WISE 0647−6232
WISE 0647−6232 (full designation is WISE J064723.23−623235.5) is a nearby brown dwarf of spectral type Y1 ± 0.5, located in constellation Pictor at approximately 28 light-years from Earth. It is one of the two or three reddest and one of the four latest-type brown dwarfs known.[1]
| Observation data Epoch J2000[1] Equinox J2000[1] | |
|---|---|
| Constellation | Pictor |
| Right ascension | 06h 47m 23.2270s[1] |
| Declination | −62° 32′ 39.744″[1] |
| Characteristics | |
| Spectral type | Y1 ± 0.5[1] |
| Apparent magnitude (J (LCO filter system)) | >23.0 ± 0.1[1] |
| Apparent magnitude (J (MKO filter system)) | 22.65 ± 0.27[1] |
| Apparent magnitude (H (LCO filter system)) | >21.7 ± 0.3[1] |
| Apparent magnitude (H (MKO filter system)) | 23.40 ± 0.29[1] |
| Apparent magnitude (W1) | >19.09[1] |
| Apparent magnitude (W2) | 15.32 ± 0.08[1] |
| Apparent magnitude (W3) | >13.49[1] |
| Apparent magnitude (W4) | >9.66[1] |
| Astrometry | |
| Proper motion (μ) | RA: 7 ± 12[1] mas/yr Dec.: 387 ± 22[1] mas/yr |
| Parallax (π) | 115 ± 12[1] mas |
| Distance | approx. 28 ly (approx. 8.7 pc) |
| Details | |
| Mass | 5–30[1] MJup |
| Surface gravity (log g) | 3.0–5.0[1] cgs |
| Temperature | 350–400[1] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
History of observations
Discovery
WISE 0647−6232 was discovered by Kirkpatrick et al. from data, collected by 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. The discovery was announced in 2013.
WISE 0647−6232 was first imaged by WISE on 9 May 2010. On 17 June 2010 after preliminary data processing it was uncovered as a very cold brown dwarf candidate.
Then were carried out follow-up observations:
- using the Infrared Array Camera (IRAC) on Spitzer Space Telescope, starting from MJD 55458.43 (possibly 16 September 2010);
- J- and H-band images using Persson's Auxiliary Nasmyth Infrared Camera (PANIC) at the 6.5-meter Magellan Baade telescope at the Las Campanas Observatory, Chile, on 25 November 2010;
- with the FourStar infrared camera also at Magellan Baade telescope on 15 January 2013 and 23 March 2013;
- with the Folded-port InfraRed Echellette (FIRE) spectrograph also at Magellan Baade telescope on 24 March 2013;
- using the Wide Field Camera 3 (WFC3) on Hubble Space Telescope on 13–14 May 2013, and pre-image was obtained on 11 February 2013.
On 25 August 2013 Kirkpatrick et al. submitted the discovery paper to The Astrophysical Journal.
WISE 0647−6232 became the 17th Y-type dwarf discovered and confirmed spectroscopically (in addition, WD 0806-661B is also almost certainly a Y-type dwarf, which was found before discovery of WISE 0647−6232, but it still lacks a spectroscopical confirmation).[1]
Distance
Preliminary parallax of WISE 0647−6232, measured using WISE, HST and Spitzer and published in its discovery paper is 115 ± 12 mas, corresponding to a distance 8.7+1.0
−0.8 pc, or 28.4+3.3
−2.7ly.[1]
| Source | Parallax, mas | Distance, pc | Distance, ly | Ref. |
|---|---|---|---|---|
| Kirkpatrick et al. (2013) | 115 ± 12 | 8.7+1.0 −0.8 | 28.4+3.3 −2.7 | [1] |
The best estimate is marked in bold.
Properties
WISE 0647−6232 has effective temperature 350–400 K and mass ∼5–30 MJup, but its kinematics suggests that it may belong to Columba moving group (probability of this is 92.9%, and corresponding radial velocity should be ∼22 km/s), if it is so, it may be very young (~30 Myr) and have even lower mass (<2 MJup). Its blue J − H color may suggest that its surface gravity may be relatively low (log(g)=3.0–3.5, where g is in units of cm·s−2). For ages from 0.1 to more than 10 Gyr log(g)=4.0–5.0.[1]
The only redder than WISE 0647−6232 confirmed Y dwarf is WISE 1828+2650. WD 0806-661B may also be redder than WISE 0647−6232.
The other three latest-type Y dwarfs are: WISE 0350−5658 (Y1), WISE 0535−7500 (≥Y1)[2] and WISE 1828+2650 (≥Y2).[1]
References
- Kirkpatrick, J. Davy; Cushing, Michael C.; Gelino, Christopher R.; Beichman, Charles A.; Tinney, C. G.; Faherty, Jacqueline K.; Schneider, Adam; Mace, Gregory N. (2013). "Discovery of the Y1 Dwarf WISE J064723.23-623235.5". The Astrophysical Journal. 776: 128. arXiv:1308.5372v1. Bibcode:2013ApJ...776..128K. doi:10.1088/0004-637X/776/2/128.
- 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.