Alpha Apodis

Alpha Apodis (Alpha Aps, α Apodis, α Aps) is the brightest star in the southern circumpolar constellation of Apus, with an apparent magnitude of approximately 3.825. It had the Greek alpha designation at part of the constellation Johann Bode called Apis Indica in his 1603 Uranometria star atlas. With a declination of –79°, this is a circumpolar star for much of the southern hemisphere. It can be identified on the night sky by drawing an imaginary line through Alpha Centauri and Alpha Circini then extending it toward the south celestial pole.

This is a giant star with a stellar classification of K2.5III, indicating that this star has consumed the hydrogen at its core and has evolved away from the main sequence. It has expanded to an estimated radius of about 48 times the radius of the Sun and is emitting 980 times the Sun's luminosity. The photosphere has an effective temperature of 4,256 K, giving the star the characteristic orange hue of a K-type star. Based upon parallax measurements, this star is roughly 447 light-years from the Earth. It is not known to have a companion.

AB Pictoris

AB Pictoris (abbreviated AB Pic, also catalogued as HD 44627) is a K-type star, approximately 148 light-years away in the constellation of Pictor. It has been identified as a member of the young (30 million years old) Tucana–Horologium association. The star has also been classified as a BY Draconis variable. In 2005 it was announced that an astronomical object (AB Pictoris b, abbreviated AB Pic b) had been imaged in 2003 and 2004 close to and apparently in orbit around the star. Its mass suggests that it is at the borderline between being a brown dwarf or a planet.

Possible planetary system

In 2003 and 2004, an object (now catalogued as AB Pictoris b) was observed close to the star by a team of astronomers at the European Southern Observatory. Since it had common proper motion with AB Pictoris, it was concluded that it was physically close to the star. Its spectral type was estimated as between L0V and L3V. Using evolutionary models, its mass was estimated as from 13 to 14 Jupiter masses. However, because modelling such young objects is difficult, this estimate is very uncertain; some models give masses as low as 11 Jupiter masses or as high as 70 Jupiter masses. Temperature estimates range from 1600 K to 2400 K. As it is not known if the mass of the object exceeds the deuterium burning limit of 13 Jupiter masses, it is not clear whether the object should be classified as an extrasolar planet or a brown dwarf.

Gamma Microscopii

Gamma Microscopii (γ Microscopii, γ Mic) is the brightest star in the faint southern constellation of Microscopium. It has an apparent visual magnitude of 4.68, which is too dim to be viewed from city skies. The distance to this star has been determined using parallax measurements made during the Hipparcos mission, which place it around 229 light-years (70 parsecs) away with a 2% margin of error.

Based upon a stellar classification of G6 III, this is a G-type giant star. It is a core helium fusing star that is classified as a member of the red clump evolutionary branch, although the metallicity of this star—meaning the abundance of elements other than hydrogen and helium—is anomalously low for a member of this group. The effective temperature of the star's outer envelope is 5,050 K, giving it the yellow-hued glow typical of G-type stars.

In the galactic coordinate system, this star has space velocity components of [U, V, W] = [+13.75, +3.47, –10.50] km s⁻¹. The peculiar velocity of this star, relative to its neighbors, is 1.2 km s⁻¹. It has been listed as likely member of the Ursa Major Moving Group of stars that share a similar location and a common trajectory through space. Backwards extrapolation of the motion of γ Microscopii has shown that approximately 3.8 million years ago, it was only around 6 light-years from the Sun. It would then have had an apparent magnitude of −3 and have been brighter than Sirius is now.