| Observation data Epoch J2000.0 Equinox J2000.0 |
|
|---|---|
| Constellation | Taurus |
| Right ascension | 04h 00m 40.8s |
| Declination | +12° 29' 25" |
| Apparent magnitude (V) | +3.41 |
| Distance | 370 ± 42 ly (114 ± 13 pc) |
| Spectral type | B3V+A4IV |
| Other designations | |
Lambda Tauri (λ Tau, λ Tauri) is a triple star system in the constellation Taurus. The primary component, Lambda Tauri A, is a blue-white B-type main sequence dwarf with a mean apparent magnitude of +3.41. It has a luminosity of about 4,000 times that of the Sun and a radius of 6.6 times solar. The companion is a white A-type subgiant of 5.5 solar radii and 95 solar luminosities. They orbit around a common centre of gravity once every 3.95 days. The spatial separation between these two stars is measured at 0.1 astronomical unit.
Because the system is an eclipsing binary its brightness varies from magnitude +3.37 to +3.91 as first one star and then the other pass in front of its companion. The system has a third, dimmer star with an orbital period of 33 days. The Lambda Tauri system is approximately 370 light years from Earth.
It, along with δ Librae, was the first star on which rotational line broadening[1] was observed, by Frank Schlesinger in 1909.
E.B Knobel, in the journal titled On a catalogue of stars in the Calendarium of Al Achsasi Al Mouakket, told that this star was designated as Sadr al Tauri which was translated in Latin as Pectus Tauri, meaning the bull chest[2]