J/ApJ/899/128 Validated & new members of NGC 7000/IC 5070 Complex (Kuhn+, 2020)
The Formation of a Stellar Association in the NGC 7000/IC 5070 Complex: Results
from Kinematic Analysis of Stars and Gas.
Kuhn M.A., Hillenbrand L.A., Carpenter J.M., Avelar Menendez A.R.
<Astrophys. J., 899, 128 (2020)>
=2020ApJ...899..128K 2020ApJ...899..128K
ADC_Keywords: Star Forming Region; YSOs; Spectra, millimetric/submm;
Photometry, infrared; Optical
Keywords: Star formation ; Star forming regions ; Stellar associations ;
Stellar kinematics ; Space astrometry ; Young stellar objects ;
T Tauri stars ; Giant molecular clouds ; Millimeter astronomy ;
OB stars
Abstract:
We examine the clustering and kinematics of young stellar objects
(YSOs) in the North America/Pelican Nebulae, as revealed by Gaia
astrometry, in relation to the structure and motions of the molecular
gas, as indicated in molecular-line maps. The Gaia parallaxes and
proper motions allow us to significantly refine previously published
lists of YSOs, demonstrating that many of the objects previously
thought to form a distributed population turn out to be nonmembers.
The members are subdivided into at least six spatio-kinematic groups,
each of which is associated with its own molecular cloud component or
components. Three of the groups are expanding, with velocity gradients
of 0.3-0.5km/s/pc, up to maximum velocities of ∼8km/s away from the
groups' centers. The two known O-type stars associated with the
region, 2MASS J20555125+4352246 and HD 199579, are rapidly escaping
one of these groups, following the same position-velocity relation as
the low-mass stars. We calculate that a combination of gas expulsion
and tidal forces from the clumpy distribution of molecular gas could
impart the observed velocity gradients within the groups. However, on
a global scale, the relative motions of the groups do not appear
either divergent or convergent. The velocity dispersion of the whole
system is consistent with the kinetic energy gained due to
gravitational collapse of the complex. Most of the stellar population
has ages similar to the freefall timescales for the natal clouds.
Thus, we suggest the nearly freefall collapse of a turbulent molecular
cloud as the most likely scenario for star formation in this complex.
Description:
We obtained stellar astrometry from Gaia's second data release.
We obtained 13COJ=1-0 (110.201354GHz) observations of the
molecular clouds associated with the NAP region using the Five College
Radio Astronomy Observatory (FCRAO) 14m telescope in 1998 June. The
observations were obtained with the Second Quabbin Optical Imaging
Array (SEQUOIA). The spectrometer contained 512 channels with a
bandwidth of 40MHz, which provided a channel spacing of 0.21km/s. The
FCRAO telescope has an FWHM angular resolution of 47" at the
13COJ=1-0 frequency.
Finally, high-dispersion optical spectra of the Bajamar Star were
taken on 2019 December 1 and 2020 January 3 (UT). These data were
taken with the Keck I telescope and High Resolution Echelle
Spectrometer (HIRES) and cover ∼4800-9200Å at R∼37000.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 45 395 Astrometrically validated members
table7.dat 51 1187 New member candidates from Gaia
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See also:
III/274 : Galactic O-Star Spectroscopic Survey (GOSSS) (Sota+, 2014)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
VIII/64 : Westerhout's Catalogue of 82 Discrete Sources (Westerhout, 1958)
VII/7 : Lynds' Catalogue of Dark Nebulae (LDN) (Lynds 1962)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/AJ/123/2597 : Hα stars and HH objects near BRCs (Ogura+, 2002)
