.jpg) WISE 0458+6434 with theHubble Space Telescope, with the component A on the left and the component B being the fainter object on the right. | |
| Observation data EpochMJD 55453.42[1] EquinoxJ2000[1] | |
|---|---|
| Constellation | Camelopardalis |
| Right ascension | 04h 58m 53.93s[1] |
| Declination | +64° 34′ 52.72″[1] |
Characteristics | |
| Whole system | |
| Apparent magnitude(Y (FanCam)) | 18.34 ± 0.07[2] |
| Apparent magnitude(J (2MASS filter system)) | 17.47 ± 0.05[1] |
| Apparent magnitude(H (2MASS filter system)) | 17.41 ± 0.06[1] |
| Component A | |
| Spectral type | T8.5[3][4][5] |
| Apparent magnitude(J (MKO filter system)) | 17.50 ± 0.07[4] |
| Apparent magnitude(H (MKO filter system)) | 17.77 ± 0.11[4] |
| Component B | |
| Spectral type | T9.5[4][5] |
| Apparent magnitude(J (MKO filter system)) | 18.48 ± 0.07[4] |
| Apparent magnitude(H (MKO filter system)) | 18.79 ± 0.11[4] |
| Astrometry | |
| Proper motion (μ) | RA: 136 ± 45[6]mas/yr Dec.: 317 ± 22[6]mas/yr |
| Parallax (π) | 108.3±1.7 mas[7] |
| Distance | 30.1 ± 0.5 ly (9.2 ± 0.1 pc) |
| Orbit[7] | |
| Primary | A |
| Companion | B |
| Period (P) | 43+7 −12yr |
| Semi-major axis (a) | 5+0.3 −0.6 au |
| Eccentricity (e) | 0.18+0.09 −0.18 |
| Inclination (i) | 76.5+1.5 −2.3° |
| Details | |
| Component A | |
| Mass | 57+25 −28[7] MJup |
| Radius | 0.807+0.008 −0.007[8] RJup |
| Surface gravity (log g) | 5.0–5.5[2][~ 1] cgs |
| Temperature | 600[3][~ 2] K |
| Metallicity | 1.35+0.19 −0.15 ([Fe/H])[8] |
| Component B | |
| Mass | 14+21 −22[7] MJup |
| Radius | 0.807+0.008 −0.007[8] RJup |
| Temperature | 500[3][~ 2] K |
| Position (relative to A) | |
| Component | B |
| Epoch of observation | UT 2011 August 29 |
| Angular distance | 455.1 ± 4.2mas[4] |
| Position angle | 322.9 ± 0.4°[4] |
| Projected separation | 5 ± 0.4AU[3] |
| Other designations | |
| WISEPC J045853.90+643451.9[2] WISEPA J045853.89+643452.9[1] WISE J0458+6434[1] WISE 0458+6434[1] WISEPC J0458+64[2] | |
| Database references | |
| SIMBAD | data |
WISEPC J045853.90+643451.9 (designation is abbreviated toWISE 0458+6434) is a binary system of two (A andB) ultracoolbrown dwarfs ofspectral classes T8.5 and T9.5, respectively,[4][5] located in constellationCamelopardalis at approximately 47ly from Earth.[6]
WISE 0458+6434 A was discovered in 2010 by A. Mainzeret al. from data, collected byWide-field Infrared Survey Explorer (WISE)Earth-orbitingsatellite —NASAinfrared-wavelength 40cm (16in)space telescope, which mission lasted from December 2009 to February 2011.
