Department of Physics and Astronomy

Rice University

Evolving Ideas About HH Objects

Patrick Hartigan Stromfest April 4, 2008

History• The Reflection Nebula Hypothesis• Subsequent Development of Field

New Stuff• Conditions near the Star• MHD far from the star

Herbig 1951, ApJ 113 697

Haro 1952, ApJ 115 572

Ambarzumian, 1954 Comm. Burakan Obs No 13Argues these are related to young stars – coins term HH object

DISCOVERY!

Emission lines… Photoionized… but where is the blue star?

What Causes the Emission Lines?

1956 ApJ 123 379

High ionization, low temperature:“The most obvious means of explaining the ionization is to

assume a strong radiation field in the far-ultraviolet”

HH Objects as Reflection Nebulae ApJ 191, 111, 1974

They are polarized! ApJ 191, L93, 1974

But Wait, Emission Lines Unpolarized ApJ 234, L191, 1979

What went wrong?

Examples can be more complex:

Hartigan et al 1999

What went right?

• Model made TESTABLE PREDICTIONS (i.e. it could be proved wrong)

• Motivated future work

• There are reflection nebulae in these objects

• HH Objects are displaced from host stars

• HH Objects are usually not photoionized nebulae

Spectra, Supersonic Velocities Imply Shocks Schwartz 1975Large Linewidths Imply Bow Shocks Schwartz 1978Proper Motions Imply “Bullets” Herbig and Jones 1981UV Spectra Confirm Shocks Bohm et al 1981 Ortolani and D’Odorico 1980

Bow Shock Models Hartmann & Raymond 1984 Raga & Bohm 1985 Hartigan etal 1987

Jet Connection Mundt & Fried 1983Bow Shock/Mach Disk Hartigan 1989 Reipurth & Heathcote 1992

Physical Conditions in Jets Brugel, Bohm Mannery 1981 Hartigan et al 1994 Bacciotti & Eisloffel 1998 Nisini 2005HST Proper Motions Reipurth, Bally, Hartigan etc. 1996-2007

Tilting Filter ImagesApJS 62, 39, 1986

Close to the source: Slit Mapping, Image Slicers

Lavalley et al 1997, A&A 327, 671 Jet is fastest along the axis

Bacciotti et al 2000, ApJ 537, L49 …and gets denser close to the star

Coffey et al 2004, ApJ 604, 758 … and may even be rotating

NEW RESULTS1. Near the Source2. Far From the Source

Physical Conditions Throughout the Jet

Jet Collimation

RW AURKeck, NIRSPAO [Fe II] 1.64 Slit=0.068” (9.6 AU)

Linewidths

Spectroastrometry

NEW RESULTS1. Near the Source2. Far From the Source

Scaled Laser Experiments

Brugel, Bohm and Mannery 1981

No single density or temperature describes HH objects Filling factor is low