Zeta Leporis

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Star
Zeta Leporis
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation Hare
Right ascension 05 h 46 m 57.3 s
declination −14 ° 49 ′ 19 ″
Apparent brightness 3.52 mag
Typing
B − V color index +0.114 
U − B color index +0.113 
Spectral class A2 IV-V (n)
Astrometry
Radial velocity +20.0 km / s
+24.7 km / s
parallax 46.28 ± 0.16  mas
distance 70.5 ± 0.2  ly
21.61 ± 0.07  pc
Proper movement 
Rec. Share: −14.54  mas / a
Dec. portion: −1.07  mas / a
Physical Properties
Dimensions 1.46  M ☉
radius 1.5  R ☉
Luminosity

14  L ☉

Effective temperature 9772  K
Metallicity [Fe / H] −0.76
Age approx. 230 million (50 to 350 million)  a
Other names
and catalog entries
Bayer name ζ Leporis
Flamsteed name 14 Leporis
Bonn survey BD −14 ° 1232
Bright Star Catalog HR 1998 [1]
Henry Draper Catalog HD 38678 [2]
Gliese catalog FY 217.1 [3]
Hipparcos catalog HIP 27288 [4]
SAO catalog SAO 150801 [5]
Tycho catalog TYC 5359-1778-1 [6]Template: Infobox star / maintenance / specification of the TYC catalog
2MASS catalog 2MASS J05465735-1449189 [7]
Other names FK5  219, GJ 9190, Wolf 9190, GCTP 1326

Zeta Leporis (ζ Leporis, ζ Lep) is a star in the southern constellation Rabbit , 70.5 light-years from Earth. It has an apparent magnitude of 3.5 mag, making it bright enough to be visible to the naked eye. In 2001, an asteroid belt around the star was confirmed.

properties

Zeta Leporis has the spectral class of A2 IV-V (n) and is therefore in the transition stage from a main sequence star to a subgiant . The suffix (n) means that the absorption lines in the star's spectrum appear nebulous because of its rapid rotation, which leads to the broadening of the lines due to the Doppler effect . The proposed rotation speed is 245 km / s, which results in a lower equatorial and azimuthal speed of the star.

The star has 1.46 times the mass, 1.5 times the radius, and 14 times the luminosity of the sun . The abundance of elements other than hydrogen and helium, referred to by astronomers as the star's metallicity , is only 17% that of the sun. Zeta Leporis appears to be very young, around 231 million years old, but the margin of error is between 50 and 347 million years.

Asteroid belt

The asteroid belt (main belt) in the solar system
The asteroid belt around the star Zeta Leporis (scale as above)

In 1983, the Infrared Astronomical Satellite (IRAS) space telescope discovered that Zeta Leporis was orbited by dust. The size of this debris disk has been restricted to a diameter of 12.2 astronomical units (AU).

With the Long Wavelength Spectrometer at the Keck Observatory on Mauna Kea on the island of Hawaii , the diameter of the debris disk could be limited more precisely in 2001. It was found to be within a 5.4 AU radius. The temperature of the dust was estimated to be around 340 Kelvin . Depending on the heating by the star, the dust grains could extend up to 2.5 AU at Zeta Leporis.

As things stand today, the dust can be traced back to a massive asteroid belt in orbit around Zeta Leporis, the first extrasolar asteroid belt to be discovered. The estimated mass of the belt is more than 200 times the mass of the asteroid belt in the solar system , namely 4 × 10 23 kg. Astronomers Christine Chen and Michael Jura found that the dust contained in this belt should actually have fallen into the star within 20,000 years, a much shorter time than the estimated age of Zeta Leporis, suggesting that some mechanism has hit the asteroid belt always refreshes.

Encounter with the sun

Calculations by Vadim V. Bobylev in 2010 suggest that Zeta Leporis came close to the Sun to within 1.28 parsecs (4.17 light years) 861,000 years ago. In 2001, J. Sanchez-Garcia assumed that a million years ago the star passed the Sun 1.64 parsecs (5.34 light years) away.

further reading

Individual evidence

  1. ↑ a b c d Gutierrez-Moreno, Adelina et al. (1966), A System of photometric standards 1, Publicaciones Universidad de Chile, Department de Astronomy, pp. 1-17
  2. ^ A b R. O. Gray, CJ Corbally, RF Garrison, MT McFadden, EJ Bubar, CE McGahee, AA O'Donoghue, ER Knox: Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Southern Sample . arxiv : astro-ph / 0603770 .
  3. ↑ a b c d García-Sánchez, J .; Weissman, PR; Preston, RA; Jones, DL; Lestrade, J.-F .; Latham, DW; Stefanik, RP; Paredes, JM: Stellar encounters with the solar system . bibcode : 2001A & A ... 379..634G .
  4. ↑ a b Vadim V. Bobylev: Searching for Stars Closely Encountering with the Solar System . arxiv : 1003.2160 .
  5. ^ A b F. van Leeuwen: Validation of the new Hipparcos reduction . arxiv : 0708.1752 .
  6. ^ A b c Ed Shaya, Rob Olling: Very Wide Binaries and Other Comoving Stellar Companions: A Bayesian Analysis of the Hipparcos Catalog . arxiv : 1007.0425 .
  7. ↑ a b R.L. Akeson, DR Ciardi, R. Millan-Gabet, A. Merand, E. Di Folco, JD Monnier, CA Beichman, O. Absil, J. Aufdenberg, H. McAlister, T. ten Brummelaar, J. Sturmann, L. Sturmann , N. Turner: Dust in the inner regions of debris disks around A stars . arxiv : 0810.3701 .
  8. ↑ a b Malagnini, ML; Morossi, C .: Accurate absolute luminosities, effective temperatures, radii, masses and surface gravities for a selected sample of field stars . bibcode : 1990A & AS ... 85.1015M .
  9. ↑ a b Inseok Song, J.-P. Caillault, David Barrado y Navascués, John R. Stauffer: Ages of A-type Vega-like stars from uvbyβ Photometry . arxiv : astro-ph / 0010102 .
  10. ↑ a b c d e Morledge, Paul (November 2011): Tightening a Star's Belt , in: Astronomy 29 (11)