Jan. 12, 2005 205th AAS Meeting, San Diego

The HST Survey of the Orion Nebula Cluster

Science team: M. Robberto (ESA-STScI), D. Soderblom (STScI), C. R. O’Dell (Vanderbilt), L. A. Hillenbrand (Caltech),

M. Simon (Stony Brook), E. D. Feigelson (Penn State), J. Najita (NOAO), K. G. Stassun (Vanderbilt), J. Stauffer (IPAC-Caltech), M. Meyer (Steward), J. Krist (JPL), N. Panagia (STScI), M. Romaniello (ESO), F.

Palla (Arcetri), I.N. Reid (STScI), P. McCullough (STScI), R. Makidon (STScI)Home team:

E. Bergeron (STScI), M. McMaster (STScI), V. Kozhurina-Platais (STScI), H. McLaughlin (STScI),K. Smith (STScI), W. Sherry (NOAO)

Jan. 12, 2005 205th AAS Meeting, San Diego

Goals• Use deep, simultaneous, high precision photometry to

assemble the richest, most accurate, unbiased HR diagram of PMS stars ever made– IMF and its variation with environment

– Accretion and disk dissipation vs. environment

– Stellar multiplicity vs. disk fraction

• Discover substantial population of PMS binaries, low mass stars and brown dwarfs down to ~10MJ

• Ha survey of disks, jets, proplyds

Jan. 12, 2005 205th AAS Meeting, San Diego

Strategy

104 HST orbits, parallel ACS+WFPC2+NIC3• ACS: B s, V s, I s, z s, Hs• WFPC-2: U s, B s, I s, H s• NIC-3: J s, H s

2 Orientations• 100° (36 orbits, Fall 2004) • 280° (68 orbits, Spring 2005)

Precise tiling pattern allows for full coverage with ACS and WFPC2

Jan. 12, 2005 205th AAS Meeting, San Diego

Survey areaCurrent on 2-Mass

final on ESO-WFI

•ACS & WFP2: ~0.15sq. deg; NIC3~113-127 sq.arcmin•WFPC2: 205.4 Mpix•ACS: 904 Mpix•NIC-3: 7.4-8.3 Mpix

Jan. 12, 2005 205th AAS Meeting, San Diego

An ACS strip

B, H-V, I

Jan. 12, 2005 205th AAS Meeting, San Diego

Jan. 12, 2005 205th AAS Meeting, San Diego

Jan. 12, 2005 205th AAS Meeting, San Diego

WFPC2H

Jan. 12, 2005 205th AAS Meeting, San Diego

NICMOSFOM increases area surveyedby 1.6. Factor ~2 possible.

Galaxies in NICMOS fields

Jan. 12, 2005 205th AAS Meeting, San DiegoF435W

F555W

F775W

F850LP

F658N

ACS+NICMOS

Jan. 12, 2005 205th AAS Meeting, San Diego

NIC3

Jan. 12, 2005 205th AAS Meeting, San Diego

Two populations: • J~12-14 (M type stars)• J~18-22 (background objects)

NIC-3 photometry

Jan. 12, 2005 205th AAS Meeting, San Diego

CM diagrams: V vs. V-I

Jan. 12, 2005 205th AAS Meeting, San Diego

CM diagrams: I vs. I-z

Jan. 12, 2005 205th AAS Meeting, San Diego

Stellar density

Jan. 12, 2005 205th AAS Meeting, San Diego

Star counts – I band

Jan. 12, 2005 205th AAS Meeting, San Diego

Ground-based follow-up

• Simultaneous UBVIJHK photometry of the ONC– ISPI @ CTIO Blanco 4m: JHK– WFI @ ESO 2.2m: UBVI+Ha

Plus CTIO 0.9m, data taken on Jan 1-2, 2005

• Optical Multi-object spectroscopy (Hillenbrand)

• Near-IR spectroscopy (Meyer)

Jan. 12, 2005 205th AAS Meeting, San Diego

A look at the core region

Jan. 12, 2005 205th AAS Meeting, San Diego

New objects in the outer regions

V

H