The Astrophysical Journal (Jan 2025)
The Diversity of Cold Worlds: A Blended-light Binary Straddling the T/Y Transition in Brown Dwarfs
- Daniella C. Bardalez Gagliuffi,
- Jacqueline K. Faherty,
- Genaro Suárez,
- Sherelyn Alejandro Merchan,
- Brianna Lacy,
- Ben Burningham,
- Klara Matuszewska,
- Rocio Kiman,
- Johanna M. Vos,
- Austin Rothermich,
- Jonathan Gagné,
- Caroline Morley,
- Melanie J. Rowland,
- Dan Caselden,
- Aaron Meisner,
- Adam C. Schneider,
- Marc J. Kuchner,
- Charles A. Beichman,
- Peter R. Eisenhardt,
- Christopher R. Gelino,
- Ehsan Gharib-Nezhad,
- Eileen C. Gonzales,
- Federico Marocco,
- Niall Whiteford,
- J. Davy Kirkpatrick
Affiliations
- Daniella C. Bardalez Gagliuffi
- ORCiD
- Department of Physics & Astronomy, Amherst College , Amherst, MA 01002, USA ; [email protected]; Department of Astrophysics , American Museum of Natural History, New York, NY, USA
- Jacqueline K. Faherty
- ORCiD
- Department of Astrophysics , American Museum of Natural History, New York, NY, USA
- Genaro Suárez
- ORCiD
- Department of Astrophysics , American Museum of Natural History, New York, NY, USA
- Sherelyn Alejandro Merchan
- ORCiD
- Department of Astrophysics , American Museum of Natural History, New York, NY, USA; Department of Physics , The Graduate Center City University of New York, New York, NY, USA
- Brianna Lacy
- ORCiD
- Department of Astronomy, University of Texas at Austin , Austin, TX, USA; Department of Astronomy and Astrophysics, University of California , Santa Cruz, CA, USA
- Ben Burningham
- ORCiD
- Department of Physics, Astronomy and Mathematics, University of Hertfordshire , Hatfield, UK
- Klara Matuszewska
- ORCiD
- Department of Physics & Astronomy, Amherst College , Amherst, MA, USA
- Rocio Kiman
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA, USA
- Johanna M. Vos
- ORCiD
- School of Physics, Trinity College Dublin, The University of Dublin , Dublin, Ireland
- Austin Rothermich
- ORCiD
- Department of Astrophysics , American Museum of Natural History, New York, NY, USA; Department of Physics , The Graduate Center City University of New York, New York, NY, USA
- Jonathan Gagné
- ORCiD
- Planétarium Rio Tinto Alcan , Montreal, Quebec, Canada; Département de Physique, Université de Montréal , Montreal, Quebec, Canada
- Caroline Morley
- ORCiD
- Department of Astronomy, University of Texas at Austin , Austin, TX, USA
- Melanie J. Rowland
- ORCiD
- Department of Astronomy, University of Texas at Austin , Austin, TX, USA
- Dan Caselden
- ORCiD
- Department of Astrophysics , American Museum of Natural History, New York, NY, USA
- Aaron Meisner
- ORCiD
- NSF’s National Optical-Infrared Astronomy Research Laboratory , Tucson, AZ, USA
- Adam C. Schneider
- ORCiD
- United States Naval Observatory , Flagstaff, AZ, USA
- Marc J. Kuchner
- ORCiD
- Exoplanets and Stellar Astrophysics Laboratory , NASA Goddard Space Flight Center, Greenbelt, MD, USA
- Charles A. Beichman
- ORCiD
- IPAC , Caltech, Pasadena, CA, USA
- Peter R. Eisenhardt
- NASA Jet Propulsion Laboratory, California Institute of Technology , Pasadena, CA, USA
- Christopher R. Gelino
- ORCiD
- IPAC , Caltech, Pasadena, CA, USA
- Ehsan Gharib-Nezhad
- ORCiD
- NASA Ames Research Center , Mountain View, CA, USA
- Eileen C. Gonzales
- ORCiD
- Department of Physics and Astronomy, San Francisco State University San Francisco , CA, USA
- Federico Marocco
- ORCiD
- IPAC , Caltech, Pasadena, CA, USA
- Niall Whiteford
- ORCiD
- Department of Astrophysics , American Museum of Natural History, New York, NY, USA
- J. Davy Kirkpatrick
- ORCiD
- IPAC , Caltech, Pasadena, CA, USA
- DOI
- https://doi.org/10.3847/1538-4357/adb61e
- Journal volume & issue
-
Vol. 984,
no. 1
p. 74
Abstract
We present the first brown dwarf spectral binary characterized with JWST: WISE J014656.66+423410.0, the coldest blended-light brown dwarf binary straddling the T/Y transition. We obtained a moderate resolution ( R ∼ 2700) G395H spectrum of this unresolved binary with JWST/NIRSpec and we fit it to late T and Y dwarf spectra from JWST/NIRSpec, and model spectra of comparable temperatures, both as individual spectra and pairs mimicking an unresolved binary system. We find that this tightly separated binary is likely composed of two unequal-brightness sources with a magnitude difference of 0.50 ± 0.08 mag in IRAC [4.5] and a secondary 1.01 ± 0.13 mag redder than the primary in [3.6]–[4.5]. Despite the large color difference between the best-fit primary and secondary, their temperature difference is only 92 ± 23 K, a feature reminiscing of the L/T transition. Carbon disequilibrium chemistry strongly shapes the mid-infrared spectra of these sources, as a complex function of the metallicity and surface gravity. While a larger library of JWST/NIRSpec spectra is needed to conclusively examine the peculiarities of blended-light sources, this spectral binary is a crucial pathfinder to both understand the spectral features of planetary-mass atmospheres and detect binarity in unresolved, moderate-resolution spectra of the coldest brown dwarfs.
Keywords
