R Aquarii

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R Aquarii
Aquarius constellation map.svg
Red circle.svg
Location of R Aquarii (circled in red)
Observation data
Epoch J2000       Equinox J2000
Constellation Aquarius
Right ascension 23h 43m 49.46343s [1]
Declination −15° 17′ 04.1763″ [1]
Apparent magnitude  (V)5.2 - 12.4 [2]
Characteristics
Spectral type M5e-M8.5e + pec [2]
U−B color index −0.62 [3]
B−V color index +1.98 [3]
Variable type Mira + Z And [2]
Astrometry
Radial velocity (Rv)−22.0 [4]  km/s
Proper motion (μ)RA: +40.587 [1]   mas/yr
Dec.: −30.411 [1]   mas/yr
Parallax (π)4.59 ± 0.24  mas [5]
Distance 711+39
−36  ly
(218+12
−11  pc) [5]
Orbit [6]
Period (P)15,943±471
Semi-major axis (a)0.071 - 0.084"
(14.2 - 16.8 AU)
Eccentricity (e)0.25±0.07
Inclination (i)70°
Details
A
Mass 1 - 1.5 [6]   M☉
Radius 430 [6]   R☉
Luminosity 4,780 [7]   L☉
Surface gravity (log g)−0.5 [7]   cgs
Temperature 2,800 [7]   K
B
Mass 0.6 - 1 [6]   M☉
Radius >0.1 [8]   R☉
Luminosity5-20 [9]   L☉
Temperature 60,000 [9]   K
Other designations
R  Aqr, BD−16°6352, HD  222800, HIP  117054, HR  8992, SAO  165849
Database references
SIMBAD data
Data sources:
Hipparcos Catalogue,
CCDM (2002),
Bright Star Catalogue (5th rev. ed.)

R Aquarii (R Aqr) is a variable star in the constellation Aquarius. [10]

Contents

R Aquarii is a symbiotic star believed to contain a white dwarf and a Mira-type variable in a binary system. The orbital period is approximately 44 years. [6] The main Mira-type star is a red giant, and varies in brightness by a factor of several hundred and with a period of slightly more than a year; this variability was discovered by Karl Ludwig Harding in 1810. It has a distance of about 218 parsecs, [5] and is one of the nearest symbiotic stars and a well-known jet source. [11] The two components have been resolved at a separation of 55 mas. [12]

By its gravitational pull, the white dwarf draws in material from the red giant and occasionally ejects some of the surplus in loops to form the nebula seen in the linked image. [13] The whole system appears reddened because it is situated in a very dusty region of space, and its blue light is absorbed before reaching Earth.

The light curve of R Aquarii, from AAVSO V band data RAqrLightCurve.png
The light curve of R Aquarii, from AAVSO V band data

The nebula around R Aquarii is also known as Cederblad 211. [14] It is possible that the nebula is the remnant of a nova-like outburst, which may have been observed by Japanese astronomers, in the year 930 AD. [15] It is reasonably bright but small and dominated by its central star. Visual observations are difficult and rare. [16] The central region of the jet shows an ejection that took place around 190 years ago, as well as much younger structures. [17]

The giant primary star is a Mira variable, a star that pulsates and changes temperature, leading to very large visual brightness changes. The total range of 5.2 - 12.4 is a variation of 750 times in brightness, from a naked eye star to one beyond the range of binoculars. The pulsations occur every 390 days but are not entirely regular. [2]

Related Research Articles

<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">Mu Aquarii</span> Binary star system in the constellation Aquarius

Mu Aquarii, Latinized from μ Aquarii, is the Bayer designation for a binary star system in the equatorial constellation of Aquarius. It is visible to the naked eye with a combined apparent visual magnitude of 4.7. Based upon parallax measurements, the distance to this system is about 157 light-years. It is drifting closer to the Sun with a radial velocity of −9.1 km/s.

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

Chi Aquarii, Latinized from χ Aquarii, is the Bayer designation of a star in the equatorial constellation of Aquarius. The distance to this star, based upon parallax measurements with a 7% margin of error, is roughly 610 light-years. It is visible to the naked eye with an apparent visual magnitude of about 5.

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

Rho Aquarii, Latinized from ρ 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 visual magnitude of +5.34. Based upon parallax measurements, this star is at a distance of roughly 870 light-years from Earth. It is drifting closer with a radial velocity of –9 km/s. The proximity of this star to the ecliptic means it is subject to lunar occultations.

<span class="mw-page-title-main">3 Aquarii</span> Star in the constellation Aquarius

3 Aquarii is a variable star in the equatorial constellation of Aquarius. 3 Aquarii is the Flamsteed designation; it also bears the Bayer designation k Aquarii and the variable star designation EN Aquarii. With a mean apparent visual magnitude of 4.429, it is visible to the naked eye in dark skies. It has an annual parallax shift of 5.57 milliarcseconds with a 5% margin of error, which translates to a physical distance of around 590 light-years from Earth.

