An Etymological Dictionary of Astronomy and Astrophysics

A → carbon star of the → asymptotic giant branch type located in the constellation of → Antlia. Its other designations are HIP 51821 (→ Hipparcos Star Catalogue), HD 91793, and HR 4153. U Antliae is an → irregular variable that changes its → visual magnitude between 5.27 and 6.04. About 850 → light-years from Earth, it shines with a → luminosity approximately 8,000 times that of the → solar luminosity and has a → surface temperature 2,800 K. It is surrounded by a complex structure of dust shells.
Around 2,700 years ago, U Antliae went through a short period of rapid → mass loss. During this period of only a few hundred years, the material making up the shell seen in the → Atacama Large Millimeter Array (ALMA) data was ejected at high speed (Kerschbaum et al., 2017, A&A 605, A116, arXiv:1708.02915).

See also: U, according to → variable star designation; → Antlia.

A → carbon star of the → asymptotic giant branch type located in the constellation of → Antlia. Its other designations are HIP 51821 (→ Hipparcos Star Catalogue), HD 91793, and HR 4153. U Antliae is an → irregular variable that changes its → visual magnitude between 5.27 and 6.04. About 850 → light-years from Earth, it shines with a → luminosity approximately 8,000 times that of the → solar luminosity and has a → surface temperature 2,800 K. It is surrounded by a complex structure of dust shells.
Around 2,700 years ago, U Antliae went through a short period of rapid → mass loss. During this period of only a few hundred years, the material making up the shell seen in the → Atacama Large Millimeter Array (ALMA) data was ejected at high speed (Kerschbaum et al., 2017, A&A 605, A116, arXiv:1708.02915).

See also: U, according to → variable star designation; → Antlia.

The prototypical and first discovered → cataclysmic variable. It is a → dwarf nova system with a relatively long → orbital period of 4 hr 17 minutes. U Gem undergoes → outbursts on time-scales between 30 and 250 days and shows → grazing occultations.
The → accretion disk is partially eclipsed, but the → white dwarf remains visible during mideclipse. The mass of the white dwarf → primary is estimated to be 1.24 Msun, about two times higher than the mass of the → secondary; the → angle of inclination is 69°.7 (P. J. Groot 2001, ApJ 551, L89).

See also: → variable star designation; → Gemini.

The prototypical and first discovered → cataclysmic variable. It is a → dwarf nova system with a relatively long → orbital period of 4 hr 17 minutes. U Gem undergoes → outbursts on time-scales between 30 and 250 days and shows → grazing occultations.
The → accretion disk is partially eclipsed, but the → white dwarf remains visible during mideclipse. The mass of the white dwarf → primary is estimated to be 1.24 Msun, about two times higher than the mass of the → secondary; the → angle of inclination is 69°.7 (P. J. Groot 2001, ApJ 551, L89).

See also: → variable star designation; → Gemini.