Astronomy:RW Tauri

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Short description: Eclipsing binary star in the constellation Taurus
RW Tauri
RWTauLightCurve.png
A light curve for RW Tauri, plotted from TESS data[1]
Observation data
Equinox J2000.0]] (ICRS)
Constellation Taurus
Right ascension  04h 03m 54.316s[2]
Declination 28° 07′ 33.49″[2]
Apparent magnitude (V) 7.98 - 11.59[3]
Characteristics
Spectral type B8Ve + K0IV[4]
B−V color index 0.079±0.015[5]
Variable type Algol (semidetached)[3]
Astrometry
Proper motion (μ) RA: 0.271[2] mas/yr
Dec.: −18.651[2] mas/yr
Parallax (π)3.4691 ± 0.0428[2] mas
Distance940 ± 10 ly
(288 ± 4 pc)
Orbit
Period (P)2.7688439 d[6]
Semi-major axis (a)11.94 R☉[7]
Eccentricity (e)0.293±0.037[8]
Inclination (i)90[6]°
Argument of periastron (ω)
(secondary)		36.45±5.57[8]°
Semi-amplitude (K1)
(primary)		53.34±1.74[8] km/s
Details[7]
Mass gaining star
Mass2.43 M☉
Radius2.27 R☉
Luminosity83 L☉
Surface gravity (log g)3.85[6] cgs
Temperature11,560 K
Rotational velocity (v sin i)94[6] km/s
Age20.0±17.2[9] Myr
Donor star
Mass0.55 M☉
Radius3.00 R☉
Luminosity2.81 L☉
Temperature4,330 K
Rotational velocity (v sin i)88[6] km/s
Other designations
RW Tau, BD+27°623, HD 25487, HIP 18972, SAO 76418, PPM 93202, WDS J04039+2808AB[10]
Database references
SIMBADdata

RW Tauri is a binary star system in the equatorial constellation of Taurus. It has the designation HD 25487 in the Henry Draper Catalogue, while RW Tauri is the variable star designation. With a peak apparent visual magnitude of 8.05,[5] it is too faint to be visible to the naked eye. The distance to this system is approximately 940 light years based on parallax measurements.[2]

This system was reported as an eclipsing binary by H. Shapley in 1913, who found a period of 2.769 days and a magnitude change of 3.42 during the primary eclipse.[11] A light curve of the eclipse was generated by H. N. Russell and associates in 1917.[12] Measurements by L. Binnendijk in 1941 suggested the system consisted of a hot component with a class of A0 in orbit with a cooler, larger star with a K0 class. He derived an orbital inclination of 86.95°±0.15° to the line of sight from the Earth, and showed that the times of the eclipse minimum appeared to vary on a cycle.[13] Velocity measurements allowed W. A. Hiltner and R. H. Hardie to publish orbital elements for the system in 1949.[8] Longer term observations of the system demonstrated that period variation is not periodic but occurs with abrupt changes, ruling out a third body in the system.[14]

In 1934, A. B. Wyse found varying emission lines in the spectrum. A. H. Joy in 1947 discovered these are paired emission lines with Doppler shifts of 350 km/s. The lines originate from a ring around the smaller, hotter component in the system. Both the star and the ring are completely occulted during an eclipse. The variation of the emission lines was confirmed, suggesting an uneven distribution of matter.[15] The disk is the result of Roche lobe overflow from the larger component. It is no more than 1.5 times the radius of the hotter star and is rotating more slowly than orbital velocity, leading to an in-fall of gas.[16]

This is a semi-detached binary[17] with a period of 2.7688439 days as of 2020,[7] and an orbital eccentricity of 0.3.[8] During the primary eclipse the visual magnitude of the system decreases by 3.61 (ie. at minimum it is only 4% as bright as at maximum) while the secondary eclipse decreases the magnitude by 0.11.[17] The primary eclipse is the deepest known among eclipsing binaries.[16][6] The primary component is a B-type main-sequence star with a stellar classification of B8Ve, where the 'e' indicates emission lines. The larger secondary is a more evolved subgiant star with a class of K0IV.[4]

In 1947, a faint, magnitude 12.5 companion was detected by A. H. Joy at an angular separation of ~1″ from the pair,[15] and this was confirmed by other observers. A 1993 study failed to detect this object,[18] but Gaia records a magnitude 12.5 star just under 2″ from RW Tauri.[19]

