Multiplicity and clustering in Taurus star-forming region. I. Unexpected ultra-wide pairs of high-order multiplicity in Taurus

Abstract

We collected the multiplicity data of stars in Taurus to build an up-to-date stellar/multiplicity catalog. After a general study of nearest-neighbor statistics on spatial random distribution, we introduce the one-point correlation $\Psi$ function to complement the pair correlation function and define the spatial regimes departing from randomness in Taurus. We then perform a set of statistical studies to characterize the binary regime that prevails in Taurus. The $\Psi$ function in Taurus has a scale-free trend with a similar exponent as the correlation function at small scale. It extends almost 3 decades up to $\sim 60$ kAU showing a potential extended wide binary regime. This was hidden in the correlation function due to the clustering pattern blending. Distinguishing two stellar populations, single stars versus multiple systems (separation $\le 1$ kAU), within Class II/III stars observed at high angular resolution, we highlight a major spatial neighborhood difference between the two populations using nearest-neighbor statistics. The multiple systems are three times more likely to have a distant companion within 10 kAU when compared to single stars. We show that this is due to the presence of most probable physical ultra-wide pairs. These UWPs are biased towards high multiplicity and higher-stellar-mass components at shorter separations. The multiplicity fraction per ultra-wide pair with separation less than 10 kAU may be as high as 83.5 $\pm$ 19.6\%. We suggest that these young pre-main sequence UWPs may be pristine imprints of their spatial configuration at birth resulting from a cascade fragmentation scenario of the natal molecular core. They could be the older counterparts, at least for those separated by less than 10 kAU, to the $\le$ 0.5 Myr prestellar cores/Class 0 multiple objects observed at radio/mm wavelengths.

References in corpus (24)

• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• An Optical Spectroscopic Study of T Tauri Stars. I. Photospheric Properties
• The Nature of the Dense Core Population in the Pipe Nebula: Thermal Cores Under Pressure
• The Disk Around CoKu Tau/4: Circumbinary, not Transitional
• Chains of dense cores in the Taurus L1495/B213 complex
• New Distant Companions to Known Nearby Stars. II. Faint companions of Hipparcos stars and the frequency of wide binary systems
• A VLT/NACO Survey for Triple and Quadruple Systems among Visual Pre-Main Sequence Binaries
• The Evolution of the Multiplicity of Embedded Protostars I: Sample Properties and Binary Detections
• Multiple protostellar systems. II. A high resolution near-infrared imaging survey in nearby star-forming regions
• Spatial Distributions of Young Stars
• The Spatial Distribution of Brown Dwarfs in Taurus
• A Survey for New Members of the Taurus Star-Forming Region with the Sloan Digital Sky Survey
• The evolution of stars in the Taurus-Auriga T association
• Multiplicity and Optical Excess Across the Substellar Boundary in Taurus
• The relationship between the prestellar core mass function and the stellar initial mass function
• Sub-stellar Companions and Stellar Multiplicity in the Taurus Star-Forming Region
• GG Tau: the fifth element
• A Search for Companions to Brown Dwarfs in the Taurus and Chamaeleon Star Forming Regions
• Discovery of a Circumbinary Disk around Herbig Ae/Be system v892 Tau
• Internal and relative motions of the Taurus and Ophiuchus star-forming regions
• Tidal foces as a regulator of star formation in Taurus
• On the gravitational content of molecular clouds and their cores
• The stellar correlation function from SDSS - A statistical search for wide binary stars
• Open clusters and associations in the Gaia era

Cited by in corpus (2)

• The Origin of the Stellar Mass Distribution and Multiplicity
• 2MASS J15491331-3539118: a new low-mass wide companion of the GQ Lup system