94 Aquarii is a triple star system in the equatorial constellation of Aquarius. 94 Aquarii is the Flamsteed designation. The brightest member has an apparent visual magnitude of 5.19, making it visible to the naked eye. The parallax measured by the Gaia spacecraft yields a distance estimate of around 73 light-years from Earth.

41 Aquarii is a double star in the equatorial constellation of Aquarius. 41 Aquarii is its Flamsteed designation. It is visible to the naked eye as a dim, orange-hued point of light with a combined apparent visual magnitude of 5.354. The pair are located at a distance of around 239 light-years from the Sun based on parallax, but are drifting closer with a radial velocity of –25 km/s.

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.

<span class="mw-page-title-main">74 Aquarii</span> Triple star system in the constellation Aquarius

74 Aquarii is a triple star system in the constellation of Aquarius. 74 Aquarii is its Flamsteed designation and it also bears the variable star designation HI Aquarii. The combined apparent visual magnitude is 5.8, although it is very slightly variable, and it is located at a distance of 590 light-years from Earth.

82 Aquarii is a star in the equatorial constellation of Aquarius. 82 Aquarii is its Flamsteed designation. It has an apparent visual magnitude of 6.15, which, according to the Bortle Dark-Sky Scale, means it is a faint star that requires dark rural skies to view. The annual parallax shift of 82 Aquarii is 3.6764±0.1715 mas, which equates to a distance of roughly 890 light-years from Earth. Because this star is positioned near the ecliptic, it is subject to lunar eclipses.

<span class="mw-page-title-main">70 Aquarii</span> Star in the constellation Aquarius

70 Aquarii is a variable star located 425 light years away from the Sun in the equatorial constellation of Aquarius. It has the variable star designation FM Aquarii; 70 Aquarii is the Flamsteed designation. It is near the lower limit of visibility to the naked eye, appearing as a dim, yellow-white hued star with a baseline apparent visual magnitude of 6.19. This star is moving closer to the Earth with a heliocentric radial velocity of –5.8 km/s.

<span class="mw-page-title-main">29 Aquarii</span> Binary star in the constellation Aquarius

29 Aquarii is a binary star system located around 590 light years away from the Sun in the equatorial constellation of Aquarius. 29 Aquarii is the Flamsteed designation; the system also bears the variable star designation DX Aquarii. It is a challenge to view with the naked eye, appearing as a dim star with a combined apparent visual magnitude of 6.39. The system is moving further from the Earth with a heliocentric radial velocity of about +15 km/s.

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

U Aquarii, abbreviated U Aqr, is a variable star in the equatorial constellation of Aquarius. It is invisible to the naked eye, having an apparent visual magnitude that ranges from 10.6 down to as low as 15.9. Based on parallax measurements, the distance to this star is approximately 38 kly (12 kpc). In 1990, W. A. Lawson and associates provided a distance estimate of 43 kly (13.2 kpc) based on the assumption of a bolometric magnitude of −5. It appears to lie several kiloparsecs below the galactic plane, and thus may belong to an old stellar population.

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

LP Aquarii is a pulsating variable star in the constellation of Aquarius that varies between magnitudes 6.30 and 6.64. The position of the star near the ecliptic means it is subject to lunar occultations.

<span class="mw-page-title-main">14 Aquarii</span> Star in the constellation Aquarius

14 Aquarii is red giant star. 14 Aquarii is the Flamsteed designation; it also bears the variable star designation IW Aquarii. It is a semiregular variable with an amplitude of a tenth of a magnitude, and shows variations on a timescale of just one day.

<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">QZ Puppis</span> Star in the constellation Puppis

QZ Puppis is a class B2.5V star in the constellation Puppis. Its apparent magnitude is 4.5 and it is approximately 650 light years away based on parallax.

<span class="mw-page-title-main">HD 65750</span> Star in the constellation Carina

HD 65750, also known as V341 Carinae is a bright red giant star in the constellation Carina. It is surrounded by a prominent reflection nebula, known as IC 2220, nicknamed the Toby Jug Nebula.

<span class="mw-page-title-main">W Aquilae</span> Variable star in the constellation Aquila

W Aquilae is a variable star in the constellation of Aquila. It is a type of evolved star known as an S-type star. Due to its relatively close distance of 1,200 light-years and equatorial location, it is easy to observe and heavily studied.

<span class="mw-page-title-main">HM Sagittae</span> Symbiotic nova in the constellation of Sagitta

HM Sagittae is a dusty-type symbiotic nova in the northern constellation of Sagitta. It was discovered by O. D. Dokuchaeva and colleagues in 1975 when it increased in brightness by six magnitudes. The object displays an emission line spectrum similar to a planetary nebula and was detected in the radio band in 1977. Unlike a classical nova, the optical brightness of this system did not rapidly decrease with time, although it showed some variation. It displays activity in every band of the electromagnetic spectrum from X-ray to radio.

