BD+20°307
An artist's impression of two planets colliding in the system | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Aries |
| A | |
| Right ascension | 01h 54m 50.3440s |
| Declination | +21° 18′ 22.461″ |
| Apparent magnitude (V) | 9.01 |
| B | |
| Right ascension | 01h 54m 50.7493s |
| Declination | +21° 18′ 16.203″ |
| Apparent magnitude (V) | 16.45 |
| Characteristics | |
| A | |
| Spectral type | G0V |
| U−B color index | +1.26 |
| B−V color index | +0.56 |
| B | |
| Evolutionary stage | white dwarf |
| Spectral type | DA |
| Astrometry | |
| A | |
| Proper motion (μ) | RA: +38.801 mas/yr Dec.: −22.508 mas/yr |
| Parallax (π) | 8.5240±0.0189 mas |
| Distance | 382.6 ± 0.8 ly (117.3 ± 0.3 pc) |
| Absolute magnitude (MV) | +4.10 |
| B | |
| Parallax (π) | 8.4278±0.0647 mas |
| Distance | 387 ± 3 ly (118.7 ± 0.9 pc) |
| Details | |
| Aa | |
| Mass | 1.3±0.1 M☉ |
| Radius | 1.3–1.6 R☉ |
| Temperature | 6,500 K |
| Age | >1 Gyr |
| Ab | |
| Mass | 1.2±0.1 M☉ |
| Radius | 1.3–1.6 R☉ |
| Temperature | 6,250 K |
| Age | >1 Gyr |
| B | |
| Mass | 0.575 M☉ |
| Luminosity | 0.013 L☉ |
| Surface gravity (log g) | 7.93 cgs |
| Temperature | 16,594 K |
| Other designations | |
| BD+20°307, 2MASS J01545034+2118225, TYC 1212-207-1, AG+21° 173, HIP 8920, PPM 91187, YZ 21 572, GSC 01212-00207, IRAS 01520+2103, SAO 75016. | |
| Database references | |
| SIMBAD | data |
| B | |
BD+20°307 is a close binary star system approximately 300 light-years away in the constellation Aries. The system is surrounded by a dusty ring, and probably orbited by a 0.48 M☉ white dwarf on a wide (980 AU) orbit.
The dust that orbits around several hundred main-sequence stars is cold and comes from a Kuiper-belt analogous region. In the Solar System the ongoing collisions between asteroids generate a tenuous cloud of dust known as the zodiacal light. When the Solar System was young such collisions were more common and the rate of dust production was probably many times higher. Zodiacal dust around stars much younger than the Sun has been rarely found. Only a few main-sequence stars have revealed warm (>120 K) zodiacal dust.
An exceptionally large amount of warm, small, silicate dust particles around the solar-type star BD+20°307 (HIP 8920, SAO 75016) has been reported. The composition, quantity and temperature of the dust may be explained by recent, frequent or huge collisions between asteroids or other planetesimals whose orbits are being perturbed by a nearby planet.