J/ApJ/921/81 M20 young stellar population (Kalari, 2021)
The young stellar population, distance, and cloud-cloud collision induced star
formation scenario of the Trifid Nebula.
Kalari V.M.
<Astrophys. J., 921, 81-81 (2021)>
=2021ApJ...921...81K 2021ApJ...921...81K (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Stars, pre-main sequence ; Photometry, H-alpha
Keywords: star formation - star forming regions - H II regions -
young stellar objects - pre-main sequence stars
Abstract:
The Trifid Nebula is a young, nearby star-forming region where star
formation is proposed to have been triggered by cloud-cloud collision
(CCC), based on observations of molecular clouds. It offers a unique
opportunity to test whether the CCC hypothesis is supported by the
spatial distribution and star formation chronology of young stars. We
present the first study of the optically visible pre-main sequence
(PMS) population of the region using riHα imaging and Gaia
astrometry. Combined with an analysis of young stellar objects (YSOs)
using infrared imaging, we capture the spatial distribution and star
formation chronology of the young stellar population. From the
analysis, 15 Flat/Class I YSOs, 46 Class II YSOs, and 41 accreting PMS
stars are identified (diskless/non-accreting sources are not included
in the analysis). The distance based on Gaia parallaxes is ∼1250pc,
significantly closer than previously reported. The Class II YSOs and
PMS stars (∼1.5Myr old) are spread toward the edge of the molecular
clouds. They are slightly younger than the estimated crossing time of
∼2.7Myr and closer to the estimated dynamical age ∼0.85Myr. Younger
Class I YSOs are more concentrated spatially. There exists a cavity
devoid of young stars where the two clouds overlap. This evidence
suggests that the current generation of stars formed after the
collision of two clouds ∼1Myr ago, and this result can be corroborated
using future spectroscopic studies.
Description:
Class I YSOs identified based on mid-infrared photometry, and Class II
YSOs identified based on Hα excess are listed.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 174 61 Infrared photometry of young stellar objects
in the Trifid nebula
table2.dat 203 41 Optical photometry, Gaia astrometry, and
estimated stellar properties of pre-main
sequence stars in the Trifid nebula
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See also:
II/293 : GLIMPSE Source Catalog (I + II + 3D) (IPAC 2008)
II/341 : VPHAS+ DR2 survey (Drew+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- GLIMPSE GLIMPSE identifier (GLLL.llll+BB.bbbb)
19- 34 A16 --- 2MASS 2MASS catalog identifier
36- 37 I2 h RAh Right Ascension (J2000)
39- 40 I2 min RAm Right Ascension (J2000)
42- 46 F5.2 s RAs Right Ascension (J2000)
48 A1 --- DE- Declination sign (J2000)
49- 50 I2 deg DEd Declination (J2000)
52- 53 I2 arcmin DEm Declination (J2000)
55- 58 F4.1 arcsec DEs Declination (J2000)
60- 65 F6.3 mag Jmag ?=- 2MASS J band magnitude
67- 71 F5.3 mag e_Jmag ?=- Uncertainty in Jmag
73- 78 F6.3 mag Hmag ?=- 2MASS H band magnitude
80- 84 F5.3 mag e_Hmag ?=- Uncertainty in Hmag
86- 91 F6.3 mag Kmag ?=- 2MASS Ks band magnitude
93- 97 F5.3 mag e_Kmag ?=- Uncertainty in Kmag
99-104 F6.3 mag 3.6mag Spitzer/IRAC 3.6 um band magnitude
106-110 F5.3 mag e_3.6mag Uncertainty in 3.6mag
112-117 F6.3 mag 4.5mag Spitzer/IRAC 4.5 um band magnitude
119-123 F5.3 mag e_4.5mag Uncertainty in 4.5mag
125-130 F6.3 mag 5.8mag Spitzer/IRAC 5.8 um band magnitude
132-136 F5.3 mag e_5.8mag Uncertainty in 5.8mag
138-143 F6.3 mag 8.0mag Spitzer/IRAC 8.0 um band magnitude
145-149 F5.3 mag e_8.0mag Uncertainty in 8.0mag
151-154 F4.2 mag 24mag ?=- Spitzer/MIPS 24 um band magnitude
156-159 F4.2 mag e_24mag ?=- Uncertainty in 24mag
161-165 F5.2 --- alpha IR SED slope
167-169 F3.1 --- e_alpha Uncertainty in alpha
171-174 A4 --- Class 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- 12 I12 --- VPHAS+ VPHAS+ DR3 identifier
14- 15 I2 h RAh Right Ascension (J2000)
17- 18 I2 min RAm Right Ascension (J2000)
20- 24 F5.2 s RAs Right Ascension (J2000)
26 A1 --- DE- Declination sign (J2000)
27- 28 I2 deg DEd Declination (J2000)
30- 31 I2 arcmin DEm Declination (J2000)
33- 36 F4.1 arcsec DEs Declination (J2000)
38- 43 F6.3 mag rmag Apparent r band magnitude (Vega)
45- 49 F5.3 mag e_rmag Uncertainty in rmag
51- 56 F6.3 mag imag Apparent i band magnitude (Vega)
58- 62 F5.3 mag e_imag Uncertainty in imag
64- 69 F6.3 mag Hamag Apparent Hα band magnitude
71- 75 F5.3 mag e_Hamag Uncertainty in Hamag
77- 83 F7.2 0.1nm EWHa Hα equivalent width
85- 88 F4.1 0.1nm e_EWHa Uncertainty in EWHa
90- 95 F6.3 mas/yr pmRA Gaia EDR3 proper motion along RA
97-101 F5.3 mas/yr e_pmRA Uncertainty in pmRA
103-108 F6.3 mas/yr pmDE Gaia EDR3 proper motion along Declination
110-114 F5.3 mas/yr e_pmDE Uncertainty in pmDE
116-122 F7.4 mas Plx Gaia EDR3 parallax
124-129 F6.4 mas e_Plx Uncertainty in plx
131-136 F6.3 mag Jmag ?=- 2MASS J band magnitude
138-142 F5.3 mag e_Jmag ?=- Uncertainty in Jmag
144-149 F6.3 mag Hmag 2MASS H band magnitude
151-155 F5.3 mag e_Hmag Uncertainty in Hmag
157-162 F6.3 mag Kmag ?=- 2MASS Ks band magnitude
164-168 F5.3 mag e_Kmag ?=- Uncertainty in Ksmag
170-173 F4.2 Msun Mass Mass
176-179 F4.2 Msun E_Mass Upper uncertainty in Mass (1)
182-185 F4.2 Msun e_Mass Lower uncertainty in Mass (1)
187-191 F5.2 Myr Age Age
193-196 F4.2 Myr E_Age Upper uncertainty in Age (1)
199-203 F5.2 Myr e_Age Lower uncertainty in Age (1)
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Note (1): Mass and age errors denote the upper and lower deviations based on
the propagated photometric uncertainties, and assuming a distance
and reddening uncertainty of 200pc, and 0.2mag.
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Acknowledgements:
Venu Kalari, venu.kalari(at)noirlab.edu
(End) Patricia Vannier [CDS] 25-Nov-2021