Lambda Arae

Lambda Arae (λ Ara, λ Arae) is the Bayer designation for a star in the southern constellation of Ara. It is at a distance of 68 light-years (21 parsecs) from Earth. The apparent visual magnitude of this star is 4.77,[2] making it bright enough to be seen with the naked eye.

Lambda Arae
Location of λ Arae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ara
Right ascension 17h 40m 23.82558s[1]
Declination −49° 24′ 56.0993″[1]
Apparent magnitude (V) 4.77[2]
Characteristics
Spectral type F4 V[3]
U−B color index −0.04[2]
B−V color index +0.40[2]
R−I color index +0.22
Variable type 3.10[4]
Astrometry
Radial velocity (Rv)+3.6[4] km/s
Proper motion (μ) RA: +104.233[1] mas/yr
Dec.: −175.956[1] mas/yr
Parallax (π)47.7045 ± 0.1368 mas[1]
Distance68.4 ± 0.2 ly
(20.96 ± 0.06 pc)
Absolute magnitude (MV)+3.06[5]
Details
Mass1.4[1] M☉
Radius1.7[1] R☉
Luminosity4.7[1] L☉
Surface gravity (log g)4.06[1] cgs
Temperature6,495[1] K
Metallicity [Fe/H]−0.24[4] dex
Rotational velocity (v sin i)15.5[6] km/s
Age2.4[1] Gyr
Other designations
CD−49°11616, GJ 9597, HD 160032, HIP 86486, HR 6569, NSV 23218, NLTT 45187, SAO 228257[7]
Database references
SIMBADdata

The spectrum of this star matches a stellar classification of F4 V,[3] which places it among the category of F-type main sequence stars. It shines with 4.7 times the luminosity of the Sun. The outer atmosphere is radiating this energy at an effective temperature of 6,495 K, giving it the yellow-white hue of an F-type star. There is some evidence that this may be a binary star system consisting of two stars with identical masses.[6]

Examination of Lambda Arae with the Spitzer Space Telescope shows an excess of infrared emission at a wavelength of 70 μm. This suggests it may be orbited by a disk of dust at a radius of more than 15 astronomical units[8]

References
  1. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
  3. Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal, 132 (1): 161–170, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637, S2CID 119476992.
  4. Holmberg, J.; Nordstrom, B.; Andersen, J. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191, S2CID 118577511.
  5. Ammler-von Eiff, Matthias; Reiners, Ansgar (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics, 542: A116, arXiv:1204.2459, Bibcode:2012A&A...542A.116A, doi:10.1051/0004-6361/201118724, S2CID 53666672.
  6. Fuhrmann, K.; et al. (August 2011), "Evidence for the nearby F4V star λ Ara as a binary system", Monthly Notices of the Royal Astronomical Society, 415 (2): 1240–1243, Bibcode:2011MNRAS.415.1240F, doi:10.1111/j.1365-2966.2011.18764.x.
  7. "lam Ara", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2010-07-30.
  8. Lawler, S. M.; et al. (November 2009), "Explorations Beyond the Snow Line: Spitzer/IRS Spectra of Debris Disks Around Solar-type Stars", The Astrophysical Journal, 705 (1): 89–111, arXiv:0909.0058, Bibcode:2009ApJ...705...89L, doi:10.1088/0004-637X/705/1/89, S2CID 1272803.
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