BE Ursae Majoris

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BE Ursae Majoris
BEUMaLightCurve.png
A light curve for BE Ursae Majoris, adapted from Shimanskii et al. (2008). [1] The inset plot shows the time around the eclipse with an expanded scale.
Observation data
Epoch J2000       Equinox J2000
Constellation Ursa Major
Right ascension 11h 57m 44.828s [2]
Declination +48° 56′ 18.31″ [2]
Apparent magnitude  (V)14.8 to 17.8 [3]
Characteristics
Spectral type DO + M1e–M5e [4]
Variable type Detached Algol [3]
Astrometry
Radial velocity (Rv)−67±2 [5]  km/s
Proper motion (μ)RA: 10.706  mas/yr [2]
Dec.: −12.783  mas/yr [2]
Parallax (π)0.7079 ± 0.0257  mas [2]
Distance 4,600 ± 200  ly
(1,410 ± 50  pc)
Details
Subdwarf O star
Mass 0.59±0.07 [1]   M☉
Radius 0.078±0.004 [5]   R☉
Surface gravity (log g)6.5±0.1 [5]   cgs
Temperature 105,000±5,000 [5]   K
M class dwarf
Mass 0.25±0.08 [1]   M☉
Radius 0.72±0.05 [5]   R☉
Temperature 4,750±150 [1]   K
Other designations
PG 1155+492, SVS 1424, BE UMa, 2MASS J11574483+4856184 [6]
Database references
SIMBAD data

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. [3] 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. [2]

The variability of SVS 1424 was announced in 1964 by N. E. Kurochkin from Sternberg, [7] and was found to have a period of 2.291 days while ranging in brightness from magnitude 14.1 down to 15.6. [8] After being assigned the variable star designation BE UMa, it was discovered to be a source of hot ultraviolet emission with a helium-rich spectrum by D. H. Ferguson and associates in 1981. [9] B. Margon and associates found variability of spectral features on a time scale as low as a few hours. They interpreted this as a detached binary system consisting of a compact, high temperature white dwarf and a cool red dwarf star. The outer layers of the cooler star are being ionized by radiation from the hotter component, [10] and the changing orientation of this heated region over the course of an orbit is creating a sinusoidal variability of about 1.5 magnitudes. [11]

In 1982, a deep eclipse was discovered in the light curve by H. Ando and associates. This put a strong limit on the possible models for the system, which indicated that the compact component is a hot O-type subdwarf. [12] D. Crampton and associates in 1983 found that the temperature and radius of the cool component suggested that it is an evolved subgiant star. At present, no mass transfer is taking place, but the system appears to be evolving into a cataclysmic variable as the subdwarf cools to become a normal white dwarf. [11]

In 1995, J. Liebert and associates discovered that the system is surrounded by a planetary nebula with a diameter of 3′ , which was likely shed when the present day subdwarf was leaving the asymptotic giant branch stage. The two components would have shared a common envelope as little as 10,000 years ago. As a result, rather than being a subgiant, the cool component has not yet reached the thermal equilibrium of a late dwarf star. [13] The pair have a circular orbit with a period of 2.2911658 days and a separation of 7.5±0.5  R☉ . The orbital plane is inclined at an angle of 84°±1° to the line of sight from the Earth. [5]

Related Research Articles

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<span class="mw-page-title-main">44 Boötis</span> Triple star system in the constellation Boötes

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<span class="mw-page-title-main">S Antliae</span> Star in the constellation Antlia

S Antliae is a W Ursae Majoris-type eclipsing binary star in Antlia.

<span class="mw-page-title-main">Y Sextantis</span> Variable star in the constellation Sextans

Y Sextantis, abbreviated as Y Sex, is a variable star system in the equatorial constellation of Sextans. The system is invisible to the naked eye with a mean apparent visual magnitude of 9.88. It is located roughly at 1,300 light years from the Sun based on parallax.

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

AN Ursae Majoris is a binary star 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. 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.

