Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Corona Borealis |
Right ascension | 15h 38m 12.91478s [1] |
Declination | +36° 14′ 48.5597″ [1] |
Apparent magnitude (V) | 6.9 (total)[ citation needed ] |
Characteristics | |
Spectral type | F4V, F5V, G4V, F3V, F7V, M3V? [2] |
Astrometry | |
A | |
Proper motion (μ) | RA: 73.197 [3] mas/yr Dec.: −57.740 [3] mas/yr |
Parallax (π) | 9.0945 ± 0.0175 mas [3] |
Distance | 358.6 ± 0.7 ly (110.0 ± 0.2 pc) |
B | |
Proper motion (μ) | RA: 71.824 [4] mas/yr Dec.: −54.140 [4] mas/yr |
Parallax (π) | 9.1101 ± 0.0307 mas [4] |
Distance | 358 ± 1 ly (109.8 ± 0.4 pc) |
C | |
Proper motion (μ) | RA: 75.165 [5] mas/yr Dec.: −59.731 [5] mas/yr |
Parallax (π) | 9.0970 ± 0.0199 mas [5] |
Distance | 358.5 ± 0.8 ly (109.9 ± 0.2 pc) |
D | |
Proper motion (μ) | RA: 72.818 [6] mas/yr Dec.: −58.281 [6] mas/yr |
Parallax (π) | 9.0870 ± 0.0322 mas [6] |
Distance | 359 ± 1 ly (110.0 ± 0.4 pc) |
Orbit | |
Other designations | |
Database references | |
SIMBAD | data |
ADS 9731 is a star system that consists of six stars, located in the constellation of Corona Borealis. Four of the stars are visually separate in the sky, forming a visual star system, which was resolved using adaptive optics in 1995. [7] Two of these stars were themselves found to be spectroscopic binaries in 1998, resulting in a total of six known stars in the system. [2] It is one of very few multiple star systems known to have at least six members. [2]
Aa | |||||||||||||||
Period = 3.27 d | |||||||||||||||
Ab | |||||||||||||||
Period = 450 y | |||||||||||||||
B | |||||||||||||||
Period = 20,000 y | |||||||||||||||
C | |||||||||||||||
Period = 1000 y | |||||||||||||||
Da | |||||||||||||||
Period = 14.28 d | |||||||||||||||
Db | |||||||||||||||
Hierarchy of orbits
The components are organised thus: Aa and Ab are yellow-white main sequence stars of spectral types F4V and F5V and 1.35 and 1.32 solar masses respectively, which orbit each other every 3.27 days. This pair is in a 450-year orbit with star B, a star of spectral type G4V that has around the same mass as the Sun. Star C is a yellow white star of spectral type F3V around 1.41 times as massive as the sun, which has just started brightening and moving off the main sequence. It is in a 1000-year orbit with a pair of stars, Da and Db, a yellow-white main sequence star of spectral type F7V and a red dwarf of spectral type M3V. Da and Db take 14.28-days to orbit each other. Finally the system of stars C and Dab, and the system of stars Aab and B, take over 20,000 years to orbit each other. [2]
The combined light from the whole system results in an integrated V magnitude of 6.9. Published apparent magnitudes for the components vary greatly and some are certainly in error, [2] but components A, B, C, and D are approximately of visual magnitude 8, 10, 9, and 9 respectively. [8] Models of all six components show that Aa and Ab have magnitudes 8.5 and 8.7 respectively while the faint secondary to component D is about 16th magnitude. The CD pair is slightly brighter than the AB pair, although component A is slightly brighter than component C. [2]
Gaia EDR3 catalogues parallaxes for the four resolved stars, all at a distance of 360 light-years (110 pc) with a statistical margin of error of less than a parsec.
The star system has been considered as a possible target for direct imaging searches for exoplanets, [9] but no planets have yet been detected in the system.
36 Ophiuchi is a triple star system 19.5 light-years from Earth. It is in the constellation Ophiuchus.
Epsilon Volantis, Latinized from ε Volantis, is a quadruple star system in the southern constellation Volans. This star is at the center of the constellation of Volans and connects the "wings" of the constellation. Based upon parallax measurements, is roughly 640 light years from Earth.
13 Vulpeculae is a blue giant with a stellar classification of class B9.5III in the northern constellation Vulpecula. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 4.57 and it is approximately 339 light years away from the Sun based on parallax. The star is radiating 180 times the luminosity of the Sun from its photosphere at an effective temperature of 8,801 K.
