36 Ursae Majoris is a double star [5] in the northern constellation of Ursa Major. With an apparent visual magnitude of 4.8, it can be seen with the naked eye in suitable dark skies. Based upon parallax measurements, this binary lies at a distance of 42 light-years (13 parsecs ) from Earth.
The brighter star of the two is a solar analog—meaning it has physical properties that make it similar to the Sun. It has 10% more mass and a radius 17% larger than the Sun, with an estimated age of four billion years. The spectrum of this star matches a stellar classification of F8 V, which indicates this is a main sequence star that is generating energy at its core through the nuclear fusion of hydrogen. The energy is being radiated into space from its outer envelope at an effective temperature of 6,066 K . This gives the star the characteristic yellow-white hue of an F-type star. [13]
The fainter of the two stars has an apparent magnitude 8.86 and shares a common proper motion witIts spectral type of K7Ve indicates it is a red dwarf. Its has a mass 60% of the Sun's, a temperature of 4,132 K and a bolometric luminosity only 10% of the Sun's.
36 Ursae Majoris has a second companion with a magnitude of 11.44 located at an angular separation of 240.6″ along a position angle of 292°, as of 2004. [14] It does not share the proper motion of the other two stars and is a more massive and luminous star but much further away. [15]
According to Nelson & Angel (1998), [16] 36 Ursae Majoris could host one or two (or at least three) jovian planets (or even brown dwarfs) at wide separations from the host star, with orbital periods of 10–15, 25 and 50 years respectively. The authors have set upper limits of 1.1–2, 5.3 and 24 Jupiter masses for the putative planetary objects. Also Lippincott (1983) [17] had previously noticed the possible presence of a massive unseen companion (with nearly 70 times the mass of Jupiter, just below the stellar regime, thus a brown dwarf). Putative parameters for the substellar object show an orbital period of 18 years and quite a high eccentricity (e=0.8). Even Campbell et al. 1988 [18] inferred the existence of planetary objects or even brown dwarfs less massive than 14 Jupiter masses around 36 Ursae Majoris.
Nevertheless, no certain planetary companion has yet been detected or confirmed. The McDonald Observatory team has set limits to the presence of one or more planets [19] with masses between 0.13 and 2.5 Jupiter masses and average separations spanning between 0.05 and 5.2 AU.
An infrared excess has been detected around this star, most likely indicating the presence of a circumstellar disk at a radius of 38.6 AU. The temperature of this dust is 50 K. [20]
14 Herculis or 14 Her is a K-type main-sequence star 58.4 light-years away in the constellation Hercules. It is also known as HD 145675. Because of its apparent magnitude, of 6.61 the star can be very faintly seen with the naked eye. As of 2021, 14 Herculis is known to host two exoplanets in orbit around the star.
47 Ursae Majoris, formally named Chalawan, is a yellow dwarf star approximately 45.3 light-years from Earth in the constellation of Ursa Major. As of 2011, three extrasolar planets are believed to orbit the star.
Gliese 777, often abbreviated as Gl 777 or GJ 777, is a yellow subgiant approximately 52 light-years away in the constellation of Cygnus. The system is also a binary star system made up of two stars and possibly a third. As of 2005, two extrasolar planets are known to orbit the primary star.
HR 7703 is a binary star system in the constellation of Sagittarius. The brighter component has an apparent visual magnitude of 5.31, which means it is visible from suburban skies at night. The two stars are separated by an angle of 7.10″, which corresponds to an estimated semimajor axis of 56.30 AU for their orbit.
Theta Ursae Majoris is a suspected spectroscopic binary star system in the northern circumpolar constellation of Ursa Major. It has an apparent visual magnitude of 3.17, placing it among the brighter members of this constellation. The distance to this star has been measured directly using the parallax method, yielding an estimated value of 43.96 light-years.
Omicron Ursae Majoris, formally named Muscida, is a star system in the northern circumpolar constellation of Ursa Major. It has an apparent visual magnitude of +3.35 and is located at a distance of around 179 light-years from the Sun. In 2012, an exoplanet designated Omicron Ursae Majoris Ab was found to be orbiting the primary.
