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WISEPA J173835.53+273258.9

WISEPA J173835.53+273258.9 (abbreviated WISE 1738+2732) is a brown dwarfofspectral class Y0,^[1][2] located in the constellation Hercules at 24.9 light-years from Earth.^[3]

History of observations[edit]

Discovery[edit]

WISE 1738+2732 was discovered in 2011 from data, collected by the Wide-field Infrared Survey Explorer (WISE) Earth-orbiting satellite — NASA infrared-wavelength 40 cm (16 in) space telescope, which mission lasted from December 2009 to February 2011. WISE 1738+2732 has two discovery papers: Kirkpatrick et al. (2011) and Cushing et al. (2011), however, basically with the same authors and published nearly simultaneously.^[1][4]

• Kirkpatrick et al. presented discovery of 98 new found by WISE brown dwarf systems with components of spectral types M, L, T and Y, among which also was WISE 1738+2732.^{[1][~ 1]}
• Cushing et al. presented discovery of seven brown dwarfs — one of T9.5 type, and six of Y-type — first members of the Y spectral class, ever discovered and spectroscopically confirmed, including "archetypal member" of the Y spectral class WISE 1828+2650, and WISE 1738+2732.^[4] These seven objects are also the faintest seven of 98 brown dwarfs, presented in Kirkpatrick et al. (2011).^[1]

Distance[edit]

Currently the most accurate distance estimate of WISE 1738+2732 is a trigonometric parallax, published in 2021 by Kirkpatrick et al.: 130.9±2.1 mas, corresponding to a distance of 7.6±0.1 pc, or 24.9±0.4 ly.^[3]

Space motion[edit]

WISE 1738+2732 has a proper motion of 481.2±1.1 milliarcseconds per year.^[3]

Properties[edit]

The object's temperature estimate is 350 (350–400) K.^[4] Its spectrum is similar with spectrum of another Y-dwarf WISE 1405+5534.

Disequilibrium chemistry models suggest that this Y-dwarf has a low mass of about 3-9 M_Jup, making it a possible isolated planetary-mass object, together with WISE 0350-5658.^[5] A more recent paper finds a mass of 5-14 M_Jup.^[6]

WISE 1405 is variable in the near- and mid-infrared. The observations were made with the Gemini Observatory and Spitzer. It has a rotation period of 6.0±0.1 hours and the amplitude is 3% for 4.5 μm and may be as high as 5-30% in the near-infrared. This dependence on wavelength can be reproduced with patchy cloud layers made up of potassium chloride (KCl) and sodium sulfide (Na₂S).^[7]

See also[edit]

• List of star systems within 20–25 light-years
• List of Y-dwarfs
• WISE 0148-7202 (T9.5)
• WISE 0410+1502 (Y0)
• WISE 1405+5534 (Y0 (pec?))
• WISE 1541-2250 (Y0.5)
• WISE 1828+2650 (≥Y2)
• WISE 2056+1459 (Y0)

Notes[edit]

References[edit]

• Marsh, Kenneth A.; Wright, Edward L.; Kirkpatrick, J. Davy; Gelino, Christopher R.; Cushing, Michael C.; Griffith, Roger L.; Skrutskie, Michael F.; Eisenhardt, Peter R. (2013). "Parallaxes and Proper Motions of Ultracool Brown Dwarfs of Spectral Types Y and Late T". The Astrophysical Journal. 762 (2): 119. arXiv:1211.6977. Bibcode:2013ApJ...762..119M. doi:10.1088/0004-637X/762/2/119. S2CID 42923100.