In 2010 Mainzeret al. had conducted follow-up observations of WISE 0458+6434:
In early 2011 Mainzeret al. published a paper inThe Astrophysical Journal, where they presented discovery of one new found by WISEbrown dwarf — ultra-cool object WISE 0458+6434. This object became the first brown dwarf, found by WISE.[2]
Several months later, also in 2011, Kirkpatricket al. published a paper inThe Astrophysical Journal Supplement, where they presented characteristics of 104 first discovered by WISE brown dwarf systems — 98 new found systems and six systems, presented in published earlier papers (one inMainzer et al. (2011), and five inBurgasser et al. (2011)[9]), among which also was WISE 0458+6434.[1]
WISE 0458+6434 B was discovered in 2011 by Gelinoet al., when they examined for binarity nine brown dwarfs usingLaser Guide StarAdaptive Optics system (LGS-AO) onKeck II telescope onMauna Kea; seven of these nine brown dwarfs were also newfound, and two were discovered before, including WISE 0458+6434. These observations had indicated that two of these nine brown dwarfs, including WISE 0458+6434, are binary. Angular separation of WISE 0458+6434 components was 80mas.[3] Component B is also of late T-type — T9.5[4] (initially was estimated as T9).[3]
Currently the most accurate distance estimate of WISE 0458+6434 is atrigonometric parallax, measured usingSpitzer Space Telescope and published in 2013 by Trent Dupuy and Adam Kraus: 0.070 ± 0.019arcsec, corresponding to a distance 14.3+5.3
−3.0 pc, or 46.6+17.4
−9.9 ly.[6]
WISE 0458+6434 distance estimates
| Source | Parallax,mas | Distance,pc | Distance,ly | Ref. |
|---|---|---|---|---|
| Mainzeret al. (2011) (spectrophotometric) | 6–8 | 19.6–26.1 | [2] | |
| Mainzeret al. (2011) (photometric) | 9.0 ± 1.9 | 29.4 ± 6.2 | [2] | |
| Mainzeret al. (2011) (combined) | 6–10 | 19.6–32.6 | [2][10] | |
| Kirkpatricket al. (2011) (spectrophotometric, assuming a single source) | ~7.3 | ~23.8 | [1] | |
| Gelinoet al. (2011), (according to Kirkpatricket al. (2011), Appendix I.) | 12.3 ± 2.3 | 40.1 ± 7.5 | [1] | |
| Gelinoet al. (2011) | 10.5 ± 1.4 | 34.2 ± 4.6 | [3] | |
| Burgasseret al. (2012) (component A) | 10.5 ± 1.8 | 34.2 ± 5.9 | [4] | |
| Burgasseret al. (2012) (component B) | 11.2 ± 2.2 | 36.5 ± 7.2 | [4] | |
| Burgasseret al. (2012) (combined A + B) | ~11 | ~35.9 | [5] | |
| Dupuy & Kraus (2013) | 70 ± 19[~ 3] | 14.3+5.3 −3.0 | 46.6+17.4 −9.9 | [6] |
Non-trigonometric distance estimates are marked initalic. The best estimate is marked inbold.
WISE 0458+6434 has proper motion of about 347 milliarcseconds per year.[6]
WISE 0458+6434 proper motion estimates
| Source | μ, mas/yr | P. A., ° | μRA, mas/yr | μDEC, mas/yr | Ref. |
|---|---|---|---|---|---|
| Mainzeret al. (2011) | 253 | 51 | 196.8 ± 29.1 | 159.3 ± 29.1 | [2] |
| Kirkpatricket al. (2011) | 219 | 57 | 185 ± 141 | 118 ± 149 | [1] |
| Dupuy & Kraus (2013) | 347 ± 26 | 23 ± 7 | 136 ± 45 | 317 ± 22 | [6] |
The most accurate estimates are marked inbold.
The brown dwarfs' temperature estimates are 600K, or 327°C (A)[3] and 500K, or 227°C (B),[3] both cooler thanVenus.
In 2025 an analysis of theJames Webb Space Telescope spectrum was presented. The analysis found the expected moleculeswater vapor (H2O),methane (CH4) andammonia (NH3) in the spectrum of the binary. The analysis foundhydrogen cyanide (HCN) andacetylene (C2H2) in the spectrum of the binary. The detection of hydrogen cyanide is expected in highsurface gravity brown dwarfs with a high vertical mixing. The high vertical mixing would however lead to a detectable amount ofcarbon monoxide (CO), which is not detected. Acetylene is an unexpected detection. It occurs inJupiter and is claimed to be present inHD 209458 b, but in these instances it is formed viaphotochemistry under the influence ofUV-light. WISE 0458+6434 does not orbit astar and the acetylene occurs deeper in the atmosphere. Other processes could be responsible for the production of acetylene, such asaurora orlightning.[8] There is some discrpancy in the mass. The dynamical mass, determined from the orbit, finds a total mass of70+15
−24MJ.[7] A derived total mass of132+38
−28MJ from log g and radius is much higher than this dynamical mass and higher than expected from evolutionary models.[8]
According proposed by Cushinget al. in 2011T/Y transition standard,[11] WISE J0458+6434 B does not relate to Y-type. However, its spectrum has feature similar to those in the spectra of the Y0 dwarfsWISE 1405+5534 andWISE 1738+2732, which were tentatively attributed toNH3 (ammonia) absorption[4][11] — a compelling evidence for NH3 absorption.[4]
The other five earliest brown dwarf discoveries from data collected by WISE:
The other eight objects, checked for binarity byGelino et al. (2011) on Keck II:[3]