HD 225218 is a quadruple star system in the northern constellation of Andromeda. The primary component, HD 225218 A, is a giant star with a stellar classification of B9III, an apparent magnitude of 6.16, and is a candidate Lambda Boötis star. It has a fainter, magnitude 9.65 companion, HD 225218 B, at an angular separation of 5.2″ along a position angle of 171°. The primary itself has been identified as a binary star system through interferometry, with the two components separated by 0.165″. The pair, HD 225218 Aa and Ab, orbit each other with a period of about 70 years and an eccentricity of 0.515. Component B is likewise a spectroscopic binary.
HD 6114 is a visual binary star system in the northern constellation of Andromeda. With a combined apparent magnitude of 6.46, the star can only be seen with the naked eye by keen-eyed observers even on the best of nights. Based upon an annual parallax shift of 10.4 mas as seen from Earth's orbit, the system is located approximately 108 parsecs (350 ly) distant.
4 Camelopardalis is a probable multiple star in the northern constellation of Camelopardalis, located 177 light years away from the Sun, based upon parallax. With a combined apparent visual magnitude of 5.29, it is visible to the naked eye as a faint, white-hued star. The pair have a relatively high proper motion, traversing the celestial sphere at an angular rate of 0.158″ per year. The system's proper motion makes it a candidate for membership in the IC 2391 supercluster. They are moving away from the Earth with a heliocentric radial velocity of 22.5 km/s.
S Monocerotis, also known as 15 Monocerotis, is a massive multiple and variable star system located in the constellation Monoceros. It is the brightest star in the Christmas Tree open cluster in the area catalogued as NGC 2264.
2MASS J04414489+2301513 is a young star system hosting a planet and a couple of brown dwarfs, approximately 470 light years away.
1 Camelopardalis is a double star system in the constellation Camelopardalis. Its combined apparent magnitude is 5.56 and it is approximately 800 parsecs (2,600 ly) away.
2 Equulei is a double star system in the constellation of Equuleus.
ADS 7251 is a binary star system 6.33 parsecs from the Sun. The components are near-identical red dwarfs separated by 17″ in 2019.
EBLM J0555-57 is a triple star system approximately 670 light-years from Earth. EBLM J0555-57Ab, the smallest star in the system, orbits its primary star with a period of 7.8 days, and at the time of discovery, was the smallest known star with a mass sufficient to enable the fusion of hydrogen in its core.
1 Delphini is the Flamsteed designation for a close binary star in the equatorial constellation Delphinus. With a combined apparent magnitude of 6.08, it is barely visible to the naked eye, even under ideal conditions. Parallax measurements put the components at a distance 703 and 780 light years respectively. However, its approaching the Solar System with a radial velocity of 15 km/s.
CD-73°375 is a binary star located in the constellation Volans about 820 light years away. The two components, HR 2979 and HR 2980, are separated by two arc-seconds. The pair has a combined apparent magnitude of 6.34. It has a radial velocity of about 13 km/s, which means it drifting away from the Solar System.
HD 155448 is a quintuple star system consisting of 5 young B-type stars. With an apparent magnitude of 8.72, it is too dim to be visible with the naked eye.
GK Tauri is a young T Tauri-type pre-main sequence star in the constellation of Taurus about 421 light years away, belonging to the Taurus Molecular Cloud.
HR 3831, also known as HD 83368, is a binary star system in the southern constellation of Vela at a distance of 233 light years. This object is barely visible to the naked eye as a dim, blue star with an apparent visual magnitude of 6.232. It is approaching the Earth with a heliocentric radial velocity of 4.0±0.3 km/s.
HD 139319 is a ternary system composed of the binary Algol variable star known as TW Draconis, and a main-sequence companion star at a separation of 3 arcseconds. The system lies in the constellation of Draco about 540 light years away.
13 Delphini is a binary star in the equatorial constellation Delphinus, with a combined apparent magnitude of 5.64. The system is located at a distance of 471 light years but is approaching the Solar System with a heliocentric radial velocity of about −7 km/s.
HD 199223 is a double star in the equatorial constellation Delphinus. However, the system was originally in Equuleus prior to the creation of official IAU constellation borders. The components have a separation of 2″ at a position angle of 282° as of 2016. They have apparent magnitudes of 6.34 and 7.49 and distances of 354 and 359 light years respectively. The system is drifting closer with a radial velocity of −33 km/s.