BETA ZEN
Vy 1-2
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| Emission nebula | |
|---|---|
| Planetary nebula | |
 Image from the NASA/ESA Hubble Space Telescope with color rendering done by aladin software | |
| Observation data: J2000 epoch | |
| Right ascension | 17h 54m 22.98s[1] |
| Declination | +27° 59′ 58.1″[1] |
| Distance | 15,300-47,292[2][3] ly |
| Constellation | Hercules |
| Designations | PK 053+24 1, PN G053.3+24.0[1] |
Vy 1-2 is a planetary nebula discovered by Russian-American astronomer Alexander N. Vyssotsky in 1942.[4]
General information
Vy 1-2 contains a faint outer shell and two much fainter knots at a position angle (PA) of 305°. The south knot is located 14.5 arcsec from the central star while the north knot is located 11.5 arcsec form the central star. The knots deprojected radial expansion velocity is 90–100 km s−1, and their kinematic age is 5200 ± 750 yr for a distance = 9.7 kpc.[5] Vy 1-2 also has a bright-elliptical ring like structure with a minor axis of 2.4 arcsec and a major axis of 3.2 arcsec. The distance of Vy 2-1 remains uncertain, with estimates ranging from 7.0 to 14.5 kpc,[3] calculated using a mean radius of ~1.4 arcsec.[6] The systemic heliocentric radial velocity of the nebula is Vsys = -85 ± 4 km s-1.[7] Vy 1-2 has been a candidate for a halo PN because of its high systemic velocity (~500 pc) from the galactic plane.[8]
The Zanstra temperature of the He I line is 75.4 ± 10.2kK while the He II line is 99.8 ±4.3kK. The logarithmic Hβ flux is estimated to be -11.52 ± 0.01.[9] The N II emission line shows a high expansion velocity of 90–100 km s−1 only along the PA = 310° and the He II expansion velocity is ~23-25 ± 4 km s-1.[10]
The electron temperatures of the N II and O I emission line is Te = 10,850 ±2100 K and 10,400 ± 5400 K respectively, while the electron densities of the following emission lines are: the S II with a Ne = 4500 ± 650 cm-3, the Cl III with a Ne = 4330 ± 1600 cm-3, and the Ar IV with a Ne = 4550 ± 1300 cm-3.[11]
Central star
The central star is unknown, possibly a WR or a strong and fast WEL nucleus,[12] with the detection of C II, C IV, and O III stellar lines supports the scenario. Anonther scenario used to prove a anomaly in BD +30° 3639" suggests the central star is a binary system.[13]
References
- 1 2 3 "PN Vy 1-2". Simbad.cds.unistra.fr.
- ↑ Maciel, W. J. (February 1984). "A catalogue of distances of planetary nebulae". Astronomy & Astrophysics Supplement Series. 55: 253–258. Bibcode:1984A&AS...55..253M.
- 1 2
- ↑ Vyssotsky, A. N. (June 1942). "Four New Planetary Nebulae". Publications of the Astronomical Society of the Pacific. 54 (319): 152. Bibcode:1942PASP...54..152V. doi:10.1086/125424.
- ↑ name = "dist">Akras, S.; Boumis, P.; Meaburn, J.; López, J. A.; Gonçalves, D. R. (September 2015). "Evidence for a [WR] or WEL-type binary nucleus in the bipolar planetary nebula Vy 1-2". Monthly Notices of the Royal Astronomical Society. 452 (3): 2911–2929. doi:10.1093/mnras/stv1468.
- ↑ Cahn, J. H.; Kaler, J. B. (January 1971). "The Distances and Distribution of Planetary Nebulae". Astrophysical Journal Supplement Series. 22: 319. Bibcode:1971ApJS...22..319C. doi:10.1086/190227.
- ↑ Schneider, S. E.; Terzian, Y.; Perinotto, M.; Purgathofer, A. (August 1983). "Radial velocities of planetary nebulae". Astrophysical Journal Supplement Series. 52: 339–423. Bibcode:1983ApJS...52..399S. doi:10.1086/190874.
- ↑ Quireza, C.; Rocha-Pinto, H. J.; Maciel, W. J. (November 2007). "Bayesian posterior classification of planetary nebulae according to the Peimbert types". Astronomy and Astrophysics. 475 (1): 217–231. arXiv:0709.0711. Bibcode:2007A&A...475..217Q. doi:10.1051/0004-6361:20078087.
- ↑ Barker, T. (February 1978). "Spectrophotometry of planetary nebulae. I. Physical conditions". Astrophysical Journal. 219: 914–930. Bibcode:1978ApJ...219..914B. doi:10.1086/155854.
- ↑ Meaburn, J.; Boumis, P.; López, J. A.; Harman, D. J.; Bryce, M.; Redman, M. P.; Mavromatakis, F. (July 2005). "The creation of the Helix planetary nebula (NGC 7293) by multiple events". Monthly Notices of the Royal Astronomical Society. 360 (3): 963–973. arXiv:astro-ph/0504295. Bibcode:2005MNRAS.360..963M. doi:10.1111/j.1365-2966.2005.09083.x.
- ↑ Crabtree, D. R.; Barnes, J. V.; Hanisch, R. J.; Shaw, R. A.; Dufour, R. J. (1994). Astronomical Data Analysis Software and Systems III (Handcover). Astronomical Society of the Pacific. ISBN 9780937707807.
- ↑ Gesicki, K.; Zijlstra, A. A. (January 2003). "High-velocity regions in planetary nebulae". Monthly Notices of the Royal Astronomical Society. 338 (2): 347–359. arXiv:astro-ph/0211029. Bibcode:2003MNRAS.338..347G. doi:10.1046/j.1365-8711.2003.06048.x.
- ↑ Steffen, W.; Akras, S. (May 2012). "'Distance mapping' and the 3D structure of BD +30° 3639". Monthly Notices of the Royal Astronomical Society. 423 (1): 925–933. arXiv:1203.3579. Bibcode:2012MNRAS.423..925A. doi:10.1111/j.1365-2966.2012.20928.x.
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