Astronomy:ER Vulpeculae

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Short description: Variable star in the constellation Vulpecula
ER Vulpeculae
ERVulLightCurve.png
A light curve for ER Vulpeculae, plotted from TESS data[1]
Observation data
Equinox J2000.0]] (ICRS)
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[2] mas/yr
Dec.: 6.364[2] mas/yr
Parallax (π)19.8012 ± 0.0187[2] mas
Distance164.7 ± 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 astronomical unit|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
Mass1.108±0.033[8] M
Radius1.16±0.06[7] R
Luminosity1.56±0.15[7] L
Temperature5,900[4] K
Rotational velocity (v sin i)84[8] km/s
ER Vul B
Mass1.052±0.034[8] M
Radius1.18±0.14[7] R
Luminosity1.52±0.37[7] L
Temperature5,750[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
SIMBADdata

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 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]

References

  1. MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html, retrieved 21 August 2022. 
  2. 2.0 2.1 2.2 2.3 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  3. 3.0 3.1 3.2 Samus, N. N. et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1 61 (1): 80–88, doi:10.1134/S1063772917010085, Bibcode2017ARep...61...80S. 
  4. 4.0 4.1 4.2 Strassmeier, Klaus G. (September 2009), "Starspots", The Astronomy and Astrophysics Review 17 (3): 251–308, doi:10.1007/s00159-009-0020-6, Bibcode2009A&ARv..17..251S. 
  5. 5.0 5.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  6. 6.0 6.1 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, doi:10.1111/j.1365-2966.2004.07588.x, Bibcode2004MNRAS.349.1069K. 
  7. 7.0 7.1 7.2 7.3 7.4 7.5 Çakırlı, Ö. et al. (March 2003), "Hα variations of the RS CVn type binary ER Vulpeculae", Astronomy and Astrophysics 400: 257–264, doi:10.1051/0004-6361:20021885, Bibcode2003A&A...400..257C. 
  8. 8.00 8.01 8.02 8.03 8.04 8.05 8.06 8.07 8.08 8.09 8.10 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, Bibcode2019CoSka..49..278O. 
  9. 9.0 9.1 9.2 9.3 Northcott, Ruth J.; Bakos, Gustav A. (May 1956), "A new eclipsing spectroscopic binary, HD 200391", Astronomical Journal 61: 188, doi:10.1086/107417, Bibcode1956AJ.....61..188N. 
  10. "ER Vul". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=ER+Vul. 
  11. Heard, J. F. (October 1956), "Reports of observatories, 1955-56", Astronomical Journal 61: 318, doi:10.1086/107352, Bibcode1956AJ.....61..318H. 
  12. Northcott, Ruth J.; Bakos, Gustav A. (February 1967), "Spectroscopic and photometric observations of ER Vulpeculas", Astronomical Journal 72: 89, doi:10.1086/110205, Bibcode1967AJ.....72...89N. 
  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, doi:10.1086/128911, Bibcode1970PASP...82..321B. 
  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) 60: p. 287, doi:10.1007/978-94-010-1175-4_15, ISBN 978-94-010-1177-8, Bibcode1976ASSL...60..287H. 
  15. 15.0 15.1 15.2 Ibanoglu, C. et al. (August 1987), "Light curve variations in ER vulpeculae", Astrophysics and Space Science 136 (2): 225–229, doi:10.1007/BF00642114, Bibcode1987Ap&SS.136..225I. 
  16. Rucinski, S. M. (1979), "Sizes of spots in spotted stars", Acta Astronomica 29: 203–209, Bibcode1979AcA....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, doi:10.1086/158842, Bibcode1981ApJ...245..671W. 
  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, doi:10.1086/133106, Bibcode1992PASP..104.1177R. 
  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, Bibcode1993AAS...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, Bibcode1993A&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, doi:10.1086/431364, Bibcode2005AJ....130..799S. 

