Zeta Leporis
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| Observation data Epoch J2000 |
|
|---|---|
| Constellation (pronunciation) |
Lepus |
| Right ascension | 05h 46m 57.3s |
| Declination | -14° 49′ 19″ |
| Apparent magnitude (V) | 3.55 |
| Characteristics | |
| Spectral type | A2 Vann |
| U-B color index | 0.08 |
| B-V color index | 0.10 |
| Variable type | None |
| Astrometry | |
| Radial velocity (Rv) | 18.6 km/s |
| Proper motion (μ) | RA: -14.84 mas/yr Dec.: -1.18 mas/yr |
| Parallax (π) | 46.47 ± 0.68 mas |
| Distance | 70.2 ly (21.5 pc) |
| Absolute magnitude (MV) | 1.89 |
| Details | |
| Mass | 2 M☉ |
| Radius | 1.7 R☉ |
| Luminosity | 15 L☉ |
| Temperature | 9,000 K |
| Metallicity | ? |
| Rotation | ~202 km/s. |
| Age | ~50-500 × 106 years |
| Other designations | |
Zeta Leporis (ζ Lep / ζ Leporis) is a star in the north-eastern section of the constellation Lepus, near the constellation of Orion. It lacks a traditional name that was often given to stars of greater apparent magnitude.
This is a main sequence star that has nearly double the mass of our Sun, and radiates a blue-white light. It is a suspected spectroscopic binary, but this is yet to be confirmed.
In 1983, based on radiation in the infrared portion of the electromagnetic spectrum, the Astronomical Satellite was used to identify dust orbiting this star. The region containing the dust was constricted to a radius of 12.2 Astronomical units, or just over twelve times the distance from the Earth to the Sun.
By 2001, the Long Wavelength Spectrometer at the Keck Observatory on Mauna Kea, Hawaii, was used more accurately constrain the radius of the dust. It was found to lie within a 5.4 AU radius. The temperature of the dust was estimated as about 340 K. Based on heating from the star, this could place the grains as close as 2.5 AU from Zeta Leporis.
It is now believed that the dust is coming from a massive asteroid belt in orbit around Zeta Leporis, making it the first extra-solar asteroid belt to be discovered. The estimated mass of the belt is about 200 times the total in our own asteroid belt, or 4 × 1023 kg. (For comparison, that is more than half the total mass of our Moon.) The belt's age is estimated to be 3 × 108 years.
[edit] References
- Cote, J., 1987, "B and A type stars with unexpectedly large colour excesses at IRAS wavelengths", Astronomy and Astrophysics, vol. 181, no. 1.
- Aumann, H. H.; Probst, R. G, 1991, "Search for Vega-like nearby stars with 12 micron excess", Astrophysical Journal, vol. 368, Feb. 10.
- Chen, C. H.; Jura, M., 2001, "A Possible Massive Asteroid Belt around zeta Leporis", Astrophysical Journal, Volume 560, Issue 2.
- M. M. Moerchen, C. M. Telesco, C. Packham, T. J. J. Kehoe (2006). "Mid-infrared resolution of a 3 AU-radius debris disk around Zeta Leporis" (subscription required). Astrophysical Journal Letters.
