RW Tauri

RW Tauri

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

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. A light curve of the eclipse was generated by H. N. Russell and associates in 1917. 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. Velocity measurements allowed W. A. Hiltner and R. H. Hardie to publish orbital elements for the system in 1949. 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.

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. 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.

This is a semi-detached binary with a period of 2.7688439 days as of 2020, and an orbital eccentricity of 0.3. During the primary eclipse the visual magnitude of the system decreases by 3.61 (i.e. at minimum it is only 4% as bright as at maximum) while the secondary eclipse decreases the magnitude by 0.11. The primary eclipse is the deepest known among eclipsing binaries. 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.

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

References

  1. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  2. 1 2 3 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.
  3. 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.
  4. 1 2 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 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, Bibcode:1959PASP...71..345A, doi:10.1086/127397.
  6. 1 2 3 4 5 6 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, Bibcode:1993PASP..105..731V, doi:10.1086/133224, S2CID 120953483.
  7. 1 2 3 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, Bibcode:2020MNRAS.491.5489M, doi:10.1093/mnras/stz3363.
  8. 1 2 3 4 5 Hiltner, W. A.; Hardie, R. H. (November 1949), "The Spectrum of RW Tauri", Astrophysical Journal, 110: 438, Bibcode:1949ApJ...110..438H, doi:10.1086/145218.
  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, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873.
  10. ↑ "RW Tau", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 20 June 2022.
  11. ↑ Shapley, H. (September 1913), "The orbits of eighty-seven eclipsing binaries---a summary", Astrophysical Journal, 38: 158–174, Bibcode:1913ApJ....38..158S, doi:10.1086/142018, hdl:2027/mdp.39015069424953. 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, Bibcode:1917ApJ....45..306R, doi:10.1086/142331.
  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), "Period changes of the interacting binary RW Tau", in Zejda, M. (ed.), The Proceedings of the 27th Conference on Variable Star Research. November 10–12, 1995. Brno, Czech Republic, Brno, p. 95, Bibcode:1996vsr..conf...95S, ISBN 80-85882-05-1.{{citation}}: CS1 maint: location missing publisher (link)
  15. ↑ Joy, A. H. (February 1942), "Observations of RW Tauri at Minimum Light", Publications of the Astronomical Society of the Pacific, 54 (317): 35–37, Bibcode:1942PASP...54...35J, doi:10.1086/125393.
  16. 1 2 Joy, Alfred H. (August 1947), "The Emission Lines of RW Tauri at Minimum", Publications of the Astronomical Society of the Pacific, 59 (349): 171, Bibcode:1947PASP...59..171J, doi:10.1086/125933.
  17. 1 2 Kaitchuck, R. H.; Honeycutt, R. K. (July 1982), "Time-resolved spectroscopy of the accretion disk in RW Tau", Astrophysical Journal, 258: 224–235, Bibcode:1982ApJ...258..224K, doi:10.1086/160071.
  18. 1 2 Malkov, O. Yu.; et al. (February 2006), "A catalogue of eclipsing variables", Astronomy and Astrophysics, 446 (2): 785–789, Bibcode:2006A&A...446..785M, doi:10.1051/0004-6361:20053137, hdl:10995/73280.
  19. ↑ Arévalo, M. J.; et al. (1998), "Infrared Photometry of the Algol system RW Tau", in Dusek, J. (ed.), Proceedings of the 20th Stellar Conference of the Czech and Slovak Astronomical Institutes. 5th - 7th November 1997. Brno, Czech Republic, Brno, p. 25, Bibcode:1998vsr..conf...25A, ISBN 80-85882-08-6.{{citation}}: CS1 maint: location missing publisher (link)
  20. ↑ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.

Further reading