Spectral energy distributions and age estimates of 40 massive young stellar objects
In this paper, we present the spectral energy distributions (SEDs) of 40 massive young stellar objects (YSOs), detected from the NIR imaging survey carried out by Varricatt et al. 2010 and estimated their ages and masses. The SEDs of YSOs in 40 massive star forming regions have been reconstructed us...
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Tanti, K.K. Roy, J. Duorah, K. 2017-06-04T19:03:31Z 2017-06-04T19:03:31Z 2012 Spectral energy distributions and age estimates of 40 massive young stellar objects / K.K. Tanti, J. Roy, K. Duorah // Advances in Astronomy and Space Physics. — 2012. — Т. 2., вип. 2. — С. 139-142. — Бібліогр.: 11 назв. — англ. 2227-1481 https://nasplib.isofts.kiev.ua/handle/123456789/119185 In this paper, we present the spectral energy distributions (SEDs) of 40 massive young stellar objects (YSOs), detected from the NIR imaging survey carried out by Varricatt et al. 2010 and estimated their ages and masses. The SEDs of YSOs in 40 massive star forming regions have been reconstructed using 2MASS, MSX, IRAS, IRAC & MIPS, SCUBA, WISE, SPIRE and IRAM data, partly available from previous works, using the on-line SED Fitting tool (SED Fitter) developed by Robitaille et al. 2006, 2007. Apart from IRAS catalogue fluxes, the fluxes in the Mid-IR and sub-mm/mm were derived directly from the images. With the help of the analysis of SEDs, we have extracted important physical and structural parameters for each of the massive young stellar objects, along with the associated circumstellar disk and envelope. The cumulative distribution of the stellar ages and masses of the massive YSOs lead to a scenario for the formation history of massive stars in their respective star forming regions. en Головна астрономічна обсерваторія НАН України Advances in Astronomy and Space Physics Spectral energy distributions and age estimates of 40 massive young stellar objects Article published earlier |
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Spectral energy distributions and age estimates of 40 massive young stellar objects |
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Spectral energy distributions and age estimates of 40 massive young stellar objects Tanti, K.K. Roy, J. Duorah, K. |
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Spectral energy distributions and age estimates of 40 massive young stellar objects |
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Spectral energy distributions and age estimates of 40 massive young stellar objects |
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Spectral energy distributions and age estimates of 40 massive young stellar objects |
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Spectral energy distributions and age estimates of 40 massive young stellar objects |
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spectral energy distributions and age estimates of 40 massive young stellar objects |
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Tanti, K.K. Roy, J. Duorah, K. |
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Tanti, K.K. Roy, J. Duorah, K. |
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2012 |
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Advances in Astronomy and Space Physics |
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Головна астрономічна обсерваторія НАН України |
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In this paper, we present the spectral energy distributions (SEDs) of 40 massive young stellar objects (YSOs), detected from the NIR imaging survey carried out by Varricatt et al. 2010 and estimated their ages and masses. The SEDs of YSOs in 40 massive star forming regions have been reconstructed using 2MASS, MSX, IRAS, IRAC & MIPS, SCUBA, WISE, SPIRE and IRAM data, partly available from previous works, using the on-line SED Fitting tool (SED Fitter) developed by Robitaille et al. 2006, 2007. Apart from IRAS catalogue fluxes, the fluxes in the Mid-IR and sub-mm/mm were derived directly from the images. With the help of the analysis of SEDs, we have extracted important physical and structural parameters for each of the massive young stellar objects, along with the associated circumstellar disk and envelope. The cumulative distribution of the stellar ages and masses of the massive YSOs lead to a scenario for the formation history of massive stars in their respective star forming regions.
|
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2227-1481 |
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https://nasplib.isofts.kiev.ua/handle/123456789/119185 |
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Spectral energy distributions and age estimates of 40 massive young stellar objects / K.K. Tanti, J. Roy, K. Duorah // Advances in Astronomy and Space Physics. — 2012. — Т. 2., вип. 2. — С. 139-142. — Бібліогр.: 11 назв. — англ. |
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2025-11-26T04:51:07Z |
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1850612420701061120 |
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Spectral energy distributions and age estimates
of 40 massive young stellar objects
K.K.Tanti1∗, J. Roy2, K.Duorah1
Advances in Astronomy and Space Physics, 2, 139-142 (2012)
© K.K.Tanti, J. Roy, K.Duorah, 2012
1Department of Physics, Gauhati University, Guwahati, 781014, Assam, India
2Indian Institute of Astrophysics, Bangalore, 560034, India
In this paper, we present the spectral energy distributions (SEDs) of 40 massive young stellar objects (YSOs),
detected from the NIR imaging survey carried out by Varricatt et al. 2010 and estimated their ages and masses.
