Sagittarius A*, abbreviated as Sgr A*, is the supermassive black hole at the Galactic Center of the Milky Way. Viewed from Earth, it is located near the border of the constellations Sagittarius and Scorpius, about 5.6° south of the ecliptic, visually close to the Butterfly Cluster (M6) and Lambda Scorpii.
The red-giant branch (RGB), sometimes called the first giant branch, is the portion of the giant branch before helium ignition occurs in the course of stellar evolution. It is a stage that follows the main sequence for low- to intermediate-mass stars. Red-giant-branch stars have an inert helium core surrounded by a shell of hydrogen fusing via the CNO cycle. They are K- and M-class stars much larger and more luminous than main-sequence stars of the same temperature.
Delta Velorum is a triple star system in the southern constellation of Vela, near the border with Carina, and is part of the False Cross. Based on parallax measurements, it is approximately 80.6 light-years from the Sun. It is one of the stars that at times lies near the south celestial pole due to precession.
VV Cephei, also known as HD 208816, is an eclipsing binary star system located in the constellation Cepheus. It is both a B[e] star and shell star.
The Arches Cluster is the densest known star cluster in the Milky Way, about 100 light-years from its center in the constellation Sagittarius, 25,000 light-years from Earth. Its discovery was reported by Nagata et al. in 1995, and independently by Cotera et al. in 1996. Due to extremely heavy optical extinction by dust in this region, the cluster is obscured in the visual bands, and is observed in the X-ray, infrared and radio bands. It contains approximately 135 young, very hot stars that are many times larger and more massive than the Sun, plus many thousands of less massive stars.
GCIRS 13E is an infrared and radio object near the Galactic Center. It is believed to be a cluster of hot massive stars, possibly containing an intermediate-mass black hole (IMBH) at its center.
S2, also known as S0–2, is a star in the star cluster close to the supermassive black hole Sagittarius A* (Sgr A*), orbiting it with a period of 16.0518 years, a semi-major axis of about 970 au, and a pericenter distance of 17 light hours – an orbit with a period only about 30% longer than that of Jupiter around the Sun, but coming no closer than about four times the distance of Neptune from the Sun. The mass when the star first formed is estimated by the European Southern Observatory (ESO) to have been approximately 14 M☉. Based on its spectral type, it probably has a mass of 10 to 15 solar masses.
HD 5980 is a multiple star system on the outskirts of NGC 346 in the Small Magellanic Cloud (SMC) and is one of the brightest stars in the SMC.
AB7, also known as SMC WR7, is a binary star in the Small Magellanic Cloud. A Wolf–Rayet star and a supergiant companion of spectral type O orbit in a period of 19.56 days. The system is surrounded by a ring-shaped nebula known as a bubble nebula.
V602 Carinae is a red supergiant and variable star of spectral type M3 in the constellation Carina. It is considered to be one of largest known stars, being around 1,000 times larger than the Sun.
WR 46 is a Wolf-Rayet star in the constellation of the Southern Cross of apparent magnitude +10.8. It is located at 55 arcmin north of Theta2 Crucis. The star is a member of the distant stellar association Cru OB4, and is around 2,900 parsecs or 9,300 light years from the Solar System.
HD 15558 is a massive O-type multiple star system in Cassiopeia and is specifically in our galaxy's Heart Nebula in the open cluster IC 1805. The primary is a very massive star with 152 M☉ and 660,000 L☉.
HP Lyrae is a variable star in the constellation Lyra, with a visual magnitude varying between 10.2 and 10.8. It will likely be an RV Tauri variable, an unstable post-AGB star losing mass before becoming a white dwarf.
AB8, also known as SMC WR8, is a binary star in the Small Magellanic Cloud (SMC). A Wolf-Rayet star and a main sequence companion of spectral type O orbit in a period of 16.638 days. It is one of only nine known WO stars, the only Wolf-Rayet star in the SMC not on the nitrogen sequence, and the only Wolf-Rayet star in the SMC outside the main bar.
TV Geminorum is a variable red supergiant in the constellation Gemini. Its visual magnitude varies from 6.3 to 7.5.
BP Crucis is an X-ray binary system containing a blue hypergiant and a pulsar.
V752 Centauri is multiple star system and variable star in the constellation of Centaurus. An eclipsing binary, its apparent magnitude has a maximum of 9.10, dimming to 9.66 during primary eclipse and 9.61 during secondary eclipse. Its variability was discovered by Howard Bond in 1970. From parallax measurements by the Gaia spacecraft, the system is located at a distance of 410 light-years from Earth.
GCIRS 7 is a red supergiant located in the Galactic Center. It is very bright and is one of the largest stars currently discovered, with a size about 1,170 solar radii. If placed in the Solar System, its photosphere would engulf the orbit of Jupiter.
The Sagittarius A* cluster is the cluster of stars in close orbit around Sagittarius A*, the supermassive black hole at the center of the Milky Way. The individual stars are often listed as "S-stars", but their names and IDs are not formalized, and stars can have different numbers in different catalogues.
CV Serpentis is a binary star system in the equatorial constellation of Serpens. It is a detached eclipsing binary with an orbital period of 29.7 days. The system includes a Wolf–Rayet (WR) star with the identifier WR 113. The system is located at a distance of approximately 6,700 light years from the Sun based on parallax measurements. It is a member of the Serpens OB2 association of co-moving stars.
