ER Vulpeculae

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ER Vulpeculae
ERVulLightCurve.png
A light curve for ER Vulpeculae, plotted from TESS data [1]
Observation data
Epoch J2000       Equinox J2000
Constellation Vulpecula
Right ascension 21h 02m 25.907s [2]
Declination 27° 48′ 26.44″ [2]
Apparent magnitude  (V)7.27 to 7.49 [3]
Characteristics
Spectral type G0V + G5V [4]
B−V color index 0.614±0.010 [5]
Variable type W UMa/RS CVn [3]
Astrometry
Radial velocity (Rv)−24.6±0.5 [6]  km/s
Proper motion (μ)RA: 87.102  mas/yr [2]
Dec.: 6.364  mas/yr [2]
Parallax (π)19.8012 ± 0.0187  mas [2]
Distance 164.7 ± 0.2  ly
(50.50 ± 0.05  pc)
Absolute magnitude  (MV)3.75 [5] (4.28 + 4.31) [7]
Orbit
Period (P)0.698095 d [8]
Semi-major axis (a)4.28±0.04  AU [8]
Eccentricity (e)0.017±0.007 [9]
Inclination (i)66.63 [8] °
Periastron epoch (T)2,445,220.40964  JD [8]
Argument of periastron (ω)
(secondary)		62.6±29.0 [9] °
Semi-amplitude (K1)
(primary)		138.67±2.06 [8] km/s
Semi-amplitude (K2)
(secondary)		146.13±1.90 [8] km/s
Details
ER Vul A
Mass 1.108±0.033 [8]   M☉
Radius 1.16±0.06 [7]   R☉
Luminosity 1.56±0.15 [7]   L☉
Temperature 5,900 [4]   K
Rotational velocity (v sin i)84 [8]  km/s
ER Vul B
Mass 1.052±0.034 [8]   M☉
Radius 1.18±0.14 [7]   R☉
Luminosity1.52±0.37 [7]   L☉
Temperature 5,750 [4]   K
Rotational velocity (v sin i)78 [8]  km/s
Other designations
ER Vul, CD+27°3952, HD  200391, HIP  103833, SAO  89396, PPM  112323 [10]
Database references
SIMBAD data

ER Vulpeculae is a binary star system in the northern constellation of Vulpecula, abbreviated ER Vul. It is a variable star system with a brightness that ranges from an apparent visual magnitude of 7.27 down to 7.49, [3] which is too faint to be visible to the naked eye. This system is located at a distance of 165  light years from the Sun based on parallax measurements. It is drifting closer with a radial velocity of −25 km/s. [6]

This star was observed to be a double-lined spectroscopic binary by R. J. Northcott [11] in 1946, [9] indicating this is a binary star system where the individual spectra of each component is visible. G. A. Bakos found it to be a candidate eclipsing binary in 1955, and orbital elements were produced in 1956. The light curve of the system showed a very short orbital period of 16.75 hours and was found to vary continually between the minima. Both components were classified as G-type main-sequence stars. [9]

The wavy shape of the light curve of ER Vul resembles those of a W UMa star for a detached binary, indicating that the stars are not in direct contact but are close enough to gravitationally distort their shapes. By 1967, studies showed unexplained fluctuations in the light curve. [12] H. E. Bond in 1970 found calcium H and K lines in emission. [13] D. S. Hall classified the ER Vul system as a short period RS Canum Venaticorum variable in 1970, based on the spectral type and emission lines. [14] These emission lines suggest some form of chromospheric activity on the star. Dark star spots were proposed as an explanation of the intrinsic variability of these types of stars by H. M. Al-Naimiy, [15] and ER Vul was determined to be heavily spotted. [16]

The corona of ER Vul was found to be a strong source of soft X-rays by F. M. Walter and S. Bowyer in 1981. [17] [15] The eclipsing nature of the system was confirmed by T. H. Kadouri in 1981, with the primary eclipse being an occultation. [15] Radio emission was detected with the VLA in 1992, and it was found to be the one of the most luminous main-sequence stars known in that band. [18] Due to gravitational interaction that has forced a tidal lock with their close orbit, both stars are rotating rapidly – more than 40 times the rotation rate of the Sun, which is driving their magnetic dynamo. They show the "strongest coronal and chromospheric emissions of any main-sequence G-type star". [19]

