J/A+A/626/A79 ONC stars masses from literature (Pavlik+, 2019)
Do star clusters form in a completely mass-segregated way?
Pavlik V., Kroupa P., Subr L.
<Astron. Astrophys. 626, A79 (2019)>
=2019A&A...626A..79P 2019A&A...626A..79P (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Populations, stellar ; Stars, masses
Keywords: methods: numerical - methods: data analysis -
galaxies: star clusters: individual: ONC - stars: formation
Abstract:
ALMA observations of the Serpens South star-forming region suggest
that stellar protoclusters may be completely mass segregated at birth.
Independent observations also suggest that embedded clusters form
segregated by mass.
As the primordial mass segregation seems to be lost over time, we aim
to study on which timescale an initially perfectly mass-segregated
star cluster becomes indistinguishable from an initially not
mass-segregated cluster. As an example, the Orion Nebula Cluster (ONC)
is also discussed.
We used N-body simulations of star clusters with various masses and
two different degrees of primordial mass segregation. We analysed
their energy redistribution through two-body relaxation to quantify
the time when the models agree in terms of mass segregation, which
sets in only dynamically in the models that are primordially not mass
segregated. A comprehensive cross-matched catalogue combining optical,
infrared, and X-ray surveys of ONC members was also compiled and made
available.
The models evolve to a similar radial distribution of high-mass stars
after the core collapse (about half a median two-body relaxation time,
trh) and become observationally indistinguishable from the point of
view of mass segregation at time tauv∼3.3trh. In the case of the
ONC, using the distribution of high-mass stars, we may not rule out
either evolutionary scenario (regardless of whether they are initially
mass segregated). When we account for extinction and elongation of the
ONC, as reported elsewhere, an initially perfectly mass-segregated
state seems to be more consistent with the observed cluster.
Description:
We performed numerical simulations of star clusters represented
by N-body models (i.e. idealised mathematical models without
gas or interstellar medium).
Table3 contains Data of the ONC used in this work.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 87 2399 Data of the ONC used in this work
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 F11.8 deg RAdeg Right Ascension J2000 (degrees)
13- 23 F11.8 deg DEdeg Declination J2000 (degrees)
25- 29 A5 --- [H97b] Simbad identifier of the data from
Hillenbrand (1997, Cat. J/AJ/113/1733)
with multiplicity index
31- 33 I3 --- [HC2000] ? Simbad identifier of the data from
Hillenbrand and Carpenter
(2000, Cat. J/ApJ/540/236)
35- 38 I4 --- MLLA ? Simbad identifier of the data from
Muench et al. (2002, Cat. J/ApJ/573/366)
40- 42 I3 --- [FDM2003]Opt ? Simbad identifier of the data from
Flaccomio et al. (2003, Cat. J/ApJ/582/382
and 2003ApJ...582..398F 2003ApJ...582..398F), optical sample
44- 46 I3 --- [FDM2003]X ? Simbad identifier of the data from
Flaccomio et al. (2003, Cat. J/ApJ/582/382
and 2003ApJ...582..398F 2003ApJ...582..398F), X-ray sample
48- 50 I3 --- [FDM2003]X2 ? Simbad identifier of the data from
Flaccomio et al. (2003, Cat. J/ApJ/582/382
and 2003ApJ...582..398F 2003ApJ...582..398F), X-ray sample (1)
52- 55 I4 --- [DRH2012] ? Simbad identifier of the data from
Da Rio et al. (2012, Cat. J/ApJS/183/261)
57- 60 I4 --- COUP ? Simbad identifier of the data from
Getman et al. (2005, J/ApJS/160/319)
62- 63 I2 --- [PMF2008] ? Simbad identifier of the data from
Prisinzano et al. (2008,
Cat. J/ApJ/677/401)
65- 69 F5.2 Msun MH97b ? Mass given in Hillenbrand (1997,
Cat. J/AJ/113/1733)
71- 75 F5.2 Msun MFDM2003 ? Mass given in Flaccomio et al. (2003,
Cat. J/ApJ/582/382 & 2003ApJ...582..398F 2003ApJ...582..398F)
77- 81 F5.3 Msun MB98 ? Mass given in Da Rio et al. (2012,
Cat. J/ApJS/183/261), from
Baraffe+ (1998, Cat. J/A+A/337/403)
83- 87 F5.3 Msun MDM98 ? Mass given in Da Rio et al. (2012,
Cat. J/ApJS/183/261), from D'Antonna and
Mazzitelli (1998,
ASP Conf. Ser., 134, 442)
--------------------------------------------------------------------------------
Note (1): Simbad identifier of an additional source from Flaccomio et al.
(Cat. J/ApJ/582/382 & 2003ApJ...582..398F 2003ApJ...582..398F), X-ray sample was cross-matched
to the optical sample.
--------------------------------------------------------------------------------
Acknowledgements:
Vaclav Pavlik, pavlik(at)sirrah.troja.mff.cuni.cz
(End) Patricia Vannier [CDS] 27-May-2019