 WISE bands W1-W4 showing infrared excess around W1200−7845, indicating a primordial disk. | |
| Observation data EpochJ2000.0 EquinoxJ2000.0 | |
|---|---|
| Constellation | Chamaeleon |
| Right ascension | 12h 00m 37.712s[1] |
| Declination | −78° 45′ 08.38″[1] |
| Astrometry | |
| Proper motion (μ) | RA: –41.664 [0.080][1]mas/yr Dec.: –6.050 [0.074][1]mas/yr |
| Parallax (π) | 9.8383[1]±0.0714[1] mas |
| Distance | 333.73 ± 3.13[2] ly (102.32 ± 0.96[2] pc) |
| Details | |
| Mass | 42–58[2] MJup |
| Luminosity (bolometric) | 0.078[2] L☉ |
| Temperature | T eff, BD = 2784–2850[2]K |
| Metallicity | 0.7998 Fe abundance (from GSP using BP/RP spectra)[1] |
| Age | 3.7+4.6 −1.4[2] Myr |
| Database references | |
| SIMBAD | data |
WISEA J120037.79−784508.3, also calledW1200−7845 or2MASS J12003792−7845082, is abrown dwarf with aprimordial disk 333.73 ± 3.13lightyears fromEarth in the 3.7+4.6
−1.4Myr-oldε Chamaeleontis (ε Cha)association, currently making it the closest known brown dwarf with an associatedcircumstellar disk.[2] It was discovered bycitizen scientists in 2020 volunteering for theDisk Detective project.[3]
Disk Detective's science team then cross-matched W1200−7845 with BANYAN Σ, aBayesian analysis tool used to estimate the likelihood that an object is a member of ayoungmoving group based on its position, proper motion,parallax (usingGaia DR2 data, if available) andradial velocity. The analysis revealed (with 99.8% probability) that the brown dwarf was a member of the ε Cha young moving group association.[2][3]
The brown dwarf has a mass of about 42–58MJ and has a spectral type of aboutM6.0γ. The gamma (γ) signifies the low surface gravity of the object, which is typical for young brown dwarfs. Noaccretion was detected frompaschen andbrackett spectral lines.[2]
Later observations by Kubiak et al. 2021 found a strongH-alpha emission line, which indicates strong accretion of material. Named candidate #22 in their sample, it was the strongest accreting object in their entire sample.[4]
Three possible scenarios were considered for the disk: i) Ablackbody disk (a disk with uniform temperature), ii) two blackbody disks (a disk with a gap) and iii) apower-law disk.[2]
The blackbody disk model has a temperature of 516 K (243°C; 469°F). The two-blackbodies model compromises of an inner disk with a temperature of 730 K (457°C; 854°F) and an outer disk with a temperature of 230 K (–43°C; –46°F). The best-fit model is a power-law disk with a power-law slope of α = –0.94, which is consistent with aclass II disk. The close proximity of this system to theSolar System makes this disk a good candidate to image the disk withALMA.[2]
