Luhman’16AB · Wavelength (!m) 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Absolute F (10 h-17 erg/cm 2 /s/!...

Luhman 16AB: A Remarkable, Variable,

L/T Transition Binary at 2 pc

Adam J. Burgasser (UC San Diego) Jacqueline Faherty (U. Chile), Yuri Beletsky (Magellan Obs), Jacqueline

Radigan (STScI), Michael Gillon (U. Liege), Peter Plavchan (Caltech/IPAC), Nidia Morrell (Magellan Obs.), Rachel Osten (STScI), Rachel Street (LCO), Carl Melis (UC San Diego), Amaury Triaud (MIT) & Robert Simcoe (MIT)

WISE 1049-‐5319AB aka Luhman 16AB

Identified by Luhman (2013) in a proper motion/very cold source search of multi-‐epoch WISE data (2MASS dropouts).

µ = 2.78 “/yr, detection back in 1978

R = 18.6, J = 10.7, Ks = 8.8, W2 = 7.3

b = 5º (are you kicking yourself yet?)

d = 2.02±0.15 pc – 3rd closest system to Sun (closest to α Centauri)

Kinematics nominally consistent with normal field dwarf system, but a suggested association with Argus (Mamajek 2013)

http://xkcd.com/1212

Why is this source so awesome?

•  It is a binary that is both well-‐separated (1”5) and relatively tight (3.1 AU, P ≈ 20-‐40 yr)

•  It is a flux reversal binary straddling the L dwarf/T dwarf transition

•  It is highly variable in the optical

Easy spectroscopic follow-‐up Resolved optical (Kniazev et al. 2013) and near-‐infrared (Burgasser et al. 2013) spectroscopy and photometry has been published,

Classified L7.5-‐L8 + T0-‐T0.5 optical & NIR

cf. SDSS 1534+1615AB (Liu et al. 2006) 2MASS 1404-‐3159AB (Looper et al. 2008) spectral binary candidates (Burgasser et al. 2010; Geiβler et al. 2011; Day-‐Jones et al. 2013)

Burgasser et al. (2013) also Kniazev et al. (2013)

A late bloomer?

Luhman 16A & B are both red and underluminous @ J for their spectral types; young and/or cloudy? (cf. Looper et al. 2008)

Burgasser et al. (2013)

L7-‐L8 T0-‐T1

ESO/TRAPPIST

Michael Gillon

Gillon et al. (2013) 4.87±0.01 hr binary period variability appears to originate from T dwarf

ATCA (5/2)

Keck/NIRSPEC IRTF/SpeX

IRTF/CSHELL

ESO/TRAPPIST Magellan/FIRE Magellan/MagE DuPont/Retrocam CTIO/Andicam CTIO/Las Cumbres

SAAO/ Las Cumbres

2013 April 22-‐28 Monitoring Campaign

NIR & Optical imaging and spectroscopy + radio interferometry Goals: characterize panchromatic variability, measure radial &

rotational velocities, search for magnetic emission

•  ESO TRAPPIST

–  optical variability: published (Gillon et al. 2013) •  LCO/Retrocam + CTIO/Andicam + NTT/SofI

–  optical and NIR variability: analysis underway (Radigan & Faherty) •  Las Cumbres Chile + South Africa

–  semi-‐continuous monitoring: analysis underway (Street) •  Magellan/FIRE: NIR resolved moderate resolution (multi-‐epoch)

–  improved RV & ΔRV and association membership: analysis complete (Faherty) –  spectral variability: analysis underway (Faherty)

•  Magellan/MagE: Optical resolved moderate resolution (multi-‐epoch) –  spectral variability incl. Hα & Li I: analysis underway (Beletsky & Faherty)

•  IRTF/SpeX: NIR resolved spectral monitoring

–  component classification: submitted (Burgasser et al. 2013) –  spectral variability: analysis underway (Burgasser)

•  IRTF/CSHELL: NIR resolved high resolution –  v sin i & ΔRV: analysis underway (Plavchan)

•  Australian Telescope Compact Array –  search for radio emission: analysis underway (Osten)

2013 April 22-‐28 Monitoring Campaign

SOFI/NTT monitoring •  Apr 27 2013 (J. Radigan)

•  Non-ideal conditions (2” seeing) – combined light photometry

•  J and K alternating

•  fastPhot mode: variable “shade” pattern frame to frame currently limiting data reduction

achromatic trends

color variation

Magellan/FIRE

0.8 1.0 1.2

Nor

mal

ized

Flu

x (F

)

1.4 1.6 1.8Wavelength (!m)

Luhman16A + L8 Standard

Luhman16B + T0 Standard

2.0 2.2 2.4

Faherty et al. (in prep)

Faherty et al. (in prep)

Magellan/FIRE

0.8 1.0 1.2

Nor

mal

ized

Flu

x (F

)

1.4 1.6 1.8Wavelength (!m)

Luhman16A + L8 Standard

Luhman16B + T0 Standard

2.0 2.2 2.4

0.95 1.00 1.05 1.10Wavelength (!m)

Nor

mal

ized

Flu

x (F

)

FeH

FeH

CH4+H20

Luhman 16A

Luhman 16B

2.00 2.05 2.10 2.15 2.20 2.25 2.30 2.35Wavelength (!m)

Norm

alize

d Fl

ux (F

) CO

CH4

CIA H2

Luhman 16A

Luhman 16B

1.15 1.20 1.25 1.30 1.35Wavelength (!m)

