IRAS 19475+3119
 IRAS 19474+3119 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19h 49m 29.5627s[1] |
| Declination | +31° 27′ 16.221″[1] |
| Apparent magnitude (V) | 9.52[2] 9.33 - 9.50[3]) |
| Characteristics | |
| Evolutionary stage | Protoplanetary nebula |
| Spectral type | F3 Ibe[4] |
| Variable type | SRd[3] |
| Astrometry | |
| Proper motion (μ) | RA: -0.6[2] mas/yr Dec.: -2.8[2] mas/yr |
| Distance | 4,900[5] pc |
| Details | |
| Mass | 0.63[5] M☉ |
| Radius | 58[5] R☉ |
| Luminosity | 8,300[5] L☉ |
| Surface gravity (log g) | 0.5[5] cgs |
| Temperature | 7,200[4] K |
| Metallicity [Fe/H] | −0.25[4] dex |
| Other designations | |
IRAS 19475+3119 is a protoplanetary nebula in the constellation of Cygnus, 15,000 light-years away. The central star is an F-type post-AGB star.
The brightest portion of the nebula shows a quadrupolar structure, with elongated bipolar lobes, all surrounded by a faint halo.[6]
The distance is essentially unknown. Assumptions about the luminosity have been used to estimate the distance and other stellar parameters. At an assumed kinematical distance of 4.9 kpc, the luminosity is 8,300 L☉ and the radius 58 R☉.[5] The star was originally at least 2.5 M☉ and is now 0.63 M☉.[6] Assuming a luminosity of 3,500 L☉, the distance becomes 1.5 kpc.[7] Estimates based on the oxygen spectral line strengths give much higher values luminosities with an absolute magnitude of at least −8.[4]
The central star is variable, from about 9.33 to 9.50. A primary period of 41 days has been determined, but a slightly shorter secondary period leads to long beats causing variations in the amplitude and apparent period from year to year. The variations are caused by stellar pulsations, with the star being brightest when it is hottest. The temperature varies by up to 400 K.[8]
References
- 1 2 Hog, E.; Kuzmin, A.; Bastian, U.; Fabricius, C.; Kuimov, K.; Lindegren, L.; Makarov, V. V.; Roeser, S. (1998). "The TYCHO Reference Catalogue". Astronomy and Astrophysics. 335: L65. Bibcode:1998A&A...335L..65H.
- 1 2 3 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27. Bibcode:2000A&A...355L..27H.
- 1 2 Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
- 1 2 3 4 Klochkova, V. G.; Panchuk, V. E.; Tavolzhanskaya, N. S. (2002). "HD 331319: A Post-AGB F Supergiant with He I Lines". Astronomy Letters. 28: 49. Bibcode:2002AstL...28...49K. doi:10.1134/1.1434453.
- 1 2 3 4 5 6 Hsu, Ming-Chien; Lee, Chin-Fei (2011). "An Envelope Disrupted by a Quadrupolar Outflow in the Pre-planetary Nebula IRAS 19475+3119". The Astrophysical Journal. 736: 30. arXiv:1105.2410
. Bibcode:2011ApJ...736...30H. doi:10.1088/0004-637X/736/1/30. - 1 2 Sahai, Raghvendra; Sánchez Contreras, Carmen; Morris, Mark; Claussen, Mark (2007). "A Quadrupolar Preplanetary Nebula: IRAS 19475+3119". The Astrophysical Journal. 658: 410. Bibcode:2007ApJ...658..410S. doi:10.1086/511294.
- ↑ Vickers, Shane B.; Frew, David J.; Parker, Quentin A.; Bojičić, Ivan S. (2015). "New light on Galactic post-asymptotic giant branch stars - I. First distance catalogue". Monthly Notices of the Royal Astronomical Society. 447 (2): 1673. arXiv:1403.7230. Bibcode:2015MNRAS.447.1673V. doi:10.1093/mnras/stu2383.
- ↑ Hrivnak, Bruce J.; Lu, Wenxian; Nault, Kristie A. (2015). "Variability in Proto-planetary Nebulae. IV. Light Curve Analysis of Four Oxygen-rich, F Spectral Type Objects". The Astronomical Journal. 149 (6): 184. Bibcode:2015AJ....149..184H. doi:10.1088/0004-6256/149/6/184.