Crux is a constellation of the southern sky that is centred on four bright stars in a cross-shaped asterism commonly known as the Southern Cross. It lies on the southern end of the Milky Way's visible band. The name Crux is Latin for cross. Even though it is the smallest of all 88 modern constellations, Crux is among the most easily distinguished as its four main stars each have an apparent visual magnitude brighter than +2.8. It has attained a high level of cultural significance in many Southern Hemisphere states and nations.
A nova is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star that slowly fades over weeks or months. All observed novae involve white dwarfs in close binary systems, but causes of the dramatic appearance of a nova vary, depending on the circumstances of the two progenitor stars. The main sub-classes of novae are classical novae, recurrent novae (RNe), and dwarf novae. They are all considered to be cataclysmic variable stars.
Telescopium is a minor constellation in the southern celestial hemisphere, one of twelve named in the 18th century by French astronomer Nicolas-Louis de Lacaille and one of several depicting scientific instruments. Its name is a Latinized form of the Greek word for telescope. Telescopium was later much reduced in size by Francis Baily and Benjamin Gould.
Circinus is a small, faint constellation in the southern sky, first defined in 1756 by the French astronomer Nicolas-Louis de Lacaille. Its name is Latin for compass, referring to the drafting tool used for drawing circles. Its brightest star is Alpha Circini, with an apparent magnitude of 3.19. Slightly variable, it is the brightest rapidly oscillating Ap star in the night sky. AX Circini is a Cepheid variable visible with the unaided eye, and BX Circini is a faint star thought to have been formed from the merger of two white dwarfs. Two sun-like stars have planetary systems: HD 134060 has two small planets, and HD 129445 has a Jupiter-like planet. Supernova SN 185 appeared in Circinus in 185 AD and was recorded by Chinese observers. Two novae have been observed more recently, in the 20th century.
Musca is a small constellation in the deep southern sky. It was one of 12 constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman, and it first appeared on a celestial globe 35 cm (14 in) in diameter published in 1597 in Amsterdam by Plancius and Jodocus Hondius. The first depiction of this constellation in a celestial atlas was in Johann Bayer's Uranometria of 1603. It was also known as Apis for 200 years. Musca remains below the horizon for most Northern Hemisphere observers.
The American Association of Variable Star Observers (AAVSO) is an international nonprofit organization. Founded in 1911, the organization focuses on coordinating, analyzing, publishing, and archiving variable star observations made largely by amateur astronomers. The AAVSO creates records that establish light curves depicting the variation in brightness of a star over time. The AAVSO makes these records available to professional astronomers, researchers, and educators.
Carolyn Hurless was an American astronomer and an American Association of Variable Star Observers merit award winner. She made an estimated 78,876 astronomical observations in her lifetime.
Leah Brown Allen was an American astronomer and Professor of Astronomy at Hood College.
3 Centauri is a triple star system in the southern constellation of Centaurus, located approximately 300 light years from the Sun. It is visible to the naked eye as a faint, blue-white hued star with a combined apparent visual magnitude of 4.32. As of 2017, the two visible components had an angular separation of 7.851″ along a position angle of 106°. The system has the Bayer designation k Centauri; 3 Centauri is the Flamsteed designation. It was a suspected eclipsing binary with a variable star designation V983 Centauri, however the AAVSO website lists it as non-variable, formerly suspected to be variable.
A Lambda Eridani Variable is a class of Be stars that show small amplitude variations of a few hundredths of a magnitude. The variations are highly regular with periods between 0.5 and 2.0 days, and they were initially described as periodic Be stars. Lambda Eridani is an example and the prototype. This has been ascribed to non-radial pulsations, inhomogeneous rotating discs, or the rotation of the star itself.
SS Virginis is a Mira variable star that appears with a strong red hue. It varies in magnitude from a minimum of 9.5 to a maximum of 7.4 over a period of 361 days. It is also considered to be a semiregular variable star, as its minimum and maximum magnitude are themselves variable over a period of decades. Its spectral class is C63e. Because it is so rich in carbon, SS Virginis is classified as a carbon star, along with stars like T Geminorum. SS Virginis, like all carbon Mira variables, has a hydrogen-alpha emission line that varies widely, synchronized with the overall variations in light. The hydrogen-alpha emission line becomes far more prominent as the star becomes brighter. Observations made in the near-infrared spectrum indicate that it has a radius of 500 solar radii, and its temperature is between 2405 and 2485 kelvins.
RY Sagittarii is a yellow supergiant and an R Coronae Borealis type variable star in the constellation Sagittarius. Although it ostensibly has the spectrum of a G-type star, it differs markedly from most in that it has almost no hydrogen and much carbon.
V1369 Centauri, also known as Nova Centauri 2013, was a bright nova in the constellation Centaurus that occurred in 2013. It was discovered on December 2, 2013 by amateur astronomer John Seach in Australia with a magnitude of 5.5. On December 14, 2013 it peaked at about magnitude 3.3, making it the brightest nova so far of this millennium.
Phoebe Waterman Haas was one of the earliest American women to be awarded a doctorate in astronomy (1913). While her formal professional career ended upon her marriage, she contributed as a citizen scientist, volunteering for the American Association of Variable Star Observers (AAVSO). The Phoebe Waterman Haas Public Observatory was supported by donations from her family and is named in her honor.
R Pictoris is a semiregular variable type star in the constellation Pictor. It ranges between apparent magnitude 5.1 and 14.4, and spectral types M1IIe to M4IIe, over a period of 168 days. It should be faintly visible to the naked eye of an observer with excellent observing conditions, when it is near its maximum brightness.
BH Crucis, also known as Welch's Red Variable, is a star in the constellation Crux. A long period (Mira-type) variable, its apparent magnitude ranges from 6.6 to 9.8 over 530 days. Hence at its brightest it is barely visible with the unaided eye in a rural sky. A red giant, it had been classified ranging between spectral types SC4.5/8-e and SC7/8-e, but appears to have evolved into a C-type spectrum by 2011.
S Boötis is a Mira variable in the constellation Boötes. It ranges between magnitudes 7.8 and 13.8 over a period of approximately 270 days. It is too faint to be seen with the naked eye, however when it is near maximum brightness it can be seen with binoculars.
V1400 Centauri, also known as 1SWASP J140747.93−394542.6 or simply J1407, is a young, pre-main-sequence star that was eclipsed by the likely free-floating substellar object J1407b in April–June 2007. With an age around 20 million years, the star is about as massive as the Sun and is located in the constellation Centaurus at a distance of 451 light-years away from the Sun. V1400 Centauri is a member of Upper Centaurus–Lupus subgroup of the Scorpius–Centaurus association, a group of young, comoving stars close to the Sun.
R Microscopii is a star in the constellation Microscopium. It is a red giant star of spectral type M4e that is also a Mira variable, with an apparent magnitude ranging between 8.3 and 13.8 over 138 days. Located around 1000 light-years distant, it shines with a luminosity 444 times that of the Sun and has a surface temperature of 3141 K. The Astronomical Society of Southern Africa in 2003 reported that observations of R Microscopii were urgently needed as data on its light curve was incomplete.
T Microscopii is a semiregular variable star in the constellation Microscopium. It ranges from magnitude 6.74 to 8.11 over a period of 352 days. Located around 700 light-years distant, it shines with a bolometric luminosity 7,509 times that of the Sun and has a surface temperature of 2,750 K.