The SEDs of YSOs in 40 massive star forming regions have been reconstructed using 2MASS, MSX, IRAS, IRAC &
MIPS, SCUBA, WISE, SPIRE and IRAM data, partly available from previous works, using the on-line SED Fitting
tool (SED Fitter) developed by Robitaille et al. 2006, 2007. Apart from IRAS catalogue �uxes, the �uxes in the
Mid-IR and sub-mm/mm were derived directly from the images. With the help of the analysis of SEDs, we have
extracted important physical and structural parameters for each of the massive young stellar objects, along with
the associated circumstellar disk and envelope. The cumulative distribution of the stellar ages and masses of the
massive YSOs lead to a scenario for the formation history of massive stars in their respective star forming regions.
Key words: stars: massive, stars: pre-main-sequence, radiative transfer
introduction
The formation and the initial stages of the evolu-
tion of massive stars in our galaxy take place inside
dense regions within molecular clouds, from which
they are born. This process deals with the proto-
stars/YSOs in the environment of interstellar gas
and dust from the parent cloud. In this environ-
ment, the young stellar objects and protostars are as-
sociated with circumstellar dust and molecular gas,
which absorbs the stellar radiation and re-emits it
to wavelengths long wards than 1µm [3]. Accord-
ing to [3], the protostars have a SED with a pos-
itive slope in the 2-20µm spectral range. By the
shapes of the SEDs, [3] �rst classi�ed pre-main se-
quence (PMS) stars into an evolutionary sequence,
Classes I through III (later an earlier stage, Class 0
was also proposed to describe more deeply embed-
ded sources). This has been proved for low mass
YSOs [2]. The case for young massive stars is topic
of recent investigation [11].
To understand the pre-main sequence evolution
processes of the stars, the study of the circum-
stellar environment of YSOs is crucial. For this,
multi-wavelength photometry can be done and sub-
sequently, the SEDs can be constructed by comput-
ing the radiation transfer models, considering given
circumstellar dust and gas geometry, as well as dust
properties, and thus �nding a set of parameters that
reproduce the observations.
sed model fitting
In order to characterise the physical properties
and the evolutionary status of disks and envelopes
around all the selected 40 YSO out�ow sources,
the SEDs of YSOs were modelled using on-line SED
Fitting Tool of [5], that uses a grid of 2D radia-
tive transfer models presented in [4], developed by
[9, 10]. To obtain better results for constructing
SEDs for all sources, we compiled and used all the
available NIR, MIR and FIR data, e. g., 2MASS J-
H-Ks band data, magnitudes in the Spitzer IRAC
bands 1-4 & MIPS bands 1-2, IRAS 12, 25, 60, 100-
µm data, MSX Bands A, C, D & E data, SCUBA
450 & 850-µm data, WISE 3.4, 4.6, 12, 22-µm data,
SPIRE 250, 350, 500-µm data and the IRAM 1.2mm
data.
selection of ysos
We selected intermediate and massive young stel-
lar out�ow candidates from the NIR imaging survey
carried out in [7]. The reason for selecting these out-
�ow candidates is that bipolar molecular out�ows
have long indicated that accretion discs are present
at the heart of massive star formation. In [7] those
candidates that are young, high-mass objects with
evidence of out�ows, were selected.∗research.kamal@gmail.com
139
Advances in Astronomy and Space Physics K.K.Tanti, J. Roy, K.Duorah
discussion
As stars form and evolve following an evolution-
ary sequence, physical and structural properties of
YSOs also evolve. Fitting their SEDs can provide
us these properties, which can give us insights to un-
derstand the physical and structural evolution of pre-
main sequence stars as well as the evolution of star
clusters where these massive stars were born. The
physical properties of the central source, such as ef-
fective temperature and luminosity, are the most im-
portant parameters in understanding the evolution-
ary status of the central source, and play a crucial
role in the physical properties of disks and envelopes,
because dust in the disks and envelopes are heated by
irradiation from the star and from accretion shocks
at the stellar surface [6].
