The Galactic Orbits of Ultracool Subdwarfs - CASSajb/presentations/0909uhertfordshire.pdf ·...

© 2009 Adam J. Burgasser

The Galactic Orbits of Ultracool

Subdwarfs Adam J. Burgasser UC San Diego/MIT © 2009 Adam J. Burgasser


Adam Burgasser, Andrew West, John Bochanski (MIT) and Jackie Faherty

(AMNH/SUNY Stony Brook)

Robyn Sanderson (MIT)

Nitya Kallivayalil (MIT) © 2009 Adam J. Burgasser

Background & Motivation

Orbit Calculations & Spectral Model Fits

Results & Future Directions



What are Ultracool Subdwarfs?


Kuiper (1939); Joy (1947) also Adams & Joy (1922); Adams (1935); Kuiper (1940); Chamberlain & Aller (1951)

What are Subdwarfs?

What are subdwarfs?

What are ultracool subdwarfs?

Why study ultracool subdwarfs?


Metallicity Effects in Subdwarf Spectra

Metal-‐poor

Metal-‐rich

Lepine et al. (2003) see also Mould (1976); Gizis & Reid (1997); Burgasser et al. (2006)

What are subdwarfs?




Lepine, Rich & Shara (2007) also Gizis (1997); Burgasser & Kirkpatrick (2006)

dwarfs

subdwarfs

extreme subdwarfs

ultra subdwarfs

What are subdwarfs?





Lepine, Rich & Shara (2007)

also Jao et al (2008)

Metallicity

Temp

erature

What are subdwarfs?





Cushing et al. (2009)

also Gizis (1997); Lepine et al. (2004); Burgasser et al. (2008,2009)

What are subdwarfs?



Subdwarfs have Halo Kinematics


Burgasser et al. (2008) also Gizis & Harvin (2007)

What are Ultracool Subdwarfs?

sdM8

sdM8.5

sdM9.5

sdL4

sdL7

Ultracool subdwarfs are sources typed sdM7/esdM7/usdM7 or later, and have Teff ≤ 3000 K

What are subdwarfs?




Kirkpatrick et al. (1999); Burgasser et al. (2008) also Cushing et al. (2006)

Cooler is Cloudier

What are subdwarfs?




L subdwarfs

Burgasser et al. (2003) also Burgasser (2004); Cushing et al. (2008)

What are subdwarfs?




Burgasser et al. (2009) also Scholz et al. (2004); Dahn et al. (2008); Schilbach et al. (2009)

1 2 3 4 5 6i’-J

-1.0

-0.5

0.0

0.5

1.0

1.5J-

Ks

0.0

-0.5

-1.0

-1.5

-2.0

-2.5

2000

2100 2200

2300

2400

2500

2600

2700

2800

2900

3000

3100

3200

3300

3400

3500

SDSS J1256-0256

SSSPM J1013-1356

2MASS J1626+3925

2MASS J0532+8246

LSR 1425+7102

2MASS 0142+0523

M0M1M2M3 M4M5

M6M7

M8M9

L0

GAIA Cond-Phoenix models log g = 5.5

Highly sensitive probes of metallicity

What are subdwarfs?



© 2009 Adam J. Burgasser Burgasser et al. (2008)

Sample the Z-dependent stellar/substellar boundary

What are subdwarfs?



2M 0532+8246 sdL7


Witte et al. (2009) also Burrows et al. (2006)

Examine Z-dependent chemistry in cool atmospheres

What are subdwarfs?



Do condensates clouds form in metal-poor atmospheres?

Orbits & Atmospheres: Motivation



Motivation: Different Properties of Inner/Outer Halo

Inner/Outer Halo

Kinematics & Colors in UCDs

Galactic Streams & Substructure

Program Outline

Carollo et al. (2007) also Searle & Zinn (1978); Sommer-Larson & Zhen (1990); Chiba & Beers (2000)


Motivation: Kinematics & Atmospheres in Ultracool Dwarfs

Faherty et al. (2009) also Zapatero Osorio et al. (2007); Jameson et al. (2008)

Inner/Outer Halo



Program Outline


Streams & Galactic Substructure

Belokurov et al. (2006); Klement et al. (2009) also Ibata et al. (1994); Majewski et al. (1999); Helmi (2008 review)

Inner/Outer Halo



Program Outline


Orbits & Atmospheres: Ingredients

•  Calculate Galactic orbits of UCSDs

and examine constants of motion

–  Identify distinct halo populations

– Search for streams/groupings

•  Determine atmospheric parameters

– Teff, [M/H], log g, “clouds”

•  Search for correlations

Inner/Outer Halo



Program Outline


Orbits


Cushing et al. (2009); Schilbach et al. (2009) also Monet et al. (1995); Burgasser et al. (2008); Dahn et al. (2008)

Gathering data – positions and velocities

Data Gathering

Potential Models

Variety of orbits

Extrema

Conserved Quantities


Calculating Galactic Orbits

0 2 4 6 8 10 120

1

2

3

4

5

6

r �kpc�

M�1010

Msun�

Enclosed Mass in Model I

total

halo

bulge

disk

Models I and II from Binney & Tremaine (2008)

Data Gathering

Potential Models

Variety of orbits

Extrema



Calculating Galactic Orbits

Models I and II from Binney & Tremaine (2008) 0 2 4 6 8 10 12

0

1

2

3

4

5

6

r �kpc�

M�1010

Msun�

Enclosed Mass in Model II

total

halo

bulge

disk

Data Gathering

Potential Models

Variety of orbits

Extrema



Galactic Orbits: Wide Diversity

Data Gathering

Potential Models

Variety of orbits

Extrema


!!" !# " # !"

