Gliese 436
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Leo |
| Right ascension | 11h 42m 11.09368s |
| Declination | +26° 42′ 23.6537″ |
| Apparent magnitude (V) | 10.67 |
| Characteristics | |
| Spectral type | M2.5 V |
| Apparent magnitude (B) | ~12.20 |
| Apparent magnitude (V) | ~10.68 |
| Apparent magnitude (J) | 6.900 ± 0.024 |
| Apparent magnitude (H) | 6.319 ± 0.023 |
| Apparent magnitude (K) | 6.073 ± 0.016 |
| U−B color index | +1.23 |
| B−V color index | +1.52 |
| Astrometry | |
| Radial velocity (Rv) | +10.0 km/s |
| Proper motion (μ) |
RA: +896.07 mas/yr Dec.: –813.54 mas/yr |
| Parallax (π) | 98.61 ± 2.33mas |
| Distance | 33.1 ± 0.8 ly (10.1 ± 0.2 pc) |
| Absolute magnitude (MV) | 10.63 |
| Details | |
| Mass | 0.41 ± 0.05 M☉ |
| Radius | 0.42 R☉ |
| Luminosity | 0.025 L☉ |
| Surface gravity (log g) | 5.0 cgs |
| Temperature | 3,318 K |
| Metallicity [Fe/H] | –0.32 ± 0.12 dex |
| Rotation | 39.9±0.8 d |
| Rotational velocity (v sin i) | 1.0 km/s |
| Age | 7.41–11.05 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Extrasolar Planets Encyclopaedia |
data |
Gliese 436 is a red dwarf approximately 33.1 light-years (10.1 parsecs) away in the zodiac constellation of Leo. It has an apparent visual magnitude of 10.67, which is much too faint to be seen with the naked eye. However, it can be viewed with even a modest telescope of 2.4 in (6 cm) aperture. In 2004, the existence of a transiting extrasolar planet, Gliese 436b, was verified as orbiting the star. In 2012, the existence of a second planet, UCF-1.01, was also verified.
Gliese 436 is a M2.5V star, which means it is a red dwarf. Stellar models give an estimated size of about 42% of the Sun's radius. The same model predicts that the outer atmosphere has an effective temperature of 3,318 K, giving it the orange-red hue of an M-type star. Small stars such as this generate energy at a low rate, giving it only 2.5% of the Sun's luminosity.
Gliese 436 is older than the Sun by several billion years and it has an abundance of heavy elements (with masses greater than helium-4) equal to 48% that of the Sun. The projected rotation velocity is 1.0 km/s, and the chromosphere has a low level of magnetic activity. Gliese 436 is a member of the "old-disk population" with velocity components in the galactic coordinate system of U=+44, V=−20 and W=+20 km/s.
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