The All-Orion Spectroscopic Survey and other Hecto Surveys of Pre-main Sequence Populations
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Transcript of The All-Orion Spectroscopic Survey and other Hecto Surveys of Pre-main Sequence Populations
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The All-Orion Spectroscopic Survey
and other Hecto Surveys of Pre-main Sequence Populations
James Muzerolle (for Lori Allen)
withTom Megeath, Elaine Winston, Luis Chavarria, Xavier Koenig, Gabor Furesz (CfA)Kevin Flaherty (UofA)Cesar Briceno, Jesus Hernandez (CIDA, Venezuela)
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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
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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 nearbylaboratory spanning a widevariety of environments, ages
(Complementary to Furesz et al. ONC survey)
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OB 1a:~10 Myr, no gas
OB 1b: ~4 Myr, some gas
ONC (OB 1d):< 1Myr, gas
NGC 2068/2071
NGC 2024
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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
HR diagram: ages ~1-3 Myr, masses ~0.2-1.5 Msun evidence for separate, 10 Myr-old population??
Flaherty et al. in prep.
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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
Optical photometry + spectroscopy provide ages, masses
10
3
1
30
3
10
1
30
ZA
MS
ZA
MS
Siess et al. 2000
~4 Myr ~10 Myr
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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
● 25 Ori: B1Ve● V346 Ori: Herbig Ae/Be● ~200 TTS
1
10
~ 8 Myr
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Other star formation projects with Hectospec
Infrared and X-ray Properties of Young Stellar ClustersElaine Winston (University College Dublin) SAO pre-doc
(Tom Megeath, SAO advisor)
Photodissociation Regions in Massive Star Forming RegionsLuis Chavarria (University of Chile) SAO pre-doc
(Lori Allen, SAO advisor)
The Star Formation History of W5Xavier Koenig (Harvard University)(Lori Allen, advisor)
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IRAC 4.5
MIPS 24
Hectospec+SpitzerFirst HR diagram of this region = Luminous (young?) 24-micron sources
d=2kpc
[Chavarria, Koenig & Allen 2006]
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What is the star-forming history of W5 ?
[Koenig, Muzerolle & Allen 2006]
MIPS 24
results on distributed star formation in the L1641 cloudand massive star forming regions in the ONC & W5 on the way!
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Serpens Class DistributionIRAC 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?
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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]