WISEPA J173835.53+273258.9
Brown dwarf star in the constellation Hercules
From Wikipedia, the free encyclopedia
WISEPA J173835.53+273258.9 (abbreviated WISE 1738+2732) is a brown dwarf of spectral class Y0,[1][2] located in the constellation Hercules at 24.9 light-years from Earth.[7] It is the nearest celestial object in Hercules.[8]
| Observation data Epoch MJD 55451.22[1] Equinox J2000[1] | |
|---|---|
| Constellation | Hercules |
| Right ascension | 17h 38m 35.54s[1] |
| Declination | 27° 32′ 58.78″[1] |
| Characteristics | |
| Spectral type | Y0[1][2] |
| Apparent magnitude (J (MKO filter system)) | 19.47 ± 0.08[1] |
| Apparent magnitude (H (MKO filter system)) | 20.66 ± 0.38[1] |
| Astrometry | |
| Proper motion (μ) | RA: 36.08 ±0.20 mas/yr[3] Dec.: –341.46 ±0.17 mas/yr[3] |
| Parallax (π) | 133.65±0.83 mas[3] |
| Distance | 24.4 ± 0.2 ly (7.48 ± 0.05 pc) |
| Details[4] | |
| Mass | 13+11 −7 MJup |
| Radius | 1.14±0.03 RJup |
| Luminosity | 3.02+0.37 −0.27×10−7 L☉ |
| Surface gravity (log g) | 4.46+0.26 −0.34 cgs |
| Temperature | 402+12 −9 K |
| Rotation | 6.01±0.07 hours[5] |
| Age | 1–4 Gyr |
| Other designations | |
| WISEPA J173835.53+273258.9[1] WISEP J1738+2732[6] WISE J1738+2732[1] WISE 1738+2732[1] | |
| Database references | |
| SIMBAD | data |
History of observations
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][6]
- 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.[6] These seven objects are also the faintest seven of 98 brown dwarfs, presented in Kirkpatrick et al. (2011).[1]
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.[7] WISE 1738+2732 has a proper motion of 481.2±1.1 milliarcseconds per year.[7]
Properties
The object's temperature estimate is 350 (350–400) K.[6] Its spectrum is similar to the spectrum of another Y-dwarf, WISE 1405+5534.
Disequilibrium chemistry models suggest that this Y-dwarf has a low mass of about 3–9 MJup, making it a possible isolated planetary-mass object, together with WISE 0350-5658.[9] A more recent paper finds a mass of 5–14 MJup.[10]
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).[11]
See also
- 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
- These 98 brown dwarf systems are only among first, not all brown dwarf systems, discovered from data, collected by WISE: six discoveries were published earlier (however, also listed in Kirkpatrick et al. (2011)) in Mainzer et al. (2011) and Burgasser et al. (2011), and the other discoveries were published later.