An HST survey of photometry and multiplicity of brown dwarfs and planetary-mass objects in the field of Taurus
Abstract
We present a photometric and multiplicity survey of 26 young objects with masses between 6 Mj and 37 Mj and spectral type later than M8 in the Taurus star-forming region with the Hubble Space Telescope. We search for companion candidates using two methods: a dedicated photometric technique based on the combination of colours from multi-band photometry and point spread function fitting. No companion candidates are detected beyond 30 au. With an updated membership and age identification, we determine luminosity, temperature, and mass for the 26 young objects using evolutionary models. We demonstrate that our HST observations are sensitive to companions down to masses of 1 Mj and even lower for some targets by artificial star injection tests. After survey completeness correction, we derive a binary frequency < 6.5% for this sample in the 68% confidence interval for companions with mass ratios between 0.1 and 1 and separations between 30 and 7,000 au. We find no significant difference in binary frequency among planetary-mass objects in Taurus, Upper Scorpius, and the field. These findings support that the binary frequency of planetary-mass objects is settled at young ages, probably younger than 1--10 Myr, suggesting that the formation of wide-orbit planetary-mass binaries is inefficient and the disruption of them likely occurs at a very early stage in a low density environment.
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BibTeX
@misc{liu2026survey,
title = {{An HST survey of photometry and multiplicity of brown dwarfs and planetary-mass objects in the field of Taurus}},
author = {Pengyu Liu and Beth A. Biller and Clémence Fontanive and Michele Scalco and Loïc Albert and Luigi R. Bedin and Matthew De Furio and Belinda Damian and Jessy Jose and Zhoujian Zhang and Wen-Ping Chen and Sophie Dubber and Bhavana Lalchand and Michael C. Liu},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.21566},
eprint = {2610.21566},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.21566},
}
RIS
TY - UNPB
TI - An HST survey of photometry and multiplicity of brown dwarfs and planetary-mass objects in the field of Taurus
AU - Pengyu Liu
AU - Beth A. Biller
AU - Clémence Fontanive
AU - Michele Scalco
AU - Loïc Albert
AU - Luigi R. Bedin
AU - Matthew De Furio
AU - Belinda Damian
AU - Jessy Jose
AU - Zhoujian Zhang
AU - Wen-Ping Chen
AU - Sophie Dubber
AU - Bhavana Lalchand
AU - Michael C. Liu
PY - 2026
DA - 2026/10/15
PB - arXiv
DO - 10.48550/arxiv.2610.21566
UR - https://arxiv.org/abs/2610.21566
AB - We present a photometric and multiplicity survey of 26 young objects with masses between 6 Mj and 37 Mj and spectral type later than M8 in the Taurus star-forming region with the Hubble Space Telescope. We search for companion candidates using two methods: a dedicated photometric technique based on the combination of colours from multi-band photometry and point spread function fitting. No companion candidates are detected beyond 30 au. With an updated membership and age identification, we determine luminosity, temperature, and mass for the 26 young objects using evolutionary models. We demonstrate that our HST observations are sensitive to companions down to masses of 1 Mj and even lower for some targets by artificial star injection tests. After survey completeness correction, we derive a binary frequency < 6.5% for this sample in the 68% confidence interval for companions with mass ratios between 0.1 and 1 and separations between 30 and 7,000 au. We find no significant difference in binary frequency among planetary-mass objects in Taurus, Upper Scorpius, and the field. These findings support that the binary frequency of planetary-mass objects is settled at young ages, probably younger than 1--10 Myr, suggesting that the formation of wide-orbit planetary-mass binaries is inefficient and the disruption of them likely occurs at a very early stage in a low density environment.
ER -