C. İbanoğlu and associates in 1993 were able to explain the light curve of this system through a combination of "proximity effects, wavelike distortions, mutual eclipses, and short-term light fluctuations". [20] By measuring variations in Hydrogen alpha emission, Ö. Çakırlı and associates in 2003 found that cooler secondary component is the more active of the pair. [7] However, other observers have observed that the primary is the more active. This changeover may be the result of magnetic interaction between the stars. [8] In 2005, E. Shkolnik and associates discovered a high-velocity stream passing between the stars toward the secondary component. This stream is creating a large active area on the companion. [21]

Related Research Articles

<span class="mw-page-title-main">QU Vulpeculae</span> 1984 Nova seen in the constellation Vulpecula

QU Vulpeculae, also known as Nova Vulpeculae 1984 Number 2, was the second nova which occurred in 1984 in the constellation Vulpecula. It was discovered by Peter Collins, an amateur astronomer from Cardiff, California at 22:08 UT on 22 December 1984. At the time of its discovery, the nova's apparent magnitude was 6.8. By the next night, Collins reported its brightness had increased to magnitude 5.6, making it visible to the naked eye.

2 Vulpeculae is a binary star system in the northern constellation of Vulpecula, located around 1,800 light years away from the Sun. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 5.43.

<span class="mw-page-title-main">T Vulpeculae</span> Variable star in the constellation Vulpecula

T Vulpeculae is a possible binary star system in the northern constellation of Vulpecula, near the star Zeta Cygni, close to the pair 31 Vulpeculae and 32 Vulpeculae. It is visible to the naked eye with an apparent visual magnitude that ranges around 5.75. The distance to this system is around 1,900 light years, as determined from its annual parallax shift of 1.67 mas.

<span class="mw-page-title-main">RS Canum Venaticorum</span> Binary star in the constellation Canes Venatici

RS Canum Venaticorum is a binary star system in the northern constellation of Canes Venatici. It serves as the prototype to the class of RS Canum Venaticorum variables. The peak apparent visual magnitude of this system is below the level needed to observe it with the naked eye. It is located at a distance of approximately 443 light years from the Sun based on parallax, but is drifting closer with a net radial velocity of −14 km/s. Olin J. Eggen (1991) included this system as a member of the IC 2391 supercluster, but it was later excluded.

<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">EQ Tauri</span>

EQ Tauri is a triple star system in the equatorial constellation of Taurus that includes a contact eclipsing binary. The system is too faint to be viewed with the naked eye, having a baseline apparent visual magnitude of 10.5. During the primary eclipse, the brightness of the system drops to magnitude 11.03, then to 10.97 during the secondary minimum. The secondary eclipse is total. Based on parallax measurements, it is located at a distance of approximately 730 light years from the Sun.

<span class="mw-page-title-main">SZ Piscium</span> Star system in the constellation Pisces

SZ Piscium is a suspected triple star system in the equatorial constellation of Pisces. The inner pair form a double-lined spectroscopic binary with an orbital period of 3.966 days. It is a detached Algol-type eclipsing binary of the RS Canum Venaticorum class with a subgiant component. The system is too faint to be readily visible to the naked eye with a combined apparent visual magnitude of 7.18. It is located at a distance of approximately 306 light years based on parallax measurements.

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

BH Virginis is a binary star system in the equatorial constellation of Virgo. With a typical apparent visual magnitude of 9.6, it is too faint to be visible to the naked eye. Based on parallax measurements, it is located at a distance of approximately 488 light years from the Sun. The system is drifting closer with a net radial velocity of −23 km/s.

<span class="mw-page-title-main">HU Tauri</span> Binary star in the constellation Taurus

HU Tauri is a tight binary star system in the equatorial constellation of Taurus. It is an eclipsing binary, which means that the member stars periodically eclipse each other every 2.056 days. They have a combined apparent visual magnitude of 5.85, which is bright enough to be dimly visible to the naked eye. During the primary eclipse, the magnitude drops to 6.68, while the secondary eclipse decreases the magnitude to 5.91. The distance to this system, based on parallax measurements, is approximately 414 light years.

