HD 4222, also known as HR 196, is the primary of a binary star [17] located in the northern constellation Cassiopeia. It is faintly visible to the naked eye as a white-hued point of light with an apparent magnitude of 5.41. [2] Gaia DR3 parallax measurements imply a distance of 353 light-years and it is drifting closer with a heliocentric radial velocity of −8.5 km/s . [10] At its current distance, HD 4222's brightness is diminished by an interstellar extinction of 0.13 magnitudes and it has an absolute magnitude of +0.44. [11]
HD 4222 has a stellar classification of A2 Vs or A1 V, [6] [7] both classes indicating that it is an A-type main-sequence star that is generating energy via hydrogen fusion at its core. The former class includes the presence of 'sharp' or narrow absorption lines due to slow rotation. Consistent with the class, HD 4222 spins modestly with a projected rotational velocity of approximately 25 km/s . [7] It has 2.59 times the mass of the Sun [5] and 3.47 times the radius of the Sun. [12] It radiates 69.1 times the luminosity of the Sun [5] from its photosphere with an effective temperature of 9,886 K . [14] HD 4222 is metal deficient with an iron abundance of [Fe/H] = −0.26 or 55% of the Sun's. [15] At the age of 407 million years, [1] HD 4222 has completed 81.5% of its main sequence lifetime. [5]
HD 4222 and BU 492B make up the binary system BU 492. The companion is a red dwarf with a stellar classification of M2-5V; it is located 1.5" away from the primary along a position angle of 173°. BU 492B was first noticed by astronomer S. W. Burnham in 1878. HD 4222 also has one optical companion; an 11th magnitude star located 88.6" away, which itself is also a double star. [4] A X-ray emission with a luminosity of 3.031×1020 W was detected around the star. [9] A-type stars are not expected to emit X-rays, so it might be coming from the companion. HD 4222 is considered to be a probable member of the Sirius supercluster, a group of stars moving with the bright star Sirius and share a common origin with the system. [18]
Eta Volantis, Latinized from η Volantis, is a single star in the southern constellation of Volans. It has an apparent visual magnitude of 5.28, which is bright enough to be seen with the naked eye as a dim, white-hued star. Based upon parallax measurements, it is approximately 387 light years from the Sun. The star is moving further away from the Sun with a radial velocity of 20 km/s.
HD 30442 is a solitary star in the northern circumpolar constellation Camelopardalis. It is faintly visible to the naked eye with an apparent magnitude of 5.47 and is estimated to be 403 light years away from the Solar System. The object has a heliocentric radial velocity of −37 km/s, indicating that it is drifting closer.
HD 24479, also designated as HR 1204, is a solitary, bluish-white hued star located in the northern circumpolar constellation Camelopardalis. The star is visible to the naked eye with an apparent visual magnitude of 5.04. Based on Gaia DR3 parallax measurements, it is located 385 light years from the Sun. However, it is receding with a somewhat constrained heliocentric radial velocity of 4.6 km/s. At its current distance, HD 24479's brightness is diminished by 0.29 magnitudes due to interstellar dust.
Eta2 Coronae Australis, Latinized from η2 Coronae Australis, is a solitary star located in the southern constellation of Corona Australis. It is visible to the naked eye as a dim, blue-white hued star with an apparent visual magnitude of 5.59. Gaia DR3 parallax measurements imply a distance of 770 light years from the Solar System, but it is drifting closer with a radial velocity of −23 km/s. At its current distance Eta2 CrA's brightness is diminished by 0.27 magnitudes due to stellar extinction from interstellar dust and it has an absolute magnitude of −0.24.
HD 96146 is a binary star located in the southern constellation Antlia. The system has a combined apparent magnitude of 5.41, making it visible to the naked eye under ideal conditions. Parallax measurements from the Gaia spacecraft place the pair at a distance of 710 light years with a large margin of error. It is currently receding with a poorly constrained heliocentric radial velocity of 4.7 km/s.
HD 124099 is a solitary orange-hued star located in the southern circumpolar constellation Apus. It has an average apparent magnitude of 6.47, placing it very close to the limit for naked eye visibility, even under ideal conditions. The object is located relatively far at a distance of approximately 2,030 light-years based on Gaia DR3 parallax measurements, but it is drifting closer with a heliocentric radial velocity of −10.2 km/s. At its current distance, HD 124099's average brightness is diminished by 0.47 magnitudes due to interstellar extinction and it has an absolute magnitude of −2.10.
HD 26764, also known as HR 1314 or rarely 14 H. Camelopardalis, is a solitary white hued star located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.19, making it faintly to the naked eye if viewed under good conditions. Gaia DR3 parallax measurements place the object at a distance of 266 light years and is drifting closer with a poorly constrained heliocentric radial velocity of 3 km/s. At its current distance, HD 26764's brightness is diminished by 0.26 magnitudes due to interstellar dust.
HD 47500, also known as HR 2446, is a binary star in the southern constellation Columba. The primary has an apparent magnitude of 5.91, making it faintly visible to the naked eye if viewed under ideal conditions. As for the companion, its visual magnitude is 7.51. The system is located relatively far at a distance of 1,120 light years based on parallax measurements, and is receding with a heliocentric radial velocity of 21 km/s.
