V1494 Aquilae
Template:Location mark Location of V1494 Aquilae (circled in red) | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Aquila |
| Right ascension | Template:RA[1] |
| Declination | Template:DEC[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 | Script error: No such module "val".[3] pc |
| Absolute magnitude (MV) | −8.2 Max. 4.8 Min.[2][3] |
| Orbit[6] | |
| Period (P) | 0.1346 days |
| Semi-major axis (a) | Template:Solar radius |
| Inclination (i) | 78.5[7]° |
| Details | |
| white dwarf | |
| Mass | 0.92 - 1.13[6] Template:Solar mass |
| Luminosity | 750 - 3,000[7] Template:Solar luminosity |
| Temperature | >100,000 (2000)[8] K |
| donor | |
| Mass | 0.28[6] Template:Solar mass |
| Temperature | 3,000[7] K |
| Metallicity [Fe/H] | {{{metal_fe2}}} dex |
| Other designations | |
| Template:Odlist | |
| Database references | |
| SIMBAD | data |
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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 1.20[[Solar mass|Template:Solar mass]], and it is accreting mass from the donor star at a rate of 2.1 × 10−10 Template:Solar mass 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 Script error: No such module "val". 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 Script error: No such module "val". 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 Script error: No such module "val"..[7] Later models assumed distances of up to Script error: No such module "val"..[6] Comparison of the measured shell size with the observed expansion velocity give a distance of Script error: No such module "val"..[13] Gaia DR2 published a parallax of Script error: No such module "val"., corresponding to a distance of Script error: No such module "val"..[3] Gaia EDR3 published a parallax of Script error: No such module "val"., corresponding to a distance around Script error: No such module "val"..[5]
References
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- ↑ a b Template:Cite simbad
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- ↑ a b Template:Cite Gaia EDR3
- ↑ a b c d e Script error: No such module "Citation/CS1".
- ↑ a b c d Script error: No such module "Citation/CS1".
- ↑ a b Script error: No such module "Citation/CS1".
- ↑ Template:Cite APOD
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- ↑ a b Script error: No such module "Citation/CS1".
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- ↑ a b c Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
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External links
- www.tsm.toyama.toyama.jp
- Simbad
- Image V1494 Aquilae
- V1494 Aql International Variable Star Index
- V1494 Aql AAVSO comparison chart