J/ApJ/962/174 3D kinematics in the ONC. II. Mass-dependent results (Wei+, 2024)
The 3D Kinematics of the Orion Nebula Cluster.
II. Mass-dependent kinematics of the inner cluster.
Wei L., Theissen C.A., Konopacky Q.M., Lu J.R., Hsu C.-C., Kim D.
<Astrophys. J., 962, 174 (2024)>
=2024ApJ...962..174W 2024ApJ...962..174W
ADC_Keywords: Clusters, open; Star Forming Region; Radial velocities;
Effective temperatures; Proper motions; Rotational velocities;
Stars, masses; Spectra, infrared; Optical
Keywords: Star formation ; Stellar kinematics ; Star forming regions ;
Star clusters ; Radial velocity ; Initial mass function
Abstract:
We present the kinematic analysis of 246 stars within 4' from the
center of Orion Nebula Cluster (ONC), the closest massive star cluster
with active star formation across the full mass range, which provides
valuable insights in the formation and evolution of star cluster on an
individual-star basis. High-precision radial velocities and surface
temperatures are retrieved from spectra acquired by the NIRSPEC
instrument used with adaptive optics (NIRSPAO) on the Keck II 10m
telescope. A 3D kinematic map is then constructed by combining with
the proper motions previously measured by the Hubble Space Telescope
Advanced Camera for Surveys/WFPC2/WFC3IR and Keck II NIRC2. The
measured root-mean-squared velocity dispersion is 2.26±0.08km/s,
significantly higher than the virial equilibrium's requirement of
1.73km/s, suggesting that the ONC core is supervirial, consistent with
previous findings. Energy equipartition is not detected in the
cluster. Most notably, the velocity of each star relative to its
neighbors is found to be negatively correlated with stellar mass.
Low-mass stars moving faster than their surrounding stars in a
supervirial cluster suggests that the initial masses of forming stars
may be related to their initial kinematic states. Additionally, a
clockwise rotation preference is detected. A weak sign of inverse mass
segregation is also identified among stars excluding the Trapezium
stars, although it could be a sample bias. Finally, this study reports
the discovery of four new candidate spectroscopic binary systems.
Description:
Our sample consists of a total of 246 sources with 2D positions and 3D
velocities. 91 of them are observed by the NIRSPEC instrument used
with adaptive optics (NIRSPAO) on the Keck II 10m telescope within 2'
of the central Trapezium, and 172 sources are reanalyzed APOGEE
sources within 4' of the Orion Nebula Cluster (ONC) core, with
17 sources overlapping.
The NIRSPAO sources were chosen based on their inclusion in the
proper-motion catalog presented in K19 (Kim+ 2019, J/AJ/157/109).
We supplement the sample observed with an updated analysis of
172 stars observed by APOGEE within of the center of the ONC (T22;
Theissen+ 2022, J/ApJ/926/141).
To observe our 91 targets, we utilized NIRSPEC in conjunction with the
Keck II facility laser guide star (LGS) AO system. The observations
were conducted between 2015 to 2022. The exposures with NIRSPAO
utilize the 0.041"2.26" slit in the NIRSPEC-7 filter and the upgraded
Kband-new filter before and after the upgrade, covering the wavelength
of 1.839-2.630 and 1.907-2.554, respectively.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 30 92 Log of NIRSPEC with AO system (NIRSPAO) observations
table3.dat 325 235 NIRSPAO forward-modeling results
