NOMINAL VALUES FOR SELECTED SOLAR AND PLANETARY QUANTITIES: IAU 2015 RESOLUTION B3^{* †}

Abstract

In this brief communication we provide the rationale for, and the outcome of the International Astronomical Union (IAU) resolution vote at the XXIX th General Assembly in Honolulu, Hawaii, in 2015, on recommended nominal conversion constants for selected solar and planetary properties. The problem addressed by the resolution is a lack of established conversion constants between solar and planetary values and SI units: a missing standard has caused a proliferation of solar values (e.g., solar radius, solar irradiance, solar luminosity, solar effective temperature and solar mass parameter) in the literature, with cited solar values typically based on best estimates at the time of paper writing. As precision of observations increases, a set of consistent values becomes increasingly important. To address this, an IAU Working Group on Nominal Units for Stellar and Planetary Astronomy formed in 2011, uniting experts from the solar, stellar, planetary, exoplanetary and fundamental astronomy, as well as from general standards fields to converge on optimal values for nominal conversion constants. The effort resulted in the IAU 2015 Resolution B3, passed at the IAU General Assembly by a large majority. The resolution recommends the use of nominal solar and planetary values, which are by definition exact and are expressed in SI units. These nominal values should be understood as conversion factors only, not as the true solar/planetary properties or current best estimates. Authors and journal editors are urged to join in using the standard values set forth by this resolution in future work and publications to help minimize further confusion.

AMD-stability in the presence of first-order mean motion resonances

“…We plot in this Figure D.2 the quantity δα R /ε 1/4 ; we see that the curves are almost similar, particularly for the smaller values of ε. (Prša et al 2016). …”

A refined analysis of the low-mass eclipsing binary system T-Cyg1-12664

“…The adopted radii, T eff2 and orbital inclination were computed from the mean for the two fits and their uncertainties are the standard deviations. The secondary is an M3V star, based on its effective temperature (Mamajek 2015 Prša et al 2016). The bolometric corrections were computed using the BC scale by Flower (1996) (but see Torres 2010, Sect.…”

The Absolute Magnitude of the Sun in Several Filters

“…To rationalize the use of solar constants, the IAU in 2015 adopted a nominal value for the Sun's luminosity L e =3.828×10 8 W (Prša et al 2016), which corresponds to an average TSI of 1361 W m −2 at 1 au and an absolute bolometric magnitude of M Bol =4.74.…”

“…To derive the Sun's absolute magnitudes, the IAU 2012 definitions of the astronomical unit (au) (Prša et al 2016) and parsec were used, giving a distance modulus for the Sun of −31.5721 mag. To rationalize the use of solar constants, the IAU in 2015 adopted a nominal value for the Sun's luminosity L e =3.828×10 8 W (Prša et al 2016), which corresponds to an average TSI of 1361 W m −2 at 1 au and an absolute bolometric magnitude of M Bol =4.74.…”