NGTS clusters survey - VII. An Enigmatic Short-Period Circumsecondary Disk Candidate in Orion

@misc{mallaghan2026ngts,
  title = {{NGTS clusters survey - VII. An Enigmatic Short-Period Circumsecondary Disk Candidate in Orion}},
  author = {Niamh Mallaghan and Ernst J. W. de Mooij and Christopher A. Watson and Edward Gillen and Matthew Kenworthy and Louise D. Nielsen and David R. Anderson and Matthew P. Battley and Edward M. Bryant and Matthew R. Burleigh and Benjamin M. J. Cadell and Sarah L. Casewell and Alexander Chaushev and V. S. Dhillon and Elsa Ducrot and Jorge Fernandez Fernandez and Samuel Gill and Michael Gillon and Michael R. Goad and Faith Hawthorn and Katlyn L. Hobbs and James McCormac and Maximiliano Moyano and Catriona A. Murray and Toby Rodel and Suman Saha and Ramotholo R. Sefako and John Southworth and Mathilde Timmermans and Amaury H. M. J. Triaud and Jose Vines and Richard G. West and Peter J. Wheatley and Tafadzwa Zivave},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.26447},
  eprint = {2609.26447},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.26447},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - NGTS clusters survey - VII. An Enigmatic Short-Period Circumsecondary Disk Candidate in Orion
AU  - Niamh Mallaghan
AU  - Ernst J. W. de Mooij
AU  - Christopher A. Watson
AU  - Edward Gillen
AU  - Matthew Kenworthy
AU  - Louise D. Nielsen
AU  - David R. Anderson
AU  - Matthew P. Battley
AU  - Edward M. Bryant
AU  - Matthew R. Burleigh
AU  - Benjamin M. J. Cadell
AU  - Sarah L. Casewell
AU  - Alexander Chaushev
AU  - V. S. Dhillon
AU  - Elsa Ducrot
AU  - Jorge Fernandez Fernandez
AU  - Samuel Gill
AU  - Michael Gillon
AU  - Michael R. Goad
AU  - Faith Hawthorn
AU  - Katlyn L. Hobbs
AU  - James McCormac
AU  - Maximiliano Moyano
AU  - Catriona A. Murray
AU  - Toby Rodel
AU  - Suman Saha
AU  - Ramotholo R. Sefako
AU  - John Southworth
AU  - Mathilde Timmermans
AU  - Amaury H. M. J. Triaud
AU  - Jose Vines
AU  - Richard G. West
AU  - Peter J. Wheatley
AU  - Tafadzwa Zivave
PY  - 2026
DA  - 2026/09/22
PB  - arXiv
DO  - 10.48550/arxiv.2609.26447
UR  - https://arxiv.org/abs/2609.26447
AB  - Young stellar systems provide key insights into the processes governing star/planet formation, often exhibiting complex and evolving photometric variability. In this paper, we present an analysis of the object around NOI 105872, observed by the Next Generation Transit Survey (NGTS) to eclipse a young (4.1±0.4 Myr) M-type star in the Orion Nebula Cluster. The system displays deep, asymmetric eclipses with a period of ∼0.69 days, alongside variability in morphology. We combine photometric observations spanning approximately a decade from multiple ground- and space-based facilities to investigate the nature of this system. We explore a range of physical scenarios to reproduce the eclipse profiles and their evolution. After analysis, our preferred explanation is a circumsecondary disk surrounding a companion in orbit around the M-type primary. We adopt a six-parameter disk model and fit the eclipse profiles independently to each dataset. The best-fitting solution yields a disk radius of ∼ 0.005 au or 0.98 R_*, with broadly consistent orientations across epochs, but with variations that may be attributed to disk precession or intrinsic stellar variability. Constraints from the Hill radius imply a companion mass consistent with a very low-mass stellar companion. These results establish NOI 105872 as a candidate for a circumsecondary disk system in a young stellar environment. Continued photometric monitoring and spectroscopic follow-up will be essential to confirm this interpretation. If confirmed, systems such as NOI 105872 provide valuable benchmarks for understanding disk dynamics, companion formation, and the origin of complex eclipse phenomena in young stars.
ER  -