Explorations of Disk Formation and Multiplicity with the ngVLA
John Tobin University of Oklahoma
http://nhn.ou.edu/~jjtobin/VANDAM/ Image: Bill Saxton (NRAO) Thanks to the VANDAM Team! VANDAM: VLA/ALMA Nascent Disk and Multiplicity Survey VANDAM Perseus Team: VANDAM Orion Team: John Tobin (PI) John Tobin (PI) Leslie Looney (Illinois) VANDAM Perseus+ Zhi-Yun Li (Virginia) Tom Megeath (Toldeo) Claire Chandler (NRAO) Magnus Persson (Onsala) Mike Dunham (CfA) Mihkel Kama (Cambridge) Kaitlin Kratter (Arizona) Nadia Murillo (Leiden) Dominique Segura-Cox (Illinois) Stella Offner (UMASS) Sarah Sadavoy (MPIA) Marina Kounkel (Michigan) Laura Perez (Bonn/UC Chile) Ewine van Dishoeck (Leiden) Carl Melis (UCSD) Ana Karla Diaz Rodriguez (IAA) Robert Harris (Illinois) Mayra Osorio (IAA) Lukasz Tychoniec (Leiden/AMU-Poland) Guillem Anglada (IAA) Erin Cox (Illinois) Joesph Booker (Toledo) Frederick Wyrowski (MPIfR) Elise Furlan (IPAC) Ruud Visser (ESO) James Di Francesco (HIA) Nick Reynolds (OU) Brian Stephenson (OU) Lisa Patel (OU) Nicole Karnath (Toledo) Disks in the Protostellar Phase
● Proto-planetary disk – disk around pre- main sequence star; no infalling envelope
● Protostellar disk – disk around embedded protostar; infalling envelope feeding disk
● Disk forms and grows w/protostar
● Significant growth, evolution prior to PPD state, ~ few x Myr
● Grain growth may be happening early
● PPDs might start with large grains
TW Hya (Andrews+2016) Multiple Star Formation
Separation log (AU) 0.01 0.1 1 10 100 1000 10000 ● Large fraction of MS stars are multiple
● Dependence on spectral type (mass)
● Multiplicity important aspect of star
and planet formation U A
0 ● Protostellar multiplicity only examined 5 for small region of parameter space
● Most protostars multiple in this range Chen+2013 Lada 2006 Raghavan+10 ● Sub/Millimeter/Centimeter interferometry essential for characterizing early multiplicity VLA and ALMA Nascent Disk And Multiplicity (VANDAM) Survey ● VANDAM I: Perseus – 264 hour VLA large program (executed 2013-2015)
● 92 protostars, 0.06” (~15AU); 0.1 - ~40 Lsun ● 8 mm, 1 cm, 4 cm, 6.4 cm ● ALMA follow-up for subset ● VANDAM II: Orion – 350 hour VLA large program; 9 hour ALMA (2016-2017)
● 330 protostars (ALMA); 150 (VLA); 0.1 - ~1000 Lsun ● 0.06” - 0.12” (25 – 50 AU) ● 0.87 mm, 8 mm, 1 cm Western Perseus Molecular Cloud
NGC 1333 B1
L1448
L1451 2 pc L1455 Herschel 250, 350, 500 μm Pezzuto+2012 VANDAM Class 0 Disk Candidates 7 1 0 2 + x o C - a r u g e S L1448
NGC 1333 B1
0.2 pc Spitzer L1451 3.6, 4.5, 8.0 μm Tobin+2007
Tobin+2016 Evidence for Fragmenting Disks
1.3 mm
Orbit of Pluto!
Tobin+2016
● Companions detected @ < 20 AU toward 3 protostars
● Disk optically thick at 1.3 mm – Difficult for ALMA to detect such a binary system Perseus Separation Distribution
Disk Frag. Turbulent Frag.
Tobin+2016 ● Suggest that disk and turbulent fragmentation operating for distinct scales Highlights from Orion Orion Multiplicity Highlights
(NGC 2071 IR)
ALMA Tobin+in prep Orion Multiplicity Highlights
(NGC 2071 IR)
VLA Tobin+in prep Orion Multiplicity Highlights
(NGC 2071 IR)
VLA Tobin+in prep Orion Multiplicity Highlights
(NGC 2071 IR)
VLA Tobin+in prep Frontiers Opened by the ngVLA
Perseus Separation Distribution U A
U 5 . A
1
5 – 1
t ~ i
t i m i l m
i l x
0 A 1
L A V L V g n
● Number of protostars at d < 300 pc is limiting for statistics Orion Separation Distribution
@ 420 pc U U A
A
3
0 – 3
t ~ i
t i m i l m
i l x
0 A 1
L A V L V g n
● Orion @ 420 pc has ~ 400 protostars ● Closest systems need ngVLA Cygnus - X Separation Distribution
@ 1500 pc U A U
1 A
9
7
~
– t
i t i m i m l i
l
A x L 0 V 1
A L V g n
● ngVLA opens door for SF regions out to 1.5 kpc! IRAS 03292- A Benchmark System
1.3 mm
Orbit of Pluto!