References

  1. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 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. Bibcode: 2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 Samus, N. N. et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1 61 (1): 80–88, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S. 
  4. ↑ 4.0 4.1 Abt, Helmut A.; van Biesbroeck, G. (August 1959), "The Visual Companion of RW Tauri", Publications of the Astronomical Society of the Pacific 71 (421): 345, doi:10.1086/127397, Bibcode: 1959PASP...71..345A. 
  5. ↑ 5.0 5.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A. 
  6. ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Vesper, David N.; Honeycutt, R. K. (July 1993), "Full-Orbit H-alpha Emission in RW Tau", Publications of the Astronomical Society of the Pacific 105: 731, doi:10.1086/133224, Bibcode: 1993PASP..105..731V. 
  7. ↑ 7.0 7.1 7.2 Malkov, Oleg Yu (February 2020), "Semidetached double-lined eclipsing binaries: Stellar parameters and rare classes", Monthly Notices of the Royal Astronomical Society 491 (4): 5489–5497, doi:10.1093/mnras/stz3363, Bibcode: 2020MNRAS.491.5489M. 
  8. ↑ 8.0 8.1 8.2 8.3 8.4 Hiltner, W. A.; Hardie, R. H. (November 1949), "The Spectrum of RW Tauri", Astrophysical Journal 110: 438, doi:10.1086/145218, Bibcode: 1949ApJ...110..438H. 
  9. ↑ Tetzlaff, N. et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode: 2011MNRAS.410..190T. 
  10. ↑ "RW Tau". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=RW+Tau. 
  11. ↑ Shapley, H. (September 1913), "The orbits of eighty-seven eclipsing binaries---a summary", Astrophysical Journal 38: 158–174, doi:10.1086/142018, Bibcode: 1913ApJ....38..158S.  See p. 163.
  12. ↑ Russell, H. N. et al. (June 1917), "Comparison of visual and photographic observations of eclipsing variables", Astrophysical Journal 45: 306–347, doi:10.1086/142331, Bibcode: 1917ApJ....45..306R. 
  13. ↑ Binnendijk, L. (April 1941), "The period and the photometric orbit of RW Tauri (Errata: 9 224)", Bulletin of the Astronomical Institutes of the Netherlands 9: 173, Bibcode: 1941BAN.....9..173B. 
  14. ↑ Šimon, V. (1996), Zejda, M., ed., "Period changes of the interacting binary RW Tau", The Proceedings of the 27th Conference on Variable Star Research. November 10–12, 1995. Brno, Czech Republic (Brno): p. 95, ISBN 80-85882-05-1, Bibcode: 1996vsr..conf...95S. 
  15. ↑ 15.0 15.1 Joy, Alfred H. (August 1947), "The Emission Lines of RW Tauri at Minimum", Publications of the Astronomical Society of the Pacific 59 (349): 171, doi:10.1086/125933, Bibcode: 1947PASP...59..171J. 
  16. ↑ 16.0 16.1 Kaitchuck, R. H.; Honeycutt, R. K. (July 1982), "Time-resolved spectroscopy of the accretion disk in RW Tau", Astrophysical Journal 258: 224–235, doi:10.1086/160071, Bibcode: 1982ApJ...258..224K. 
  17. ↑ 17.0 17.1 Malkov, O. Yu. et al. (February 2006), "A catalogue of eclipsing variables", Astronomy and Astrophysics 446 (2): 785–789, doi:10.1051/0004-6361:20053137, Bibcode: 2006A&A...446..785M. 
  18. ↑ Arévalo, M. J. et al. (1998), Dusek, J., ed., "Infrared Photometry of the Algol system RW Tau", Proceedings of the 20th Stellar Conference of the Czech and Slovak Astronomical Institutes. 5th - 7th November 1997. Brno, Czech Republic (Brno): p. 25, ISBN 80-85882-08-6, Bibcode: 1998vsr..conf...25A. 
  19. ↑ Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.