<span class="mw-page-title-main">UV Piscium</span> Binary star system in the Pisces constellation

UV Piscium is a binary star system in the constellation of Pisces. With a peak apparent visual magnitude of 8.98, it is too faint to be visible to the naked eye. This is an eclipsing binary system that decreases to magnitude 10.05 during the primary eclipse, then to magnitude 9.54 with the secondary eclipse. It is located at a distance of 232 light years from the Sun based on parallax measurements, and is receding with a radial velocity of 6.5 km/s. The position of this star near the ecliptic means it is subject to lunar occultation.

<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">SZ Lyncis</span> Variable star in the constellation of Lynx

SZ Lyncis is a binary star system in the northern constellation of Lynx, abbreviated SZ Lyn. It is a variable star with an apparent visual magnitude that fluctuates around 9.58, which is too faint to be visible to the naked eye. The distance to this system is approximately 1,700 light years based on parallax measurements, and it is drifting further away with a radial velocity of 34 km/s.

<span class="mw-page-title-main">PU Vulpeculae</span> Variable star in the constellation Vulpecula

PU Vulpeculae is a very slowly evolving symbiotic nova in the northern constellation of Vulpecula, abbreviated PU Vul. It is too faint to be visible to the naked eye, reaching a maximum apparent visual magnitude of 8.7 following a minimum of 16.6. The system is located at a distance of approximately 17,000 light years from the Sun based on parallax measurements.

<span class="mw-page-title-main">QQ Vulpeculae</span> Variable star in the constellation Vulpecula

QQ Vulpeculae is a cataclysmic variable binary star system in the northern constellation of Vulpecula, abbreviated QQ Vul. It has a brightness that fluctuates around an apparent visual magnitude of 14.7, which is too faint to be viewed with the naked eye. The distance to this system is approximately 981 light years based on parallax measurements.

<span class="mw-page-title-main">AH Virginis</span> Star in the constellation Virgo

AH Virginis is a contact binary star system in the equatorial constellation of Virgo, abbreviated AH Vir. It is a variable star with a brightness that peaks at an apparent visual magnitude of 9.18, making it too faint to be viewed with the naked eye. The distance to this system is approximately 338 light years based on parallax measurements, and it is drifting further away with a mean radial velocity of 7 km/s. O. J. Eggen in 1969 included this system as a probable member of the Wolf 630 group of co-moving stars.

<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">RT Persei</span> Star system in the constellation Perseus

RT Persei is a variable star system in the northern constellation of Perseus, abbreviated RT Per. It is an eclipsing binary system with an orbital period of 0.84940032 d (20.386 h). At peak brightness the system has an apparent visual magnitude of 10.46, which is too faint to be viewed with the naked eye. During the eclipse of the primary this decreases to magnitude 11.74, then to magnitude 10.67 with the secondary eclipse. The distance to this system is approximately 628 light years based on parallax measurements. It is drifting closer with a heliocentric radial velocity of about −12 km/s.