● Fν (9 mm) ~ A: 170 μJy/bm (S/N ~ 17), B: 130 μJy/bm (S/N ~ 13)
– @ Orion/Serpens: Fν ~ A: 51 μJy/bm, B: 39 μJy/bm
– @ 1.5 kpc: Fν ~ A: 4 μJy/bm, B: 3 μJy/bm
● ngVLA rms @ 30 GHz: 0.79 μJy/bm/hr ● S/N=10 at 1.5 kpc w/ngVLA with ~4 hr on source! ● ngVLA resolution will enable orbital motion for nearby sources – Protostar masses! Summary
● Unbiased surveys crucial for disk and multiplicity studies
● Large sample of protostellar disk candidates revealed by VLA
● Multiplicity early in protostellar phase becoming characterized
● ngVLA will open-up study of more distant star forming regions – Terrestrial planet forming regions for nearby SF regions
aka HH1-2 MMS ) ” 2 . 0 (
U A
0 5 ~ Orion Disk/Well-Resolved Highlights
ALMA Tobin+in prep. Orion Disk/Well-Resolved Highlights
aka OMC MMS6N
VLA Tobin+in prep. Orion Multiplicity Highlights
aka HH1-2 MMS
ALMA Tobin+in prep, Stephenson+in prep. Orion Multiplicity Highlights
aka HH1-2 MMS
VLA Tobin+in prep, Stephenson+in prep. Preliminary! Orion Separations
Tobin+in prep Research Supported By:
● NWO Veni Fellowship ● EU A-ERC Grant CHEMPLAN
● NASA Hubble Fellowship (formerly) ● NRAO funded by National Science Foundation Protostellar Jets: IRAS2B
Tychoniec+2016 in prep. Protostellar Jets: IRAS2B
x
Tychoniec+2016 in prep. Protostellar Jets: IRAS2B Spectral Index Spectral Index Error
α = -0.75 +/- 0.17
x
Tychoniec+2016 in prep.
● X-ray emission possibly detected, blended with nearby Class III YSO ● Class III source has negative spectral index at 4 cm/6 cm Multiplicity Statistics
● Multiplicity Fraction (MF) and Companion Star Fraction (CSF) depend on scales of interest
● 15 AU to 10000 AU – Class 0 – MF = 0.57 – CSF = 1.21 – Class I – MF = 0.23 – CSF = 0.23 – due to wide Class 0/I pairs
● 15 AU to 2000 AU – Class 0 – MF = 0.35 – CSF = 0.43 – Class I – MF = 0.28 – CSF = 0.28
● 15 AU to 1000 AU – Class 0 – MF = 0.27 – CSF = 0.30 – Class I – MF = 0.27 – CSF = 0.27
● Most stars are born in wide multiple systems that rapid dissolve
– Smaller fraction have closer companions Tobin+2015 submitted Evidence for Fragmenting Disks Western Perseus Molecular Cloud
NGC 1333 B1
L1448
L1451 2 pc L1455 Herschel SPIRE Tobin+2015 in prep. Eastern Perseus Molecular Cloud
IC348
Herschel SPIRE Tobin+2015 in prep. Western Perseus Molecular Cloud
NGC 1333 B1
L1448
L1451 2 pc L1455 Herschel SPIRE Western Perseus Molecular Cloud
NGC 1333 B1
L1448
L1451 2 pc L1455 Herschel SPIRE Tobin+2015 in prep. Western Perseus Molecular Cloud
NGC 1333 B1
L1448
L1451 2 pc L1455 Herschel SPIRE Tobin+2015 submitted Western Perseus Molecular Cloud
NGC 1333 B1
L1448
L1451 2 pc L1455 Herschel SPIRE 500 µm Tobin+2015 in prep. Western Perseus Molecular Cloud
NGC 1333 B1
L1448
L1451 2 pc L1455 Herschel SPIRE 500 µm Tobin+2015 in prep. Protostellar Disks: Big or Small? Large, massive – Gravitaitionally Unstable Small, low-mass, and/or no rotational support
Continuum of disk sizes? ~20 AU
400 AU Adapted from Kratter+2010 e.g., Vorobyov 2010, Kratter+2010 Significant magnetic braking? Allen+2003, Little or no magnetic braking (e.g. TSC 1984) Galli2006, Mellon & Li 2008, et al. ● Youngest protostellar disks have long eluded direct observation VANDAM 'Disk' Masses
0.027 M sun
0.079 M sun
Tobin+2016 in prep. ● Masses from 8 mm emission corrected for free-free contribution – Extrapolation from 4 cm and 6.4 cm data – Assume Ossenkopf & Henning 1994 at 1.3 mm, β = 1 to 8 mm Perseus Separation Distribution
Resolution limit
Field solar-type stars Raghavan+10 Tobin+2016 ● Perseus Class 0 and Class I Separation Distribution ● Excess relative to field at ~75 AU and > 1000 AU Western Perseus Molecular Cloud
NGC 1333 B1
L1448
L1451 2 pc L1455 Herschel 250, 350, 500 μm Pezzuto+2012 Western Perseus Molecular Cloud
NGC 1333 B1
L1448
L1451 2 pc L1455 Herschel 250, 350, 500 μm Pezzuto+2012 Western Perseus Molecular Cloud
NGC 1333 B1
L1448
0.2 pc Spitzer L1451 3.6, 4.5, 8.0 μm Tobin+2007 L1455 Western Perseus Molecular Cloud
NGC 1333 B1
L1448
0.2 pc Spitzer L1451 3.6, 4.5, 8.0 μm Tobin+2007 L1455 Western Perseus Molecular Cloud
NGC 1333 B1
L1448
0.2 pc Spitzer L1451 3.6, 4.5, 8.0 μm Tobin+2007 L1455 Protostellar Phase
Epoch of Disk Formation
outflow
Envelope
Envelope Disk
outflow
~0.1 pc Image: Bill Saxton (NRAO)