Vy 1-2
| 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
[edit source]Vy 1-2 contains a faint outer shell and two much fainter knots at a (position angle) PA of 305°. The S knot is located 14.5 arcsec from the central star while the N 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 found to be 5200 ± 750 yr for a distance = 9.7 kpc.[3] 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.[5] The systemic heliocentric radial velocity of the nebula is Vsys = -85 ± 4 km s-1.[6] Vy 1-2 has been a candidate for a halo PN because of its high systemic velocity (~500 pc) from the galactic plane.[7]
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.[8] The [N II] emission line shows a high expansion velocity of 90–100 km s−1 only along the PA = 310° whereas the He II expansion velocity is ~23-25 ± 4 km s-1.[9]
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.[10]
Central star
[edit source]The central star is relatively unknown, it is possibly a WR or a strong and fast WEL nucleus,[11] 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.[12]
References
[edit source]- 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 3 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. Cite error: Unknown parameter "<ref" in
<ref>tag; supported parameters are dir, follow, group, name (see the help page). - ↑ 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.
- ↑ 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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