References

  1. 1 2 3 4 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  2. 1 2 3 4 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.
  3. 1 2 Celis s., L. (1982). "Red variable stars. I - UBVRI photometry and photometric properties". Astronomical Journal. 87: 1791. Bibcode:1982AJ.....87.1791C. doi:10.1086/113268.
  4. ↑ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington. Bibcode:1953GCRV..C......0W.
  5. 1 2 3 Min, Cheulhong; Matsumoto, Naoko; Kim, Mi Kyoung; Hirota, Tomoya; Shibata, Katsunori M.; Cho, Se-Hyung; Shizugami, Makoto; Honma, Mareki (2014-04-01). "Accurate Parallax Measurement toward the Symbiotic Star R Aquarii". Publications of the Astronomical Society of Japan. 66 (2): 38. doi:10.1093/pasj/psu003. ISSN   2053-051X.
  6. 1 2 3 4 5 M. Gromadzki & J. Mikołajewska (March 2009). "The spectroscopic orbit and the geometry of R Aquarii". Astronomy & Astrophysics. 495 (3): 931–936. arXiv: 0804.4139 . Bibcode:2009A&A...495..931G. doi:10.1051/0004-6361:200810052. S2CID   2034734.
  7. 1 2 3 Mayer, A.; Jorissen, A.; Kerschbaum, F.; Ottensamer, R.; Nowotny, W.; Cox, N. L. J.; Aringer, B.; Blommaert, J. A. D. L.; Decin, L.; Van Eck, S.; Gail, H.-P.; Groenewegen, M. A. T.; Kornfeld, K.; Mecina, M.; Posch, Thomas; Vandenbussche, B.; Waelkens, C. (2013). "Large-scale environments of binary AGB stars probed by Herschel. I. Morphology statistics and case studies of R Aquarii and W Aquilae". Astronomy & Astrophysics. 549: A69. arXiv: 1211.3595 . Bibcode:2013A&A...549A..69M. doi:10.1051/0004-6361/201219259. S2CID   55538633.
  8. ↑ Burgarella, D.; Vogel, M.; Paresce, F. (1992). "R Aquarii : An attempt at a unified model". Astronomy and Astrophysics. 262: 83. Bibcode:1992A&A...262...83B.
  9. 1 2 Sankrit, Ravi; Omelian, Eric; Gorti, Uma; Wagner, R. Mark; Goldman, Steven; Whitelock, Patricia A. (2022). "SOFIA/FORCAST Monitoring of the Dust Emission from R Aqr: Start of the Eclipse". The Astrophysical Journal. 926 (2): 177. arXiv: 2112.13118 . Bibcode:2022ApJ...926..177S. doi: 10.3847/1538-4357/ac4792 . S2CID   245502364.
  10. ↑ "R Aquarii | aavso.org". www.aavso.org. Retrieved 2018-07-11.
  11. ↑ Stute, Matthias; Sahai, Raghvendra (2007). "Hydrodynamical Simulations of the Jet in the Symbiotic Star MWC 560. III. Application to X-Ray Jets in Symbiotic Stars". The Astrophysical Journal. 665 (1): 698–706. arXiv: 0704.2240 . Bibcode:2007ApJ...665..698S. doi:10.1086/518930. S2CID   11053317.
  12. ↑ Hollis, J. M.; Pedelty, J. A.; Lyon, R. G. (1997). "Spatial Resolution of the R Aquarii Binary System". The Astrophysical Journal. 482 (1): L85–L88. Bibcode:1997ApJ...482L..85H. doi: 10.1086/310687 .
  13. ↑ "Aladin previewer". CDS.
  14. ↑ Cederblad, S (1946). "Studies of bright diffuse galactic nebulae with special regard to their spatial distribution". Lund Medd. Astron. Obs. Series II. 119: 1. Bibcode:1946MeLuS.119....1C.
  15. ↑ Kafatos, Minas; Michalitsianos, Andrew G (1982). "The peculiar variable star R Aquarii and its jet". Nature. 298 (5874): 540. Bibcode:1982Natur.298..540K. doi:10.1038/298540a0. S2CID   4238750.
  16. ↑ "The Drama-Ridden Couple of R Aquarii". Sky & Telescope . Retrieved 2018-01-18.
  17. ↑ Paresce, Francesco; Hack, Warren (1994). "New HST observations of the core of R Aquarii. 1: Imaging". Astronomy and Astrophysics. 287: 154. Bibcode:1994A&A...287..154P.
  18. ↑ "Dancing with the Enemy - ESO's R Aquarii Week continues with the sharpest R Aquarii image ever". www.eso.org. Retrieved 12 December 2018.
  19. ↑ "VLT view of binary system R Aquarii from 2012". www.eso.org. Retrieved 10 December 2018.
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