WISE J2354+0240

WISE J2354+0240 (WISE J235402.77+024015.0, WISE 2354+0240) is a brown dwarf or free-floating planetary-mass object. It is a Y-dwarf, meaning it is one of the coldest directly imaged astronomical objects.^[1]

WISE J2354+0240

WISE J2354+0240 with NIRCam
Observation data Epoch J2000      Equinox J2000
Constellation	Pisces
Right ascension	23h 54m 02.42s
Declination	+02° 40′ 18.54″
Characteristics
Evolutionary stage	brown dwarf or planetary-mass object
Spectral type	Y1[1]
Astrometry
Proper motion (μ)	RA: 503.5 ±2.3 mas/yr[1] Dec.: -399.5 ±2.2 mas/yr[1]
Parallax (π)	130.6 ± 3.3 mas[1]
Distance	25.0 ± 0.6 ly (7.7 ± 0.2 pc)
Details
Mass	11 ±3[2] MJup
Radius	0.101[3][a] R☉
Luminosity (bolometric)	10−6.800 ±0.023[3] L☉
Surface gravity (log g)	4.0−5.0[1] cgs
Temperature	362+10 −12[3] K
Age	>1.5[1] Gyr
Other designations
WISEA J235402.79+024014.1, CNS5 5897, WISE J235402.77+024015.0
Database references
SIMBAD	data

It was discovered in 2015, using the Wide-field Infrared Survey Explorer and spectroscopy from the Hubble Space Telescope. The authors find that the J-band peak in the spectrum is narrower than the Y0 standard and therefore assigned a spectral type of Y1, with an estimated temperature of 300−400 Kelvin. The age was estimated to be at least 1.5 billion years.^[1] Parallax measurement places this object at 7.7 parsec from the solar system.^[4]

Near-infrared photometry was later obtained with Hubble and a temperature of 335 ±11 K and a mass of 11 ±3 M_J was estimated.^[2] WISE 2354+0240 was observed with the JWST and the temperature was estimated to be 362+10
−12 K. The object is not described in detail in this work. The authors however mention that they see a number of absorption features in their sample, including water vapor, methane, ammonia, carbon monoxide and carbon dioxide. They note that none of their objects show absorption due to phosphine, which is predicted to occur in these objects.^[3]

See also

• List of Y-dwarfs

• WISE J0825+2805 another Y-dwarf discovered by Schneider et al. 2015

Notes

1. Calculated using temperature and luminosity

References

1. Schneider, Adam C.; Cushing, Michael C.; Kirkpatrick, J. Davy; Gelino, Christopher R.; Mace, Gregory N.; Wright, Edward L.; Eisenhardt, Peter R.; Skrutskie, M. F.; Griffith, Roger L.; Marsh, Kenneth A. (2015-05-01). "Hubble Space Telescope Spectroscopy of Brown Dwarfs Discovered with the Wide-field Infrared Survey Explorer". The Astrophysical Journal. 804 (2): 92. arXiv:1502.05365. Bibcode:2015ApJ...804...92S. doi:10.1088/0004-637X/804/2/92. ISSN 0004-637X.
2. Fontanive, Clémence; Bedin, Luigi R.; De Furio, Matthew; Biller, Beth; Anderson, Jay; Bonavita, Mariangela; Allers, Katelyn; Pantoja, Blake (2023-12-01). "An HST survey of 33 T8 to Y1 brown dwarfs: NIR photometry and multiplicity of the coldest isolated objects". Monthly Notices of the Royal Astronomical Society. 526 (2): 1783–1798. arXiv:2309.09923. Bibcode:2023MNRAS.526.1783F. doi:10.1093/mnras/stad2870. ISSN 0035-8711.
3. Beiler, Samuel A.; Cushing, Michael C.; Kirkpatrick, J. Davy; Schneider, Adam C.; Mukherjee, Sagnick; Marley, Mark S.; Marocco, Federico; Smart, Richard L. (11 Jul 2024). "Precise Bolometric Luminosities and Effective Temperatures of 23 late-T and Y dwarfs Obtained with JWST". arXiv:2407.08518 [astro-ph.SR].
4. Kirkpatrick, J. Davy; Gelino, Christopher R.; Faherty, Jacqueline K.; Meisner, Aaron M.; Caselden, Dan; Schneider, Adam C.; Marocco, Federico; Cayago, Alfred J.; Smart, R. L.; Eisenhardt, Peter R.; Kuchner, Marc J.; Wright, Edward L.; Cushing, Michael C.; Allers, Katelyn N.; Bardalez Gagliuffi, Daniella C. (2021-03-01). "The Field Substellar Mass Function Based on the Full-sky 20 pc Census of 525 L, T, and Y Dwarfs". The Astrophysical Journal Supplement Series. 253 (1): 7. arXiv:2011.11616. Bibcode:2021ApJS..253....7K. doi:10.3847/1538-4365/abd107. ISSN 0067-0049.