KVN

KVN Key Science Project for Evolved Stars

Simultaneous Monitoring Obs. of H2O and SiOMasers toward Evolved Stars

2019 Radio Telescope User’s Meeting

August 29-30, 2019

Seoul National University in Pyeongchang

Se-Hyung Cho and KVN KSP Members

KVN

◆ Scientific Goals ◆ Target Sources & Number of Obs.

◆ Individual Sources: SFPR Maps & Movies of H2O and SiOMasers etc.○ VX Sgr, VY CMa, IK Tau, R Crt, V627 Cas

◆ Summary and Issues of 1st Stage KSP Results

◆ Published Papers◆ Theses and Paper Preparations ◆ Future Works

◈KVN KSP Members

Se-Hyung Cho (P.I), Youngjoo Yun, Dong-Hwan Yoon, Haneul Yang,

Dongjin Kim (MPI), Jaeheon Kim (SHAO), Richard Dodson, María Rioja

(ICRAR), Hiroshi Imai (Kagoshima U)

Contents

KVN

1. Spatial structure and dynamical effect from SiO to 22 GHz H2Omaser regions according to stellar pulsation throughsimultaneous monitoring obs. of KVN 4 bands

○ Pulsation and shock wave propagation effect from SiO to H2O maser region via dust layer : development of outflow motion and asymmetry ► Mass loss mechanism based on combined studies of SiO and H2O masers.

2. Correlation and difference of maser properties (spatio-kinematic properties etc) among SiO J=1-0, J=2-1, J=3-2 masers ► Constraints on SiO maser excitation and

pumping models (collisional and/or radiative)

▶ Synergy with KaVA (KVN+VERA) Evolved Star Large Programand ALMA Observations.

Scientific Goals of KSP

eso.org

KVN

Target Sources & Number of VLBI Obs.

● Successful obs. rate of VLBI on obs. log. but not included failures of correlation results.

● Focused on 9 successful SFPR objects from 2016B

● Data reduction: SFPR method (Dodson et al. 2014) and SFPR pipeline (by YJ Yun 2019)

No Objects No of Obs 2015 2016 2017 2018 2019A

1 IK Tau 41 5/7 5/8 11/11 4/8 3/7

2 VY CMa 45 8/10 10/11 6/9 4/9 2/6

3 VX Sgr 34 3/6 7/9 6/8 4/9 2/2, Fin

4 R Crt 11 8/8 3/3 Fin Fin Fin

5 V1111 Oph 35 7/8 3/4 8/9 1/8 3/6

6 W Hya 38 3/5 7/10 7/8 2/9 4/6

7 V627 Cas 34 5/5 4/4 8/9 2/9 1/7

8 V5102 Sgr 24 3/4 2/2 8/9 8/8 1/1, Fin

9 WX Psc 31 1/2 5/6 6/8 6/8 4/7

10 Χ Cyg 25 1/1 1/3 6/8 2/8 1/5

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Obs. Status of KSP in 2019

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DH Yoon’s PhD thesis (2019.8)

Semi-regular variable, P~732 days

D=1.57 kpc (Chen et al. 2007)

Individual Sources : Supergiant Star VX Sgr

VLBI

SD

KVN

43 GHz SiO maps of whole monitoring: 2014-2019A

517d

583d658d

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Ring radius variations of SiO masers according to optical phases

658d 583d 517d

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Astrometrically registered integrated intensity maps

(moment zero map) of 22.2 GHz H2O and

43.1/42.8/86.2/129.3 GHz SiO masers toward VX Sgr

SFPR Maps of H2O and SiO Masers toward VX Sgr

Epoch IV

DH Yoon et al. 2018 Nature Comm.

IV

Variation of SiO ring

radius with optical light

curve. Green triangle:129.3

GHz SiO masers.

● Ring radius of 129

GHz maser increases

near max. ► Radiative

pumping is dominant.

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Astrometrically Registered Maps of H2O & SiO Masers

Supergiant Star VY CMa

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K band

(22 GHz) Q band

(43 GHz)

Q band

(42 GHz)

W band

(86 GHz)

Movies of H2O & SiO Masers (Single Band): VY CMa

Movies by YJ Yun

Sample movies

for 8 epochs

2015-02-10

2015-03-16

2016-01-11

2016-02-27

2016-04-29

2016-12-01

2017-01-04

2017-02-11

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Epoch 10, 2016 Jan. 26

Epoch 9, 2016 Jan. 7

Ring radius (SRb Type R Crt)

SiO v=1, J=1-0, J=2-1Epoch 3 13.32 12.72 (mas)Epoch 9 13.83 11.76 Epock 10 13.44 11.95

DJ Kim’s MS thesis (2017.2) ► DJ Kim et al. 2018 ApJL

Semi-regular Variable Star R Crt (SRb)

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We investigated that the variations of H2O & SiO masers are associated with the orbital motion of hot companion.

