An Etymological Dictionary of Astronomy and Astrophysics

A type of → brown dwarf with an → effective temperature ranging from about 2200 K to about 1300 K, corresponding to luminosities about 4 x 10^-4 to 3 x 10^-5 times that of the Sun. L dwarfs are intermediate in temperature between M and → T dwarfs. Their spectra in the optical show weak titanium oxide (TiO) and vanadium oxide (VO) absorption lines and strong metallic hydrides CrH (8611 and 9969 Å) and FeH (8692 and 9896 Å). Also are present strong neutral atomic lines of alkali metals Na I (8183, 8195 Å), K I (7665, 7699 Å), Rb I (7800, 7948 Å), Cs I (8521, 8943 Å), and sometimes Li I (6708 Å). The prototype of the L-dwarf class is → GD 165B. The spectral classification was first defined by Kirkpatrick et al. 1999, ApJ 519, 802 and Martin et al. 1999, AJ 118, 2466.

See also: For the reasoning behind the choice of the letter L, see Kirkpatrick et al. 1993, ApJ 406, 701; → dwarf.

A type of → brown dwarf with an → effective temperature ranging from about 2200 K to about 1300 K, corresponding to luminosities about 4 x 10^-4 to 3 x 10^-5 times that of the Sun. L dwarfs are intermediate in temperature between M and → T dwarfs. Their spectra in the optical show weak titanium oxide (TiO) and vanadium oxide (VO) absorption lines and strong metallic hydrides CrH (8611 and 9969 Å) and FeH (8692 and 9896 Å). Also are present strong neutral atomic lines of alkali metals Na I (8183, 8195 Å), K I (7665, 7699 Å), Rb I (7800, 7948 Å), Cs I (8521, 8943 Å), and sometimes Li I (6708 Å). The prototype of the L-dwarf class is → GD 165B. The spectral classification was first defined by Kirkpatrick et al. 1999, ApJ 519, 802 and Martin et al. 1999, AJ 118, 2466.

See also: For the reasoning behind the choice of the letter L, see Kirkpatrick et al. 1993, ApJ 406, 701; → dwarf.

A → semiregular variable with a period of 141 days. It has a → spectral type of M5 III corresponding to an → effective temperature of ~ 3500 K. It has a radial velocity relative to the → Local Standard of Rest of 33.3 km s^-1. At a distance of 64 → parsecs,
L₂ Pup is the second nearest → asymptotic giant branch (AGB) star next to R Doradus; it is ~ 30% closer than → Mira. Recent → near-infrared JHKL band observations by Kervella et al. (2014, 2015) show a compact dust disk around the central star, with an inner rim of 6 → astronomical units and an outer edge of 13 au, at an inclination of approximately 82°.

The → circumstellar environment of L₂ Pup was observed with → ALMA. The → molecular emission shows a → differentially rotating disk, inclined to a nearly edge-on position (Homan et al., 2017, A&A 601, A5 and references therein).

See also: Star name in the → Bayer designation scheme; → Puppis.

A → semiregular variable with a period of 141 days. It has a → spectral type of M5 III corresponding to an → effective temperature of ~ 3500 K. It has a radial velocity relative to the → Local Standard of Rest of 33.3 km s^-1. At a distance of 64 → parsecs,
L₂ Pup is the second nearest → asymptotic giant branch (AGB) star next to R Doradus; it is ~ 30% closer than → Mira. Recent → near-infrared JHKL band observations by Kervella et al. (2014, 2015) show a compact dust disk around the central star, with an inner rim of 6 → astronomical units and an outer edge of 13 au, at an inclination of approximately 82°.

The → circumstellar environment of L₂ Pup was observed with → ALMA. The → molecular emission shows a → differentially rotating disk, inclined to a nearly edge-on position (Homan et al., 2017, A&A 601, A5 and references therein).

See also: Star name in the → Bayer designation scheme; → Puppis.