Age dependence of planetary-mass binary frequency

Characterize how the binary frequency of planetary-mass objects varies with age, using sufficiently large and sensitive samples to determine whether young and field populations follow the same evolutionary trend.

Background

The survey compares its Taurus sample with older field late-T and Y dwarfs and with planetary-mass objects in Upper Scorpius. Although the measured frequencies appear broadly consistent, the survey contains no companion detections and consequently constrains primarily upper limits rather than precise binary fractions.

The authors state that the available sample sizes and uncertainties do not establish a conclusive age trend. Resolving this issue requires larger samples spanning multiple ages and observations capable of probing the tight separations where planetary-mass binaries may preferentially occur.

References

Therefore, with the current small sample statistics and large uncertainty of the binary frequency, we cannot draw a conclusive summary of the trend of binary frequency as a function of age, although both the field and young planetary-mass objects clearly have low binary frequencies.

— An HST survey of photometry and multiplicity of brown dwarfs and planetary-mass objects in the field of Taurus  (2610.21566 - Liu et al., 15 Oct 2026) in Section 4.2, “Binary frequency as a function of age”