# CFBDSIR J145829+101343

CFBDSIR J145829+101343 (designation abbreviated to CFBDSIR 1458+10, or CFBDSIR J1458+1013) is a binary system of two brown dwarfs of spectral classes T9 + Y0 orbiting each other, located in constellation Boötes about 104 light-years away from Earth.
The smaller companion, CFBDSIR 1458+10B, has a surface temperature of approx 370 K (≈100 °C). It used to be known as the coolest known brown dwarf until the discovery of WISE 1828+2650 in August 2011.

## Discovery

CFBDSIR 1458+10 A was discovered in 2010 by Delorme et al. from the Canada-France Brown Dwarf Survey using the facilities MegaCam and WIRCam mounted on the 3.6 m Canada-France-Hawaii Telescope, located on Mauna Kea Observatory, Hawaii. Image in z` band was taken on 2004 July 15 with MegaCam, and image in J band was taken on 2007 April 1 with WIRCam. In 2009 they made follow-up photometry, using the SOFI near infrared camera at the ESO 3.5 m New Technology Telescope (NTT) at the La Silla Observatory, Chile. In 2010 Delorme et al. published a paper in Astronomy and Astrophysics where they reported the identification of 55 T-dwarfs candidates, six of which were photometrically confirmed as T-dwarfs, including 3 ultracool brown dwarfs (later than T7 dwarfs and possible Y dwarfs), including CFBDSIR 1458+10.

### Discovery of B

CFBDSIR 1458+10 B was discovered in 2011 by Liu et al. with laser guide star (LGS) adaptive optics (AO) system of the 10 m Keck II Telescope on Mauna Kea, Hawaii, using infra-red camera NIRC2 (the observations were made on 2010 May 22 and 2010 July 8 (UT)). In 2011 Liu et al. published a paper in The Astrophysical Journal where they presented discovery of CFBDSIR 1458+10 system component B (the only discovery presented in the article). Also they presented a near-infrared (J-band) trigonometric parallax of the system, measured using WIRCam on the Canada-France-Hawaii Telescope (CFHT), Mauna Kea, in seven epochs during the 2009–2010; and spectroscopy with the X-Shooter spectrograph at the European Southern Observatory's Very Large Telescope (VLT) Unit Telescope 2 (UT2) in Chile (the observations have been performed from May 5 to July 9, 2010), that allowed to calculate the temperature (and other physical parameters) of the two brown dwarfs.

## 2012 Keck LGS-AO imaging

In 2012 CFBDSIR 1458+10 system was observed by Liu et al. with laser guide star (LGS) adaptive optics (AO) system of the 10 m Keck II Telescope on Mauna Kea, Hawaii, using infra-red camera NIRC2 (the observations were made on 2012 April 13 (UT)). In 2012 Liu et al. published a paper in The Astrophysical Journal where they presented results of observations with Keck II LGS-AO of three brown dwarf binary systems, binarity of the two of which was first presented in this paper, and binarity of the other one, CFBDSIR 1458+10, was known before.

## Distance

Trigonometric parallax of CFBDSIR 1458+10, measured under The Hawaii Infrared Parallax Program by Dupuy & Liu in 2012, is 31.3 ± 2.5 mas, corresponding to a distance 31.9$^{+2.8}$ $_{−2.4}$ pc, or 104.2$^{+9.0}$ $_{−7.7}$ ly.
CFBDSIR 1458+10 distance estimates
| Source | Parallax, mas | Distance, pc | Distance, ly |
| Delorme et al. (2010) | | ~23 | ~75 |
| Liu et al. (2011) | 43.3 ± 4.5 | 23.1 ± 2.4 | 75.3 ± 7.8 |
| Dupuy & Liu (2012) (preprint version 1) | 34.0 ± 2.6 | 29.4$^{+2.4}$ $_{−2.1}$ | 95.9$^{+7.9}$ $_{−6.7}$ |
| Dupuy & Liu (2012) | 31.3 ± 2.5 | 31.9$^{+2.8}$ $_{−2.4}$ | 104.2$^{+9.0}$ $_{−7.7}$ |
Non-trigonometric distance estimates are marked in italic. The best estimate is marked in bold.