!!"

!#

"

#

!"

$%&'()*

+%&'()*

" # !"!,

!-

!.

!/

"

/

.

-

,

0%&'()*

1%&'()*

23456%78779!/#-!"//.%:;8<=6%>.

!#"" " #"""

/

.

-

,

!"

!/

0%&'()*

?@><%&:A5*!#"" " #""!,

!-

!.

!/

"

/

.

-

,

?@><%&:A5*

1%&'()*

Sanderson et al. (in prep.)



!!" !# " # !"

!!"

!#

"

#

!"

$%&'()*

+%&'()*

" # !"!",-

!",.

"

",.

",-

/%&'()*

0%&'()*

12345%.6377!8.89:;.#%<=>?@5%6-

!#"" " #"""

.

-

8

A

!"

!.

/%&'()*

BC6?%&<D4*!#"" " #""

!",-

!",:

!",.

!",!

"

",!

",.

",:

BC6?%&<D4*

0%&'()*

Data Gathering

Potential Models

Variety of orbits

Extrema




!! " !

!!

"

!

#$%&'()

*$%&'()

" + , - .!.

!-

!,

!+

"

+

,

-

.

/$%&'()

0$%&'()

12345$+63778-,"98+:8$;<=>?5$6,

!!"" " !"""

+

,

-

.

/$%&'()

@A6>$%;B4)!!"" " !""!.

!-

!,

!+

"

+

,

-

.

@A6>$%;B4)

0$%&'()


Data Gathering

Potential Models

Variety of orbits

Extrema




Galactic Orbits: Extremum LSR 1610-004

Data Gathering

Potential Models

Variety of orbits

Extrema



!5 0 5

!5

0

5

X (kpc)

Y (

kpc)

0 5 10!5

0

5

R (kpc)

Z (

kpc)

Star: lsr1610!0040 Model: m4

!500 0 5000

2

4

6

8

R (

kpc)

Time (Myr)!500 0 500!5

0

5

Time (Myr)

Z (

kpc)


!50 0 50

!50

0

50

X (kpc)

Y (

kpc)

0 20 40 60!20

!10

0

10

20

R (kpc)

Z (

kpc)

Star: 2mass1227!0447 Model: m4

!1000 !500 0 500 10000

10

20

30

40

50

60

70

R (

kpc)

Time (Myr)!1000 !500 0 500 1000!20

!15

!10

!5

0

5

10

Time (Myr)

Z (

kpc)

Galactic Orbits: Extremum 2M 1227-0447

Data Gathering

Potential Models

Variety of orbits

Extrema




From +Z

From +X

LSR 1610-‐0040 2M 1227-‐0447

Sun





1.0 0.8 0.6 0.4Eccentricity

-3•106

-2•106

-1•106

0

1•106

2•106

3•106

Lz

(km

2 s

-1)

Data Gathering

Potential Models

Variety of orbits

Extrema


prograde

retrograde

2M 1227-0447

2M 0616-6407

d/sd sd esd usd

Spectral Model Fits


© 2009 Adam J. Burgasser 6500 7000 7500 8000 8500 9000

Wavelength (Angstroms)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Norm

aliz

ed f!

SDSS J1256-0256

GAIA Cond-Phoenix modelTeff = 2300 K

log g = 5.5 (cgs)

[M/H] = -1.5

" = 2.25

Burgasser et al. (2008) Drift-Phoenix models by Helling et al. (2008)

Spectral Model Fitting: Near-Infrared is Best

1.0 1.5 2.0Wavelength (µm)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

No

rma

lize

d f!

SDSS J1256-0256

GAIA Cond-Phoenix modelTeff = 2300 K

log g = 5.5 (cgs)

[M/H] = -1.0

" = 0.51

Near-infrared

Red Optical

Motivation

Results

Orbits & Atmospheres

Exemplary Cases



0.0

0.2

0.4

0.6

0.8

1.0

No

rmal

ized

F!

2MASS 1227-0447

T = 2900 K

[M/H] = -2.0

log g = 5.0 (cgs)

"2 = 6.06

DOF = 111

Results: The Good

2000 2500 3000 3500Teff (K)

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

[M/H

]

0.0

01

0.0

01

0.0

10

0.0

10

0.1

00

0.5

00

Burgasser et al. (in prep)

Motivation

Results


Exemplary Cases



0.0

0.2

0.4

0.6

0.8

1.0

No

rmal

ized

F!