HD 76236, also designated as HR 3543 or rarely 11 G. Chamaeleontis, is a solitary star located in the southern circumpolar constellation Chamaeleon. It is faintly visible to the naked eye as an orange-hued star with an apparent magnitude of 5.77. Based on parallax measurements from the Gaia satellite, the object is estimated to be 612 light years away. Currently, it is receding with a heliocentric radial velocity of 7 km/s. At its current distance, HD 76236's brightness is diminished by 0.39 magnitudes due to interstellar dust. It has an absolute magnitude of −0.13.
HD 182509, also designated as HR 7370, is an orange hued star located in the southern constellation Telescopium. It has an apparent magnitude of 5.69, making it faintly visible to the naked eye if viewed under ideal conditions. Parallax measurements place the object at a distance of 635 light years. It has a poorly constrained heliocentric radial velocity of −5 km/s, indicating that it is drifting towards the Solar System.
HD 198716, also known as HR 7987 or 33 G. Microscopii, is a solitary star located in the southern constellation Microscopium. Eggen (1993) lists it as a member of the Milky Way's old disk population.
HD 196737, also designated as HR 7893, is a solitary orange hued star located in the southern constellation Microscopium. It has an apparent magnitude of 5.47, allowing it to be faintly visible to the naked eye. The object is located relatively close at a distance of 241 light years based on Gaia DR3 parallax measurements, but is receding with a heliocentric radial velocity of 14.2 km/s. At its current distance, HD 196737's brightness is diminished by 0.14 magnitudes due to interstellar dust. It has an absolute magnitude of 1.17.
HD 36187, also known as HR 1835, is a solitary, bluish-white hued star located in the southern constellation Columba, the dove. It has an apparent magnitude of 5.55, making it faintly visible to the naked eye under ideal conditions. Based on parallax measurements from the Gaia spacecraft, it is estimated to be 282 light years away from the Solar System. However, it is receding rapidly with a heliocentric radial velocity of 50 km/s. At its current distance, HD 36187's brightness is diminished by 0.21 magnitude due to interstellar dust.
HD 117566, also known as HR 5091, is a solitary yellow-hued star located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.74, making it faintly visible to the naked eye. This object is relatively close at a distance of 291 light years based on Gaia DR3 parallax measurements but is receding with a heliocentric radial velocity of 14 km/s. At its current distance, HD 117566's brightness is diminished by 0.12 magnitudes due to interstellar dust.
HD 168592, also designated as HR 6862 or rarely 7 G. Coronae Australis, is a solitary star located in the southern constellation Corona Australis. It is faintly visible to the naked eye as an orange-hued star with an apparent magnitude of 5.07. Gaia DR3 parallax measurements place it at a distance of 490 light years and is currently receding with a heliocentric radial velocity of 18 km/s. At its current distance, HD 168592's brightness is diminished by 0.38 magnitudes due to interstellar dust. It has an absolute magnitude of −0.76.
HD 31134, also designated as HR 1561, is a solitary star located in the northern circumpolar constellation Camelopardalis, the giraffe. It is faintly visible to the naked eye as a white-hued star with an apparent magnitude of 5.74. Gaia DR3 parallax measurements place it 473 light years away. It appears to be approaching the Solar System with a heliocentric radial velocity of −15.1 km/s. At its current distance, HD 31134's brightness is diminished by 0.35 magnitudes due to interstellar dust. It has an absolute magnitude of +0.19.
HD 189080, also known as HR 7621 or rarely 74 G. Telescopii, is a solitary orange-hued star located in the southern constellation Telescopium. It has an apparent magnitude of 6.18, placing it near the limit for naked eye visibility. Gaia DR3 parallax measurements place it at a distance of 357 light years and it is currently receding rapidly with a heliocentric radial velocity of 66.9 km/s. At its current distance, HD 189080's brightness is diminished by 0.17 magnitudes due to extinction from interstellar dust. It has an absolute magnitude of +1.1.
HD 187420 and HD 187421, are the components of a binary star located in the southern constellation Telescopium. Gaia DR3 parallax measurements place the stars at a distance of 407 and 414 light years respectively. The two are separated by 23″, and they are approaching the Solar System with heliocentric radial velocities of −17.9 km/s and −21.5 km/s respectively.
HD 172991, also known as HR 7031 or rarely 20 G. Coronae Australis, is a binary star located in the southern constellation Corona Australis. It has a combined apparent magnitude of 5.44, making it faintly visible to the naked eye. The system is located relatively far at a distance of 1,220 light years based on Gaia DR3 parallax measurements but is receding with a heliocentric radial velocity of −17.4 km/s. At its current distance HD 172991's brightness is diminished by magnitudes due to interstellar dust and it has an absolute magnitude of −2.56.
HD 27322, also known as HR 1342, is a binary star located in the northern circumpolar constellation Camelopardalis. The visible component is faintly visible to the naked eye as a white-hued point of light with an apparent magnitude of 5.92. The object is located relatively close at a distance of 313 light-years based on Gaia DR3 parallax measurements, and it is drifting closer with a heliocentric radial velocity of approximately −13 km/s. At its current distance, HD 27322's brightness is diminished by 0.24 magnitudes due to interstellar extinction and it has an absolute magnitude of +0.98.