Jeong-Eun LeeSejong University

Infrared study of a star forming region, L1251B

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

L1251, d=300pc

13CO 1-0 map

L1251B

L1251B : a group of low mass protostars

IRS2IRS1

IRS4

IRAS 22376+7455

IRS-NW

Lee et al. 2007

Thick contours: N2H+

Thin contours: HCO+

Gray: 3 mm continuum

IRS2 P-V diagram

Contours: H2CO

Gray: 1 mm continuumIRS1

Gas Distribution (OVRO)

Spitzer Infrared Spectrograph (IRS)Four separate 128x128 arrays with

angular resolution of 3 to 10

Total wavelength coverage: 5.3 – 42 μmShort-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

H2O ice

IRS Spectra of L1251B

H2O ice

H2O ice

IRS Mapping of L1251B

SL module

SH module

Ice Maps of CO2 and H2O

CO2 ice

Heated by IRS1

H2O ice

Heated by shock

IRS1 for XDR (?)

Fe II 17.9Ne II 12.8

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

Fe Fe+ Si Ne S++

7.9 eV 16.2 eV

8.2 eV 21.6 eV

23.3 eV

Need high spectral resolution observations of Fe III

Outflows & Shocks

Outflows & Shocks

Fe II 26

H2 S(1)

CO 2-1

Outflows & Shocksoutflow around IRS2 – only ionic lines → a dissociative shock ??

FeII 6D7/2-6D9/2 (25.98 μm)SiII 2P0

3/2-2P01/2 (34.81 μm)

outflow at NW– strong H2 emission + ionic lines → various shock properties??

NeII 2P01/2-2P0

3/2 (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

SummaryThe 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?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.