AN Ursae Majoris

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AN Ursae Majoris
ANUMaLightCurve.png
A light curve for AN Ursae Majoris. The main plot (from Catalina Sky Survey data [1] ) shows the long term variation, and the inset plot (from TESS data [2] ) shows the variation over the orbital period.
Observation data
Epoch J2000.0        Equinox J2000.0
Constellation Ursa Major
Right ascension 11h 04m 25.65570s [3]
Declination +45 03 13.9415° [3]
Apparent magnitude  (V)14.9 – 20.2 [4]
Characteristics
Spectral type pec(e+cont) [4]
Variable type Eclipsing + Polar [4]
Astrometry
Proper motion (μ)RA: −44.989 [3]   mas/yr
Dec.: −24.972 [3]   mas/yr
Parallax (π)3.0993 ± 0.1371  mas [3]
Distance 1,050 ± 50  ly
(320 ± 10  pc)
Orbit [5]
Period (P)0.0798 d
Eccentricity (e)0.00
Periastron epoch (T)2,444,217.9961  JD
Argument of periastron (ω)
(secondary)		0.00°
Semi-amplitude (K1)
(primary)		321 km/s
Details
White dwarf
Mass 0.4–0.6 [6]   M☉
Temperature ≈ 20,000 [6]   K
Other designations
AN UMa, PG 1101+453, [7] S 07738, X 11016+454 [4]
Database references
SIMBAD data

AN Ursae Majoris is a binary star [5] system in the northern circumpolar constellation of Ursa Major. It is a variable star, with AN Ursae Majoris being the variable star designation, and ranges in brightness from 14.90 down to 20.2. [4] Even at its peak brightness though, the system is much too faint to be visible to the naked eye. Based on parallax measurements, the system is located roughly 1,050  light years away from the Sun. [3]

This is a single-lined spectroscopic binary system with a period of 1.92 hours in a close, circular orbit. [5] The pair form an eclipsing binary system that decreases from magnitude 14.9 down to 20.2, once per orbit. [8] This object, along with AM Herculis, define a class of cataclysmic variables known as polars . [9] The pair consist of a low mass white dwarf with a strong magnetic field, interacting with a low–mass main sequence star that has filled its Roche lobe. Matter is being energetically accreted from the main sequence star onto one or both magnetic poles of the white dwarf star, producing emission lines in the spectrum. The magnetic field of the white dwarf has an estimated strength of 35.8  MG . [6]

Related Research Articles

<span class="mw-page-title-main">W Ursae Majoris</span> Star in the constellation Ursa Major

W Ursae Majoris is the variable star designation for a binary star system in the northern constellation of Ursa Major. It has an apparent visual magnitude of about 7.9, which is too faint to be seen with the naked eye. However, it can be viewed with a small telescope. Parallax measurements place it at a distance of roughly 169 light years (52 parsecs) from Earth.

Xi Ursae Majoris is a star system in the constellation of Ursa Major. It has the traditional name Alula Australis; Xi Ursae Majoris is the Bayer designation, which is Latinised from ξ Ursae Majoris and abbreviated Xi UMa or ξ UMa. It was the first visual double star for which an orbit was calculated, when it was computed by Félix Savary in 1828. It is also a variable star with a small amplitude. Xi Ursae Majoris is found in the left hind paw of the Great Bear.

<span class="mw-page-title-main">AM Herculis</span> Star in the constellation Hercules

AM Herculis is a binary variable star located in the constellation Hercules. This star, along with the star AN Ursae Majoris, is the prototype for a category of cataclysmic variable stars called polars, or AM Her type stars.

<span class="mw-page-title-main">HR 4072</span> Star in the constellation Ursa Major

HR 4072 is a binary star system in the northern circumpolar constellation of Ursa Major. It has the variable star designation ET Ursae Majoris, abbreviated ET Uma, while HR 4072 is the system's designation from the Bright Star Catalogue. It has a white hue and is faintly visible to the naked eye with an apparent visual magnitude that fluctuates around 4.94. The system is located at a distance of approximately 339 light years from the Sun based on parallax measurements. The radial velocity measurement is poorly constrained, but it appears to be drifting closer to the Sun at the rate of around −3 km/s.

<span class="mw-page-title-main">65 Ursae Majoris</span> Star system in the constellation Ursa Major

65 Ursae Majoris, abbreviated as 65 UMa, is a star system in the constellation of Ursa Major. With a combined apparent magnitude of about 6.5, it is at the limit of human eyesight and is just barely visible to the naked eye in ideal conditions. It is about 760 light years away from Earth.

