1) Search for Associations Containing Young stars (SACY): Chem ical
tagging IC 2391 & the Argus association
G. M . De Silva1, V. D’Orazi2,6, C. M elo3, C. A. O. Torres4, M . Gieles5,7, G.
R. Quast4, M . Sterzik3	  1301.5967
less than about 10% of the clusters formed in molecular clouds survive longer than 10Myr. Lada & Lada (2003)(1) <10Myr
massive stars that expels the gas from the star forming region
cluster expansion and star loss by twobody relaxation is also a relevant process(2) >100Myr
Galactic tidal field and interactions with Giant Molecular Clouds (GMCs)
Data: search for associations containing young stars (SACY)
the Argus association and the open cluster IC 2391
Question:a common origin scenario where the Argus association stars were oncebound members of open cluster IC 2391?
Result: The common ages, kinematics and chemical abundances strongly support that
the Argus association stars originated from the open cluster IC 2391
2) THE LUM INOSITIES OF PROTOSTARS IN THE SPITZER C2D AND
GOULD BELT LEGACY CLOUDS
M ichael M . Dunham 1,2, et al. 1301.4416
long-standing “luminosity problem” in low-mass star formation■obs-->the protostellar luminosity distribution extended from 0.09 – 22 L , with amean and median of 2.3 L

and 0.7 L , respectively, and a strong peak around 0.3 L .

Lacc=facc GMMdot/R
M=0.1Msol R=1Rsol --> Mdot~10^-7 Msol/y■theoretically-->Standard Accretion Rate : Mdot ~ 2 × 10^−6 M

yr−1 for 10 K gas.

■Observed luminosity is two low.==> Luminosity Problem
VELLO (very low luminosity objects)
Enoch et al. (2009) and Evans et al. (2009)
the c2d protostellar luminosity distribution by using the Spitzer data

==> mean and median values of 5.3 Land 1.5 L .

(a) accretion is variable or episodic,(b) Offner & McKee (2011): accretion models
accretion models that tend toward a constant accretion time rather than a constant accretion rate provide agood match to the Evans et al. c2d observations.

(c) Dalba & Stahler (2012): external accretion onto collapsing cores from thesurrounding background cloud will reduce accretion rates and luminosities.
DATA: c2d と the Spitzer Gould Belt Legacy Survey (hereafter GB)
RESULT: a mean and median of 4.3 Land 1.3 L

our new results do not invalidate the conclusions of any of these studies.
3) M agnetized Accretion and Dead Zones in Protostellar Disks
Natalia Dzyurkevich1,3, Neal J. Turner2, Thom as Henning3 and Wilhe lm
Kley41301.14874) Testing m aser-based evolutionary schem es: A new search for 37.7-GHzm ethanol m asers
Sim on Ellingsen1, Shari Breen2, M axim Voronkov2 and Joanne Dawson1
1212.3330
close association of methanol masers withtheearlystagesofhigh-mass

star

formation --> useful signposts: details of
the processes through which high-massstars form.
four common types of interstellar masers:- ground-state main-line OH masers at
1.6 GHz,- 22-GHz water masers, 小質量～大質量星形成- class II methanol masers (characterised by the 6.7- and 12.2-GHz transitions) 赤外線
励起、HII 領域や赤外線源、OH メーザ天体に付随、大質量星形成- class I methanol masers (characterised by the 44-GHz transition). 衝突励起、アウトフローの先端に付随

OBS: the Australia Telescope National Facility Mopra 22-m antenna to search for37.7-GHz (7−2 ! 8−1E) methanol masers towards a sample of thirty six class II methanolmasers.
RESULT: Seven new 37.7-GHz methanol masers were detected
The relatively high detection rate for this rare methanol transition is in line withprevious predictions that the 37.7-GHz transition is associated with a late stage of theclass II methanol maser phase of high-mass star formation.
5) The Interior Structure Constants as an Age Diagnostic for Low-M ass,
Pre-M ain Sequence Detached Eclipsing Binary Stars
Gregory A. Feiden1 and Aaron Dotter2 1301.6049
accurate age estimates
方法 apsidal motion of detached eclipsing binaries (DEBs)を使う。can provide precise
masses and radii for the component stars
If the binary orbit is elliptical, the distorted gravitational potential will cause the orbit
to precess.
the equilibrium configuration of star A will become ellipsoidal. Subsequently, thegravitational potential of star A will also become ellipsoidal.

low-mass, pre-main sequence stars undergoing radiative core contraction display
rapidly changing interior structure constants (greater than 5% per 10 Myr) that, whencombined with observational determinations of the interior structure constants (with 5– 10% precision), allow for a robust age estimate.
観測	  no known systems where this technique is applicable. Kepler/LSST6) On the radio–X-simultaneous X-ray and radio observations
METHOD: the Orion Nebula Cluster (ONC) の(To considerably increase the samplesize) multi-epoch non-simultaneous archival Chandra X-ray and NRAO Very Large
Array (VLA) single-band radio data.
RESULTS: (1) We find that only a small fraction of the X-ray sources (7%) have radio
counterparts, even if 60% of the radio sources have X-ray counterparts.
WTTSproplyd(2) too low to distinguish thermal and nonthermal radio sources.
Both detection のものは the empirical “G¨udel-Benz” (GB) relation	 

LX/LR ≈ 1015±1 Hzに似る。
(3) the sources not compatible with the GB relation are proplyds
7)

TheEffectofIrradiationontheJeans

M ass

inFragm enting

Self-Gravitating Protostellar Discs
Duncan Forgan1 and Ken Rice1 1301.1151(1) to first-order, that disc fragmentation is suppressed when compared to thenon-irradiated case, although previous work has shown that the details are complicatedby the source of the irradiation.
(2) We expand on previous analysis of the Jeans mass inside spiral structures inself-gravitating discs, incorporating the effects of stellar irradiation and background
irradiation.

