V603 Orel (New in Orel, 1918, V603 Aql, Nova Aquilae 1918) is the brightest new star recorded over the past 300 years. The unexpectedly large number — 603 — in New Eagle of 1918 is explained by the fact that the system of designations for variable stars was consistently extended to all new stars after World War II [7] .
| V603 Eagle | |||
|---|---|---|---|
| Double star | |||
| Research history | |||
| opening date | June 8, 1918 | ||
| Observational data ( Epoch J2000.0 ) | |||
| Type of | New star | ||
| Right ascension | |||
| Declination | |||
| Distance | 800 of sv. years (250 pc ) -1200 over . years (370 pc ) [1] | ||
| Visible magnitude ( V ) | V max = -1.1 m , V min = +10.8 m [2] | ||
| Constellation | Eagle | ||
| Astrometry | |||
| Radial velocity ( R v ) | -23 [2] km / s | ||
| Proper motion (μ) | RA: 10.81 [2] mas per year Dec: mas per year | ||
| Parallax (π) | 4.21 ± 2.59 [2] mas | ||
| Specifications | |||
| Spectral class | |||
| Color Indicator ( B - V ) | -0.2 ± 0.5 [2] | ||
| Color Index ( U - B ) | -0.92 [2] | ||
| Variability | New star | ||
| physical characteristics | |||
| Luminosity | ~ 2 L ☉ | ||
| Properties | Intermediate polar | ||
| Orbit elements | |||
| Period ( P ) | 3 h. 19.5 m. [3] - 0.0003 years | ||
| |||
| Information in databases | |||
| SIMBAD | data | ||
| The star has 2 components Their parameters are presented below: | |||
1918 flare
The first observation was made on the night of June 8, 1918 , when a star of the first magnitude appeared in the sky 6 ° north of the constellation Shield . At the time of discovery, the new one was brighter than the nearby Altair , and after a few hours it became the second star in the northern hemisphere of the sky (-1 m , 1 [7] ), slightly reaching the brightness of Sirius (−1 m , 47) [1] .
Among the first observers was Edward Barnard . According to photographic plates, he determined that until June 3, a small asterisk of 11 magnitude was in place of the new one, on June 7 it reached 6 m , and on June 9 (at maximum brightness) it reached −1 m , 4. After this, the new one slowly began to fade, reaching 4 m at the end of June, and 6 m in March of the following year, and it became invisible to the naked eye . During its greatest brightness, the spectrum of the star showed the presence of a gas envelope, which expanded into the interstellar medium at a speed of from 1,600 to 2,000 km / s. A few months later, a gas nebula formed around the star, whose diameter increased over several years at a speed of about 2 angular seconds per year [1] . Spectroscopic studies have shown that the mass of matter emitted during a flash (subject to the spherical shape of a nebula) is about 6 × 10 −5 [4] . The number of individual elements emitted during the explosion (in tons) was also estimated: hydrogen — 2.8 × 10 23 , helium — 3.6 × 10 23 , oxygen — 10 23 , neon — 8 × 10 20 , carbon — 5, 5 × 10 20 [8] . Subsequently, this nebula became increasingly dull, and then dissipated in space. The distance calculated by parallax is estimated from 800 to 1200 sv. years and from here it can be concluded that the ordinary luminosity of a star is about 2 times the solar one . Its maximum absolute magnitude was about −9 m , 3. This means that in just six days (from June 3 to June 9, 1918), the system increased its brightness 100,000 times [1] .
Eagle's V603 System
The V603 Eagle system itself is an intermediate polar [9] . Intermediate polars are cramped binary systems consisting of a cold subdwarf (usually a red star) and a hot white dwarf . Circulation periods in such systems are very short: for the Eagle's V603, 3 hours 19.5 minutes [3] . The orbit of this system is inclined to the line of sight at an angle of about 17 °, that is, it is almost visible from the edge. This makes it difficult to observe, especially spectral. Also, this study showed that the mass of a white dwarf is 0.8 and the satellite mass is 0.3 [4] . An analysis conducted in the late 1950s showed that the white dwarf temperature at rest is 60,000 K , and during the outbreak it reached 145,000 K [8] . The reason for the giant flare that occurred in 1918 is not entirely clear, since other stars of this class did not have such powerful flares. It is possible that they occur in other intermediate polars, but the intervals between flashes are very long: tens and hundreds of thousands of years.
In April 2001, observations of the Eagle's V603 system were carried out on Chandra and RXTE X-ray telescopes. It was found that the X-ray luminosity and the energy distribution in the V603 Aql spectrum resemble the Cygnus SS system. The fact that the variability of the x-ray flux is weakly dependent on energy can be explained by the fact that it is associated with changes only in the maximum plasma temperature. Plasma density is very high; It is concentrated in a relatively small area. An excess of Ne in the Eagle V603 spectrum indicates that the stars forming the system are quite young [10] . Also, pulsations were detected in the ultraviolet with a period of 62.9 minutes, which is very close to the period of x-ray and optical pulsations discovered earlier. The UV pulses have a sinusoidal shape and amplitude that differs by 8 percent from the amplitudes in the X-ray and optical ranges . The origin of the pulses is the same in all ranges: it is associated with the rotation of a magnetized white dwarf [11] .
Notes
- ↑ 1 2 3 4 Fredi de Maria. V603 (ital.) (Inaccessible link) . Stelle dell'Aquila . Archived December 28, 2012.
- ↑ 1 2 3 4 5 6 7 : NOVA Aql 1918 (Eng.) . SIMBAD . Center de Données astronomiques de Strasbourg . Archived December 28, 2012.
- ↑ 1 2 V.P. Tsesevich . The nature of "dwarf" new stars (Inaccessible link) . Variable stars and their research methods (1969). Archived December 28, 2012.
- 2 1 2 3 4 Pierluigi Selvelli, Michael Friedjung, Angelo Cassatella. The HST-GHRS Spectrum of the Old Nova V603 Aql (eng.) . Archived December 28, 2012.
- ↑ From the dependence of the mass-radius for white dwarfs
- ↑ SIMBAD Astronomical Database
- ↑ 1 2 Samus N. N. CHAPTER 3. EXPLOSIVE AND NEW-LIKE VARIABLE STARS . VARIABLE STARS . Archived July 6, 2012.
- 2 1 2 Pottasch, S. The nova outburst: V. Annales d'Astrophysique, Vol. 22, p. 412 (February 1959). Archived December 28, 2012.
- ↑ Gnedin, Yu. N .; Borisov, NV; Natsvlishvili, TM The intermediate polar V603 AQL (English) . The Smithsonian / NASA Astrophysics Data System (July 16, 1990). Archived December 28, 2012.
- ↑ K. Mukai, M. Orio. X-ray Observations of the Old Nova V603 Aquilae (English) . arxiv.org (December 20, 2004).
- ↑ Schwarzenberg-Czerny, A .; Udalski, A .; Monier, R. Possible first detection of ultraviolet pulses from an intermediate polar - V603 Aquila (Eng.) . Astronomy Abstract Service (December 1992). Archived December 28, 2012.