THE STAR FORMATION NEWSLETTER
No.273 - 13 September 2015
2015/10/02
36-40• YSOVAR: Mid-Infrared Variability in NGC 1333
• Disc fragmentation rarely forms planetary-mass objects• No evidence for protoplanetary disk by OB stars in theMYStIX sample• Detection of water vapor in the terrestrial planet forming
region of a transition disk
• Disentanling the jet emission from protostellar systems.
The ALMA view of VLA1623
泉奈都子 (D3)YSOVAR: Mid-Infrared Variability in NGC 1333!
L. M. Rebull et al. Accepted by AJ http://arxiv.org/pdf/1508.04705

Young Stellar Object VARiability (YSOVAR) program: NGC 1333
• Target- Very young (1-2 Myr) and relatively nearby (D ~ 235 pc)- Av: ~ 6-7 mag- NGC1333 has many very embedded young stars, making it an ideal laboratory forstudying the IR viability of such objects.

YSOVAR• Observation:- Telescope: Spitzer

3.6 µm- Band: 3.6 and 4.5 µm- Field of view: ~ 10’ × 10’(centered on 03:29:06 +31:19:30)- Spacing: 4 ~ 16 hrs (non-uniform)- Monitoring period: ~ 35 dayChandra

これらに加えて、NIR (J,H,Ks from PAIRITEL, 2MASS),
MIR (3.4,4.6,12,22 µ, from WISE),
Cryogenic-era Spitzer archival data (early mission),
X-ray (from Chandra)
Optical (i’, z’ from Subaru, CFHT)のデータも取得

4.5 µm• Results- YSOVARの観測期間中で、78 objectsにおけるMIRの変動を検出(Cryo to YSOVAR だと92objects)‣ NGC 1333 のmemberだと ~ 50%がvariable （他のclusterと比較すると低い値）- Color change ([3.6]-[4.5]): typically ~ 0.05 mag, most extreme > 0.2 mag- Timescales for the variability: ≲ 5day-…

Disk fragmentation rarely forms planetary-mass objects!
Ken Rice et al. Accepted by MNRAS http://arxiv.org/pdf/1508.06528

• r > 50 AUでplanetary-mass objectsが形成された場合の、その後の進化について調べるNo evidence for protoplanetary disk destruction by OB stars
in the MYStIX sample!
Alexander J.W. Richert et al. Accepted by ApJ http://arxiv.org/pdf/1508.01338“Theory: Young ,OB-dominated massive HII regions are inhospitable to thesurvival of protoplanetaty disk” が本当か確かめる• Method- O starの周囲 (~0.5pc) における disk-bearing YSO, disk-free YSOの分布を調べる

ECDF (Empirical cumulative distribution function)

• Sample- MYStIX surveyによって得られた20個のmassivestar-forming region• Results- 7/20 : O starがない or 解析の際に、PAHのcontaminationの除去と一緒に排除してしまった- 7/20 : O starの周囲の disk-bearing YSOが少なすぎてdisk destructionの検出ができない- 4/20 : O starの影響による disk depletionは明らかに検出されなかった- 2/20 : inconclusive results

The massive star-forming regions are not very hostile to the survival of protoplanetarydisks and, presumably, to the formation of planetsDetection of water vapor in the terrestrial planet forming
region of a transition disk!
Colette Salyk et al. Accepted by ApJL http://arxiv.org/pdf/1508.07483

Spectrally resolved observations of water vapor from DoAr 44: DoAr 44• Target- Young K3 star in the ρ Ophiuchus cloud (Bouvier & Appenzeller 1992)• Observation- Instrument: Texas Echelon Cross Echele Spectrograph(visitor instrument on Gemini north)- Date: 2014/08/15, 08/16- The total target integration times: 56min (08/15), 39min (08/16)- Mode: “high-medium” cross-dispersed mode
(R ~ 80,000 at ~ 12.4 µm)- FWHM: 3.5 ± 0.1 km s-1 (R ~ 85000)- Slit size: 0.52” × 4”

• Results- Water vapor のemissionはinner disk (near 0.3 AU)から出ている‣ Inner rim of the optically thick outer disk ~ 36AU よりも内側で、dusty innerdisk regions とかぶっている- Emissionはある程度の幅をもつ温度の領域から出ている（単一の温度ではない）- Self shielding modelをもとにして導出したvertical hydrogen column densityは
NH > 1022 cm-2
‣ gas/(small-) ≳ 1000 を示す

hot model : NH2O = 1019 cm-2
T = 800 K
R = 0.15 AU
warm model : NH2O = 2 × 1018 cm-2
T = 450 K
R = 0.79 AU

Disentangling the jet emission from protostellar systems. The
ALMA view of VLA1623!
G. Santangelo et al. Accepted by A&A http://arxiv.org/pdf/1508.05022

Study the physical properties of the jet emission in VLA1623 at highangular resolution: VLA1623• Target- ρ Ophiuchus (d ~ 120 pc) に位置する- Triple non-coeval system : VLA1623A, VLA1623B, VLA1623Wからなる: ALMA Early Science cycle 0• Observation- CO(2-1) のmapping- Band: Band 6 (230GHz) using extended configuration- Baseline range: 36 - 400m (maximum recoverable scale of 4”)- Total observing time: 1 hour
- The synthesised beam: 0”.74 ×-10”.58 (PA=93°)- The rms noise: 3 - 5 mJy beam per 1 km s-1 channel

Large scale CO outflow (driven by source A)

PACS [OI] 63 µm line emission peaks

• Results- Bに非常に近いところで、Compact jet emissionを検出 (Bb1, Br1)
- AとBの離れたところに、2つのoutflow componentを検出‣ Fast component (Bb2, Br2) : [OI] 63 µm のピークに付随
Large scale outflowとは逆の方向‣ Slow component (Ar1, Ar2, Ar3) : [OI] 63 µm のピークの周囲に分布
red-shifted cavity-like structure1) precession of the A jet2) the presence of a fast compact
jet associated with source B
BはAよりも若いことを裏付ける
Very early stage of evolution,
driving a faster, more collimated, andmore compact jet with respect to thelarge-scale slower outflow driven by A