Toomre's criterion(a)gravitationally unstable, (b) spiral waves, (c) producing stresses and providing

heating through shocks. <-- described as a pseudo-viscosity
pseudo-viscosity description fails if the disc is too massive or geometrically thickbalancebetweencoolingand

heating-->

marginallystabledisk(Paczynski 1978).
A consensus: there is a maximum value of that the disc can sustain before quasisteady
self-gravitating torques saturate:
αcrit <~0.06 (Gammie 2001; Rice et al. 2005), which is supported by numericalexperiments (Cossins et al. 2009),
方法：We construct simple one dimensional disc models, where the disc maintains
thermal equilibrium between the heating due to self-gravitating spiral structures,
irradiation and the radiative cooling
結果：If irradiation is present, fragmentation is suppressed for marginally unstable discs
at low accretion rates (compared to the no-irradiation case), but these lower accretion
rates correspond to higher mass discs.

Jeans masssuppressed8) An analysis of the deuterium fractionation of star-forming cores in the Perseus
molecular cloud
R.K. Friesen1,2, H.M. Kirk3 and Y.L. Shirley4 1301.1875
背景：重水素化 H_3+の重水素化による。元素比 D/H=10^-5 だが	 発熱反応だがΔE=232K 小ゆえ、T>～20K では両反応が十分起こる、低温で右への反応が進み、重水素化。
H_3^+が関与する化学反応により、他の分子も重水素化する。
低質量星なしコア N2D の重元素同位体比 R_D<0.2、原始星 R_D<0.5。

OBSERVATION: first systematic survey of N2D+ 2-1 and N2D+ 3-2 observations
toward 64 N2H+-bright starless and protostellar cores in the Perseus molecular cloud.
using the Arizona Radio Observatory Submillimeter Telescope and Kitt Peak 12m
telescope.
結果：(1) a mean deuterium fractionation in N2H+, RD = N(N2D+) /N(N2H+), of 0.08,
with a maximum RD = 0.2.
(2) In detected sources, we find no significant difference in the deuterium fractionation
between starless and protostellar cores, nor between cores in clustered or isolatedenvironments.
(3) significant correlations between the deuterium fraction and increased H2 columndensity, as well as with increased central core density, for 22 all cores.
(4) protostellar sources, a significant anti-correlation between RD and bolometrictemperature.
議論：the Perseus cores are characterized by low CO depletion values relative toprevious studies of star forming cores, similar to recent results in the Ophiuchus
molecular cloud.
the low average CO depletion is the dominant mechanism that constrains the average
deuterium fractionation in the Perseus cores to small values. CO が豊富な環境では生成された H2D+が DCO+生成などに使われる。
9) A three-phase chem ical m odel of hot cores: the form ation of glycine
Robin T. Garrod1
A new chemical model is presented that simulates fully-coupled gas-phase,grain-surface and bulk-ice (3-phase) chemistry in hot cores.
Glycine (グリシンアミノ酸 NH2CH2COOH), glycinal (amino aldehyde NH2CH2CHO),
propionic acid ( プ ロ パ ン 酸 CH3CH2COOH) and propanal (propionaldehydeCH3CH2CHO)
結果：1) Glycine is found to form in moderate abundance 場所は within and upondust-grain ices
Peak gas-phase glycine fractional abundances lie in the range 8×10^-11~8×10^-9,occuring at

200 K, the evaporation temperature of glycine. within and upon dust-grain

ices via three radical-addition mechanisms
gas-phase reaction is insignificant.
2) The current lack of a detection of glycine toward hot cores may be explained by its
high temperature of evaporation, which results in a small emission radius. Glycine is
not expected to be detectable with single-dish instruments over realizable integration

times toward any hot-core source.
10) XM M -Newton m onitoring of the close pre-m ain-sequence binary AK Sco.
Evidence of tide driven filling of the inner gap in the circum binary disk
Ana In´es G´om ez de Castro1, Javier L´opez-Santiago2, Antonio Talavera3,A.Yu. Sytov4, and D. Bisikalo4 1301.6966
背景：AK Sco: pre-main sequence binaries because of its prominent ultraviolet excess.
two F5 type stars that get as close as 11R

at periastron2) a dense (n_e10^11 cm^−3) extended envelope = stellar magnetosphere; Eachextends toand is highly turbulent

1.7R

OBSERVATION: X-ray/UV monitor of AK Sco by XMM (March 15th-22nd, 2011)
RESULTS: at periastron, X-ray and UV fluxes are enhanced by a factor of3 withrespect to the apastron values.
Using XSPEC: T

6.4×10^6 K and the NH column density ~0.35×10^21 cm^−2 atperiastron to 1.11×10^21 cm^−2 at apastron,
シ ミ ュ レ ー シ ョ ン と の 比 較 ： Numerical simulations of the mass flow from thecircumbinary disk1) At apastron, matter is dragged efficiently from the inner disk border, filling the innergap and producing accretion streams that end as ring-like structures around eachcomponent of the system.
2) At periastron, the ring-like structures come into contact, leading to angularmomentum loss, and thus producing an accretion outburst.
主星への降着率。近星点付近で最大

近星点

遠星点

遠星点