WISE 0535−7500

WISE J053516.80−750024.9

WISE 0535-7500 Credit: NASA/ESA/CSA JWST MIRI
Observation data Epoch J2000[1]      Equinox J2000[1]
Constellation	Mensa
Right ascension	05^h 35^m 16.8^s[1]
Declination	−75° 00′ 24.9″[1]
Characteristics
Spectral type	Y1[2]
Apparent magnitude (J (MKO-NIR filter system))	>21.1[1]
Apparent magnitude (H (MKO-NIR filter system))	>21.6[1]
Astrometry
Proper motion (μ)	RA: −127±4[3] mas/yr Dec.: 13±4[3] mas/yr
Parallax (π)	70 ± 5 mas[3]
Distance	47 ± 3 ly (14 ± 1 pc)
Details
Mass	8 - 20[3] MJup
Temperature	526+16 −26[2] K
Age	3 - 8[3] Gyr
Other designations
WISE J053516.80−750024.9,[1] WISE 0535−7500[1]
Database references
SIMBAD	data

Hertzsprung-Russell diagram of all the nearest stars out to Gliese 1, as well as most brown dwarfs and some planets. WISE 0535−7500 is at bottom right

WISE J053516.80−750024.9 (designation abbreviated to WISE 0535−7500) is either a sub-brown dwarf or a free planet. It has spectral class Y1^[2] and is located in constellation Mensa. It is estimated to be 47 light-years from Earth.^[3]

In 2017, more accurate analysis found it to be a binary system made up of two substellar objects of spectral class≥Y1 in orbit less than one astronomical unit from each other.^[3]

Discovery

WISE 0535−7500 was discovered in 2012 by J. Davy Kirkpatrick et al. from data, collected by Wide-field Infrared Survey Explorer (WISE) Earth-orbiting satellite — NASA infrared-wavelength 40-centimetre (16 in) space telescope, which mission lasted from December 2009 to February 2011. In 2012 Kirkpatrick et al. published a paper in The Astrophysical Journal, where they presented the discovery of seven new found by WISE brown dwarfs of spectral type Y, among which also was WISE 0535−7500.^[1]

Distance

Trigonometric parallax of WISE 0535−7500 is 0.070 ± 0.005 arcsec, corresponding to a distance of 14 pc and 47 ly.^[3]

Y dwarf

Brown dwarfs are defined as substellar objects that have at some time in their lives burnt deuterium in their interior. The borderline between a brown dwarf and a planet is conventionally taken to be 13 times the mass of Jupiter. All brown dwarfs are either M dwarfs, L dwarfs, T dwarfs or Y dwarfs, in order of decreasing temperature. An increasing number after the letter in the spectral type also means decreasing temperature, a Y2 dwarf is cooler than a Y1 dwarf is cooler than a Y0 dwarf. Planets can also be L dwarfs, T dwarfs or Y dwarfs.^[4]

JWST observation

WISE 0535−7500 was studied with JWST by Beiler et al. in 2024 together with 22 other late-T and Y-dwarfs. WISE 0535−7500 stands out due to it having no discernable CO₂ band and an almost undetectable CO band. This could be due a low metallicity or high surface gravity. These features make this object extremely red in Spitzer colors. This object also showed stronger NH₃ absorption when compared to objects of the same temperature. Other common prominent features like H₂O and CH₄ are present in its spectrum. But like other late-T and Y-dwarfs it is missing PH₃, which is predicted to occur for these objects.^[2]

See also

• List of star systems within 45–50 light-years
• List of Y-dwarfs

References

1. Kirkpatrick, J. Davy; et al. (2012). "Further Defining Spectral Type "Y" and Exploring the Low-mass End of the Field Brown Dwarf Mass Function". The Astrophysical Journal. 753 (2). 156. arXiv:1205.2122. Bibcode:2012ApJ...753..156K. doi:10.1088/0004-637X/753/2/156. S2CID 119279752.
2. 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].
3. Leggett, S. K.; et al. (2017). "The Y-type Brown Dwarfs: Estimates of Mass and Age from New Astrometry, Homogenized Photometry, and Near-infrared Spectroscopy". The Astrophysical Journal. 842 (2). 118. arXiv:1704.03573. Bibcode:2017ApJ...842..118L. doi:10.3847/1538-4357/aa6fb5. S2CID 119249195.
4. I. Neill Reid and Stanimir A. Metchev, Chapter 5: The Brown Dwarf – Exoplanet Connection, in John W. Mason (ed.) Exoplanets: Detection, Formation, Properties, Habitability; Springer, Berlin, 2008.