2. 特異新星 V838 Mon の電波観測、その後。 出口修至 （国立天文台野辺山） 、 松永典之、福士比奈子 ( 東大天文セ ) Kaminski (N. Kopernicus Center, Poland)

3. V838 Monocerotis ？ Nova （  =-3° ） 2002/01 erupted Light echo Spectra->M supergiant TiO, metal 4  m SiO. Abs em. New type of Nova 7.5+0.5Msun merger 何年続くか？ SAAO 1m

4. Conclusion （２００５） 1. V838 Mon emits SiO Masers, approving a cool mass-losing star 2. V lsr : distance 7 kpc 3. --> Eruptive formation of M- supergiant : living example of stellar merger

5. Nobeyama Radio Observatory 45-m telescope 6-element 10-m mm-wave interferometer Solar Heliograph (80cm x84 elements) 22-115 GHz Beam 40” at 43 GHz Tsys=200 K (2GHz bandwidth)

6. SiO Maser? (NRO45m ） SiO J=1-0 v=1/2 at 43 GHz on 2005/02/23 2005/04/24 again (J=2-1 v=1 negative) 2005/05/23 H 2 O maser at 22GHz negative

7. 記念写真 (2005/02/23)

8. Further Observations ( Dec. 17, 2005) SiO at ~43 GHz SiO at 86 GHz CO 115 GHz H2O at ~22 GHz

9. M-supergiant created? 爆発前の観測 2MASS blue star >13 K=4-5 mag IRAS 07015-0346 (F 12 =0.25 Jy) No MSX obj. F 10 = 10 Jy at present Projenitor is not M-gaint 7.5+0.5 Main sq. stars. 何年つずくか？ (120” x120”)

10. Same type, V4332 Sgr (+ M31 RV) Nova in 1994 Feb Early M0-M5 star SiO J=1-0 v=1/2 H 2 O at Nobeyama both negative

11. Implication of this discovery V lsr ＝ 54 km/s Optical V lsr =42-52 km/s (P Cyg) --> D kin =7 kpc Munari 2002 ~1kpc Bond 2003 >6.4 kpc Munari 2004 8-10 kpc Mass losing star Nova rate 1 in 10 yr SiO life ? 2000 yr Half is 100 objects ～ 1500 SiO sources 100/1500 ～ 6.6 % 10 kpc 1 in every 1 kpc (bright)

12. V838 Mon conference 2006/05/16-19 at La Palma, Spain Munari, Goranski, Bond, Henden

13. Light Echo その後

14. Distance Echo (naive) 0.7 kpc  10 kpc [Munari 2002, 2005] Kinematic (V lsr =55 km/s) 7 kpc [Deguchi et al. 2005] Echo Polarization 6.1±0.6 kpc [Sparks et al. 2008] Cluster (luminosity) 6.2±1.2 kpc [Afsar & Bond 2007]

15. Keck Spectrum (Kaminski et al. 2008) B3V ML?

16. B3V companion eclipse 2006 short dip 2008 long

17. CO mapping (2008) Deguchi, 2007 Poland: Kaminski

18. SiO Maser J=1-0 weakening J=2-1 appearing (86.243GHZ) How long ?

19. Shell structure ? Fast flow (~200 km/s) Slow flow(~20 km/s) SiO not fast flow

20. Conclusion 1. V838 Mon emits SiO Masers, approving a cool mass-losing star 2. V lsr : distance 7 kpc 3. --> Eruptive formation of M- supergiant : living example of stellar merger How long does it continue ?

21. Structure of a Merged star Hayashi phase (1961) proto-star PASJ 13, 450 (roll of convection) SPH calc. MS-MS Lombardi et al. 2003 (references)

22. Tk=1000-3000 K r=1--2 x10 14 cm 8 micron foundamental 4 micron first overtone H 2 O maser T=300--600K. SiO maser a probe of inner envelope near photosphere SiO maser lines in vibrational states

23. Historical Light Echo Ever Observed Nova Per 1901 (GK Per) Discovered on Feb. 21, 1901(first nova in 20c) by Thomas Anderson, an Edinburgh Amature Max 0.2 Mag ->4th in 2w then oscillate 6 mo. later light echo With rapid expansion >c Kapteyn 1902 explained

24. Light Echo Where is the dust ? van Loon circumstellar origin ejected material from AGB phase Tylenda interstellar

25. Eruptive Formation of M- Supergiants Born Again Hypo. Post-AGB + MS ? He-shell flash T. Kato 2004 (V4334 Sgr Sakurai obj.) Merger Hypo. MS+dwarf binaries Tylenda 2004/5 Globular cluster SiO maser objects PN/OH/SiO/IR = V1018 Sco (Cohen et al. 2005)