Infrared study of a star forming region l1251b
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Infrared study of a star forming region, L1251B. Jeong-Eun Lee Sejong University. IGRINS for protostars. High spatial and spectral resolution studies of inflow & outflow close to protostars are lacking. With IGRINS, we can study statistically sample of protostars and explore

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Infrared study of a star forming region, L1251B

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Infrared study of a star forming region l1251b

Infrared study of a star forming region, L1251B

Jeong-Eun Lee

Sejong University


Igrins for protostars

IGRINS for protostars

  • High spatial and spectral resolution studies of inflow & outflow close to protostars are lacking.

  • With IGRINS, we can study statistically sample of protostars and explore

    • how key molecules such as CO, H2O, and H2 form and are destroyed at high temperatures

    • the complex kinematics in the inner tens of AU such as infall, outflow, and rotation

    • how does the star build up mass and what role does angular momentum play on small scales


L1251b an example case

L1251B: an example case

L1251, d=300pc

L1251B

13CO 1-0 map


L1251b a group of low mass protostars

L1251B :a group of low mass protostars

IRS4

IRS2

IRS-NW

IRS1

IRAS 22376+7455


Infrared study of a star forming region l1251b

Gas Distribution (OVRO)

Thick contours: N2H+

Thin contours: HCO+

Gray: 3 mm continuum

Contours: H2CO

Gray: 1 mm continuum

IRS1

IRS2

P-V diagram

Lee et al. 2007


Spitzer infrared spectrograph irs

Spitzer Infrared Spectrograph (IRS)

  • Four separate 128x128 arrays with angular resolution of 3 to 10

  • Total wavelength coverage: 5.3 – 42 μm

    • Short-Low (SL; 5.2-14 μm, λ/Δλ ~90)

    • Long-Low (LL;12-40 μm, λ/Δλ ~90)

    • Short-High (SH; 10-20 μm, λ/Δλ ~600)

    • Long-High (LH; 20-40 μm, λ/Δλ ~600)

  • Covered all of the H2 pure rotational lines from S(0) (28.2 μm) to S(7) (5.52 μm) as well as various ice features


Irs spectra of l1251b

IRS Spectra of L1251B

H2O ice

H2O ice


Infrared study of a star forming region l1251b

H2O ice


Irs mapping of l1251b

IRS Mapping of L1251B

SL module

SH module


Ice maps of co 2 and h 2 o

Ice Maps of CO2 and H2O

CO2 ice

Heated by IRS1

H2O ice

Heated by shock


Irs1 for xdr

IRS1 for XDR (?)


Infrared study of a star forming region l1251b

Ne II 12.8

Fe II 17.9


Irs1 for xdr1

IRS1 for XDR (?)

  • FeII, SiII, NeII, and SIII detected

    • NeII 12.8 μm has a peak, but FeII 17.9 μm has a hole at IRS1.

    • Fe is possibly doubly ionized (FeIII !?)

      ionization energy

  • X-ray flare observed with Chandra toward IRS1 (Simon 2009)

    • XSPEC Model;

      NH = 2 x 1023 cm-2 (Av = 100 mag) → XDR ?

      LX = 1032.4 erg s-1

Need high spectral resolution observations of Fe III


Outflows shocks

Outflows & Shocks


Outflows shocks1

Outflows & Shocks

H2 S(1)

Fe II 26

CO 2-1


Outflows shocks2

Outflows & Shocks

  • outflow around IRS2 – only ionic lines

    → a dissociative shock ??

    • FeII 6D7/2-6D9/2 (25.98 μm)

    • SiII 2P03/2-2P01/2 (34.81 μm)

  • outflow at NW– strong H2 emission + ionic lines

    → various shock properties??

    NeII 2P01/2-2P03/2 (12.8 μm) and SIII 3P2-3P1 (33.5 μm) peak at IRS2 with no elongated emission, so possibly related to infall or outflow very close to the protostar??

Need high spectral & spatial resolution observations


Summary

Summary

The Spitzer IRS mapping of L1251B revealed a few interesting results!!

  • Direct detection of ice evaporation from mapping of solid state features:

    • CO2 ice is heated above 30 K by IRS1.

    • H2O ice is heated above 100 K by the shock.

  • IRS1 may generate an internal XDR (if this is true, this is the first detection of a XDR by a low mass Class0 source!!)

  • The distribution of the H2 and ionic emission imply various shock velocities in this region.


What can igrins do for protostars

What can IGRINS do for protostars?

  • High velocity resolution observations of CO, H2O, H2, Fe II, and Fe III transitions

    • Each of this tracer proves slight different physical regimes

  • With high spatial and spectral resoution we can survey a large sample of protostars selected from Spitzer

    • Characterize the kinematics of infall/outflow seen in each tracer and explore dynamical evolution

    • If rotation is detected we can study the angular momentum in the innermost regions near young forming star

    • Comparison of source luminosity and outflow characteristics in a large sample can set constraints on accretion timescales


Thank you

Thank you.


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