2MASS 1626+3925

T = 2200 K

[M/H] = -1.0

log g = 5.5 (cgs)

"2 = 141.

DOF = 111

2000 2500 3000 3500Teff (K)

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

[M/H

]

0.0

01

0.001

0.0

10

0.1

00 0.500


Results: The Good

Motivation

Results


Exemplary Cases



0.0

0.2

0.4

0.6

0.8

1.0

No

rmal

ized

F!

LSR 1610-0040

T = 2900 K

[M/H] = -0.5

log g = 5.0 (cgs)

"2 = 1035

DOF = 111

2000 2500 3000 3500Teff (K)

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

[M/H

]

0.0

01 0

.001

0.0

10

0.1

00

0.5

00


Results: The Ugly

Motivation

Results


Exemplary Cases



0.0

0.2

0.4

0.6

0.8

1.0

No

rmal

ized

F!

LSR 0822+1700

T = 3300 K

[M/H] = -2.5

log g = 5.0 (cgs)

"2 = 4.88

DOF = 111

2000 2500 3000 3500Teff (K)

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

[M/H

]

0.0

01

0.0

01

0.010

0.0

10

0.1

00

0.500

0.5

00


Results: The Ugly

Motivation

Results


Exemplary Cases


Spectral Type

2000

2500

3000

3500

Tef

f (K

)

M6 M7 M8 M9 L0 L1 L2 L3 L4 L5 L6 L7

Burgasser et al. (in prep.)

Temperature v. Spectral Type

Motivation

Results


Exemplary Cases

d/sd sd esd usd


0.8 0.6 0.4 0.2

!

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

[M/H]


Metallicity v. Metallicity Type

Motivation

Results


Exemplary Cases d/sd sd esd usd


0.0 -0.5 -1.0 -1.5 -2.0 -2.5[M/H]

0.4

0.6

0.8

1.0

Eccentricity


Eccentricity v. [M/H]

Motivation

Results


Exemplary Cases

d/sd sd esd usd


0.0 -0.5 -1.0 -1.5 -2.0 -2.5[M/H]

0

10

20

30

40

Incl

inat

ion (

deg

rees

)


Motivation

Results


Exemplary Cases

Inclination v. [M/H]

d/sd sd esd usd


0.0 -0.5 -1.0 -1.5 -2.0 -2.5[M/H]

-1•106

0

1•106

2•106

3•106

Lz (

km

2 s

-1)


2M 1227-0447

Motivation

Results


Exemplary Cases

Angular Momentum v. [M/H]

d/sd sd esd usd


usdM8.5 2M 1227-0447: a Stream Star?

Anticenter Stream (Grillmair et al. 2008)

GD-1 Stream (Willett et al. 2009)

Several streams are prograde, [Fe/H] ≈ -2...-1 and reside entirely within 50 pc of the Sun Is 2M 1227-0447 a tracer of one?

Motivation

Results


Exemplary Cases


sd?M6pec LSR 1610-0040: Peculiar for Orbital Reasons?

Dahn et al. (2008) also Lepine et al. (2003); Reiners & Basri (2006); Cushing et al. (2006)

Does an orbit plunging deep into the center of the Galaxy explain LSR 1610-0040’s peculiarities?

Motivation

Results


Exemplary Cases


Summary


SUMMARY

•  Ultracool subdwarfs display a wide variety of orbits – prograde & retrograde, circular to highly elliptical, inclined to planar – and sample the inner & outer halos

•  There are very weak correlations between atmospheric and orbital properties, possibly obscured by uncertainties

•  Orbital properties may explain origins of ultra-fast mover 2M 1227-0447 and peculiar LSR 1610-0040


FUTURE WORK

•  Improve distances and RVs for known UCSDs

– FIRE spectrograph

•  Explore action space in detail (J||, Jp),

compare with known streams

•  Dedicated search for UCSDs – SDSS, UKIDSS,

PanSTARRS, SkyMapper, LSST

•  Improved spectral models particularly for

optical diagnostics (metal H bands, opacities)

•  Apply to other populations


The FIRE Spectrograph Near-infrared Echellette for the

Magellan Telescopes

0.85-2.35 µm in a single image

λ/Δλ~6000 cross-dispersed (50 km/s; 0.6” slit)

λ/Δλ~1000-2500 prism-dispersed (high throughput)

Commissioning January 2009

Simcoe, Burgasser, Schechter et al. (2008)

Don’t forget the swag!


FUTURE WORK

•  Improve distances and RVs for known UCSDs

– FIRE spectrograph

•  Explore action space in detail (J||, Jp),

compare with known streams

•  Dedicated search for UCSDs – SDSS, UKIDSS,

PanSTARRS, SkyMapper, LSST

•  Improved spectral models particularly for

optical diagnostics (metal H bands, opacities)

•  Apply to other populations


The Galactic Orbits of Ultracool

Subdwarfs Adam J. Burgasser UC San Diego/MIT

The Galactic Orbits of Ultracool Subdwarfs - CASSajb/presentations/0909uhertfordshire.pdf ·...

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