AE Aquarii

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AE Aquarii
White dwarf in AE Aquarii.jpg
Artistic illustration of the AE Aquarii system
Observation data
Epoch J2000.0       Equinox J2000.0
Constellation Aquarius
Right ascension 20h 40m 09.16206s [1]
Declination −00° 52′ 15.0618″ [1]
Apparent magnitude  (V)11.6 [2]
Characteristics
Spectral type White dwarf + K4–5 V [3]
B−V color index −1.2 [2]
Variable type DQ Her
Astrometry
Radial velocity (Rv)−53 [4]  km/s
Proper motion (μ)RA: +73.95 [1]   mas/yr
Dec.: +12.40 [1]   mas/yr
Parallax (π)11.61 ± 2.72  mas [1]
Distance approx. 280  ly
(approx. 90  pc)
Absolute magnitude  (MV)~6.6 [5]
Orbit [6]
Period (P)9.88 hours
Semi-major axis (a)2.34 ± 0.02  R☉
Inclination (i)70 ± 3°
Details
A
Mass 0.63 ± 0.05 [6]   M☉
Radius 0.01 [7]   R☉
Rotation 33.08 sec [8]
B
Mass 0.37 ± 0.04 [6]   M☉
Radius 0.79 [6]   R☉
Other designations
2E  2037.5-0102, GCRV  71273, 1RXS  J204009.4-005216, AN 342.1931, 2E  4404, GSC  05177-00636, SBC7  826, 1AXG  J204011-0052, RJHA  119, CSI-01-20376, CDS  1178, HIP  101991, 1E  2037.5-0102, 1ES  2037-01.0, 2MASS  J20400915-0052151, AAVSO  2035-01. [2]
Database references
SIMBAD data

AE Aquarii is a cataclysmic variable binary star of the DQ Herculis type. Based upon parallax measurements, the system is located at a distance of about 280 light-years (86 parsecs ) from the Earth. [1] Because of its unique properties, this system has been subject to a number of scientific studies. [3] The white dwarf in the AE Aquarii system is the first star of its type known to give off pulsar-like pulsations that are powered by its rotation and particle acceleration. [9] [10] [11]

Contents

A visual band light curve for AE Aquarii. The main plot shows the long term variability, and the inset plot shows the short term variability over one orbital period. Adapted from Simon (2020). AEAqrLightCurve.png
A visual band light curve for AE Aquarii. The main plot shows the long term variability, and the inset plot shows the short term variability over one orbital period. Adapted from Šimon (2020).

The AE Aquarii system consisting of an ordinary star in a close orbit around a magnetic white dwarf; the pair orbit each other with a period of 9.88 hours. The white dwarf primary has 63% of the Sun's mass but a radius of only about 1% of the Sun. As of 2009, it has the shortest known spin period of any white dwarf, completing a full revolution every 33.08 seconds. This spin is decreasing at a rate of 1.78  ns per year, which is unusually high. [3] The secondary star has a stellar classification of K4-5 V, making it a main sequence star that is generating energy at its core through the thermonuclear fusion of hydrogen. It has about 37% of the Sun's mass but 79% of the Sun's radius.

This system displays flare activity that has been observed across multiple bands of the electromagnetic spectrum, including X-rays. Mass is being lost from the secondary star, most of which is being flung out of the system by the rapidly spinning magnetic primary. The X-ray luminosity is likely being caused by the accretion of mass onto the white dwarf, which is occurring at an estimated rate of about 7.3 × 1010 kg per second. [3]

See also

Related Research Articles

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A pulsar is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its magnetic poles. This radiation can be observed only when a beam of emission is pointing toward Earth, and is responsible for the pulsed appearance of emission. Neutron stars are very dense and have short, regular rotational periods. This produces a very precise interval between pulses that ranges from milliseconds to seconds for an individual pulsar. Pulsars are one of the candidates for the source of ultra-high-energy cosmic rays.

<span class="mw-page-title-main">Delta Aquarii</span> Star in the constellation Aquarius

Delta Aquarii, officially named Skat, is the third-brightest star in the constellation of Aquarius. The apparent visual magnitude is 3.3, which can be seen with the naked eye. The distance to this star is about 113 light-years based upon parallax measurements, and it has a close companion.

<span class="mw-page-title-main">Beta Aquarii</span> Double star in the constellation Aquarius

Beta Aquarii is a single star in the constellation of Aquarius. It has the official name Sadalsuud and the Bayer designation β Aquarii, abbreviated Beta Aqr or β Aqr. Based upon parallax measurements obtained during the Hipparcos mission, this component is located at a distance of approximately 540 light years (165 parsecs) from the Sun. It is drifting further away with a radial velocity of 6.5 km/s. The star serves as an IAU radial velocity standard.

<span class="mw-page-title-main">Xi Aquarii</span> Star in the constellation Aquarius

Xi Aquarii is a binary star system in the equatorial constellation of Aquarius. It is visible to the naked eye with an apparent visual magnitude of 4.7. Based upon parallax measurements made during the Hipparcos mission, this system lies at a distance of around 179 light-years from the Sun.