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See also:
III/284 : APOGEE-2 data from DR16 (Johnsson+, 2020)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
I/357 : Gaia DR3 Part 3. Non-single stars (Gaia Collaboration, 2022)
J/AJ/113/1733 : Orion Nebula Cluster population (Hillenbrand 1997)
J/ApJ/676/1109 : Velocities of stars in Orion Nebula Cluster (Furesz+, 2008)
J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)
J/ApJ/697/1103 : Kinematics of Orion Nebula Cluster (Tobin+, 2009)
J/ApJ/723/684 : NIRSPEC ultracool dwarf radial velocity survey (Blake+, 2010)
J/ApJS/190/1 : A survey of stellar families (Raghavan+, 2010)
J/ApJ/753/149 : YSOVAR: 6 EBs in Orion (Morales-Calderon+, 2012)
J/ApJS/207/10 : HST Treasury Program on the ONC (Robberto+, 2013)
J/A+A/564/A125 : AGN Torus model comparison of AGN in the CDFS (Buchner+, 2014)
J/AJ/147/87 : From binaries to multiples. II. Stat. (Tokovinin, 2014)
J/ApJ/799/136 : IN-SYNC. II. Candidate young stars in NGC 1333 (Foster+, 2015)
J/ApJ/818/59 : IN-SYNC. IV. YSOs in Orion A (Da Rio+, 2016)
J/ApJ/821/8 : Spectroscopic binary pop. of ONC and NGC2264 (Kounkel+, 2016)
J/A+A/600/A141 : Orion A integral shaped filament image (Kainulainen+, 2017)
J/AJ/156/84 : APOGEE-2 survey of Orion Complex. II. (Kounkel+, 2018)
J/ApJ/871/46 : Hectoschelle sp. of 2MASS stars in Cep OB3b (Karnath+, 2019)
J/AJ/157/109 : Stellar proper motions in Orion Nebula Cluster (Kim+, 2019)
J/AJ/157/196 : Close companions around young stars (Kounkel+, 2019)
J/AJ/157/216 : Stellar mult. rate of M dwarfs within 25 pc (Winters+, 2019)
J/ApJS/257/45 : BDKP. V. Radial & rot. vel. of M, L, T dwarfs (Hsu+, 2021)
J/ApJ/926/141 : 3-D kinematics of Orion Nebula Cluster (Theissen+, 2022)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- --- [HC2000]
8- 10 I3 --- [HC2000] HC2000 identifier in
Hillenbrand+ 2000, J/ApJ/540/236
11 A1 --- m_[HC2000] Component letter on [HC2000]
13- 23 A11 "Y/M/D" Date Date of observation (UT)
25 I1 --- Nfr [2/6] Number of ABBA frames
27- 30 I4 s Exp [60/1200] Exposure time per frame
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- --- [HC2000]
8- 10 I3 --- [HC2000] ? Identifier in
Hillenbrand+ 2000, J/ApJ/540/236
11- 12 A2 --- m_[HC2000] Component on [HC2000]
14- 16 I3 --- [KLK2019] ? Identifier in Kim+ 2019, J/AJ/157/109
18- 35 A18 --- APOGEE ? Identifier in APOGEE-2 DR16 (III/284)
37- 55 A19 --- GaiaDR3 ? Identifier in Gaia DR3 (I/355)
57- 65 F9.6 deg RAJ2000 [83.75/83.9] Right ascension (J2000)
67- 75 F9.6 deg DEJ2000 [-5.5/-5.3] Declination (J2000)
77- 82 F6.1 K Teff [2666/6998] Effective temperature adopted
for analysis in this study (1)
84- 88 F5.1 K e_Teff [1.6/285] Uncertainty of Teff (1)
90- 94 F5.2 km.s-1 RVel [-3.2/50] Radial velocity adopted for
analysis in this study (1)
96- 99 F4.2 km.s-1 e_RVel [0.12/5] Uncertainty of RVel (1)
101- 105 F5.2 mas/yr pmRA [-2.5/3]? Proper motion in right ascension
adopted for analysis in this study (2)
107- 110 F4.2 mas/yr e_pmRA [0.01/2.2]? Uncertainty of pmRA (2)
112- 116 F5.2 mas/yr pmDE [-3.9/3.3]? Proper motion in declination
adopted for analysis in this study (2)
118- 121 F4.2 mas/yr e_pmDE [0.01/3]? Uncertainty of pmDE (2)
123- 128 F6.1 K Teff-AO [2666/6729]? Effective temperature derived
from NIRSPAO observation in this study
130- 134 F5.1 K e_Teff-AO [10/285]? Uncertainty of Teff-NIRSPAO
