J/ApJ/734/51 Mineralogical compositions of dust grains (Oliveira+, 2011)
On the evolution of dust mineralogy, from protoplanetary disks to planetary
systems.
Oliveira I., Olofsson J., Pontoppidan K.M., van Dishoeck E.F.,
Augereau J.-C., Merin B.
<Astrophys. J., 734, 51 (2011)>
=2011ApJ...734...51O 2011ApJ...734...51O
ADC_Keywords: Abundances ; Molecular clouds ; YSOs
Keywords: circumstellar matter - infrared: stars - methods: statistical -
protoplanetary disks - stars: pre-main sequence
Abstract:
Mineralogical studies of silicate features emitted by dust grains in
protoplanetary disks and solar system bodies can shed light on the
progress of planet formation. The significant fraction of crystalline
material in comets, chondritic meteorites, and interplanetary dust
particles indicates a modification of the almost completely amorphous
interstellar medium dust from which they formed. The production of
crystalline silicates, thus, must happen in protoplanetary disks,
where dust evolves to build planets and planetesimals. Different
scenarios have been proposed, but it is still unclear how and when
this happens. This paper presents dust grain mineralogy (composition,
crystallinity, and grain size distribution) of a complete sample of
protoplanetary disks in the young Serpens cluster. These results are
compared to those in the young Taurus region and to sources that have
retained their protoplanetary disks in the older Upper Scorpius and
η Chamaeleontis stellar clusters, using the same analysis
technique for all samples. This comparison allows an investigation of
the grain mineralogy evolution with time for a total sample of 139
disks. The mean cluster age and disk fraction are used as indicators
of the evolutionary stage of the different populations. Our results
show that the disks in the different regions have similar
distributions of mean grain sizes and crystallinity fractions
(∼10%-20%) despite the spread in mean ages. Furthermore, there is no
evidence of preferential grain sizes for any given disk geometry nor
for the mean cluster crystallinity fraction to increase with mean age
in the 1-8Myr range. The main implication is that a modest level of
crystallinity is established in the disk surface early on (≤1Myr),
reaching an equilibrium that is independent of what may be happening
in the disk midplane. These results are discussed in the context of
planet formation, in comparison with mineralogical results from small
bodies in our own solar system.
Description:
This paper presents the spectral decomposition of Spitzer/IRS
spectra using the B2C decomposition model of Olofsson et al.
(2010A&A...520A..39O 2010A&A...520A..39O). Mineralogical compositions and size
distributions of dust grains in the surface layers of protoplanetary
disks are derived for 139 YSOs belonging to four young star clusters
using the same method.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 184 213 Dust composition derived using the "B2C" procedure
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See also:
J/ApJ/720/480 : DISCS. I. Taurus protoplanetary disk data (Oberg+, 2010)
J/ApJ/714/778 : YSOs in the Serpens Molecular Cloud (Oliveira+, 2010)
J/ApJ/691/672 : YSOs in Serpens molecular cloud (Oliveira+ 2009)
J/ApJ/703/1964 : Spectra of three nearby star-forming regions (Furlan+, 2009)
J/ApJ/669/493 : Spitzer/Chandra YSOs in Serpens cloud core (Winston+, 2007)
J/ApJ/651/L49 : Upper Sco OB association IRAC observations (Carpenter+, 2006)
J/ApJ/636/1098 : Debris disks around solar-type stars (Bryden+, 2006)
Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Cl Star-forming region designation (1)
5- 21 A17 --- ID Low-mass star identification (2)
23- 26 A4 --- SpT MK spectral type
28 A1 --- m_ID [cw] c: cold or w: warm component (3)
30- 33 F4.1 % OP0.1 Combined amorphous olivine and pyroxene relative
abundance at 0.1um
35- 38 F4.1 % E_OP0.1 Positive error on OP0.1
40- 43 F4.1 % e_OP0.1 Negative error on OP0.1
45- 48 F4.1 % Ens0.1 Crystalline enstatite relative abundance at 0.1um
50- 53 F4.1 % E_Ens0.1 Positive error on Ens0.1
55- 58 F4.1 % e_Ens0.1 Negative error on Ens0.1
60- 63 F4.1 % For0.1 Forsterite relative abundance at 0.1um
65- 68 F4.1 % E_For0.1 Positive error on For0.1
70- 73 F4.1 % e_For0.1 Negative error on For0.1
75- 78 F4.1 % Sil0.1 Amorphous silica relative abundance at 0.1um
80- 85 F6.2 % E_Sil0.1 Positive error on Sil0.1
87- 90 F4.1 % e_Sil0.1 Negative error on Sil0.1
92- 95 F4.1 % OP1.5 Combined amorphous olivine and pyroxene relative
abundance at 1.5um
97 A1 --- lEOP1.5 Limit flag on E_OP1.5
98-101 F4.1 % E_OP1.5 Positive error on OP1.5
103-106 F4.1 % e_OP1.5 Negative error on OP1.5
108-111 F4.1 % Ens1.5 Crystalline enstatite relative abundance at 1.5um
113-116 F4.1 % E_Ens1.5 Positive error on Ens1.5
118-121 F4.1 % e_Ens1.5 Negative error on Ens1.5
123-126 F4.1 % For1.5 Forsterite relative abundance at 1.5um
128-131 F4.1 % E_For1.5 Positive error on For1.5
133-136 F4.1 % e_For1.5 Negative error on For1.5
138-141 F4.1 % Sil1.5 Amorphous silica relative abundance at 1.5um
143 A1 --- lESil1.5 Limit flag on E_Sil1.5
144-148 F5.1 % E_Sil1.5 Positive error on Sil1.5
150-153 F4.1 % e_Sil1.5 Negative error on Sil1.5
155-158 F4.1 % OP6.0 Combined amorphous olivine and pyroxene relative
abundance at 6.0um
160-163 F4.1 % E_OP6.0 Positive error on OP6.0
165-168 F4.1 % e_OP6.0 Negative error on OP6.0
170-173 F4.1 % Sil6.0 Amorphous silica relative abundance at 6.0um
175-179 F5.1 % E_Sil6.0 Positive error on Sil6.0
181-184 F4.1 % e_Sil6.0 Negative error on Sil6.0
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Note (1): Star-forming region use the notation:
Ser = Serpens
Tau = Taurus
UpS = Up Sco
eCh = η Cha
Note (2): In Serpens, numbers are from Oliveira et al., 2009,
Cat. J/ApJ/691/672 and 2010, Cat. J/ApJ/714/778; <[OMP2009] NNN> in Simbad.
Note (3): In the table, the first line of a given object corresponds to the
results of the fit to the warm component (flag w) and the second line
to the results of the cold component (flag c). For some objects (20 in
Serpens, 28 in Taurus, all in Upper Sco and η Cha), the S/N drops
considerably at longer wavelengths and the results of the procedure
are no longer reliable. For these sources, the cold component could
not be fitted satisfactorily and only the warm component results are shown.
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 21-Nov-2012