Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Lynx [1] |
Right ascension | 07h 21m 33.1602s [2] |
Declination | +58° 16′ 05.110″ [2] |
Apparent magnitude (V) | 10.674 ± 0.019 [3] |
Characteristics | |
Spectral type | F5V [3] |
Apparent magnitude (B) | 11.240 ± 0.029 [3] |
Apparent magnitude (V) | 10.674 ± 0.019 [3] |
Apparent magnitude (J) | 9.667 ± 0.021 [4] |
Apparent magnitude (H) | 9.476 ± 0.022 [4] |
Apparent magnitude (K) | 9.406 ± 0.023 [4] |
Astrometry | |
Proper motion (μ) | RA: −17.008(12) mas/yr [2] Dec.: 5.463(12) mas/yr [2] |
Parallax (π) | 3.7812 ± 0.0156 mas [2] |
Distance | 863 ± 4 ly (264 ± 1 pc) |
Details | |
Mass | 1.32 ± 0.02 [3] M☉ |
Radius | 1.56 ± 0.05 [3] R☉ |
Temperature | 6397 ± 70 [3] K |
Metallicity [Fe/H] | -0.04 ± 0.03 [3] dex |
Age | 2.1 ± 0.6 [3] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
XO-4 is a star located approximately 863 light-years away from Earth in the Lynx constellation. It has a magnitude of about 11 and cannot be seen with the naked eye but is visible through a small telescope. [3] A search for a binary companion star using adaptive optics at MMT Observatory was negative. [6]
The star XO-4 is named Koit. The name was selected in the NameExoWorlds campaign by Estonia, during the 100th anniversary of the IAU. Koit is Estonian for dawn, and was named for a character in a folk tale written by Friedrich Robert Faehlmann. [7] [8] [9]
One known exoplanet, XO-4b, which is classified as a hot jupiter, orbits XO-4. This exoplanet was discovered in 2008 by the XO Telescope project using the transit method. [3] It has been named Hämarik, meaning dusk, and referring to a character from the same Faehlmann story featuring Koit. [10]
Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b / Hämarik | 1.72 ± 0.20 MJ | 0.0552 ± 0.0003 | 4.1250823 ± 0.0000039 | 0(assumed) [note 1] | — | — |
XO-1 is a magnitude 11 G-type main-sequence star located approximately 530 light-years away in the constellation Corona Borealis. XO-1 has a mass and radius similar to the Sun. In 2006 the extrasolar planet XO-1b was discovered orbiting XO-1 by the transit method using the XO Telescope.
XO-1b is an extrasolar planet approximately 536 light-years away from Earth.
HD 17156, named Nushagak by the IAU, is a yellow subgiant star approximately 255 light-years away in the constellation of Cassiopeia. The apparent magnitude is 8.17, which means it is not visible to the naked eye but can be seen with good binoculars. A search for a binary companion star using adaptive optics at the MMT Observatory was negative.
HAT-P-6 also named Sterrennacht is a star in the constellation Andromeda, located approximately 895 light years or 274 parsecs away from the Earth. It is an F-type star, implying that it is hotter and more massive than the Sun. The apparent magnitude of the star is +10.54, which means that it can only be visible through the telescope. The absolute magnitude of +3.36 is brighter than the Sun's +4.83, meaning that the star itself is brighter than the Sun. A search for a binary companion star using adaptive optics at the MMT Observatory turned out negative.
HAT-P-6b is a transiting extrasolar planet discovered by Noyes et al. on October 15, 2007. It is located approximately 910 light-years away in the constellation of Andromeda, orbiting the star HAT-P-6. This hot Jupiter planet orbits with a semi-major axis of about 0.05 AU, and takes 92 hours, 28 minutes, 17 seconds to orbit the star. It has true mass of 5.7% greater than Jupiter and a radius 33% greater than Jupiter, corresponding to a density of 0.583 g/cm3, which is less than water.
HD 118203 is a star with an orbiting exoplanet located in the northern circumpolar constellation of Ursa Major. It has the proper name Liesma, which means flame, and it is the name of a character from the Latvian poem Staburags un Liesma. The name was selected in the NameExoWorlds campaign by Latvia, during the 100th anniversary of the IAU.
XO-5 is a yellow dwarf main sequence star located approximately 893 light-years away from Earth in the Lynx constellation. It has a magnitude of about 12 and cannot be seen with the naked eye but is visible through a small telescope.
XO-4b is an extrasolar planet approximately 956 light years away in the constellation of Lynx. This planet was found by the transit method by McCullough in May 2008. The planet has mass 1.72 MJ and radius 1.34 RJ. This planet orbits very close to the F-type parent star, as it is typical for transiting planets, classing this planet as Hot Jupiter.
HAT-P-9 is a magnitude 12 F star approximately 1500 light years away in the constellation Auriga. A search for a binary companion star using adaptive optics at the MMT Observatory was negative.
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.
XO-3 is a star in the constellation Camelopardalis. The star has a magnitude of 10 and is not visible to the naked eye but is visible through a small telescope. A search for a binary companion star using adaptive optics at the MMT Observatory was negative.
XO-2 is a binary star system about 490 light-years away in the constellation Lynx. It consists of two components, XO-2N and XO-2S, both of which host planetary systems.
GSC 03549-02811 is a yellow main-sequence star similar to the Sun. This star is located approximately 704 light-years away in the constellation of Draco. The apparent magnitude of this star is 11.41, which means it is not visible to the naked eye but can be seen with a medium-sized amateur telescope on a clear dark night. The age of this star is about 5 billion years.
HAT-P-3, is a metal-rich K5 dwarf star located about 441 light-years away in the constellation Ursa Major. At a magnitude of about 11.5 it is not visible to the naked eye but is visible in a small to medium-sized amateur telescope. It is believed to be a relatively young star and has a slightly enhanced level of chromospheric activity.
WASP-17 is an F-type main sequence star approximately 1,300 light-years away in the constellation Scorpius.
WASP-19, formally named Wattle, is a magnitude 12.3 star about 869 light-years away, located in the Vela constellation of the southern hemisphere. This star has been found to host a transiting hot Jupiter-type planet in tight orbit.
HAT-P-14b, officially named Sissi also known as WASP-27b, is an extrasolar planet located approximately 224.2 ± 0.6 parsecs (731.2 ± 2.0 ly) away in the constellation of Hercules, orbiting the 10th magnitude F-type main-sequence star HAT-P-14. This planet was discovered in 2010 by the HATNet Project using the transit method. It was independently detected by the SuperWASP project.
HAT-P-33 is a late-F dwarf star. It is orbited by a planet called HAT-P-33b. A search for a binary companion star using adaptive optics at the MMT Observatory was negative.
HD 179070, also known as Kepler-21, is a star with a closely orbiting exoplanet in the northern constellation of Lyra. At an apparent visual magnitude of 8.25 this was the brightest star observed by the Kepler spacecraft to host a validated planet until the discovery of an exoplanet orbiting HD 212657 in 2018. This system is located at a distance of 354 light-years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −18.2 km/s.
HD 146389, is a star with a yellow-white hue in the northern constellation of Hercules. The star was given the formal name Irena by the International Astronomical Union in January 2020. It is invisible to the naked eye with an apparent visual magnitude of 9.4 The star is located at a distance of approximately 446 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −9 km/s. The star is known to host one exoplanet, designated WASP-38b or formally named 'Iztok'.