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ρ Ophiuchi
Rho Ophiuchi (ρ Ophiuchi) is a star system, multiple star system in the constellation Ophiuchus. The central system has an apparent magnitude of 4.63. Based on the central system's stellar parallax, parallax, it is located about 450 light-years distant. The other stars in the system are slightly farther away. System The central system is known as Rho Ophiuchi AB. It consists of three blue-colored subgiants or main-sequence stars, designated Rho Ophiuchi Aa, Ab and B, respectively. Rho Ophiuchi Aa-Ab is a spectroscopic binary with an orbital period of 88 days and an orbital period of 1.1 astronomical units. Farther away is the B companion, a visual binary whose sky-projected distance from the inner pair appears to be 3.1″, corresponding to a separation of at least 344 AU. However, the actual separation is larger, and the two take about 2,400 years to complete an orbit. The two stars dominate the radiation field around the Rho Ophiuchi cloud complex. Rho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
J2000
In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a celestial body, as they are subject to perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or aphelion of its orbit, or the size of the major axis of its orbit. The main use of astronomical quantities specified in this way is to calculate other relevant parameters of motion, in order to predict future positions and velocities. The applied tools of the disciplines of celestial mechanics or its subfield orbital mechanics (for predicting orbital paths and positions for bodies in motion under the gravitational effects of other bodies) can be used to generate an ephemeris, a table of values giving ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