<span class="mw-page-title-main">V1494 Aquilae</span> Nova seen in 1999 in the constellation of Aquila

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. making it easily visible to the naked eye. 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.

<span class="mw-page-title-main">91 Aquarii</span> Triple star system in the constellation Aquarius

91 Aquarii is the Flamsteed designation for a triple star system in the equatorial constellation of Aquarius. It also bears the Bayer designation Psi1 Aquarii. It is visible to the naked eye with an apparent visual magnitude of +4.248. Parallax measurements yield an estimated distance of around 150 light-years from Earth. An extrasolar planet is known to orbit the main star.

<span class="mw-page-title-main">Iota Aquarii</span> B-type main sequence star in the constellation Aquarius

Iota Aquarii, Latinised from ι Aquarii, is the Bayer designation for a binary star system in the equatorial constellation of Aquarius. It is visible to the naked eye with an apparent magnitude of +4.279. Based upon parallax measurements made during the Hipparcos mission, the distance to this star is around 175 light-years. The system is drifting closer to the Sun with a radial velocity of −10 km/s.

<span class="mw-page-title-main">Pi Aquarii</span> Star in the constellation Aquarius

Pi Aquarii, Latinized from π Aquarii, is the Bayer designation for a binary star in the equatorial constellation of Aquarius. This system has an apparent visual magnitude of a mean apparent magnitude of +4.57. Based upon parallax measurements, it is located at a distance of roughly 780 light-years from Earth. It is drifting further away with a radial velocity of +4 km/s.

104 Aquarii (abbreviated 104 Aqr) is a star in the equatorial constellation of Aquarius. 104 Aquarii is the Flamsteed designation, although it also bears the Bayer designation A2 Aquarii. Based on an annual parallax shift of only 3.89 ± 0.25 milliarcseconds, the distance to this star is about 840 light-years (260 parsecs). At that range, the brightness of the star in the V-band is reduced by 0.10 magnitudes as a result of extinction caused by intervening gas and dust.

<span class="mw-page-title-main">1 Aquarii</span> Binary star in the constellation Aquarius

1 Aquarii is a binary star system in the zodiac constellation of Aquarius, about 257 light years away from the Sun. 1 Aquarii is the Flamsteed designation. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 5.151, located a degree north of the celestial equator. The system is moving closer to the Earth with a heliocentric radial velocity of −41 km/s.

<span class="mw-page-title-main">53 Aquarii</span> Binary star in the constellation Aquarius

53 Aquarii is a binary star system in the equatorial constellation of Aquarius. 53 Aquarii is its Flamsteed designation though the star also bears the Bayer designation of f Aquarii. The combined apparent visual magnitude of the pair is a 5.56, making it just visible to the naked eye in dark suburban skies. Based upon an annual parallax shift of 49.50 milliarcseconds for the first component, this system is located at a distance of approximately 65 light-years from Earth.

44 Aquarii is a single star located 336 light years away from the Sun in the equatorial constellation of Aquarius. 44 Aquarii is its Flamsteed designation. It is visible to the naked eye as a dim, yellow-hued star with an apparent visual magnitude of 5.75. This body is moving away from the Earth with a heliocentric radial velocity of +7.4 km/s.

15 Aquarii, abbreviated 15 Aqr, is a single, blue-white star in the zodiac constellation of Aquarius. 15 Aquarii is the Flamsteed designation. It is a dim star that is just visible to the naked eye under good viewing conditions, having an apparent visual magnitude of 5.83. Based upon an annual parallax shift of 4.6 mas, it is located around 710 light years away. At that distance, the visual magnitude is diminished by an extinction of 0.18 due to interstellar dust. It is moving closer to the Earth with a heliocentric radial velocity of −9 km/s. Relative to its neighbors, 15 Aqr has a peculiar velocity of 28.7+2.9
−3.1 km/s and may be a runaway star.

60 Aquarii is a star located 375 light years away from the Sun in the equatorial constellation of Aquarius. 60 Aquarii is its Flamsteed designation. It is visible to the naked eye as a dim, yellow-hued star with an apparent visual magnitude of 5.89. The star is moving closer to the Earth with a heliocentric radial velocity of –8 km/s.

11 Aquarii is a sun-like star in the zodiac constellation of Aquarius, located 88.5 light years away from the Sun. 11 Aquarii is the Flamsteed designation. It is difficult to see with the naked eye, appearing as a dim, yellow-hued star with an apparent visual magnitude of 6.22. This body is moving closer to the Earth with a heliocentric radial velocity of −17.8 km/s, and is expected to come as close as 65.1 ly in 700,000 years.

<span class="mw-page-title-main">R Aquarii</span> Star in the constellation of Aquarius

R Aquarii is a variable star in the constellation Aquarius.

