The All-Orion Spectroscopic Survey and other Hecto Surveys of Pre-main Sequence Populations James Muzerolle (for Lori Allen) with Tom Megeath, Elaine Winston, Luis Chavarria, Xavier Koenig, Gabor Furesz (CfA) Kevin Flaherty (UofA) Cesar Briceno, Jesus Hernandez (CIDA, Venezuela)

MIPS 24 Overview Hecto ideal for characterizing large PMS populations Hectospec: – large FOV allows efficient coverage of extended populations – wavelength coverage, resolution provides excellent spectral typing – youth diagnostics such as Li, Halpha Hectochelle: – kinematics via radial velocities – stellar rotation velocities – accretion properties via Halpha profiles provides powerful complement with Spitzer surveys

The All-Orion Spectroscopic Survey Targeting thousands of young stars in the Orion GMC, selected from Spitzer and QUEST imaging surveys. Orion region provides nearby laboratory spanning a wide variety of environments, ages (Complementary to Furesz et al. ONC survey)

OB 1a: ~10 Myr, no gas OB 1b: ~4 Myr, some gas ONC (OB 1d): < 1Myr, gas NGC 2068/2071 NGC 2024

Spectra: confirming membership Li I 6707 Å important to distinguish WTTS from field dMe stars: contamination is significant in wide-field surveys!

NGC 2068/2071

Active star formation in 3 subclusters Spitzer results: Class I protostars tightly confined in linear structures near dense gas class II objects w/ disks more spread out a few % of disks appear to be in transition, with optically thin inner regions What are the characteristics of the stellar population? ages masses dynamics accretion properties Muzerolle et al. in preparation

NGC 2068/2071 Hectochelle and Hectospec Spectral types, luminosities, masses, ages, radial velocities, rotational velocities, accretion rates. Targets selected from SDSS optical CM diagram

NGC 2068/2071 HR diagram: ages ~1-3 Myr, masses ~ Msun evidence for separate, 10 Myr-old population?? Flaherty et al. in prep.

NGC 2068/2071 disk fraction as a function of spectral type/mass Similar to slightly older cluster IC 348 (Lada et al. 2005)

Characterizing the low-mass PMS population of Orion OB1: ages Optical photometry + spectroscopy provide ages, masses ZAMS Siess et al ~4 Myr ~10 Myr

Characterizing the low-mass PMS population of Orion OB1: new groups OB 1a 25 Orionis

The 25 Orionis stellar aggregate: a kinematically distinct, rich TW Hya analogue ● 25 Ori: B1Ve ● V346 Ori: Herbig Ae/Be ● ~200 TTS 1 10 ~ 8 Myr

Other star formation projects with Hectospec Infrared and X-ray Properties of Young Stellar Clusters Elaine Winston (University College Dublin) SAO pre-doc (Tom Megeath, SAO advisor) Photodissociation Regions in Massive Star Forming Regions Luis Chavarria (University of Chile) SAO pre-doc (Lori Allen, SAO advisor) The Star Formation History of W5 Xavier Koenig (Harvard University) (Lori Allen, advisor)

IRAC 4.5 MIPS 24 Hectospec+Spitzer First HR diagram of this region = Luminous (young?) 24-micron sources d=2kpc [Chavarria, Koenig & Allen 2006]

What is the star-forming history of W5 ? [Koenig, Muzerolle & Allen 2006] MIPS 24 results on distributed star formation in the L1641 cloud and massive star forming regions in the ONC & W5 on the way!

Serpens Class Distribution IRAC three colour mosaic of central core of cluster, blue: 3.6um, green: 4.5 um, red: 8.0um. (J2000.) Showing distribution of sources with X-ray detections by class. Class I: white circles Flat Sp: blue invert. triangles Class II: green triangles Class III: red squares Class not segregated – why? Do the classes represent an evolution of the disk with age? If so, why are they mixed? Is disk structure dependant on cluster environment, are they coeval? Why the mix of CI, FS, CII in the ‘V’ formation? Clustering of CIII’s? Why not dispersed? Young?

Circles: Class I, Invert. Triangle: Flat Spectrum, Triangle: Class II Square: Transistion Disks, Large Star: an X-ray detection Small Asterisk: Not Classified (presumably Class III) H-R Diagram of Serpens Cloud [Winston & Megeath 2006]