AF Leporis, also known as HD 35850, is an F-type main-sequence star located 87.5 light-years (26.8 parsecs ) away from the Solar System in the constellation of Lepus. With an apparent magnitude of 6.3, it is near the limit of naked eye visibility under ideal conditions. While some studies consider it to be a close spectroscopic binary with a separation of 0.021 AU , [8] other studies show no evidence of binarity, and it is likely that the supposed binarity is an artifact resulting from the presence of starspots. [9] [4]
AF Leporis is a member of the Beta Pictoris moving group, with an astronomically young age of about 24 million years. It hosts a circumstellar disk and one known exoplanet. [7]
In 2023, a gas giant exoplanet was discovered in orbit around AF Leporis by direct imaging using the NIRC2 instrument at the W. M. Keck Observatory and the SPHERE instrument at the Very Large Telescope. It was also detected in astrometric data from the Hipparcos and Gaia spacecraft, allowing an accurate measurement of its mass. [7] [4] [13] Spectroscopic evidence suggests that AF Leporis b has a metal-rich atmosphere with silicate clouds. [6]
There have been multiple studies of AF Leporis b, which have found somewhat different parameters. Dynamical mass measurements range from the most recent value of 2.8 MJ [6] to 5.5 MJ. [4] Values for the planet's orbital inclination range from 50°+9°
−12° [7] to ~98°, [13] the former consistent with the stellar inclination of 54°+11°
−9° and suggesting an aligned system. [7] All studies have found that the planet has a fairly eccentric orbit.
Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (years) | Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | 2.8+0.6 −0.5 MJ | 8.2+1.3 −1.7 | 22.3+5.6 −6.7 | 0.4+0.3 −0.2 | 55+8 −13 ° | 1.2-1.55 RJ |
Debris disk | 46±9 [14] AU | — | — |
HD 38529 is a binary star approximately 138 light-years away in the constellation of Orion.
HD 142 is a wide binary star system in the southern constellation of Phoenix. The main component has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.7. The system is located at a distance of 85.5 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of +6 km/s.
Pi Mensae, also known as HD 39091, is a yellow dwarf star in the constellation of Mensa. This star has a high proper motion. The apparent magnitude is 5.67, which can be visible to the naked eye in exceptionally dark, clear skies. It is nearly 60 light-years away. The star is slightly larger than the Sun in terms of mass, size, luminosity, temperature and metallicity, and is about 730 million years younger. It hosts three known planets.
HD 50554 is a single, Sun-like star with an exoplanetary companion in the northern constellation of Gemini. It has an apparent visual magnitude of +6.84, which makes it a 7th magnitude star; it is not visible to the naked eye, but can be viewed with binoculars or a telescope. The system is located at a distance of 101 light-years from the Sun based on parallax, but is drifting closer with a radial velocity of −4 km/s.
HD 142022 is a binary star system located in the southernmost constellation of Octans. It is too faint to be visible to the naked eye, having an apparent visual magnitude of 7.70. The distance to this system is 112 light-years based on parallax, but it is drifting closer to the Sun with a radial velocity of −10 km/s.
HD 196050 is a triple star system located in the southern constellation of Pavo. This system has an apparent magnitude of 7.50 and the absolute magnitude is 4.01. It is located at a distance of 165 light-years from the Sun based on parallax, and is drifting further away with a radial velocity of +61 km/s. It is also called by the Hipparcos designation HIP 101806.
HD 213240 is a possible binary star system in the constellation Grus. It has an apparent visual magnitude of 6.81, which lies below the limit of visibility for normal human sight. The system is located at a distance of 133.5 light years from the Sun based on parallax. The primary has an absolute magnitude of 3.77.
HD 162020 is a star in the southern constellation of Scorpius with a likely red dwarf companion. It has an apparent visual magnitude of 9.10, which is too faint to be visible to the naked eye. The distance to this system is 102 light-years based on stellar parallax. It is drifting closer to the Sun with a radial velocity of −27 km/s, and is predicted to come to within ~18 light-years in 1.1 million years.
17 Leporis is a binary star system in the southern constellation of Lepus. It has an overall apparent visual magnitude which varies between 4.82 and 5.06, making it luminous enough to be visible to the naked eye as a faint star. The variable star designation for this system is SS Leporis, while 17 Leporis is the Flamsteed designation. Parallax measurements yield a distance estimate of around 910 light years from the Sun. The system is moving further away from the Earth with a heliocentric radial velocity of +18.7 km/s.
HAT-P-4 is a wide binary star consisting of a pair of G-type main-sequence stars in the constellation of Boötes. It is also designated BD+36°2593.
HD 143361 is a star in the southern constellation Norma. With an apparent visual magnitude of 9.20, this star is too dim to be seen with the naked eye. It is close enough to the Earth that its distance can be determined using parallax measurements, yielding a value of 224 light-years.
HD 164604 is a single star in the southern constellation of Sagittarius constellation. It has the proper name Pincoya, as selected in the NameExoWorlds campaign by Chile, during the 100th anniversary of the IAU. Pincoya is a female water spirit from southern Chilean mythology who is said to bring drowned sailors to the Caleuche so that they can live in the afterlife. A 2015 survey ruled out the existence of any additional stellar companions at projected distances from 13 to 340 astronomical units. It is known to host a single super-Jupiter exoplanet.
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.
HD 27631 is a star with an orbiting exoplanet in the southern constellation of Horologium. It is too faint to be visible to the naked eye, having an apparent visual magnitude of 8.24. The distance to this system is 164 light years based on parallax measurements. It is drifting further away with a radial velocity of 21 km/s.
HD 220689 is a single star in the equatorial constellation of Aquarius. It is a challenge to view with the naked eye, having an apparent visual magnitude of +7.74, but is readily viewed with a pair of binoculars. The star is located at a distance of 153 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +12 km/s. A survey in 2015 has ruled out the existence of any additional stellar companions at projected distances from 26 to 305 astronomical units.
HD 106515 is a binary star in the constellation of Virgo.
Gliese 555 is a small star with one or more orbiting exoplanets in the constellation Libra. It has the variable star designation HN Librae, abbreviated HM Lib. With an apparent visual magnitude of 11.32, it can only be viewed through a telescope. The system is located at a distance of 20.4 light years based on parallax measurements, but is drifting closer to the Sun with a radial velocity of −1.4 km/s. It does not appear to belong to any known stellar moving group or association.
AK Leporis is a variable star in the southern constellation of Lepus the hare. It has an apparent visual magnitude of 6.141, so, according to the Bortle scale, it is faintly visible from rural skies at night. This star forms a visual double with Gamma Leporis—the two have an angular separation of 97″, making them difficult to separate with the naked eye even under the best conditions. Both Gamma Leporis and AK Leporis are members of the Ursa Major Moving Group of stars that share a common motion through space.