Integ. intensity maps of H2O and SiO masers: Symbiotic Star V627 Cas

HN Yang et al. ApJL in Prep.

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One-sided conical outflow ?HN Yang et al. ApJL in Prep.

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Summary and Issues of 1st Stage KSP Results(Proceedings IAU Symp. No. 336: Astrophysical Masers, Cho et al. 2018)

■ We have obtained successful SFPR maps of H2O and SiO masers from 9 sources and focused on these 9 sources.

■ Based on SFPR maps of H2O and SiO masers, we are investigating the spatial structureand kinematics from SiO to H2O maser regions: development of outward motion from ring-like/elliptical SiO to asymmetric 22 GHz H2O maser features.► Asymmetric clumpy structure and the role of dust layer ? ► SiO & H2O maser models coupled to hydrodynamical model of CSE► Collaborations with Maser Theory & VLTI teams: M. Gray et al. (2009),

Wittkowski et al. (2012)

■ Different features of registered maps of H2O and SiO masers and different SiOmaser features (ring-like, elliptical, irregular etc.) according to KSP sources ► Investigate the relation with characteristics of sources, evolutionary stage including

the relation with light curve and pulsation mode (especially, in the case of different SiO maser features) .

■ Based on registered maps of SiO J=1-0, J=2-1 and J=3-2 masers ◈ The SiO maser distribution (location) is different among SiO J=1-0, J=2-1, J=3-2

masers.► Different dominant pumping mechanism according to different SiO

transitions & sources ?

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17 Published Papers (2010-2019): Including KVN SD Survey and Monitoring for KSP Preparations at commissioning phase

￭ Jaeheon Kim, S.-H. Cho, V. Bujarrabal, H. Imai, R. Dodson, D.-H. Yoon & B. Zhang: Time

variations of H2O and SiO masers in the proto-Planetary Nebula OH231.8+4.2, 2019,

MNRAS, 488, 1427

￭ Dong-Hwan Yoon, Se-Hyung Cho, Youngjoo Yun, Yoon Kyung Choi, Richard Dodson, María

Rioja, Jaeheon Kim, Hiroshi Imai, Dongjin Kim, Haneul Yang & Do-Young Byun:

Astrometrically registered maps of H2O and SiO masers toward VX Sagittarii, 2018,

Nature Comm. 9:2534

￭ Dong-Jin Kim, Se-Hyung Cho, Youngjoo Yun, Yoon Kyung Choi, Dong-Hwan Yoon, Jaeheon

Kim, Richard Dodson, María J. Rioja, Haneul Yang, and Suk-Jin Yoon, Simultaneous VLBI

Astrometry of H2O and SiO Masers toward the Semiregular Variable R Crateris, 2018,

ApJL, 866, 19

￭ Se-Hyung Cho, Youngjoo Yun, Jaeheon Kim, Dong-Hwan Yoon, Dong-Jin Kim, Yoon Kyung

Choi, Richard Dodson, Mara Rioja & Hiroshi Imai: A study on evolved stars by simultaneous

observations of H2O and SiO masers using KVN, 2018, Proceedings IAU Symp. No. 336

Astrophysical Masers, 359

￭ R. Dodson, M. Rioja, V. Bujarrabal, J. Kim, S. H. Cho, Y. K. Choi & Y. Youngjoo: Registration

of H2O and SiO masers in the Calabash Nebula to confirm the planetary nebula paradigm,

2018, MNRAS 476, 520–527

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Theses and Paper Preparations (2010-2019)

◈ Theses

■ SD Survey & Monitoring : JH Kim (Kyunghee Univ.)

► 2013. 02 PhD Thesis ► Post-Doc at SHAO

■ R Crt (VLBI & SD Monitoring) : DJ Kim (Yonsei Univ.)

► 2016. 08 MS Thesis ►MPI PhD Course

■ VX Sgr (VLBI & SD Monitoring) : DH Yoon (SNU)

► 2019. 08 PhD Thesis ► NRF Post-Doc

■ V627 Cas (VLBI & SD Monitoring) : HN Yang (SNU)

► Under PhD Course

◈ Paper Preparations : For 9 Successful SFPR Sources

o SFPR Results ►ApJ Letter etc.

o Whole VLBI Monitoring Results + Pilot Obs. ►ApJS

o Single Dish Monitoring Results ►ApJS

KVN

■Monitoring focused on ~3-4 successful SFPR sources for

SiO & H2O Maser movies

(VY CMa, IK Tau, W Hya, WX Psc ?)

■ Polarization obs. of both SiO & H2O Masers toward successful

SFPR sources

■ Scientific interpretation and model development for SFPR

results ► Collaboration with maser model experts:

Univ. of Manchester team etc.

■ Error analyses and increase of the success rate of SFPR

maps at 4 bands including 129.3 GHz SiO maser

Future Works : 2nd KSP Stage ?