The physical and structural parameters of all the
40 intermediate and massive YSO out�ow candi-
dates, along with the associated circumstellar disk
and envelope, are obtained with the help of SED
Fitting Tool.
The stellar masses, stellar ages, stellar tempera-
tures and total luminosities of all the central YSO
sources are shown in Table 1. The best-�t model
SEDs for few selected massive YSO out�ow sources,
viz. IRAS 18144-1723, IRAS 18345-0641, IRAS
19217+1651, IRAS 19410+2336, IRAS 21519+5613
& IRAS 22305+5803, are shown in Fig. 1. Out of all
the 40 target sources, 27 are calculated as massive
YSOs, ranging from 8.18M� to 28.6M�, whereas 13
are low and intermediate-mass YSOs, ranging from
2.51M� to 7.92M�. The stellar temperatures of the
sources are ranging from 4149K to 24 558K. The
stellar ages of all the sources are calculated. For the
13 intermediate YSO out�ow candidates, the stellar
ages are ranging from 1.82×103 yr to 8.79×105 yr. In
case of massive YSO out�ow candidates, the stellar
ages range from 1.24×103 yr to 9.80×105 yr. Sim-
ilarly, the envelopes that surrounded the central
YSO sources are large with mass range of 6.12 M�
� 4.14×103M�, whereas envelope radii range be-
tween 1.13×104AU � 1.00×105AU. The estimated
envelope accretion rates are high with a range of
4.83×10−8M�/yr � 9.71×10−3M�/yr. The large
envelope size signi�es that the accretion is spherical
on the size-scales of dense cores [1]. Also, we have
estimated the range of disk parameters as follows:
disk mass: 5.69×10−4M� � 4.64×10−1M�; disk ra-
dius: 3.79AU � 1.91×103AU; disk accretion rate:
1.52×10−9M�/yr � 3.32×10−4M�/yr. In the cur-
rent study, every SED model showed a disk for each
YSO, but at the same time, this SED model may not
be sensitive towards the presence or absence of this
disk � because in an accretion scenario, envelope
�ux always overpowers the disk �ux.
Considering the most massive among the sam-
ple of 40 individual central YSO sources, i. e.,
IRAS 19110+1045, for which we have estimated the
physical parameters as: stellar mass = 28.60M�,
stellar radius = 53.62R�, stellar temperature =
14 052K, stellar age = 5.74×103 yr and total lumi-
nosity = 1.01×105 L�.
Using an older self-consistent radiative transfer
modelling technique, in [8] the total luminosity as
3.3×105 L�, for IRAS 19110+1045, was estimated
by integrating the observed SED, whereas the total
luminosity of the resolved stars is 1.1×105 L�. From
the SED, that shows a higher composition of silicate
(60%) grains, they also estimated the other param-
eters as: dust mass = 450M�, the gas to dust ratio
by mass = 450, cold dust mass = 30M�, gas mass
= 1.3×104M�.
In [1] the physical properties of the infrared
counterparts of 380 high mass protostellar objects
were estimated and analysed by using their spec-
tral energy distributions (SED) predicted by radia-
tive transfer accretion models of YSOs, that success-
fully explained a YSO accretion model which further
represent a realistic picture of massive star forma-
tion. Using the results in the current study, we can
understand the physical and structural evolution of
the YSOs taken into consideration which will self-
consistently explain the embedded young stellar ob-
jects (YSO) in dense interstellar clouds, which will
lead to a scenario for the formation history of mas-
sive stars in their respective star forming regions.
references
[1] Grave J.M.C. & KumarM. S.N. 2009, A&A, 498, 147
[2] HartmannL., Megeath S.T., Allen L. et al. 2005, ApJ,
629, 881
[3] LadaC. J. 1987, in IAU Symposium, 115, 1
[4] Robitaille T. P., WhitneyB.A., IndebetouwR., WoodK.
& DenzmoreP. 2006, ApJS, 167, 256
[5] Robitaille T. P., WhitneyB.A., IndebetouwR. &
WoodK. 2007, ApJS, 169, 328
[6] SungH. & BessellM. S. 2010, AJ, 140, 2070
[7] VarricattW.P., DavisC. J., Ramsay S. & ToddS. P.
