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Lambda Arae

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Lambda Arae
Location of λ Arae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ara
Right ascension 17h 40m 23.826s[1]
Declination −49° 24′ 56.10″[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)+3.3±0.3[5] km/s
Proper motion (μ) RA: +104.233 mas/yr[1]
Dec.: −175.956 mas/yr[1]
Parallax (π)47.7045±0.1368 mas[1]
Distance68.4 ± 0.2 ly
(20.96 ± 0.06 pc)
Absolute magnitude (MV)+3.06[6]
Details
Mass1.37±0.04[1] M☉
Radius1.711±0.035[1] R☉
Luminosity4.69+0.03
−0.05[1] L☉
Surface gravity (log g)4.064+0.005
−0.003[1] cgs
Temperature6,495+3
−7[1] K
Metallicity [Fe/H]−0.24[4] dex
Rotational velocity (v sin i)15.5[7] km/s
Age2.44±0.39[1] Gyr
Other designations
λ Ara, λ Arae, NSV 23218, CD−49°11616, GC 23918, GJ 686.2, GJ 9597, HD 160032, HIP 86486, HR 6569, SAO 228257, PPM 323240, NLTT 45187[8]
Database references
SIMBADdata

Lambda Arae is a star in the southern constellation of Ara. Its name is a Bayer designation that is Latinized from λ Arae, and abbreviated Lambda Ara or λ Ara. The apparent visual magnitude of this star is 4.77,[2] making it bright enough to be seen with the naked eye. Based on parallax measurements, it is located at a distance of 68 light-years (21 parsecs) from Earth. This star is drifting further away from the Sun with a radial velocity of +3 km/s.[5]

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 is an estimated 2.4 billion years old,[1] and is spinning with a projected rotational velocity of 15.5 km/s.[7] This star has 40% more mass than the Sun and a 70% greater radius. 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,[1] 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.[7]

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[9]

References

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  1. ^ a b c d e f g h i j k l 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. ^ a b c d 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. ^ a b 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. ^ a b Holmberg, J.; et al. (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. ^ a b Gontcharov, G. A. (2006), "Pulkovo compilation of radial velocities for 35495 stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
  6. ^ 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.
  7. ^ a b c 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.
  8. ^ "lam Ara", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2010-07-30.
  9. ^ 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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