Norm

alize

d Fl

ux (F

)

Na

H2OFeH

CH4

1.45 1.50 1.55 1.60 1.65 1.70 1.75Wavelength (!m)

Nor

mal

ized

Flu

x (F

)

FeHCH4

Luhman 16A

Luhman 16B

Not an Argus member

1.242 1.245 1.248 1.251 1.254Wavelength (!m)

Norm

alize

d Fl

ux (F

)

Luhman 16A

Luhman 16B

2M1632 (L8 top)SD0151 (T1 bottom)

K I lines are strong, inconsistent with low surface gravity (Faherty et al. in prep)

With RV, kinematics are inconsistent with membership in any known moving group (Kniazev et al. 2013)

1.240 1.245 1.250 1.255Wavelength (!m)

0.4

0.6

0.8

1.0

1.2

Nor

mal

ized

F

1.15 1.20 1.25 1.30 1.35Wavelength (!m)

No

rmal

ized

Flux

(F)

Na

H2OFeH

CH4

K I lines: Teff and clouds

Luhman 16A Luhman 16B

1.240 1.245 1.250 1.255Wavelength (!m)

0.4

0.6

0.8

1.0

1.2

Nor

mal

ized

F

1.15 1.20 1.25 1.30 1.35Wavelength (!m)

No

rmal

ized

Flux

(F)

Na

H2OFeH

CH4



Burgasser et al. (2002); McGovern et al. (2004)

1.240 1.245 1.250 1.255Wavelength (!m)

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

Abso

lute

F (1

0-17 e

rg/c

m2 /s

/!m

)1.15 1.20 1.25 1.30 1.35Wavelength (!m)

No

rmal

ized

Flux

(F)

Na

H2OFeH

CH4


J-‐band continuum is dictated by cloud grain scattering


1.165 1.170 1.175 1.180Wavelength (!m)

0.4

0.6

0.8

1.0

1.2

1.4

Nor

mal

ized

F

1.15 1.20 1.25 1.30 1.35Wavelength (!m)

No

rmal

ized

Flux

(F)

Na

H2OFeH

CH4



1.165 1.170 1.175 1.180Wavelength (!m)

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Abso

lute

F (1

0-17 e

rg/c

m2 /s

/!m

)1.15 1.20 1.25 1.30 1.35Wavelength (!m)

No

rmal

ized

Flux

(F)

Na

H2OFeH

CH4


1.17 µm continuum is dominated by H2O and CH4 opacity


1.240 1.245 1.250 1.255Wavelength (!m)

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

Abso

lute

F (1

0-17 e

rg/c

m2 /s

/!m

)

1.165 1.170 1.175 1.180Wavelength (!m)

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Abso

lute

F (1

0-17 e

rg/c

m2 /s

/!m

)

1.15 1.20 1.25 1.30 1.35Wavelength (!m)

No

rmal

ized

Flux

(F)

Na

H2OFeH

CH4



1.160 1.165 1.170 1.175 1.180 1.185Wavelength (µm)

1700

1600

1500

1400

1300

1200

1100

Brig

htne

ss T

empe

ratu

re (K

)

1.235 1.240 1.245 1.250 1.255 1.260Wavelength (µm)

1700

1600

1500

1400

1300

1200

1100

Brig

htne

ss T

empe

ratu

re (K

)

1.15 1.20 1.25 1.30 1.35Wavelength (!m)

No

rmal

ized

Flux

(F)

Na

H2OFeH

CH4



ΔT = 100 K

shallow

deep

SpeX Spectroscopic Monitoring

Data

Model

Residuals

“Spectroscopic monitoring is a black art” -‐ anonymous

Luhman 16AB was monitored for 45 minutes with IRTF/SpeX during a downturn in TRAPPIST photometry NB: 1.2”-‐1.5” seeing, airmass = 3.4-‐3.5

Unambiguous Flux Reversal

0 10 20 30 40Pixels

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Profile

J K

1.0 1.2 1.4 1.6 1.8 2.0 2.2Wavelength (!m)

0

2•10-15

4•10-15

6•10-15

8•10-15

1•10-14

Appa

rent

F


h4p://youtu.be/DIJx0flF6uc

6.2 6.4 6.6UT Time on 26 April 2013 (hours)

0.80

0.85

0.90

0.95

1.00

1.05

1.10

1.15R

elat

ive

Flux

(B/A

) TRAPPIST light curve

Continuum Flux + 0.1

Band Flux - 0.1

Relative fluxes (B/A) show similar decline as broadband photometry

No difference between continuum and band fluxes

Consistent with a decline in B’s brightness, but better calibration is required

high resolution optical spectroscopy with

MIKE to measure ΔRV

v sin i measurements with CSHELL + 13CH4 gas cell (Anglada-‐Escudé et al. 2012)

multi-‐color continuous

photometry with the Las Cumbres

network

most stringent radio and Hα flux constraints for brown dwarfs

improved NIR spectral monitoring with HST/

WFC3 (cf. Apai et al. 2013)

tighter parallax and

proper motion

measures

let’s test those cloudy

atmosphere models! (cf. Leggett

et al. 2008)

MIR variability

with Spitzer/IRAC (cf. Heinze

et al. 2013)

orbit constraints, masses soon(astro + RV)

Luhman’16AB · Wavelength (!m) 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Absolute F (10 h-17 erg/cm 2 /s/!...

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