Further reading

  • Khaliullina, A. I. (April 2018), "The Light-time Effect in the Eclipsing Binaries with Early-type Components U CrB and RW Tau", Astronomy Reports 62 (4): 264–272, doi:10.1134/S1063772918040030, Bibcode: 2018ARep...62..264K. 
  • Lloyd, Christopher (March 2017), "The Current Ephemeris of RW Tauri", British Astronomical Association Variable Star Section Circular 171 (171): 7–9, Bibcode: 2017BAAVC.171....7L. 
  • Treuer, Z. R. et al. (September 1997), "Recent Period Changes in RW Tau", International Amateur-Professional Photoelectric Photometry Communication 69 (69): p. 23, Bibcode: 1997IAPPP..69...23T. 
  • Simon, V. (March 1997), "On the character of the orbital period changes in the interacting binary RW Tauri.", Astronomy and Astrophysics 319: 886–893, Bibcode: 1997A&A...319..886S. 
  • Vesper, D.; Honeycutt, R. K. (December 1992), "Out-of-Eclipse H-α Emission in RW Tau", Bulletin of the American Astronomical Society 25: 742, 119.08, Bibcode: 1992AAS...18111908V. 
  • van Hamme, W.; Wilson, R. E. (December 1990), "Rotation Statistics of Algol-Type Binaries and Results on RY Geminorum, RW Monocerotis, and RW Tauri", Astronomical Journal 100: 1981, doi:10.1086/115653, Bibcode: 1990AJ....100.1981V. 
  • van Hamme, W. (June 1989), "Determining Rotation Rates from Lightcurves - RW-Monocerotis and RW-Tauri", Space Science Reviews 50 (1–2): 373, doi:10.1007/BF00215976, Bibcode: 1989SSRv...50..373V. 
  • Plavec, M. J.; Dobias, J. J. (September 1983), "RW Tauri as a weak W Serpentis star.", Astrophysical Journal 272: 206–213, doi:10.1086/161280, Bibcode: 1983ApJ...272..206P. 
  • Kaitchuck, R. H. et al. (1980), Plavec, M. J.; Popper, D. M.; Ulrich, R. K., eds., "Time-resolved spectroscopy of RW Tau and X Per", "Close binary stars: observations and interpretation", IAU Symposium 88, held in Toronto, Canada, 7–10 August 1979 88: pp. 233–236, Bibcode: 1980IAUS...88..233K. 
  • Bookmyer, B. B. (August 1977), "UBVRI light curves of RW Tauri", Publications of the Astronomical Society of the Pacific 89: 533–540, doi:10.1086/130158, Bibcode: 1977PASP...89..533B. 
  • Tsouroplis, A. G. (April 1977), "Determination of the Elements of Eclipsing Variables RW Tauri and U Sagittae by an Analysis of the Light Changes in the Frequency Domain", Astrophysics and Space Science 47 (2): 361–373, doi:10.1007/BF00642844, Bibcode: 1977Ap&SS..47..361T. 
  • Battistini, Pier Luigi et al. (December 1971), "Variation of the Gradient and Balmer Discontinuity During the Eclipse of the Variable RW Tauri: Comparison Between Observations and Theory", Astrophysics and Space Science 14 (2): 438–445, doi:10.1007/BF00653330, Bibcode: 1971Ap&SS..14..438B. 
  • Horák, T. (1966), "New elements of the eclipsing variables TW Draconis, RW Tauri and KR Cygni and the influence of the rectification of the light curve upon the elements VV Ursae Maioris", Bulletin of the Astronomical Institute of Czechoslovakia 17: 272, Bibcode: 1966BAICz..17..272H. 
  • Kříž, S. (1965), "A new approach to the limb-darkening problem of the star RW Tauri", Bulletin of the Astronomical Institute of Czechoslovakia 16: 118, Bibcode: 1965BAICz..16..118K. 
  • Plavec, M. et al. (1964), "Trajectories of particles ejected from L1 in RW Tauri", Bulletin of the Astronomical Institute of Czechoslovakia 15: 171, Bibcode: 1964BAICz..15..171P. 
  • Plavec, M. (1962), "Spectrographic orbit of RW Tauri", Bulletin of the Astronomical Institute of Czechoslovakia 13: 224, Bibcode: 1962BAICz..13..224P. 
  • Grant, Gordon (January 1959), "A Photoelectric Study of the Eclipsing Variable RW Tauri", Astrophysical Journal 129: 62, doi:10.1086/146596, Bibcode: 1959ApJ...129...62G. 




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