HD 38529 is a binary star approximately 138 light-years away in the constellation of Orion.
HD 1237 is a binary star system approximately 57 light-years away in the constellation of Hydrus.
61 Ursae Majoris, abbreviated 61 UMa, is a single star in the northern circumpolar constellation of Ursa Major. It has a yellow-orange hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.35. The distance to this star is 31.2 light years based on parallax, and it is drifting closer with a radial velocity of −5.2 km/s. The star has a relatively high proper motion traversing the sky at the rate of 0.381″ yr−1.
Gliese 412 is a pair of stars that share a common proper motion through space and are thought to form a binary star system. The pair have an angular separation of 31.4″ at a position angle of 126.1°. They are located 15.8 light-years distant from the Sun in the constellation Ursa Major. Both components are relatively dim red dwarf stars.
Gliese 86 is a K-type main-sequence star approximately 35 light-years away in the constellation of Eridanus. It has been confirmed that a white dwarf orbits the primary star. In 1998 the European Southern Observatory announced that an extrasolar planet was orbiting the star.
Gliese 176 is a small star with an orbiting exoplanet in the constellation of Taurus. With an apparent visual magnitude of 9.95, it is too faint to be visible to the naked eye. It is located at a distance of 30.9 light years based on parallax measurements, and is drifting further away with a heliocentric radial velocity of 26.4 km/s.
HD 190228 is a star with an orbiting substellar companion in the northern constellation of Vulpecula. Its apparent magnitude is 7.30 – too faint to be seen with the naked eye – and the absolute magnitude is 3.34. Based on parallax measurements, it is located at a distance of 205 light-years from the Sun. The system is drifting closer with a radial velocity of −50 km/s.
HD 240210 is a star in the northern constellation of Cassiopeia. It has an orange hue but is too faint to be viewed with the naked eye, having an apparent visual magnitude of 8.33. Parallax measurements provide an estimate of its distance from the Sun as approximately 1,230 light years. It is drifting further away with a radial velocity of +8.6 km/s.
Pi Herculis is a third-magnitude star in the constellation Hercules. As one of the four stars in the Keystone asterism, it is one of the constellation's more easily recognized. It has an apparent visual magnitude of +3.2, which is visible to the naked eye and makes it one of its brighter members. The Hipparcos satellite mission estimated its distance at roughly 115 parsecs from Earth, or about 377 light years away. The overall reduction in the star's visual magnitude due to extinction from the intervening matter is 0.11.
Gliese 806 is a star in the northern constellation of Cygnus, located about a degree to the southeast of the bright star Deneb. It is invisible to the naked eye with an apparent visual magnitude of +10.79. The star is located at a distance of 39.3 light years from the Sun based on stellar parallax. It is drifting closer with a radial velocity of −24.6 km/s, and is predicted to come to within 30.1 light-years in ~198,600 years. The star hosts two known planetary companions.
HD 175167 is a star with an exoplanet companion in the southern constellation of Pavo. It is too faint to be visible with the naked eye at an apparent visual magnitude of 8.01. The system is located at a distance of 232 light-years from the Sun based on parallax measurements, and it is drifting further away with a radial velocity of 5 km/s. It shows a high proper motion, traversing the celestial sphere at an angular rate of 0.190 arcsec yr−1.
65 Ursae Majoris, abbreviated as 65 UMa, is a star system in the constellation of Ursa Major. With a combined apparent magnitude of about 6.5, it is at the limit of human eyesight and is just barely visible to the naked eye in ideal conditions. It is about 760 light years away from Earth.
HD 72945 and HD 72946 form a co-moving star system in the northern constellation of Cancer. HD 72945 is a binary star that is dimly visible to the naked eye as a point of light with an apparent visual magnitude of 5.91. At an angular separation of 10.10″ is the fainter companion star HD 72946 at magnitude 7.25. It is being orbited by a brown dwarf. The system as a whole is located at a distance of approximately 84 light years from the Sun based on parallax measurements.