Universität zu Köln

Lomax, O., Whitworth, A. P., Hubber, D. A., Stamatellos, D. and Walch, S. (2015). Simulations of star formation in Ophiuchus - II. Multiplicity. Mon. Not. Roy. Astron. Soc., 447 (2). S. 1550 - 1565. OXFORD: OXFORD UNIV PRESS. ISSN 1365-2966

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Abstract

Lomax et al. have constructed an ensemble of 60 pre-stellar cores having masses, sizes, projected shapes, temperatures, and non-thermal radial velocity dispersions that match, statistically, the cores in Ophiuchus, and have simulated the evolution of these cores using smoothed particle hydrodynamics. Each core has been evolved once with no radiative feedback from stars, once with continuous radiative feedback, and once with episodic radiative feedback. Here we analyse the multiplicity statistics from these simulations. With episodic radiative feedback, (i) the multiplicity frequency is similar to 60 per cent higher than in the field; (ii) the multiplicity frequency and the mean semimajor axis both increase with primary mass; (iii) one-third of multiple systems are hierarchical systems with more than two components; (iv) in these hierarchical systems the inner pairings typically have separations of a few au and mass ratios concentrated towards unity, whereas the outer pairings have separations of order 100 au and a flatter distribution of mass ratios. The binary statistics are compatible with observations of young embedded populations, and-if wider orbits are disrupted preferentially by external perturbations-with observations of mature field populations. With no radiative feedback, the results are similar to those from simulations with episodic feedback. With continuous radiative feedback, brown dwarfs are underproduced, the number of multiple systems is too low, and the statistical properties of multiple systems are at variance with observation. This suggests that star formation in Ophiuchus may only be representative of global star formation if accretion on to protostars, and hence radiative feedback, is episodic.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Lomax, O. UNSPECIFIED UNSPECIFIED UNSPECIFIED Whitworth, A. P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Hubber, D. A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Stamatellos, D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Walch, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-407296
DOI:	10.1093/mnras/stu2530
Journal or Publication Title:	Mon. Not. Roy. Astron. Soc.
Volume:	447
Number:	2
Page Range:	S. 1550 - 1565
Date:	2015
Publisher:	OXFORD UNIV PRESS
Place of Publication:	OXFORD
ISSN:	1365-2966
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language LOW-MASS STAR; LONG-TERM EVOLUTION; INITIAL CONDITIONS; BROWN-DWARF; STATISTICAL PROPERTIES; EPISODIC ACCRETION; RADIATION FEEDBACK; MOLECULAR CORES; MAIN CLOUD; STELLAR Multiple languages Astronomy & Astrophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/40729