2010, MNRAS, 404, 661
[8] Vig S., Ghosh S.K., KulkarniV.K., OjhaD.K. &
VermaR.P. 2006, ApJ, 637, 400
[9] WhitneyB.A., WoodK., Bjorkman J. E. & CohenM.
2003, ApJ, 598, 1079
[10] WhitneyB.A., WoodK., Bjorkman J. E. & Wol�M. J.
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[11] ZinneckerH. & YorkeH.W. 2007, ARA&A, 45, 481
140
Advances in Astronomy and Space Physics K.K.Tanti, J. Roy, K.Duorah
Table 1: The stellar masses, stellar ages, stellar temperatures and total luminosities of the 40 intermediate
and massive young stellar objects.
Sl No. YSO Source Stellar Age Stellar Mass Stellar Temperature Total Luminosity
(yr) (M�) (K) (L�)
1 IRAS 00420+5530 1.36·104 12.61 6332 6.37·103
2 IRAS 04579+4703 1.32·105 7.31 7218 9.32·102
3 IRAS 05137+3919 1.53·105 7.78 12660 3.05·103
4 IRAS 05168+3634 5.93·103 14.44 4502 7.65·103
5 IRAS 05274+3345 7.87·105 6.39 19338 1.81·103
6 IRAS 05358+3543 6.03·104 8.18 6325 1.14·103
7 IRAS 05373+2349 4.36·103 2.51 4167 4.86·102
8 IRAS 05490+2658 1.60·105 7.31 8858 1.27·103
9 IRAS 05553+1631 5.40·103 9.36 4428 1.50·103
10 IRAS 06061+2151 2.89·104 11.21 8479 4.72·103
11 IRAS 06584-0852 8.27·105 6.61 19796 1.33·103
12 IRAS 18144-1723 2.10·104 15.44 14321 2.22·104
13 IRAS 18159-1648 3.13·105 7.70 21221 2.52·103
14 IRAS 18174-1612 6.77·103 20.11 9139 2.97·104
15 IRAS 18182-1433 1.60·104 21.76 23884 7.79·104
16 IRAS 18264-1152 1.53·104 10.64 5117 3.24·103
17 IRAS 18345-0641 1.36·104 12.99 6733 7.21·103
18 IRAS 18360-0537 8.79·105 5.70 17951 7.76·102
19 IRAS 18385-0512 2.93·104 10.05 6681 2.92·103
20 IRAS 18517+0437 1.24·103 11.77 4149 4.68·103
21 IRAS 19092+0841 1.36·104 12.99 6733 7.21·103
22 IRAS 19110+1045 5.74·103 28.60 14052 1.01·105
23 IRAS 19213+1723 1.67·105 7.92 15821 4.34·103
24 IRAS 19217+1651 8.11·103 13.67 5066 8.20·103
25 IRAS 19374+2352 9.13·103 11.11 4564 3.03·103
26 IRAS 19388+2357 1.82·103 6.47 4153 7.32·102
27 IRAS 19410+2336 7.77·104 10.10 17996 9.06·103
28 IRAS 20050+2720 4.03·103 7.83 4268 1.02·103
29 IRAS 20188+3928 3.17·104 9.87 6785 2.74·103
30 IRAS 20198+3716 9.80·105 8.99 24325 4.31·103
31 IRAS 20227+4154 5.32·105 6.98 20519 1.64·103
32 IRAS 20062+3550 4.03·103 7.83 4268 1.02·103
33 IRAS 20293+3952 2.03·104 10.91 6198 3.83·103
34 IRAS 21307+5049 1.05·105 8.26 10875 2.82·103
35 IRAS 21391+5802 5.86·104 2.99 4389 8.08·101
36 IRAS 21519+5613 6.74·104 11.69 24558 1.51·104
37 IRAS 22172+5549 2.93·104 10.05 6681 2.92·103
38 IRAS 22305+5803 2.80·104 10.55 7216 3.54·103
39 IRAS 22570+5912 7.77·104 10.10 17996 9.06·103
40 IRAS 23139+5939 8.59·105 6.79 20138 1.55·103
141
Advances in Astronomy and Space Physics K.K.Tanti, J. Roy, K.Duorah
Fig. 1: The best-�t model SEDs of IRAS 18144-1723, IRAS 18345-0641, IRAS 19217+1651, IRAS 19410+2336,
IRAS 21519+5613 and IRAS 22305+5803.
142
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