3 Cancri
Star in the constellation Cancer
From Wikipedia, the free encyclopedia
3 Cancri is a single[7] star in the zodiac constellation of Cancer, located around 810 light years from the Sun. It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.60.[2] This object is moving further from the Earth with a heliocentric radial velocity of +39.5 km/s,[1] and may be a member of the Hyades group.[8] It is located near the ecliptic and thus is subject to lunar eclipses.[9]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cancer |
| Right ascension | 08h 00m 47.30744s[1] |
| Declination | +17° 18′ 31.3283″[1] |
| Apparent magnitude (V) | 5.60[2] |
| Characteristics | |
| Evolutionary stage | horizontal branch (86% chance)[3] |
| Spectral type | K3 III[4] |
| B−V color index | 1.317[5] |
| Astrometry | |
| Radial velocity (Rv) | +39.55±0.16[1] km/s |
| Proper motion (μ) | RA: −10.403[1] mas/yr Dec.: −3.905[1] mas/yr |
| Parallax (π) | 4.0087±0.1511 mas[1] |
| Distance | 810 ± 30 ly (249 ± 9 pc) |
| Absolute magnitude (MV) | −1.29[2] |
| Details | |
| Mass | 2.9[3] M☉ |
| Radius | 40[3] R☉ |
| Luminosity | 568.61[2] L☉ |
| Surface gravity (log g) | 2.05[5] cgs |
| Temperature | 4,300[5] K |
| Rotational velocity (v sin i) | 5.73[5] km/s |
| Other designations | |
| 3 Cnc, BD+17°1731, FK5 2618, HD 65759, HIP 39177, HR 3128, SAO 97472[6] | |
| Database references | |
| SIMBAD | data |
This is an aging giant star with a stellar classification of K3 III[4] that is most likely (86% chance) on the horizontal branch.[3] The star has 2.9 times the mass of the Sun and has expanded to 40 times the Sun's radius.[3] It is radiating 569[2] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,300 K.[5]
Planetary system
A candidate super-Jupiter exoplanet or brown dwarf orbiting 3 Cancri was detected in 2020 on a very mildly eccentric orbit using the radial velocity method.[10]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b (unconfirmed) | ≥20.76+0.72 −0.73 MJ |
2.52+0.03 −0.04 |
853.64+4.76 −4.73 |
0.04+0.04 −0.03 |
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