<span class="mw-page-title-main">SU Ursae Majoris</span> Variable star in the constellation Ursa Major

SU Ursae Majoris, or SU UMa, is a close binary star in the northern circumpolar constellation of Ursa Major. It is a periodic cataclysmic variable that varies in magnitude from a peak of 10.8 down to a base of 14.96. The distance to this system, as determined from its annual parallax shift of 4.53 mas, is 719 light-years. It is moving further from the Earth with a heliocentric radial velocity of +27 km/s.

<span class="mw-page-title-main">AD Phoenicis</span> Star in the constellation Phoenix

AD Phoenicis is a variable star in the constellation of Phoenix. An eclipsing binary, its apparent magnitude has a maximum of 10.27, dimming to 10.80 during primary and secondary eclipses, which are approximately equal. From parallax measurements by the Gaia spacecraft, the system is located at a distance of 655 light-years from Earth.

<span class="mw-page-title-main">V752 Centauri</span> Star in the constellation Centaurus

V752 Centauri is multiple star system and variable star in the constellation of Centaurus. An eclipsing binary, its apparent magnitude has a maximum of 9.10, dimming to 9.66 during primary eclipse and 9.61 during secondary eclipse. Its variability was discovered by Howard Bond in 1970. From parallax measurements by the Gaia spacecraft, the system is located at a distance of 410 light-years from Earth.

<span class="mw-page-title-main">TU Ursae Majoris</span>

TU Ursae Majoris is a variable star in the northern circumpolar constellation of Ursa Major. It is classified as a Bailey-type 'ab' RR Lyrae variable with a period of 0.557648 days that ranges in brightness from apparent visual magnitude of 9.26 down to 10.24. The distance to this star is approximately 2,090 light years based on parallax measurements. It is located near the north galactic pole at a distance that indicates this is a member of the galactic halo.

<span class="mw-page-title-main">TX Ursae Majoris</span> Eclipsing binary star system in the constellation of Ursa Major

TX Ursae Majoris is an eclipsing binary star system in the northern circumpolar constellation of Ursa Major. With a combined apparent visual magnitude of 6.97, the system is too faint to be readily viewed with the naked eye. The pair orbit each other with a period of 3.063 days in a circular orbit, with their orbital plane aligned close to the line of sight from the Earth. During the primary eclipse, the net brightness decreases by 1.74 magnitudes, while the secondary eclipse results in a drop of just 0.07 magnitude. TX UMa is located at a distance of approximately 780 light years from the Sun based on parallax measurements, but is drifting closer with a mean radial velocity of −13 km/s.

<span class="mw-page-title-main">UX Ursae Majoris</span>

UX Ursae Majoris is an Algol type binary star system in the northern circumpolar constellation of Ursa Major. It is classified as a nova-like variable star similar to DQ Herculis, although no eruptions have been reported. Since its discovery in 1933, this system has been the subject of numerous studies attempting to determine its properties. The combined apparent visual magnitude of UX UMa ranges from 12.57 down to 14.15. The system is located at a distance of approximately 952 light years from the Sun based on parallax, and is drifting further away with a radial velocity of 112 km/s.

<span class="mw-page-title-main">XY Ursae Majoris</span> Eclipsing binary star system in the constellation of Ursa Major

XY Ursae Majoris is a short period binary star system in the northern circumpolar constellation of Ursa Major. It is an eclipsing binary with a baseline apparent visual magnitude of 9.50. The system is located at a distance of 221.5 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −10 km/s. It has a relatively high proper motion, traversing the celestial sphere at the angular rate of 0.191″·yr−1.

<span class="mw-page-title-main">BZ Ursae Majoris</span> Dwarf Nova in the constellation Ursa Major

BZ Ursae Majoris is a dwarf nova star system in the northern circumpolar constellation of Ursa Major. It consists of a white dwarf primary in a close orbit with a red dwarf. The latter star is donating mass, which is accumulating in an accretion disk orbiting the white dwarf. The system is located at a distance of approximately 505 light years from the Sun based on parallax measurements.

<span class="mw-page-title-main">AG Virginis</span> Eclipsing binary star in the constellation Virgo

AG Virginis is an eclipsing binary star system in the equatorial constellation of Virgo. With a maximum apparent visual magnitude of 8.51 it is too faint to be visible to the naked eye. The system is located at a distance of approximately 820 light years from the Sun based on parallax measurements.

