16 relations: Astronomical unit, Brown dwarf, Chamaeleon, Dwarf nova, Epoch (astronomy), HW Virginis, Jupiter, Light-year, NN Serpentis, OY Carinae, Red dwarf, Substellar object, Sun, The Astrophysical Journal, Variable star, White dwarf.
The astronomical unit (symbol: au, ua, or AU) is a unit of length, roughly the distance from Earth to the Sun.
Brown dwarfs are substellar objects that occupy the mass range between the heaviest gas giant planets and the lightest stars, having masses between approximately 13 to 75–80 times that of Jupiter, or approximately to about.
Chamaeleon is a small 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 U Geminorum-type variable star, or dwarf nova (pl. novae) is a type of cataclysmic variable star consisting of a close binary star system in which one of the components is a white dwarf that accretes matter from its companion.
In astronomy, an epoch is a moment in time used as a reference point for some time-varying astronomical quantity, such as the celestial coordinates or elliptical orbital elements of a celestial body, because these are subject to perturbations and vary with time.
HW Virginis, abbreviated HW Vir, is an eclipsing binary system (of the Algol type) approximately 590 light-years away (based on the stellar properties and magnitudes: the Hipparcos trigonometric parallax measurement has too high an error value to be useful) in the constellation of Virgo.
Jupiter is the fifth planet from the Sun and the largest in the Solar System.
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.
NN Serpentis (abbreviated NN Ser) is an eclipsing post-common envelope binary system approximately 1670 light-years away.
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.
OY Carinae (abbreviated OY Car) is an eclipsing binary system approximately 277 light-years away from the Sun, classed as cataclysmic variable.
A red dwarf (or M dwarf) is a small and relatively cool star on the main sequence, of M spectral type.
A substellar object, sometimes called a substar, is an astronomical object whose mass is smaller than the smallest mass at which hydrogen fusion can be sustained (approximately 0.08 solar masses).
The Sun is the star at the center of the Solar System.
The Astrophysical Journal, often abbreviated ApJ (pronounced "ap jay") in references and speech, is a peer-reviewed scientific journal of astrophysics and astronomy, established in 1895 by American astronomers George Ellery Hale and James Edward Keeler.
A variable star is a star whose brightness as seen from Earth (its apparent magnitude) fluctuates.
A white dwarf, also called a degenerate dwarf, is a stellar core remnant composed mostly of electron-degenerate matter.
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.