<span class="mw-page-title-main">FO Aquarii</span> Star in the constellation Aquarius

FO Aquarii is an intermediate polar star system in the constellation Aquarius. The white dwarf and companion star orbit each other with a period of approximately 4.85 hours. The system is famous for a very strong optical pulsation which occurs every 20.9 minutes, corresponding with the rotational period of the accreting white dwarf. Prior to 2016, the system's long-term optical brightness varied between apparent magnitude 12.7 and 14.2, but in early 2016, it faded to magnitude 15.8 and thereafter began a slow recovery to its normal brightness, behavior which is indicative of a temporary dropoff in the mass-transfer rate between the two stars.

<span class="mw-page-title-main">HU Aquarii</span> Star in the constellation Aquarius

HU Aquarii is an eclipsing binary system approximately 620 light-years away from the Sun, forming a cataclysmic variable of AM Herculis-type. The two stars orbit each other every 2.08 hours and the ultra-short binary system includes an eclipsing white dwarf and red dwarf.

<span class="mw-page-title-main">AR Scorpii</span> Binary pulsar system in the constellation Scorpius

AR Scorpii is a binary pulsar that consists of a white dwarf and a red dwarf. It is located close to the ecliptic plane in the constellation Scorpius. Parallax measurements made by Gaia put the system at a distance of about 380 light-years.

<span class="mw-page-title-main">HK Aquarii</span> Star in the constellation Aquarius

HK Aquarii is a single variable star in the equatorial constellation of Aquarius. It is invisible to the naked eye, having an average apparent visual magnitude that fluctuates around 10.99. The star is located at a distance of 81 light years from the Sun based on parallax. The radial velocity is poorly constrained but it appears to be drifting further away at a rate of ~2 km/s.

References

  1. 1 2 3 4 5 6 van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv: 0708.1752 . Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID   18759600.
  2. 1 2 3 "V* AE Aqr". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved July 22, 2008.
  3. 1 2 3 4 Mauche, Christopher W. (November 2009), "Chandra High-Energy Transmission Grating Spectrum of AE Aquarii", The Astrophysical Journal, 706 (1): 130–141, arXiv: 0910.0084 , Bibcode:2009ApJ...706..130M, doi:10.1088/0004-637X/706/1/130, S2CID   16457151
  4. ↑ Evans, D. S. (June 20–24, 1966). Batten, Alan Henry; Heard, John Frederick (eds.). "The Revision of the General Catalogue of Radial Velocities". Determination of Radial Velocities and Their Applications, Proceedings from IAU Symposium. University of Toronto: International Astronomical Union. 30: 57. Bibcode:1967IAUS...30...57E.
  5. ↑ From apparent magnitude and parallax.
  6. 1 2 3 4 Echevarría, J.; et al. (July 2008). "High-dispersion absorption-line spectroscopy of AE Aqr". Monthly Notices of the Royal Astronomical Society . 387 (4): 1563–1574. arXiv: 0804.0291 . Bibcode:2008MNRAS.387.1563E. doi:10.1111/j.1365-2966.2008.13248.x. S2CID   11324791.
  7. ↑ Itoh, Kei; et al. (2005). "Density diagnostics of the hot plasma in AE Aquarii with XMM-NEWTON" (PDF). The Astrophysical Journal. 639 (1): 397–404. arXiv: astro-ph/0412559 . Bibcode:2006ApJ...639..397I. doi:10.1086/499152. S2CID   14578720. Archived from the original (PDF) on 2011-07-19. Retrieved 2009-11-15.
  8. ↑ Patterson, Joseph (December 15, 1979). "Rapid oscillations in cataclysmic variables. III. An oblique rotator in AE Aquarii". Astrophysical Journal. 234: 978. Bibcode:1979ApJ...234..978P. doi:10.1086/157582.
  9. ↑ Ikhsanov, Nazar R. (1998). "The pulsar-like white dwarf in AE Aquarii". Astronomy and Astrophysics. 338: 521–526. Bibcode:1998A&A...338..521I.
  10. ↑ Terada, Yukikatsu; Hayashi, Takayuki; Ishida, Manabu; Mukai, Koji; Dotani, Tadayasu; Okada, Shunsaku; Nakamura, Ryoko; Naik, Sachindra; Bamba, Aya; Makishima, Kazuo (2008-04-25). "Suzaku Discovery of Hard X-Ray Pulsations from a Rotating Magnetized White Dwarf, AEAquarii". Publications of the Astronomical Society of Japan. 60 (2): 387–397. arXiv: 0711.2716 . Bibcode:2008HEAD...10.1003T. doi: 10.1093/pasj/60.2.387 . ISSN   0004-6264.
  11. ↑ "NASA - White Dwarf Pulses Like a Pulsar". www.nasa.gov. Retrieved 2021-12-13.
  12. ↑ Šimon, Vojtěch (April 2020). "The long-term optical activity of the propellers AE Aquarii and AR Scorpii". Publications of the Astronomical Society of Japan. 72 (2). doi:10.1093/pasj/psaa012.
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