  | |
| Observation data EpochJ2000.0 EquinoxJ2000.0 | |
|---|---|
| Constellation | Lepus |
| Right ascension | 05h 46m 57.34096s[1] |
| Declination | −14° 49′ 19.0199″[1] |
| Apparent magnitude (V) | 3.524[2] |
| Characteristics | |
| Spectral type | A2 IV-V(n)[3] |
| U−Bcolor index | +0.113[2] |
| B−Vcolor index | +0.114[2] |
| Astrometry | |
| Radial velocity (Rv) | 20.0[4]–24.7[5] km/s |
| Proper motion (μ) | RA: −14.54[1]mas/yr Dec.: −1.07[1]mas/yr |
| Parallax (π) | 46.28±0.16 mas[1] |
| Distance | 70.5 ± 0.2 ly (21.61 ± 0.07 pc) |
| Absolute magnitude (MV) | +1.88[6] |
| Details | |
| Mass | 1.46[7] M☉ |
| Radius | 1.5[8] R☉ |
| Luminosity | 14[9] L☉ |
| Surface gravity (log g) | 4.41[9] cgs |
| Temperature | 9,772[10] K |
| Metallicity [Fe/H] | −0.76[3] dex |
| Rotational velocity (v sin i) | 245[8] km/s |
| Age | 231+126 −181[10] Myr |
| Other designations | |
| ζ Lep,14 Leporis,BD−14°1232,FK5 219,GCTP 1326,Gl 217.1, GJ 9190,HD 38678,HIP 27288,HR 1998,SAO 150801, Wolf 9190.[11] | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
Zeta Leporis,Latinized from ζ Leporis, is astar approximately 70.5light-years (21.6parsecs) away in the southernconstellation ofLepus. It has anapparent visual magnitude of 3.5,[2] which is bright enough to be seen with the naked eye. In 2001, anasteroid belt was confirmed to orbit the star.
Zeta Leporis has astellar classification of A2 IV-V(n),[3] suggesting that it is in a transitional stage between anA-type main-sequence star and asubgiant. The (n) suffix indicates that theabsorption lines in the star'sspectrum appear nebulous because it is spinning rapidly, causing the lines to broaden because of theDoppler effect. Theprojected rotational velocity is 245 km/s,[8] giving a lower limit on the star's actualequatorialazimuthal velocity.
The star has about 1.46 times themass of theSun,[7] along with 1.5 times theradius,[8] and 14 times theluminosity.[9] The abundance of elements other than hydrogen and helium, what astronomers term the star'smetallicity, is only 17% of the abundance in the Sun.[3] The star appears to be young, probably around 231 million years in age, but themargin of error spans 50–347 million years old.[10]
In 1983, based on radiation in theinfrared portion of theelectromagnetic spectrum, theInfraRed Astronomical Satellite was used to identify dust orbiting this star. Thisdebris disk is constrained to a diameter of 12.2AU.[12]
By 2001, theLong Wavelength Spectrometer at theKeck Observatory onMauna Kea,Hawaii, was used more accurately to constrain the radius of the dust. It was found to lie within a 5.4 AU radius.[12] The temperature of the dust was estimated as about 340 K.[citation needed] Based on heating from the star, this could place the grains as close as 2.5 AU from Zeta Leporis.[12]
It is now believed[by whom?] that the dust is coming from a massiveasteroid 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 mass in the Solar System's asteroid belt, or4×1023 kg. For comparison, this is more than half the total mass of theMoon. AstronomersChristine Chen and professorMichael Jura found that the dust contained within this belt should have fallen into the star within 20,000 years, a time period much shorter than Zeta Leporis's estimated age, suggesting that some mechanism must be replenishing the belt.[12] The belt's age is estimated to be3×108 years.[citation needed]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| Asteroid belt | 2.5–6.1AU | — | — | |||
Bobylev's calculations from 2010 suggest that this star passed as close as 1.28parsecs (4.17light-years) from the Sun about 861,000 years ago.[5] García-Sánchez 2001 suggested that the star passed 1.64 parsecs (5.34 light-years) from the Sun about 1 million years ago.[4] It was thebrightest star in the night sky over 1 million years ago,[13] peaking with an apparent magnitude of -2.05.[13]