References

  1. ↑ MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, retrieved 21 August 2022.
  2. 1 2 3 4 5 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. 1 2 3 Strassmeier, Klaus G. (September 2009), "Starspots", The Astronomy and Astrophysics Review, 17 (3): 251–308, Bibcode:2009A&ARv..17..251S, doi: 10.1007/s00159-009-0020-6 .
  5. 1 2 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv: 1108.4971 , Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID   119257644.
  6. 1 2 Karataș, Yüksel; et al. (2004), "Kinematics of chromospherically active binaries and evidence of an orbital period decrease in binary evolution", Monthly Notices of the Royal Astronomical Society, 349 (3): 1069–1092, arXiv: astro-ph/0404219 , Bibcode:2004MNRAS.349.1069K, doi:10.1111/j.1365-2966.2004.07588.x, S2CID   15290475.
  7. 1 2 3 4 5 6 Çakırlı, Ö.; et al. (March 2003), "Hα variations of the RS CVn type binary ER Vulpeculae", Astronomy and Astrophysics, 400: 257–264, Bibcode:2003A&A...400..257C, doi: 10.1051/0004-6361:20021885 , S2CID   122676294.
  8. 1 2 3 4 5 6 7 8 9 10 11 Özavcı, İ.; et al. (May 2019), "Surface inhomogeneities of the eclipsing binary ER Vul", Contributions of the Astronomical Observatory Skalnaté Pleso, 49 (2): 278–286, Bibcode:2019CoSka..49..278O.
  9. 1 2 3 4 Northcott, Ruth J.; Bakos, Gustav A. (May 1956), "A new eclipsing spectroscopic binary, HD 200391", Astronomical Journal, 61: 188, Bibcode:1956AJ.....61..188N, doi:10.1086/107417.
  10. ↑ "ER Vul". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2022-08-18.
  11. ↑ Heard, J. F. (October 1956), "Reports of observatories, 1955-56", Astronomical Journal, 61: 318, Bibcode:1956AJ.....61..318H, doi: 10.1086/107352 .
  12. ↑ Northcott, Ruth J.; Bakos, Gustav A. (February 1967), "Spectroscopic and photometric observations of ER Vulpeculas", Astronomical Journal, 72: 89, Bibcode:1967AJ.....72...89N, doi: 10.1086/110205 .
  13. ↑ Bond, Howard E. (April 1970), "New Peculiar Stars Noted on Objective-Prism Plates", Publications of the Astronomical Society of the Pacific, 82 (485): 321, Bibcode:1970PASP...82..321B, doi: 10.1086/128911 , S2CID   119525277.
  14. ↑ Hall, D. S. (1976), Fitch, W. S. (ed.), "The RS CVn Binaries and Binaries with Similar Properties", Multiple Periodic Variable Stars, Proceedings of IAU Colloq. 29, held in Budapest, Hungary, 1–5 September 1975, Astrophysics and Space Science Library, D. Reidel Publishers, vol. 60, p. 287, Bibcode:1976ASSL...60..287H, doi:10.1007/978-94-010-1175-4_15, ISBN   978-94-010-1177-8, S2CID   120775716.
  15. 1 2 3 Ibanoglu, C.; et al. (August 1987), "Light curve variations in ER vulpeculae", Astrophysics and Space Science, 136 (2): 225–229, Bibcode:1987Ap&SS.136..225I, doi:10.1007/BF00642114, S2CID   119647294.
  16. ↑ Rucinski, S. M. (1979), "Sizes of spots in spotted stars", Acta Astronomica, 29: 203–209, Bibcode:1979AcA....29..203R.
  17. ↑ Walter, F. M.; Bowyer, S. (April 1981), "On the coronae of rapidly rotating stars. I. The relation between rotation and coronal activity in RS CVn systems.", Astrophysical Journal, 245: 671–676, Bibcode:1981ApJ...245..671W, doi: 10.1086/158842 .
  18. ↑ Rucinski, S. M. (December 1992), "VLA Radio Light Curves of ER Vulpeculae at 3.6 and 6 CM", Publications of the Astronomical Society of the Pacific, 104: 1177, Bibcode:1992PASP..104.1177R, doi: 10.1086/133106 , S2CID   121394464.
  19. ↑ Bradstreet, D. H.; et al. (December 1993), "The Hyperactive Double Suns of the Binary ER Vulpeculae", Bulletin of the American Astronomical Society, 25: 1425, Bibcode:1993AAS...183.8504B.
  20. ↑ Ibanoglu, C.; et al. (March 1993), "Photometry of ER Vulpeculae : photometric analysis with the WINK-10 code", Astronomy and Astrophysics, 269: 310–318, Bibcode:1993A&A...269..310I.
  21. ↑ Shkolnik, Evgenya; et al. (August 2005), "Investigating Ca II Emission in the RS Canum Venaticorum Binary ER Vulpeculae Using the Broadening Function Formalism", The Astronomical Journal, 130 (2): 799–808, arXiv: astro-ph/0504428 , Bibcode:2005AJ....130..799S, doi:10.1086/431364, S2CID   119096436.

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