View source for CoKu Tau/4

{{Short description|Star in the constellation Taurus}}
{{no footnotes|date=April 2017}}
{{Starbox short
| name = CoKu Tau/4
| constell =[[Taurus (constellation)|Taurus]]
| ra ={{RA|04|41|16.809}}
| dec ={{DEC|+28|39|59.99}}
| appmag_v =14.9
| absmag_v = <!--Absolute magnitude (Johnson-Cousins V system)-->
| dist_ly =~420
| dist_pc = ~130
| class = <!--Stellar class(es, separated by '+')-->
| names =CoKu&nbsp;Tauri/4, CoKu&nbsp;Tau-Aur&nbsp;Star&nbsp;4, HBC&nbsp;421, 2MASS&nbsp;J04411681+2840000
| Simbad = 2MASS+J04411681%2B2840000
| ARICNS = <!--Search string for link to ARICNS-->
| NSTED = <!--Search string for link to NStED-->
| EPE = <!--Search string for link to Extrasolar Planets Encyclopaedia-->
}}
'''CoKu Tau/4''' is a pre-[[main-sequence]] [[binary star|binary]] [[T Tauri star]] system in the constellation [[Taurus (constellation)|Taurus]]. The stars are surrounded by a [[circumstellar disc|circumbinary disc]] with a central cavity of radius 10 [[astronomical unit]]s. Before its binary nature was known, the central cavity in the system's disc was thought to have been cleared out by [[CoKu Tau/4 b|a planet]] of at least 10 [[Jupiter mass]]es, a rare example of a so-called "transitional disc". This model was disproven in 2008 when the star was resolved using [[adaptive optics]] as a system of two near-equal-mass stars with a [[projected separation]] of 8 AU. The central cavity is thus cleared out by the stars, not by the gravitational influence of a planet.

==References==
* [http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?2008ApJ...678L..59I&db_key=AST&nosetcookie=1 Ireland & Kraus (2008): The Disk Around CoKu Tauri/4: Circumbinary, Not Transitional]
* [https://web.archive.org/web/20061021025014/https://discover.com/issues/jul-05/cover/?page=1 How Nature Builds a Planet], Adam Frank, ''Discover'' '''26''' (#7, July 2005); accessed online 1-II-2007.
* [http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2004ApJ...612L.137Q On the Planet and the Disk of CoKu TAURI/4], Alice C. Quillen et al., ''Astrophysical Journal'' '''612''' (September 2004), pp.&nbsp;L137&ndash;L140; also [https://arxiv.org/abs/astro-ph/0406445 arXiv:astro-ph/0406445].
* [http://adsabs.harvard.edu/abs/2005A&A...438..769D Pre-main sequence star Proper Motion Catalogue], C. Ducourant et al., ''Astronomy and Astrophysics'' '''438''' (August 2005), pp.&nbsp;769&ndash;778.
* [http://adsabs.harvard.edu/abs/1979ApJS...41..743C Observational studies of pre-main-sequence evolution], Martin Cohen and Leonard V. Kuhi, ''Astrophysical Journal Supplement Series'' '''41''' (December 1979), pp.&nbsp;743&ndash;843.

{{Stars of Taurus}}

{{DEFAULTSORT:CoKu Tau/4}}
[[Category:Binary stars]]
[[Category:T Tauri stars]]
[[Category:Circumstellar disks]]
[[Category:Taurus (constellation)]]


{{Multi-star-stub}}