The AllOrion Spectroscopic Survey

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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)
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Overview
MIPS 24

• 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

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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)
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OB 1a 10 Myr, no gas
NGC 2068/2071
OB 1b 4 Myr, some gas
?
?
NGC 2024
?
?
ONC (OB 1d) lt 1Myr, gas
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Spectra confirming membership

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

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NGC 2068/2071
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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
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NGC 2068/2071
Hectochelle and Hectospec Spectral types,
luminosities, masses, ages, radial velocities,
rotational velocities, accretion rates. Targets
selected from SDSS optical CM diagram
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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??
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NGC 2068/2071
disk fraction as a function of spectral
type/mass Similar to slightly older cluster IC
348 (Lada et al. 2005)
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Characterizing the low-mass PMS population of
Orion OB1 ages
4 Myr
10 Myr
1
ZAMS
1
ZAMS
3
3
10
10
30
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Siess et al. 2000

• Optical photometry spectroscopy provide ages,
  masses

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Characterizing the low-mass PMS population of
Orion OB1 new groups
OB 1a
25 Orionis
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The 25 Orionis stellar aggregate a
kinematically distinct, rich TW Hya analogue
8 Myr
1

• 25 Ori B1Ve
• V346 Ori Herbig Ae/Be
• 200 TTS

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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)

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IRAC 4.5
d2kpc
MIPS 24
HectospecSpitzer First HR diagram of this region
Luminous (young?) 24-micron sources
Chavarria, Koenig Allen 2006
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What is the star-forming history of W5 ?
MIPS 24
results on distributed star formation in the
L1641 cloud and massive star forming regions in
the ONC W5 on the way!
Koenig, Muzerolle Allen 2006
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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 CIIIs? Why not dispersed? Young?
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H-R Diagram of Serpens Cloud
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)
Winston Megeath 2006