<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">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">TX Ursae Majoris</span> Eclipsing binary star system in the constellation of Ursa Major

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<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

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<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">RZ Leonis Minoris</span> Variable star in the constellation Leo Minor

RZ Leonis Minoris is a cataclysmic variable star system in the northern constellation of Leo Minor. It undergoes frequent outbursts that vary in brightness from an apparent visual magnitude of 14.4 down to 16.8. Based on parallax measurements, this system is located at a distance of approximately 2,160 light years from the Sun.

<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">DM Ursae Majoris</span> Variable star in the constellation Ursa Major

DM Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major, abbreviated DM UMa. It is sometimes identified by the Bonner Durchmusterung catalogue designation BD +61 1211; DM UMa is the variable star designation. The system has a combined apparent visual magnitude of 9.29, which is too faint to be visible to the naked eye. Based on parallax measurements, the system is located at a distance of approximately 606 light years from the Sun, but it is drifting closer with a heliocentric radial velocity of −7 km/s.

<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.

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

ER Ursae Majoris is a variable star in the northern circumpolar constellation of Ursa Major, abbreviated ER UMa. It is a prototype system for a subclass of SU Ursae Majoris dwarf novae. The system ranges in brightness from a peak apparent visual magnitude of 12.4 down to 15.2, which is too faint to be visible to the naked eye. The distance to this system, based on parallax measurements, is approximately 1,163 light years.

References

  1. 1 2 3 4 Shimanskii, V. V.; et al. (July 2008), "Fundamental parameters of BE UMa revised", Astronomy Reports, 52 (7): 558–575, Bibcode:2008ARep...52..558S, doi:10.1134/S1063772908070056, S2CID   121594084.
  2. 1 2 3 4 5 6 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics . 649: A1. arXiv: 2012.01533 . Bibcode:2021A&A...649A...1G. doi: 10.1051/0004-6361/202039657 . S2CID   227254300. (Erratum:  doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  3. 1 2 3 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.
  4. ↑ Ferguson, Donald H.; et al. (May 1987), "BE Ursae Majoris: A Detached Binary with a Unique Reprocessing Spectrum", Astrophysical Journal, 316: 399, Bibcode:1987ApJ...316..399F, doi:10.1086/165209, hdl: 2060/19880007144 , S2CID   120810912.
  5. 1 2 3 4 5 6 Ferguson, Donald H.; et al. (June 1999), "Masses and Other Parameters of the Post-Common Envelope Binary BE Ursae Majoris", The Astrophysical Journal, 518 (2): 866–872, Bibcode:1999ApJ...518..866F, doi: 10.1086/307289 , hdl: 2299/1230 , S2CID   17318851.
  6. ↑ "BE UMa". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2022-09-27.
  7. ↑ Kurochkin, N. E. (1964), "New Variable Stars", Peremennye Zvezdy (in Russian), 15: 77, Bibcode:1964PZ.....15...77K.
  8. ↑ Kurochkin, N. E. (1971), "Seven variable stars", Peremennye Zvezdy (in Russian), 18: 85–90, Bibcode:1971PZ.....18...85K.
  9. ↑ Ferguson, D. H.; et al. (December 1981), "BE UMa (PG 1155+492) : a unique cataclysmic-variable-like object", Astrophysical Journal, 251: 205–213, Bibcode:1981ApJ...251..205F, doi:10.1086/159455.
  10. ↑ Margon, B.; et al. (September 1981), "Synchronous extreme spectral variability of BE UMa", Nature, 293: 200–202, Bibcode:1981Natur.293..200M, doi:10.1038/293200a0, S2CID   4275747.
  11. 1 2 Crampton, D.; et al. (September 1983), "A new look at BE Ursae Majoris", Astrophysical Journal, 272: 202–205, Bibcode:1983ApJ...272..202C, doi: 10.1086/161279 .
  12. ↑ Ando, H.; et al. (1982), "Discovery of an eclipse in the unique binary system BE UMa", Publications of the Astronomical Society of Japan, 34: 141–146, Bibcode:1982PASJ...34..141A.
  13. ↑ Liebert, James; et al. (March 1995), "BE Ursae Majoris: Precataclysmic Binary System and Planetary Nucleus", Astrophysical Journal, 441: 424, Bibcode:1995ApJ...441..424L, doi:10.1086/175366.

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