 | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 19h 23m 05.30s[1] |
| Declination | 04° 57′ 19.1″[1] |
| Apparent magnitude (V) | 3.9 Max. 17.1 Min.[2][3] |
| Characteristics | |
| Variable type | Classical Nova[3], eclipsing binary[4] |
| Astrometry | |
| Parallax (π) | 0.5615 ± 0.1281 mas[5] |
| Distance | 1,239+422 −127[3] pc |
| Absolute magnitude (MV) | −8.2 Max. 4.8 Min.[2][3] |
| Orbit[6] | |
| Period (P) | 0.1346 days |
| Semi-major axis (a) | 1.17 - 1.24 R☉ |
| Inclination (i) | 78.5[7]° |
| Details | |
| white dwarf | |
| Mass | 0.92 - 1.13[6] M☉ |
| Luminosity | 750 - 3,000[7] L☉ |
| Temperature | >100,000 (2000)[8] K |
| donor | |
| Mass | 0.28[6] M☉ |
| Temperature | 3,000[7] K |
| Other designations | |
Nova Aquilae 1999 b, AAVSO 1918+04 | |
| Database references | |
| SIMBAD | data |
V1494 Aquilae or Nova Aquilae 1999 b was a nova which occurred during 1999 in the constellation Aquila and reached a brightness of magnitude 3.9 on 2 December 1999.[2] making it easily visible to the naked eye.[9] The nova was discovered with 14×100 binoculars by Alfredo Pereira of Cabo da Roca, Portugal at 18:50 UT on 1 December 1999, when it had a visual magnitude of 6.0.[10]
V1494 Aquilae is classified as a fast nova, meaning it faded from peak brightness by more than 3 magnitudes in less than 100 days.[11] During its decline, V1494 Aql produced unusual variations in its x-ray radiation, including a bright burst lasting several minutes. During 2000, the x-ray spectrum developed from a hard (high energy) emission-line spectrum to a spectrum typical of a super soft X-ray source. The x-ray intensity varied with a period of about 40 minutes, probably due to pulsations induced in the white dwarf by its re-kindled hydrogen fusion.[8]
All novae are binary systems with two stars orbiting so close to each other that one star, the "donor" star transfers matter to the other star which is a white dwarf. In the case of V1494 the white dwarf has a mass of 1.20M☉, and it is accreting mass from the donor star at a rate of 2.1 × 10−10 M☉ yr−1.[12] The stars' orbital period is 3.23 hours,[11] and the system is an eclipsing binary with two brightness minima each orbit, one 0.5 and one 0.1 magnitudes deep.[2][4] This apparently is a measurement of two stars of approximately equal brightness, the nova and a companion 1.4″ to the south east. Measuring only the brightness of the nova, the eclipses are about two magnitudes deep.[13] The white dwarf is probably an oxygen-neon-magnesium type.[6]
Unlike some novae, the material ejected from V1494 Aquilae has not formed a visible nebula around the star.[14] However, a shell approximately 6.5″ across has been detected spectroscopically in H-alpha emission.[13]
The distance to V1494 Aquilae has been estimated by different methods. Early estimates were based on assumptions about the luminosity of the nova and gave distances around 1.2 kpc.[7] Later models assumed distances of up to 2.2 kpc.[6] Comparison of the measured shell size with the observed expansion velocity give a distance of 1.2±0.2 kpc.[13] Gaia DR2 published a parallax of 0.8394±0.1415 mas, corresponding to a distance of 1,239+422
−127 kpc.[3] Gaia EDR3 published a parallax of 0.5615±0.1281 mas, corresponding to a distance around 1,800 kpc.[5]
References
- ^ a b "V1494 Aql". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-12-05.
- ^ a b c d Barsukova, E.A.; Goranskii, V.P. (March 2003). "The Orbital Period of Nova Aquilae 1999 No. 2 (V1494 Aql)". Astronomy Letters. 29 (3): 195–198. Bibcode:2003AstL...29..195B. doi:10.1134/1.1558159. S2CID 119929145.
- ^ a b c d e Schaefer, Bradley E. (2018). "The distances to Novae as seen by Gaia". Monthly Notices of the Royal Astronomical Society. 481 (3): 3033–3051. arXiv:1809.00180. Bibcode:2018MNRAS.481.3033S. doi:10.1093/mnras/sty2388. S2CID 118925493.
