C/2014 UN271 (Bernardinelli-Bernstein): The Nearly Spherical Cow of Comets

  title={C/2014 UN271 (Bernardinelli-Bernstein): The Nearly Spherical Cow of Comets},
  author={Pedro H. Bernardinelli and Gary M. Bernstein and Benjamin T. Montet and Robert J. Weryk and Richard J. Wainscoat and Michel Aguena and Sahar Allam and Felipe Andrade-Oliveira and James Annis and Santiago {\'A}vila and E. Bertin and D. Brooks and David L. Burke and A. Carnero Rosell and Matias Carrasco Kind and Jorge Carretero and R. Cawthon and C. J. Conselice and M. Costanzi and L. N. da Costa and M. E. S. Pereira and Juan Carlos de Vicente and H. Thomas Diehl and S. Everett and I. Ferrero and Brenna L. Flaugher and Joshua A. Frieman and Juan Garc'ia-Bellido and Enrique Gazta{\~n}aga and David W. Gerdes and Daniel Gruen and Robert A. Gruendl and Julia Gschwend and Gaston R. Guti{\'e}rrez and Samuel R. Hinton and Devon L. Hollowood and Klaus Honscheid and D. J. James and Kyler W. Kuehn and Nikolay Kuropatkin and Ofer Lahav and Marcio A. G. Maia and Jennifer L. Marshall and Felipe Menanteau and Ramon Miquel and R. Morgan and R. L. C. Ogando and Francisco Paz-Chinch{\'o}n and A. Pieres and Andr'es A. Plazas Malag'on and Mario Rodr{\'i}guez-Monroy and A. K. Romer and Aaron Roodman and E. Sanchez and Michael S. Schubnell and S. Serrano and Ignacio Sevilla-Noarbe and M. Smith and Marcelle Soares-Santos and Eric Suchyta and Mollye E. C. Swanson and Gregory G. Tarl{\'e} and C. To and Michael Troxel and T. N. Varga and A. R. Walker and Y. Zhang},
  journal={The Astrophysical Journal Letters},
Comet C/2014 UN271 (Bernardinelli-Bernstein), incoming from the Oort cloud, is remarkable in having the brightest (and presumably largest) nucleus of any well-measured comet and having been discovered at the heliocentric distance r h ≈ 29 au, farther than any Oort cloud comet. In this work, we describe the discovery process and observations and the properties that can be inferred from images recorded until the first reports of activity in 2021 June. The orbit has i = 95°, with a perihelion of… Expand


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