The AllOrion Spectroscopic Survey and other Hecto Surveys

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 (Cf. A) Kevin Flaherty (Uof. A) 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 1 a: ~10 Myr, no gas NGC 2068/2071 NGC 2024 � � OB 1 b: ~4 Myr, some gas � � ONC (OB 1 d): < 1 Myr, gas

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

NGC 2068/2071

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 Flaherty et al. in prep. HR diagram: ages ~1 -3 Myr, masses ~0. 2 -1. 5 Msun evidence for separate, 10 Myr-old population? ?

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 OB 1: ages ~4 Myr ~10 Myr S ZAM 1 1 3 3 30 10 10 30 Siess et al. 2000 Optical photometry + spectroscopy provide ages, masses

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

The 25 Orionis stellar aggregate: a kinematically distinct, rich TW Hya analogue ~ 8 Myr 1 10 25 Ori: B 1 Ve ● V 346 Ori: Herbig Ae/Be ● ~200 TTS ●

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 W 5 Xavier Koenig (Harvard University) (Lori Allen, advisor)

d=2 kpc IRAC 4. 5 MIPS 24 Hectospec+Spitzer First HR diagram of this region = Luminous (young? ) 24 -micron sources [Chavarria, Koenig & Allen 2006]

What is the star-forming history of W 5 ? MIPS 24 results on distributed star formation in the L 1641 cloud and massive star forming regions in the ONC & W 5 on the way! [Koenig, Muzerolle & Allen 2006]

Serpens Class Distribution IRAC three colour mosaic of central core of cluster, blue: 3. 6 um, green: 4. 5 um, red: 8. 0 um. (J 2000. ) 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?

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