17 relations: Apparent magnitude, Binary star, Centaurus, Constellation, F-type main-sequence star, Giant star, Light-year, Minute and second of arc, Nuclear fusion, Orbital eccentricity, Orbital period, Radial velocity, Solar core, South African Astronomical Observatory, Stellar classification, Stellar evolution, Stellar parallax.
The apparent magnitude of a celestial object is a number that is a measure of its brightness as seen by an observer on Earth.
A binary star is a star system consisting of two stars orbiting around their common barycenter.
Centaurus is a bright constellation in the southern sky.
Christmas is an annual festival commemorating the birth of Jesus Christ,Martindale, Cyril Charles.
The Christmas season, also called the festive season, or the holiday season (mainly in the U.S. and Canada; often simply called the holidays),, is an annually recurring period recognized in many Western and Western-influenced countries that is generally considered to run from late November to early January.
Christmas Eve is the evening or entire day before Christmas Day, the festival commemorating the birth of Jesus.
Christmas traditions vary from country to country.
A constellation is a group of stars that are considered to form imaginary outlines or meaningful patterns on the celestial sphere, typically representing animals, mythological people or gods, mythological creatures, or manufactured devices.
An F-type main-sequence star (F V) is a main-sequence, hydrogen-fusing star of spectral type F and luminosity class V. These stars have from 1.0 to 1.4 times the mass of the Sun and surface temperatures between 6,000 and 7,600 K.Tables VII and VIII.
A giant star is a star with substantially larger radius and luminosity than a main-sequence (or dwarf) star of the same surface temperature.
The light-year is a unit of length used to express astronomical distances and measures about 9.5 trillion kilometres or 5.9 trillion miles.
A minute of arc, arcminute (arcmin), arc minute, or minute arc is a unit of angular measurement equal to of one degree.
New Year is the time or day at which a new calendar year begins and the calendar's year count increments by one.
New Year's Day, also called simply New Year's or New Year, is observed on January 1, the first day of the year on the modern Gregorian calendar as well as the Julian calendar.
In the Gregorian calendar, New Year's Eve (also known as Old Year's Day or Saint Sylvester's Day in many countries), the last day of the year, is on 31 December which is the seventh day of Christmastide.
In nuclear physics, nuclear fusion is a reaction in which two or more atomic nuclei come close enough to form one or more different atomic nuclei and subatomic particles (neutrons or protons).
The orbital eccentricity of an astronomical object is a parameter that determines the amount by which its orbit around another body deviates from a perfect circle.
The orbital period is the time a given astronomical object takes to complete one orbit around another object, and applies in astronomy usually to planets or asteroids orbiting the Sun, moons orbiting planets, exoplanets orbiting other stars, or binary stars.
The radial velocity of an object with respect to a given point is the rate of change of the distance between the object and the point.
The core of the Sun is considered to extend from the center to about 0.2 to 0.25 of solar radius.
South African Astronomical Observatory (SAAO) is the national centre for optical and infrared astronomy in South Africa.
In astronomy, stellar classification is the classification of stars based on their spectral characteristics.
Stellar evolution is the process by which a star changes over the course of time.
Stellar parallax is the apparent shift of position of any nearby star (or other object) against the background of distant objects.
2018 has been designated as the third International Year of the Reef by the International Coral Reef Initiative.
2019 (MMXIX) will be a common year starting on Tuesday of the Gregorian calendar, the 2019th year of the Common Era (CE) and Anno Domini (AD) designations, the 19th year of the 3rd millennium, the 19th year of the 21st century, and the 10th and last year of the 2010s decade.