- ^ a b Kato, Taichi; Ishioka, Ryoko; Uemura, Makoto; Starkey, Donn R.; Krajci, Tom (March 2004). "V1494 Aql: Eclipsing Fast Nova with an Unusual Orbital Light Curve". Publications of the Astronomical Society of Japan. 56: S125–S131. arXiv:astro-ph/0310519. Bibcode:2004PASJ...56S.125K. doi:10.1093/pasj/56.sp1.S125. S2CID 8328265.
- ^ a b Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ a b c d e Hachisu, Izumi; Kato, Mariko (2010). "A Prediction Formula of Supersoft X-Ray Phase of Classical Novae". The Astrophysical Journal. 709 (2): 680–714. arXiv:0912.1136. Bibcode:2010ApJ...709..680H. doi:10.1088/0004-637X/709/2/680. S2CID 118577218.
- ^ a b c d Hachisu, Izumi; Kato, Mariko; Kato, Taichi (2004). "Detection of Two-armed Spiral Shocks on the Accretion Disk of the Eclipsing Fast Nova V1494 Aquilae". The Astrophysical Journal. 606 (2): L139–L142. arXiv:astro-ph/0403589. Bibcode:2004ApJ...606L.139H. doi:10.1086/421295. S2CID 16575884.
- ^ a b Drake, Jeremy J.; Wagner, R. Mark; Starrfield, Sumner; Butt, Yousaf; Krautter, Joachim; Bond, H. E.; Della Valle, M.; Gehrz, R. D.; Woodward, Charles E.; Evans, A.; Orio, M.; Hauschildt, P.; Hernanz, M.; Mukai, K.; Truran, J. W. (2003). "The Extraordinary X‐ray Light Curve of the Classical Nova V1494 Aquilae (1999 No. 2) in Outburst: The Discovery of Pulsations and a "Burst"". The Astrophysical Journal. 584 (1): 448–452. arXiv:astro-ph/0210072. Bibcode:2003ApJ...584..448D. doi:10.1086/345534. S2CID 14866037.
- ^ Nemiroff, R.; Bonnell, J., eds. (15 December 1999). "A Nova in Aquila". Astronomy Picture of the Day. NASA. Retrieved 7 December 2020.
- ^ Dicicco, D.; Vitorino, C.; Green, D.W.E. (December 1999). "Nova Aquilae 1999 No. 2". IAU Circular. 7323: 1. Bibcode:1999IAUC.7323....1D.
- ^ a b Ritter, H.; Kolb, U. (June 2003). "Catalogue of cataclysmic binaries, low-mass X-ray binaries and related objects (Seventh edition)". Astronomy & Astrophysics. 404: 301–303. arXiv:astro-ph/0301444. Bibcode:2003A&A...404..301R. doi:10.1051/0004-6361:20030330. S2CID 61117701.
- ^ Shara, Michael M.; Prialnik, Dina; Hillman, Yael; Kovetz, Attay (June 2018). "The Masses and Accretion Rates of White Dwarfs in Classical and Recurrent Novae". The Astrophysical Journal. 860 (2): 110. arXiv:1804.06880. Bibcode:2018ApJ...860..110S. doi:10.3847/1538-4357/aabfbd. S2CID 55851634.
- ^ a b c Barsukova, E. A.; Valeev, A. F.; Goranskij, V. P.; Zharova, A. V. (October 2013). "Spectroscopic detection of resolved ejecta of nova V1494 Aql". The Astronomer's Telegram. 5454 (5454): 1. Bibcode:2013ATel.5454....1B.
- ^ Sahman, D.I.; Dhillon, V.S.; Knigge, C.; Marsh, T.R. (August 2015). "Searching for nova shells around cataclysmic variables". Monthly Notices of the Royal Astronomical Society. 451 (3): 2863–2876. arXiv:1505.06048. Bibcode:2015MNRAS.451.2863S. doi:10.1093/mnras/stv1150. S2CID 62784187.
External links
- www.tsm.toyama.toyama.jp
- Simbad
- Image V1494 Aquilae
- V1494 Aql International Variable Star Index
- V1494 Aql AAVSO comparison chart
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This page was last edited on 10 September 2023, at 21:02