temperature Blackbody model parameters for
objects with significant far-IR excess χ≥6
refs.dat 105 29 References
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See also:
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
J/ApJ/738/122 : ScoCen debris disks Around F- and G-type stars (Chen+, 2011)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- HIP Hipparcos number
8- 16 A9 --- Name Star Name
20- 33 A14 --- SpType Spectral Type
35- 37 A3 --- r_SpType Reference for Spectral Type in refs.dat file
39- 43 F5.1 pc Dist Hipparcos Distance
45- 49 F5.1 pc E_Dist +1-σ error on Distance
51- 55 F5.1 pc e_Dist -1-σ error on Distance
57- 61 F5.3 mag A(V) V-band Extinction
63- 67 F5.3 mag e_A(V) 1-σ error on A(V)
71- 73 A3 --- sgr ScoCen Subgroup (G1)
75- 81 F7.3 arcsec Sep1 ? Binary Separation
82 A1 --- --- [,]
83- 89 F7.3 arcsec Sep2 ? Binary Separation
90 A1 --- --- [,]
91- 95 F5.2 arcsec Sep3 ? Binary Separation
96 A1 --- --- [,]
97-101 F5.2 arcsec Sep4 ? Binary Separation
102 A1 --- --- [,]
103-106 F4.2 arcsec Sep5 ? Binary Separation
107 A1 --- --- [,]
108-111 F4.2 arcsec Sep6 ? Binary Separation
112 A1 --- --- [,]
113-116 F4.1 arcsec Sep7 ? Binary Separation
118-125 A8 --- r_Sep Reference for Binary Separation in refs.dat
127-137 A11 --- Notes Notes about binarity or classification.
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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- 5 I5 --- HIP Hipparcos number
7 A1 --- f_F24 [Y/N] Contamination Flag for MIPS 24um Flux
9- 17 A9 --- Name Star Name
19- 26 I8 --- AOR ? Astronomical Observing Request
28- 33 F6.1 mJy F24 ? Spitzer/MIPS 24µm flux (not color-corrected)
35- 38 F4.1 mJy e_F24 ? 1-σ error on F24 (1)
40- 44 F5.1 mJy P24 ? Predicted Photospheric MIPS 24 Flux
46- 49 F4.1 --- chi24 ? MIPS 24um Excess Significance (2)
51 A1 --- l_F70 Limit Flag on MIPS 70um Flux
52- 58 F7.1 mJy F70 ? Spitzer/MIPS 70µm flux (not color-corrected)
60- 63 F4.1 mJy e_F70 ? 1-σ error on F70 (1)
65- 68 F4.1 mJy P70 ? Predicted Photospheric MIPS 70 Flux
70- 73 F4.1 --- chi70 ? MIPS 70um Excess Significance (2)
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Note (1): e_F24um and e_F70um are the statistical uncertainties in F24um and
F70um photometry. The total uncertainty can be calculated by adding the
systematic, repeatability, and calibration uncertainties in quadrature
(see Section 2.1, 2012ApJ...756..133C 2012ApJ...756..133C).
Note (2): the significance is defined as
χ=(MeasuredFlux-PredictedFlux)/Uncertainty
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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- 5 I5 --- HIP Hipparcos number
7- 15 A9 --- Name Star Name
17- 21 I5 --- Teff Stellar Effective Temperature
23- 27 F5.1 Lsun L* Stellar Luminosity
29- 32 F4.1 Lsun E_L* 1-σ error on L* (upper value)
34- 37 F4.1 Lsun e_L* 1-σ error on L* (lower value)
39- 41 F3.1 Msun M* Stellar Mass
43- 44 I2 Myr Age Stellar Age
46 A1 --- l_Tgr Limit Flag on Tgr
47- 49 I3 K Tgr Grain Temperature
51- 57 E7.2 --- LIR/L* Fractional Infrared Luminosity
59- 61 F3.1 um amin Minimum Grain Size
63 A1 --- l_Dist Limit on Dist
64- 66 I3 AU Dist Grain Distance
68- 77 F10.6 --- Mdust Dust Mass, in Moon mass
79 A1 --- l_MPB limit on MPB
80- 85 F6.3 --- MPB Parent Body Mass, in Moon mass
87- 89 A3 --- sgr ScoCen Subgroup (G1)
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Ref Reference Code
5- 23 A19 --- BibCode BibCode
25- 48 A24 --- Aut Author's name
50-105 A56 --- Com Comments
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Global notes:
Note (G1): Star-forming region name are:
US = Upper Scorpius
UCL = Upper Centaurus Lupus
LCC = Lower Centaurus Crux
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Acknowledgements:
Christine Chen, cchen(at)stsci.edu
History:
* 11-Jan-2013: Original version
* 22-Jun-2013: names in table2 fixed to be identical to those of table1
(End) Christine Chen [STScI, USA], Patricia Vannier [CDS] 11-Jan-2013