<span class="mw-page-title-main">VZ Piscium</span> Variable star in the constellation Pisces

VZ Piscium is a binary star system in the equatorial constellation of Pisces. it is located at a distance of 178 light years from the Sun based on parallax measurements, and has an apparent visual magnitude of about 10.3. This is an eclipsing binary system that undergoes shallow eclipses; the brightness decreases to magnitude 10.45 during the primary eclipse, then to magnitude 10.43 with the secondary eclipse, although as a contact binary the brightness varies continuously with no period of constant maximum brightness. The system is drifting closer with a radial velocity of approximately −4 km/s, and has a net heliocentric velocity of 144.1 km/s.

<span class="mw-page-title-main">SW Ursae Majoris</span> Variable star in the constellation Ursa Major

SW Ursae Majoris is a cataclysmic binary star system in the northern circumpolar constellation of Ursa Major, abbreviated SW UMa. During quiescence it has an apparent visual magnitude of 16.5–17, which is too faint to be visible to the naked eye. Based on parallax measurements, it is located at a distance of approximately 526 light years from the Sun.

<span class="mw-page-title-main">VV Ursae Majoris</span> Variable star system in the constellation Ursa Major

VV Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major, abbreviated VV UMa. It is a variable star system with a brightness that cycles around an apparent visual magnitude of 10.19, making it too faint to be visible to the naked eye. The system is located at a distance of approximately 1,500 light years based on parallax measurements.

<span class="mw-page-title-main">AW Ursae Majoris</span> Variable star in the constellation Ursa Major

AW Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major, abbreviated AW UMa. It is an A-type W Ursae Majoris variable with an apparent visual magnitude of 6.83, which is near the lower limit of visibility to the naked eye. This is an eclipsing binary with the brightness dropping to magnitude 7.13 during the primary eclipse and to 7.08 with the secondary eclipse. Parallax measurements give a distance estimate of 221 light years from the Sun. It is drifting closer to the Sun with a radial velocity of approximately −17 km/s. The system has a high proper motion, traversing the celestial sphere at the rate of 0.216 arc second per annum.

<span class="mw-page-title-main">BE Ursae Majoris</span> Variable star in the constellation Ursa Major

BE Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major, abbreviated BE UMa. The two components are an unusual M-class dwarf star and a subdwarf O star, borderline white dwarf. It is classified as a detached Algol variable and ranges in brightness from an apparent visual magnitude of 14.8 down to 17.8. This is too faint to be visible to the naked eye. The distance to this system is approximately 4,600 light years based on parallax measurements.

<span class="mw-page-title-main">DW Ursae Majoris</span> Variable star in the constellation Ursa Major

DW Ursae Majoris is an eclipsing binary star system in the northern circumpolar constellation of Ursa Major, abbreviated DW UMa. It is a cataclysmic variable of the SX Sextanis type, consisting of a compact white dwarf that is accreting matter from an orbiting companion star. The brightness of this source ranges from an apparent visual magnitude of 13.6 down to magnitude 18, which is too faint to be viewed with the naked eye. The distance to this system is approximately 1,920 light years based on parallax measurements.

References

  1. ↑ "The Catalina Surveys Data Release 2". Catalina Sky Survey. Caltech. Retrieved 19 April 2022.
  2. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  3. 1 2 3 4 5 6 Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics . 616. A1. arXiv: 1804.09365 . Bibcode: 2018A&A...616A...1G . doi: 10.1051/0004-6361/201833051 . Gaia DR2 record for this source at VizieR.
  4. 1 2 3 4 5 Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID   125853869.
  5. 1 2 3 Schneider, D. P.; Young, P. (September 1980). "VV Puppis and AN Ursae Majoris: a radial velocity study". Astrophysical Journal. 240: 871–884. Bibcode:1980ApJ...240..871S. doi: 10.1086/158301 .
  6. 1 2 3 Sanad, M. R. (2015). "Ultraviolet spectroscopic investigation of HU Aqr and AN UMa with the data from HST and IUE". Baltic Astronomy. 24 (3): 327–341. Bibcode:2015BaltA..24..327S. doi: 10.1515/astro-2017-0234 .
  7. ↑ "AN UMa". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2019-08-10.
  8. ↑ Avvakumova, E. A.; et al. (October 2013). "Eclipsing variables: Catalogue and classification". Astronomische Nachrichten. 334 (8): 860. Bibcode:2013AN....334..860A. doi:10.1002/asna.201311942. hdl: 10995/27061 .
  9. ↑ Krzeminski, W. & Serkowski, K. (August 1977). "Extremely high circular polarization of AN Ursae Majoris". The Astrophysical Journal Letters. 216: L45. Bibcode:1977ApJ...216L..45K. doi: 10.1086/182506 .
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