Further reading

  • Crăciun, Maria et al. (April 2015), "Detection of low-level periodic signals through enhanced self-correlation method. The case of ER Vulpeculae", Monthly Notices of the Royal Astronomical Society 448 (3): 2066–2076, doi:10.1093/mnras/stv108, Bibcode2015MNRAS.448.2066C. 
  • Xiang, Yue et al. (February 2015), "Doppler images of the eclipsing binary ER Vulpeculae", Monthly Notices of the Royal Astronomical Society 447 (1): 567–576, doi:10.1093/mnras/stu2458, Bibcode2015MNRAS.447..567X. 
  • Pop, Alexandru; Vamoş, Călin (October 2013), "Orbital period modulation of the eclipsing binary system ER Vulpeculae: Real or not?", New Astronomy 23: 27–35, doi:10.1016/j.newast.2013.02.003, Bibcode2013NewA...23...27P. 
  • Harmanec, P. et al. (February 2004), "An improved ephemeris and physical elements of ER Vul", Astronomy and Astrophysics 415: 289–297, doi:10.1051/0004-6361:20034614, Bibcode2004A&A...415..289H. 
  • Kjurkchieva, D. P. et al. (June 2003), "Spectroscopic and photometric observations of the short-period RS CVn-type star ER Vulpeculae", Astronomy and Astrophysics 404 (2): 611–620, doi:10.1051/0004-6361:20030489, Bibcode2003A&A...404..611K. 
  • Duemmler, R. et al. (May 2003), "The radial velocities and physical parameters of ER Vul", Astronomy and Astrophysics 402 (2): 745–754, doi:10.1051/0004-6361:20030299, Bibcode2003A&A...402..745D. 
  • Ekmekči, F. et al. (March 2002), "Chromospherically active binary systems, RT And and ER Vul: 1995-1998 observations and spot distributions", Astronomische Nachrichten 323 (1): 31–35, doi:10.1002/1521-3994(200203)323:1<31::AID-ASNA31>3.0.CO;2-2, Bibcode2002AN....323...31E. 
  • Osten, Rachel A. et al. (January 2002), "Multiwavelength Observations of Three Short-Period Active Binary Systems: ER Vulpeculae, CC Eridani, and EI Eridani", The Astrophysical Journal Supplement Series 138 (1): 99–120, doi:10.1086/323666, Bibcode2002ApJS..138...99O. 
  • Qian, S. B. (2001), Brekke, Pål; Fleck, Bernhard; Gurman, Joseph B., eds., "Possible Magnetic Activity Cycles of Four Chromospherically Active Binaries: ER Vul, UV Psc, AR Lac and BH Vir", Recent Insights into the Physics of the Sun and Heliosphere: Highlights from SOHO and Other Space Missions, Proceedings of IAU Symposium 203 (Astronomical Society of the Pacific) 203: p. 437, ISBN 1-58381-069-2, Bibcode2001IAUS..203..437Q. 
  • Rucinski, Slavek M. (March 1998), "VLA Observations of Radio Variability of ER Vulpeculae in 1995", The Publications of the Astronomical Society of the Pacific 110 (745): 272–275, doi:10.1086/316140, Bibcode1998PASP..110..272R. 
  • Lazaro, C.; Arevalo, M. J. (June 1997), "Time-Resolved Spectroscopy of RS CVn Short-Period Systems. I. CG Cyg, BH Vir, and ER Vul", The Astronomical Journal 113: 2283, doi:10.1086/118439, Bibcode1997AJ....113.2283L. 
  • Gunn, A. G.; Doyle, J. G. (February 1997), "Environments of active close binaries. I. ER Vulpeculae", Astronomy and Astrophysics 318: 60–72, Bibcode1997A&A...318...60G. 
  • Oláh, K.; Kövári, Zs. (1997), "Spot temperatures in binaries with two active components: By Dra and Er Vul", Astronomical and Astrophysical Transactions 13 (4): 295–299, doi:10.1080/10556799708202971, Bibcode1997A&AT...13..295O. 
  • Edalati, M. T.; Zeinali, F. (December 1995), "The Photometric Observations of ER Vulpeculae: Photometric Analysis with the W-D Code", Astrophysics and Space Science 234 (2): 271–280, doi:10.1007/BF00627672, Bibcode1995Ap&SS.234..271E. 
  • Zeinali, F. et al. (May 1995), "Photoelectric Observations of the Eclipsing Variable ER Vulpeculae", Information Bulletin on Variable Stars 4190: 1, Bibcode1995IBVS.4190....1Z. 
  • Olah, K. et al. (November 1994), "The active close binary system ER Vulpeculae", Astronomy and Astrophysics 291: 110–120, Bibcode1994A&A...291..110O. 
  • Eryurt, D. et al. (December 1991), "The Light Curve of ER Vulpeculae", Information Bulletin on Variable Stars 3692: 1, Bibcode1991IBVS.3692....1E. 