136- 140 F5.2 km.s-1 RVel-AO [-3.2/50]? Radial velocity derived from
NIRSPAO observation in this study
142- 145 F4.2 km.s-1 e_RVel-AO [0.12/5]? Uncertainty of RVel-NIRSPAO
147- 151 F5.2 km.s-1 vsini-AO [0.5/99.7]? Projected rotational velocity
derived from NIRSPAO observation in this
study
153- 157 F5.2 km.s-1 e_vsini-AO [0.13/11]? Uncertainty of vsini-NIRSPAO
159- 164 F6.2 --- SNR-O32 [1.9/127.2]? Signal-to-noise ratio, order 32
166- 171 F6.2 --- SNR-O33 [4.7/134.4]? Signal-to-noise ratio, order 33
173- 177 F5.2 --- SNR-O35 [63.83]? Signal-to-noise ratio, order 35
179- 182 F4.2 --- Veil-O32 [0/7.35]? Veiling parameter, order 32 (3)
184- 187 F4.2 --- Veil-O33 [0/6.4]? Veiling parameter, order 33 (3)
189- 192 F4.2 --- Veil-O35 [5.48]? Veiling parameter, order 35 (3)
194- 199 F6.1 K Teff-T22 [2722/6998]? Effective temperature,
Theissen+ (2022, J/ApJ/926/141)
201- 205 F5.1 K e_Teff-T22 [1.6/253]? Uncertainty on Teff-T22
207- 211 F5.2 km.s-1 RVel-T22 [19/47.7]? Radial velocity, Theissen+
(2022, J/ApJ/926/141)
213- 216 F4.2 km.s-1 e_RVel-T22 [0.1/3.6]? Uncertainty on Rvel-T22
218- 223 F6.2 km.s-1 vsini-T22 [2.2/299.5]? Projected rotational velocity,
Theissen+ (2022, J/ApJ/926/141)
225- 229 F5.2 km.s-1 e_vsini-T22 [0.04/11]? Uncertainty on vsini-T22
231- 235 F5.2 mas/yr pmRA-K19 [-2.5/3]? Proper motion in right ascension,
Kim+ (2019 J/AJ/157/109)
237- 240 F4.2 mas/yr e_pmRA-K19 [0.01/2.2]? Uncertainty of pmRA-K19
242- 246 F5.2 mas/yr pmDE-K19 [-3.85/3.21]? Proper motion in declination,
Kim+ (2019 J/AJ/157/109)
248- 251 F4.2 mas/yr e_pmDE-K19 [0.01/2.8]? Uncertainty of pmDE-K19
253- 258 F6.3 mas/yr pmRA-DR3 [-1.9/2.9]? Proper motion in right
ascension, Gaia DR3 (I/355)
260- 264 F5.3 mas/yr e_pmRA-DR3 [0.014/0.4]? Uncertainty of pmRA-DR3
266- 271 F6.3 mas/yr pmDE-DR3 [-2.5/2.8]? Proper motion in declination,
Gaia DR3 (I/355)
273- 277 F5.3 mas/yr e_pmDE-DR3 [0.012/0.3]? Uncertainty of pmDE-DR3
279- 283 F5.3 Msun Ms-MIST [0.1/2.9]? Stellar mass based on MIST model
(2016ApJS..222....8D 2016ApJS..222....8D, 2016ApJ...823..102C 2016ApJ...823..102C)
285- 289 F5.3 Msun e_Ms-MIST [0/0.7]? Uncertainty of Ms-MIST
291- 295 F5.3 Msun Ms-BHAC15 [0.02/1.4]? Stellar mass based on BHAC15
model (2015A&A...577A..42B 2015A&A...577A..42B)
297- 301 F5.3 Msun e_Ms-BHAC15 [0/0.21]? Uncertainty of Ms-BHAC15
303- 307 F5.3 Msun Ms-Feiden [0.1/3]? Stellar mass based on Feiden model
(2016A&A...593A..99F 2016A&A...593A..99F)
309- 313 F5.3 Msun e_Ms-Feiden [0/0.7]? Uncertainty of Ms-Feiden
315- 319 F5.3 Msun Ms-Palla [0.1/2.5]? Stellar mass based on Palla
model (1999ApJ...525..772P 1999ApJ...525..772P)
321- 325 F5.3 Msun e_Ms-Palla [0/0.51]? Uncertainty of Ms-Palla
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Note (1): Adopted Teff and RVel values and uncertainties are
supplemented by APOGEE values where NIRSPAO values were not
available.
Note (2): Adopted proper motions and uncertainties are supplemented by
Gaia DR3 values where Kim+ (2019 J/AJ/157/109) values (pmRA-K19, pmDE-K19)
were not available
Note (3): Veiling parameter as defined in Theissen+ (2022, J/ApJ/926/141)
originally for order 33.
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History:
From electronic version of the journal
License: CC-BY-4.0
References:
Theissen et al. Paper I. 2022ApJ...926..141T 2022ApJ...926..141T Cat. J/ApJ/926/141
(End) Prepared by [AAS), Emmanuelle Perret [CDS] 18-May-2026