## Space motion

CFBDSIR 1458+10 has proper motion of about 420 milliarcseconds per year.
CFBDSIR 1458+10 proper motion estimates
| Source | μ, mas/yr | P. A., ° | μ$_{RA}$, mas/yr | μ$_{DEC}$, mas/yr |
| Delorme et al. (2010) | 444 ± 16 | 157.5 ± 2.1 | 170 ± 16 | −410 ± 16 |
| Liu et al. (2011) | 432 ± 6 | 154.2 ± 0.7 | 188 | −389 |
| Dupuy & Liu (2012) (preprint version 1) | 418.1 ± 3.2 | 155.4 ± 0.4 | 174.3 ± 3.0 | −380.0 ± 3.2 |
| Dupuy & Liu (2012) | 419.6 ± 2.6 | 155.50 ± 0.28 | 174.0 ± 2.0 | −381.8 ± 2.7 |
The most accurate estimates are marked in bold.

## Physical properties

Using three models, Liu et al. calculated physical properties of CFBDSIR 1458+10 components.
From Lyon/COND models and L$_{bol}$:
| Component and assumed age | Mass, M$_{Jup}$ | T$_{eff}$, K | log g, cm/s$^2$ | P, yr |
| A (for 1 Gyr) | 12.1 ± 1.9 | 556 ± 48 | 4.45 ± 0.07 | |
| B (for 1 Gyr) | 5.8 ± 1.3 | 360 ± 40 | 4.10 ± 0.10 | 35$^{+28}$ $_{−10}$ |
| A (for 5 Gyr) | 31 ± 4 | 605 ± 55 | 5.00 ± 0.08 | |
| B (for 5 Gyr) | 14 ± 3 | 380 ± 50 | 4.58 ± 0.11 | 22$^{+18}$ $_{−6}$ |
From Burrows et al. (1997) models and L$_{bol}$):
| Component and assumed age | Mass, M$_{Jup}$ | T$_{eff}$, K | log g, cm/s$^2$ | P, yr |
| A (for 1 Gyr) | 13 ± 2 | 550 ± 50 | 4.47 ± 0.07 | |
| B (for 1 Gyr) | 6.8 ± 1.5 | 350 ± 40 | 4.14 ± 0.10 | 33$^{+27}$ $_{−7}$ |
| A (for 5 Gyr) | 36 ± 4 | 600 ± 60 | 5.06 ± 0.07 | |
| B (for 5 Gyr) | 17 ± 4 | 380 ± 50 | 4.65 ± 0.12 | 20$^{+17}$ $_{−6}$ |
From Burrows et al. (2003) models and M(J):
| Component and assumed age | Mass, M$_{Jup}$ | T$_{eff}$, K | log g, cm/s$^2$ | P, yr |
| A (for 1 Gyr) | 11.1 ± 0.7 | 479 ± 20 | 4.37 ± 0.03 | |
| B (for 1 Gyr) | 7.6 ± 0.6 | 386 ± 15 | 4.19 ± 0.04 | 34$^{+28}$ $_{−10}$ |
| A (for 5 Gyr) | >25 | >483 | >4.85 | |
| B (for 5 Gyr) | 18.8 ± 1.3 | 407 ± 15 | 4.69 ± 0.03 | <22 |
The adopted surface temperature of B is 370 ± 40 K, and adopted mass is 6-15 M$_{Jup}$.

### Luminosity

At the time of its discovery, CFBDSIR 1458+10 B was the least luminous brown dwarf known.
CFBDSIR 1458+10 bolometric luminosity estimates
| Source | L$_{bol}$/L$_⊙$ (A) | L$_{bol}$/L$_⊙$ (B) | Ref. |
| Liu et al. (2011) | 10$^{−6.02±0.14}$ ((1.1 ± 0.4) × 10$^{−6}$) | 10$^{−6.74±0.19}$ ((2.0 ± 0.9) × 10$^{−7}$) | |
| Liu et al. (2012) | 10$^{−5.72±0.13}$ | 10$^{−6.53±0.13}$ | |

## B's spectral class

In Liu et al. (2011) CFBDSIR 1458+10 B was assigned to the spectral class >T10, it was proposed that CFBDSIR 1458+10 B may be a member of the Y spectral class of brown dwarfs. In 2012 Liu et al. assigned it a spectral class Y0.

## Water clouds

Due to the low surface temperature for a brown dwarf, CFBDSIR 1458+10 B may be able to form water clouds in its upper atmosphere.