RV Equation ω Clarification

Very important paper.

The Standard RV Equation uses ωp, not ω∗
https://arxiv.org/abs/2212.06966

Quote :

Since the discovery of the first exoplanet orbiting a main-sequence star, astronomers have used stellar radial velocity (RV) measurements to infer the orbital properties of planets. For a star orbited by a single planet, the stellar orbit is a dilation and 180∘ rotation of the planetary orbit. Many of the orbital properties of the star are identical to those of the planet including the orbital period, eccentricity, inclination, longitude of the ascending node, time of periastron passage, and mean anomaly. There is a notable exception to this pattern: the argument of periastron, ω, which is defined as the angle between the periapsis of an orbiting body and its ascending node; in other words, ω describes the orientation of a body's elliptical path within the orbital plane. For a star-planet system, the argument of periastron of the star (ω∗) is 180∘ offset from the argument of periastron of the planet (ωp). For a conventional coordinate system with z^ pointed away from the observer, the standard RV equation is defined with ωp; however, we find that many interpretations of the RV equation are not self-consistent. For instance, the commonly used Radial Velocity Modeling Toolkit \texttt{RadVel} relies on an RV equation that uses the standard ωp, but its documentation states that it instead models ω∗. As a result, we identify 54 published papers reporting a total of 265 ω values that are likely 180∘ offset from their true values, and the scope of this issue is potentially even larger.