A Molecular Inventory of A Molecular Inventory of the L1489 IRS the L1489 IRS

Protoplanetary DiskProtoplanetary DiskMichiel R. Hogerheijde

Christian BrinchLeiden ObservatoryJes K. Joergensen

CfA

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

Origin of Protoplanetary Origin of Protoplanetary DisksDisks

It’s the angular momentum, stupid

Initial distribution of angular momentum– E.g., Goodman et al. 1998; Ohashi et al. 1997; Belloche et al. 2002

Redistribution during collapseFormation of a viscous disk– Mass, size, evolution with time, accretion shock– E.g., Stahler 1994; Velusamy et al. 2002

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

L1489 IRS: A Transitional L1489 IRS: A Transitional Object?Object?

Compact dust continuum– 2000 AU radius– Density: radial power

law with slope 1.8–2.1

– Mass 0.01–0.02 M

– Hogerheijde & Sandell 2000; Joergensen et al. 2002

Neighboring prestellar core

SCUBA 850 and 450 µmobservations from Hogerheijde

& Sandell (2000)

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

L1489 IRS: A Transitional L1489 IRS: A Transitional Object?Object?

Single-dish HCO+ lines– infall

Interferometer HCO+ image– Rotation

Hogerheijde (2001)

CO 4.5 µm absorption lines– Inward motions continue

to within 0.1 AU from star

Boogert et al. (2002)

Hogerh

eijd

e

(20

01

)

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

L1489 IRS: A Transitional L1489 IRS: A Transitional Object?Object?

Single-dish HCO+ lines– infall

Interferometer HCO+ image– Rotation

Hogerheijde (2001)

CO 4.5 µm absorption lines– Inward motions continue

to within 0.1 AU from star

Boogert et al. (2002)

Hogerh

eijd

e

(20

01

)

HCO+ 3–2 @ 1.1mmBIMA 2000

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

L1489 IRS: A Transitional L1489 IRS: A Transitional Object?Object?

NICMOS scattered light suggests flared disk– Padgett et al. (1998)

Simple model– Flared disk– 10% infall, 90% rotation– Hogerheijde (2001)

Transitional, short-lived (2x104 yr) stage between embedded and T Tauri phase?

NICMOS image from Padgett et al.

(1998)

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

Molecular Line SurveyMolecular Line SurveySingle-dish molecular line measurements– JCMT, IRAM 30m, and Onsala 20m: 14”–38” = 2000–5500

AU– C17O 1–0, 2–1, 3–2– C18O 1–0, 2–1, 3–2– CS 2–1, 5–4, 7–6– C34S 2–1, 5–4– HCO+ 1–0, 3–2, 4–3– H13CO+ 1–0, 3–2– CN 1–0, 3–2– HCN 1–0, 4–3– H13CN 1–0– HNC 4–3

Aims– More realistic model– Chemical inventory

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

Modeling ApproachModeling Approach

Physical model: density– Flattened Plummer sphere

• Consistent with SCUBA data

• p=1.8 (Joergensen et al. 2002)

Brinch, Hogerheijde, & Joergensen (in prep)

(Joergensen et al. 2002)

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

Modeling ApproachModeling Approach

Physical model: density– Flattened Plummer sphere

• Consistent with SCUBA data

• p=1.8 (Joergensen et al. 2002)

• f>0

Brinch, Hogerheijde, & Joergensen (in prep)

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

Modeling ApproachModeling Approach

Velocity field– Rotation V √M* r-0.5

– Infall Vr √M* r-0.5

Parameterize V-field by– |V|√M* r-0.5

– tg()=Vr/V

Brinch, Hogerheijde, & Joergensen (in prep)

V

V

Vr

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

Modeling ApproachModeling Approach2 minimization of synthetic single-dish spectra– Gridded physical model + (constant) abundances– Molecular excitation using Monte Carlo approach– Synthetic spectra, convolved to appropriate resolution

4+n free parameters– Flattening parameter f– Inclination i– Stellar mass M*

– Velocity field direction angle – Molecular Abundances Xi

Brinch, Hogerheijde, & Joergensen (in prep)

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

ResultsResultsB

rinch

, H

ogerh

eijd

e, &

Joerg

ense

n (

in p

rep)

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

ResultsResultsB

rinch

, H

ogerh

eijd

e, &

Joerg

ense

n (

in p

rep)

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

ResultsResultsB

rinch

, H

ogerh

eijd

e, &

Joerg

ense

n (

in p

rep)

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

ResultsResults

Preliminary values– Stellar mass 1.1 M

– Flattening parameter f=3.0• Equivalent with h/R=0.35

– Inclination 70˚– Velocity field angle =18˚

• Inspiral time approximately 105 yr• Significant fraction of embedded life time

Brinch, Hogerheijde, & Joergensen (in prep)

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

ResultsResultsAbundances– C18O 4x10-7 (-> 12CO 2x10-4 no depletion)– CS 8x10-9

– SO 8x10-9

– H2CO 1x10-9

– HCO+ 4x10-8

– HCN 4x10-9

– HNC 2x10-9

– CN 2x10-9

Dark cloud values; little depletion; HCO+

increased?Brinch, Hogerheijde, & Joergensen (in prep)

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

HCOHCO++ 1–0 Interferometry 1–0 InterferometryObservations Model Prediction

Brinch, Hogerheijde, & Joergensen (in prep)

Surrounding

Surrounding

cloud materia

l

cloud materia

l

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

Enhanced-SMA Enhanced-SMA PredictionsPredictions

SMA

CSOJCMT

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

Enhanced-SMA Enhanced-SMA PredictionsPredictions

Brinch, Hogerheijde, & Joergensen (in prep)

HCO+ 4–3 at 0.3” (40 AU)

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

A break in the V-field at 300 A break in the V-field at 300 AUAU

Brinch, Hogerheijde, & Joergensen (in prep)

HCO+ 4–3 at 0.3” (40 AU)

Submillimeter Astronomy in the Era of the SMA • June 13–16 2005 • Cambridge MA

ConclusionConclusion

L1489 IRS– Disklike rotating and infalling structure– Lifetime 105 yr, significant fraction of embedded

phase– Chemical abundances

• No evidence for depletion• HCO+ enhanced

Further high-resolution observations with, e.g., enhanced-SMA– Breaks in the velocity field on scales of T Tauri disks– Changes in the chemistry on scales of T Tauri disks