TOI-6981 b: a transiting sub-Neptune at the water ice line

@misc{scott2026toi6981,
  title = {{TOI-6981 b: a transiting sub-Neptune at the water ice line}},
  author = {Madison G. Scott and Amaury H. M. J Triaud and Emily K. Pass and Aleyna Adamson and Karen A. Collins and Khalid Barkaoui and Allyson Bieryla and Adam J. Burgasser and Mark E. Everett and Steve B. Howell and David W. Latham and Benjamin V. Rackham and Boris S. Safonov and Miquel Serra-Ricart and Abderahmane Soubkiou and Georgina Dransfield and Katharine Hesse and Pipa Fernandez de Diego and Emma Softich and Gregor Srdoc and Mathilde Timmermans and Jeroen Audenaert and Roi Alonso and Artem Y. Burdanov and Yasmin T. Davis and Fatemeh Davoudi and Julien de Wit and Shishir Dholakia and Elsa Ducrot and Michaël Gillon and Yilen Gomez Maqueo Chew and Matthew J. Hooton and Clàudia Janó-Muñoz and Emmanuel Jehin and Akanksha Khandelwal and Thomas R. Marriott and Peter P. Pedersen and Manuel Pichardo Marcano and Francisco J. Pozuelos and Rafael Rebolo-López and Manu Stalport and Alexander Venner and Selçuk Yalçinkaya and Francis Zong Lang and Sebastián Zúñiga-Fernández},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.37597},
  eprint = {2609.37597},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.37597},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - TOI-6981 b: a transiting sub-Neptune at the water ice line
AU  - Madison G. Scott
AU  - Amaury H. M. J Triaud
AU  - Emily K. Pass
AU  - Aleyna Adamson
AU  - Karen A. Collins
AU  - Khalid Barkaoui
AU  - Allyson Bieryla
AU  - Adam J. Burgasser
AU  - Mark E. Everett
AU  - Steve B. Howell
AU  - David W. Latham
AU  - Benjamin V. Rackham
AU  - Boris S. Safonov
AU  - Miquel Serra-Ricart
AU  - Abderahmane Soubkiou
AU  - Georgina Dransfield
AU  - Katharine Hesse
AU  - Pipa Fernandez de Diego
AU  - Emma Softich
AU  - Gregor Srdoc
AU  - Mathilde Timmermans
AU  - Jeroen Audenaert
AU  - Roi Alonso
AU  - Artem Y. Burdanov
AU  - Yasmin T. Davis
AU  - Fatemeh Davoudi
AU  - Julien de Wit
AU  - Shishir Dholakia
AU  - Elsa Ducrot
AU  - Michaël Gillon
AU  - Yilen Gomez Maqueo Chew
AU  - Matthew J. Hooton
AU  - Clàudia Janó-Muñoz
AU  - Emmanuel Jehin
AU  - Akanksha Khandelwal
AU  - Thomas R. Marriott
AU  - Peter P. Pedersen
AU  - Manuel Pichardo Marcano
AU  - Francisco J. Pozuelos
AU  - Rafael Rebolo-López
AU  - Manu Stalport
AU  - Alexander Venner
AU  - Selçuk Yalçinkaya
AU  - Francis Zong Lang
AU  - Sebastián Zúñiga-Fernández
PY  - 2026
DA  - 2026/09/29
PB  - arXiv
DO  - 10.48550/arxiv.2609.37597
UR  - https://arxiv.org/abs/2609.37597
AB  - We present TOI-6981 b, a cold (Teq= 170.0 +/-4.5 K, assuming an Earth-like albedo) sub-Neptune (Rb=2.40+/-0.10 R_oplus) on a 60.8 day orbit around around its M4-type host star (R*=0.304 +/- 0.012 R_odot, M*=0.296 +/- 0.026 M_odot, Teff = 3215+/-58K), part of the SPECULOOS TEMPOS program. We validate the planetary nature of TOI-6981 b using ground-based follow-up photometry, statistical validation and high-resolution spectroscopy. At such cold temperatures, TOI-6981 b sits roughly at the location of the water ice line (approx 170 K). Given its orbital period and high transmission spectroscopy metric (TSM=51 +/- 9), it is one of the only planets in the sparsely populated cold planet regime amenable for atmospheric studies with JWST. Therefore, TOI-6981 b could. possibly become a crucial benchmark in cold chemistry studies, tests of Hycean world hypotheses, and drawling parallels to the Solar System's ice giants. Additionally, given its current orbit, it may provide insight into planetary formation and migration at or beyond the water ice line.
ER  -