  • Guinan, E. F. et al. (September 1991), "Simultaneous IUE and Ground-Based Observations of ER Vul Over Two Orbits", Bulletin of the American Astronomical Society 23: 1412, Bibcode1991BAAS...23.1412G. 
  • Rucinski, S. M. (August 1991), "The radio light curve of ER Vulpeculae", Journal of the Royal Astronomical Society of Canada 85: 184, Bibcode1991JRASC..85..184R. 
  • Srivastava, R. K. et al. (August 1991), "UBV Photometry of ER-Vulpeculae", Astrophysics and Space Science 182 (2): 281–287, doi:10.1007/BF00645007, Bibcode1991Ap&SS.182..281S. 
  • Bradstreet, D. H.; Guinan, E. F. (August 1991), Marsden, B. G., ed., "ER Vulpeculae", IAU Circular 5329: p. 1, Bibcode1991IAUC.5329....1B. 
  • Heckert, P. A.; Zeilik, M. (July 1991), "1988 and 1989 BV Photometry of ER Vul", Information Bulletin on Variable Stars 3636: 1, Bibcode1991IBVS.3636....1H. 
  • Fernández-Figueroa, M. J. et al. (1991), Tuominen, I.; Moss, D.; Rudiger, G., eds., "CAII H and K Spectroscopy of ER-Vulpeculae", The Sun and Cool Stars. Activity, Magnetism, Dynamos. Proceedings of Colloquium No. 130 of the International Astronomical Union, held in Helsinki, Finland, July 17–20, 1990 (Berlin, Germany; New York, NY: Springer-Verlag) 380 (130): p. 483, doi:10.1007/3-540-53955-7_185, ISBN 3-540-53955-7, Bibcode1991LNP...380..483F. 
  • Hill, G. et al. (November 1990), "Studies of late-type binaries. IV. The physical parameters of ER Vulpeculae", Astronomy and Astrophysics 238: 145, Bibcode1990A&A...238..145H. 
  • Mennella, V. (August 1990), "Time-scale variability of the light curves of ER Vulpeculae.", Astronomy and Astrophysics 234: 203, Bibcode1990A&A...234..203M. 
  • Keskin, Varol (July 1990), "Lightcurve Variations of the RS-Canum Type Eclipsing Binary ER-Vulpeculae", Astrophysics and Space Science 169 (1–2): 165–170, doi:10.1007/BF00640705, Bibcode1990Ap&SS.169..165K. 
  • Arevalo, M. J. et al. (September 1988), "Photometric Study of ER Vul", The Astronomical Journal 96: 1061, doi:10.1086/114866, Bibcode1988AJ.....96.1061A. 
  • Evren, S. (January 1988), "Light curve variations of ER Vulpeculae in 1984 and 1985 observing seasons", Astrophysics and Space Science 140 (1): 125–130, doi:10.1007/BF00643536, Bibcode1988Ap&SS.140..125E. 
  • Akan, M. C. et al. (August 1987), "B, V Photometry of ER Vulpeculae", Information Bulletin on Variable Stars 3059: 1, Bibcode1987IBVS.3059....1A. 
  • White, N. E. et al. (August 1987), "An EXOSAT observation of 1.5 orbital cycles of the 0.7 day short-period RS CVn system ER Vul", Monthly Notices of the Royal Astronomical Society 227 (3): 545–551, doi:10.1093/mnras/227.3.545, Bibcode1987MNRAS.227..545W. 
  • Arevalo, M. J.; Fuensalida, J. J. (December 1985), "1984 UBVR Light Curves of ER Vul", Information Bulletin on Variable Stars 2831: 1, Bibcode1985IBVS.2831....1A. 
  • Ibanoglu, C.; Akan, M. C.; Evren, S.; Tunca, Z. (August 1985), "Photoelectric Observations of ER Vulpeculae", Information Bulletin on Variable Stars 2782: 1, Bibcode1985IBVS.2782....1I. 
  • Barden, S. C. (March 1984), "The Hα Nature of the Short Period RS CVn Systems HD86590, σαCr B, ER Vul and UV Psc.", Bulletin of the American Astronomical Society 16: 473, Bibcode1984BAAS...16..473B. 
  • Zeilik, M. et al. (November 1982), "1982 Photometry of ER Vul", Information Bulletin on Variable Stars 2221: 1, Bibcode1982IBVS.2221....1Z. 
  • McLean, B. J. (November 1982), "A spectroscopic investigation of the eclipsing variable ER Vul", Monthly Notices of the Royal Astronomical Society 201: 421–427, doi:10.1093/mnras/201.2.421, Bibcode1982MNRAS.201..421M. 
  • Kadouri, T. H. (December 1981), "BVR Photoelectric Observations of ER Vul June, July, 1981", Information Bulletin on Variable Stars 2057: 1, Bibcode1981IBVS.2057....1K. 
  • Al-Naimiy, H. M. K. (January 1981), "Photometric observations and light curve analysis of the peculiar system ER Vul", Astronomy and Astrophysics Supplement Series 43: 85–90, Bibcode1981A&AS...43...85A. 
  • Al-Naimiy, H. M. (October 1978), "Observation of the Peculiar Eclipsing Variable ER Vulpeculae", Information Bulletin on Variable Stars 1481: 1, Bibcode1978IBVS.1481....1A.