# 88 Tauri > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/88_Tauri > Markdown URL: https://mediated.wiki/source/88_Tauri.md > Source: https://en.wikipedia.org/wiki/88_Tauri > Source revision: 1353200969 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) This article is about d Tauri. Not to be confused with [δ Tauri](/source/Delta_Tauri). **88 Tauri**, also known as **d Tauri**, is a multiple [star](/source/Star) system in the [constellation](/source/Constellation) [Taurus](/source/Taurus_(constellation)). It has an [apparent magnitude](/source/Apparent_magnitude) of about 4.25, meaning that it is visible to the naked eye. Based upon [parallax](/source/Parallax) measurements made by the [Hipparcos](/source/Hipparcos) [spacecraft](/source/Spacecraft), the star system is some 156 light-years (48 parsecs) from the Sun.[1] 88 Tauri is a sextuple star system, meaning that it contains six stars in a hierarchical orbit. The brighter component, 88 Tauri A, is a quadruple system consisting of two [spectroscopic binaries](/source/Spectroscopic_binaries) orbiting each other with an [orbital period](/source/Orbital_period) of 18 years. The fainter component, 88 Tauri B, is also a spectroscopic binary, and is about 69 arcseconds away, bringing up the total to six stars.[2] ## Orbit Hierarchy of orbits in the 88 Tauri system 88 Tauri A is a fourth-magnitude star[3] with two components, 88 Tauri Aa and 88 Tauri Ab. 88 Tauri Aa and Ab orbit each other once every 18 years and are separated by about 0.28 arcseconds. Those two components themselves are [spectroscopic binaries](/source/Spectroscopic_binary): binary stars that are too close to be [resolved](/source/Angular_resolution) but can be detected by periodic [Doppler shifts](/source/Doppler_shift) in their [spectrum](/source/Stellar_spectrum). In this case, variability in the radial velocity has been recognized as early as 1907.[4] The Aa pair has an [orbital period](/source/Orbital_period) of 3.57 days, the Ab pair has an orbital period of 7.89 days, and both have circular orbits with low [orbital eccentricities](/source/Orbital_eccentricities).[2] 88 Tauri B, 69.56 arcseconds away,[5] is a seventh-magnitude star that is also a [binary star](/source/Binary_star) system. It is another [spectroscopic binary](/source/Spectroscopic_binary) whose components (88 Tauri Ba and Bb) orbit each other every 3.69 [years](/source/Year).[2] The orbit of 88 Tauri B around 88 Tauri A likely takes about 70,000 years.[6] ## Properties 88 Tauri Aa has a [spectral type](/source/Spectral_type) of A6m,[2] indicating that it is an [A-type star](/source/A-type_star). The "m" in its spectral type means that it is an [Am star](/source/Am_star),[2] also known as a metallic-line star. These types of stars have [spectra](/source/Spectrum) indicating varying amounts of metals, like [iron](/source/Iron).[7] The rest of the stars in 88 Tauri A have spectral types ranging from F5 to G2-3, meaning that they are regular [F-type](/source/F-type_star) or [G-type](/source/G-type_star) [main-sequence stars](/source/Main-sequence_star). The spectral types for 88 Tauri Ab1 and Ab2 are less certain, because their [spectral lines](/source/Spectral_line) are weaker, hence the colon after G2. Aa1 does not appears to be [rotating synchronously](/source/Synchronous_rotation) with its companion (nor does it have a convective atmosphere), unlike Aa2. (It is not known if the two stars of 88 Tauri Ab are in synchronous rotation with each other, because of the relatively high errors in their measurements.)[2] 88 Tauri B consists of a [F-type main sequence star](/source/F-type_main_sequence_star), with another low-mass star.[6] The mass of the smaller component is at least 0.15 [solar masses](/source/Solar_masses), so it is most likely a [red dwarf](/source/Red_dwarf).[6] ## References 1. van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". *Astronomy and Astrophysics*. **474** (2): 653–664. [arXiv:0708.1752](https://arxiv.org/abs/0708.1752). [Bibcode:2007A&A...474..653V](https://ui.adsabs.harvard.edu/abs/2007A%26A...474..653V). [doi:10.1051/0004-6361:20078357](https://doi.org/10.1051/0004-6361:20078357). [S2CID 18759600](https://api.semanticscholar.org/CorpusID:18759600) 1. Lane, Benjamin F.; Muterspaugh, Matthew W.; Fekel, Francis C.; Williamson, Michael; Browne, Stanley; Konacki, Maciej; Burke, Bernard F.; Colavita, M. M.; Kulkarni, S. R.; Shao, M. (2007). "The Orbits of the Quadruple Star System 88 Tauri A from PHASES Differential Astrometry and Radial Velocity". *The Astrophysical Journal*. **669** (2): 1209–1219. [arXiv:0710.2127](https://arxiv.org/abs/0710.2127). [Bibcode:2007ApJ...669.1209L](https://ui.adsabs.harvard.edu/abs/2007ApJ...669.1209L). [doi:10.1086/520877](https://doi.org/10.1086/520877). [S2CID 12957785](https://api.semanticscholar.org/CorpusID:12957785) 1. "88 Tau". Retrieved 16 February 2017. 1. Daniel, Zaccheus (1916). "The orbit of 88 D Tauri". *Publications of the Allegheny Observatory of the University of Pittsburgh*. **3** (12): 93. [Bibcode:1916PAllO...3...93D](https://ui.adsabs.harvard.edu/abs/1916PAllO...3...93D) 1. "88 Tau B". Retrieved 18 February 2017. 1. Tokovinin, A. A. & Gorynya, N. A. (2001). "New spectroscopic components in multiple systems. IV". *Astronomy and Astrophysics*. **374**: 227–234. [Bibcode:2001A&A...374..227T](https://ui.adsabs.harvard.edu/abs/2001A%26A...374..227T). [doi:10.1051/0004-6361:20010714](https://doi.org/10.1051/0004-6361:20010714) 1. [Am star](http://www.daviddarling.info/encyclopedia/A/Am_star.html) [Archived](https://web.archive.org/web/20170804053755/http://www.daviddarling.info/encyclopedia/A/Am_star.html) 2017-08-04 at the Wayback Machine, *The Internet Encyclopedia of Science*, David Darling. Accessed on line August 14, 2008. --- Adapted from the Wikipedia article [88 Tauri](https://en.wikipedia.org/wiki/88_Tauri) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/88_Tauri?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.