J/BaltA/15/483 : Vilnius photometry in LDN 935 (Laugalys+, 2006)
J/ApJ/654/316 : X-ray sources in IC 1396N (Getman+, 2007)
J/AJ/136/2413 : Galactic midplane Spitzer red sources (Robitaille+, 2008)
J/MNRAS/384/1277 : Hα emission line sources from IPHAS (Witham+, 2008)
J/ApJ/697/787 : The NAN complex. I. IRAC observations (Guieu+, 2009)
J/ApJ/697/1103 : Kinematics of Orion Nebula Cluster (Tobin+, 2009)
J/ApJS/193/25 : The NAN complex. II. MIPS observations (Rebull+, 2011)
J/MNRAS/426/2917 : X-rays sources in Trumpler 37 (Getman+, 2012)
J/ApJS/209/32 : Probable young stars in the MYStIX project (Broos+, 2013)
J/AJ/147/46 : Properties of clumps in the NAN complex (Zhang+, 2014)
J/A+A/589/A113 : PMS stars in h Per (Argiroffi+, 2016)
J/ApJS/224/4 : GOSSS III 142 additional O-type systems (Maiz Apellaniz+,2016)
J/MNRAS/460/2593 : Cygnus OB2 DANCe: Proper motion study (Wright+, 2016)
J/A+A/602/A115 : X-ray survey of NGC7000/IC5070 (Damiani+, 2017)
J/A+A/605/A85 : NGC 3293 Chandra X-ray observation (Preibisch+, 2017)
J/A+A/619/A106 : 3D shape of Orion A from Gaia DR2 (Grossschedl+, 2018)
J/AJ/156/84 : APOGEE-2 survey of Orion Complex. II. (Kounkel+, 2018)
J/AJ/156/271 : The stellar membership of the Taurus SFR (Luhman, 2018)
J/MNRAS/477/5191 : Ggalactic young stellar cluster lifetimes (Richert+, 2018)
J/A+A/626/A80 : Census Rho Oph candidate members from Gaia DR2 (Canovas+,2019)
J/A+A/630/A137 : Structure and kinematics of the Taurus region (Galli+, 2019)
J/ApJ/878/111 : Members Serpens Molecular Cloud with Gaia DR2 (Herczeg+, 2019)
J/ApJ/870/32 : Kinematics in young star clusters & associations (Kuhn+, 2019)
J/A+A/624/A66 : Massive runaway and walkaway stars models (Renzo+, 2019)
J/MNRAS/486/2477 : Catalogue of members of NGC 6530 (Wright+, 2019)
J/MNRAS/493/2339 : Internal motions in OB-associations (Melnik+, 2020)
J/A+A/633/A51 : Distances to molecular clouds in SFR (Zucker+, 2020)
http://gea.esac.esa.int/archive : Gaia archives
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- Gaia Gaia DR2 source designation
21- 22 I2 h RAh [20/21] Hour of Right Ascension (ICRS) (G1)
24- 25 I2 min RAm Minute of Right Ascension (ICRS) (G1)
27- 31 F5.2 s RAs Second of Right Ascension (ICRS) (G1)
33- 33 A1 --- DE- [+] Sign of the Declination (ICRS)(G1)
34- 35 I2 deg DEd [42/45] Degree of Declination (ICRS) (G1)
37- 38 I2 arcmin DEm Arcminute of Declination (ICRS) (G1)
40- 43 F4.1 arcsec DEs Arcsecond of Declination (ICRS) (G1)
45- 45 A1 --- Group kinematic group assignment for each star
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- Gaia Gaia DR2 source designation
21- 22 I2 h RAh [20/21] Hour of Right Ascension (ICRS) (G1)
24- 25 I2 min RAm Minute of Right Ascension (ICRS) (G1)
27- 31 F5.2 s RAs Second of Right Ascension (ICRS) (G1)
33- 33 A1 --- DE- [+] Sign of the Declination (ICRS)(G1)
34- 35 I2 deg DEd [40/46] Degree of Declination (ICRS) (G1)
37- 38 I2 arcmin DEm Arcminute of Declination (ICRS) (G1)
40- 43 F4.1 arcsec DEs Arcsecond of Declination (ICRS) (G1)
45- 51 A7 --- Group kinematic group assignment for each star (1)
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Note (1): Groups are the same as in Table 2, with the addition of labels for
Group G and distributed stars to the final column.
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Global Note:
Note (G1) : Positions are truncated, not rounded. Full-precision Gaia astrometry
for these sources is available from the Gaia Archive,
http://gea.esac.esa.int/archive/.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 19-Oct-2021