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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,[1] located in constellation Boötes about 104 light-years away from Earth.[3]

CFBDSIR J145829+101343

CFBDSIR 1458+10
Observation data Epoch J2000      Equinox J2000
Constellation	Boötes
Right ascension	14h 58m 29.0s
Declination	10° 13′ 43″
Characteristics
Whole system (MKO filter system)
Apparent magnitude (Y)	20.58 ± 0.21[1]
Apparent magnitude (J)	19.67 ± 0.02[2][1]
Apparent magnitude (H)	20.06 ± 0.10[2][1]
Apparent magnitude (K)	20.50 ± 0.24[1]
Component A (MKO filter system)
Spectral type	T9[1]
Apparent magnitude (Y)	20.81 ± 0.21[1]
Apparent magnitude (J)	19.83 ± 0.02[1]
Apparent magnitude (H)	20.18 ± 0.10[1]
Apparent magnitude (K)	20.63 ± 0.24[1]
Component B (MKO filter system)
Spectral type	Y0V[1]
Apparent magnitude (Y)	22.36 ± 0.24[1]
Apparent magnitude (J)	21.85 ± 0.06[1]
Apparent magnitude (H)	22.51 ± 0.16[1]
Apparent magnitude (K)	22.83 ± 0.30[1]
Astrometry
Proper motion (μ)	RA: 174.0 ± 2.0[3] mas/yr Dec.: −381.8 ± 2.7[3] mas/yr
Parallax (π)	31.3 ± 2.5 mas[3]
Distance	104 ± 8 ly (32 ± 3 pc)
Orbit[4]
Primary	A
Companion	B
Period (P)	20+17 −6—35+28 −10 yr
Details
Component A
Mass	(11.1 ± 0.7)—(36 ± 4)[4] MJup
Radius	0.15 R☉
Luminosity (bolometric)	10−5.72 ± 0.13[1] L☉
Surface gravity (log g)	(4.37 ± 0.03)—(5.06 ± 0.07)[4] cgs
Temperature	(479 ± 20)—(605 ± 55)[4] K
Component B
Mass	6–15[4] MJup
Radius	0.13 R☉
Luminosity (bolometric)	10−6.53 ± 0.13[1] L☉
Surface gravity (log g)	(4.10 ± 0.10)—(4.69 ± 0.03)[4] cgs
Temperature	370 ± 40[4] K
Position (relative to A)
Component	B
Epoch of observation	UT 2012 April 13
Angular distance	127.2 ± 1.4 mas [1]
Position angle	318.1 ± 1.1° [1]
Observed separation (projected)	4.06 AU [1][3]
Other designations
CFBDSIR J1458+1013 CFBDS 1458 CFBDS J145829+101343 WISEPA J145829.35+101341.8[2] WISE J145829.40+101341.7[5]
Database references
SIMBAD	data
Extrasolar Planets Encyclopaedia	data

The smaller companion, CFBDSIR 1458+10B, has a surface temperature of approx 370 K (≈100 °C)[6][7], which is only about as hot as a cup of coffee. It used to be known as the coolest known brown dwarf until the discovery of WISE 1828+2650 in August 2011.[8]

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.[9][note 1]

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.[6][4]

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.[1]

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.[3]

CFBDSIR 1458+10 distance estimates

Source	Parallax, mas	Distance, pc	Distance, ly	Ref.
Delorme et al. (2010)		~23	~75	[9]
Liu et al. (2011)	43.3 ± 4.5	23.1 ± 2.4	75.3 ± 7.8	[4]
Dupuy & Liu (2012) (preprint version 1)	34.0 ± 2.6	29.4+2.4 −2.1	95.9+7.9 −6.7	[10]
Dupuy & Liu (2012)	31.3 ± 2.5	31.9+2.8 −2.4	104.2+9.0 −7.7	[3]

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.[3]

CFBDSIR 1458+10 proper motion estimates

Source	μ, mas/yr	P. A., °	μRA, mas/yr	μDEC, mas/yr	Ref.
Delorme et al. (2010)	444 ± 16	157.5 ± 2.1	170 ± 16	−410 ± 16	[9][4]
Liu et al. (2011)	432 ± 6	154.2 ± 0.7	188	−389	[4]
Dupuy & Liu (2012) (preprint version 1)	418.1 ± 3.2	155.4 ± 0.4	174.3 ± 3.0	−380.0 ± 3.2	[10]
Dupuy & Liu (2012)	419.6 ± 2.6	155.50 ± 0.28	174.0 ± 2.0	−381.8 ± 2.7	[3]

The most accurate estimates are marked in bold.

Physical properties

Using three models, Liu et al. calculated physical properties of CFBDSIR 1458+10 components.[4]

From Lyon/COND models and L_bol:

Component and assumed age	Mass, MJup	Teff, K	log g, cm/s2	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, MJup	Teff, K	log g, cm/s2	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, MJup	Teff, K	log g, cm/s2	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.[4]

Luminosity

At the time of its discovery, CFBDSIR 1458+10 B was the least luminous brown dwarf known.[4]

CFBDSIR 1458+10 bolometric luminosity estimates

Source	Lbol/L⊙ (A)	Lbol/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)	[4]
Liu et al. (2012)	10−5.72 ± 0.13	10−6.53 ± 0.13	[1]

B's spectral class

In Liu et al. (2011) CFBDSIR 1458+10 B was assigned to the spectral class >T10,[4] it was proposed that CFBDSIR 1458+10 B may be a member of the Y spectral class of brown dwarfs.[9][4][11] In 2012 Liu et al. assigned it a spectral class Y0.[1]

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.[7]

See also

The other two brown dwarf binary systems, observed by Liu et al. with Keck II LGS-AO in 2012:[1]

• WISE 1217+1626 (T9 + Y0, binarity was newly discovered)
• WISE 1711+3500 (T8 + T9.5, binarity was newly discovered)

Notes

References

External links

• CFBDSIR 1458+10 (Solstation.com)

На других языках

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