Delta Normae

Delta Normae, Latinized from δ Normae, is a star system in the southern constellation of Norma. It is visible to the naked eye with an apparent visual magnitude of 4.74.[2] Based upon an annual parallax shift of 26.66 mas as seen from Earth,[1] the system is located about 122 light years distant from the Sun.

Delta Normae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Norma
Right ascension 16h 06m 29.43692s[1]
Declination −45° 10′ 23.4518″[1]
Apparent magnitude (V) 4.74[2]
Characteristics
Spectral type kA3hA7mF0 III:[3]
U−B color index +0.16[2]
B−V color index +0.24[2]
Astrometry
Radial velocity (Rv)−15.5±2.8[4] km/s
Proper motion (μ) RA: −16.19[1] mas/yr
Dec.: −38.45[1] mas/yr
Parallax (π)26.66 ± 0.74[1] mas
Distance122 ± 3 ly
(38 ± 1 pc)
Absolute magnitude (MV)+1.86[5]
Details
Mass1.75[6] M☉
Radius2.00[6] R☉
Luminosity13.4[7] L☉
Surface gravity (log g)4.04[8] cgs
Temperature7,691[8] K
Metallicity [Fe/H]+0.32[8] dex
Rotational velocity (v sin i)7[6] km/s
Age62.5±12.5[6] Myr
Other designations
δ Nor, CD−44° 10625, FK5 596, HD 144197, HIP 78914, HR 5980, SAO 226500[9]
Database references
SIMBADdata

Because the proper motion of the star has been found to change over time, this is most likely an astrometric binary.[10][11] The visible component is an Am star, which means it displays the spectrum of a metal-lined A-type chemically peculiar star. The stellar classification of kA3hA7mF0 III:[3] indicates it is an evolved giant with the calcium K-lines of an A3 class star, the hydrogen lines of an A7 star, and F0 class metallic lines. It has a magnetic field with an effective strength of (169.73±151.7)×10−4 T.[12]

Delta Normae has an estimated 1.75 times the mass of the Sun and twice the Sun's radius. It is around 63 million years old, and, as with other Am stars, has a relatively low spin rate with a projected rotational velocity of 7 km/s.[6] The star is radiating 13.4[7] times the Sun's luminosity from its photosphere at an effective temperature of 7,691 K.[8]

References
  1. van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
  2. Feinstein, A. (1974), "Photoelectric UBVRI observations of Am stars", Astronomical Journal, 79: 1290, Bibcode:1974AJ.....79.1290F, doi:10.1086/111675.
  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.
  4. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
  5. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015.
  6. Plavchan, Peter; et al. (June 2009), "New Debris Disks Around Young, Low-Mass Stars Discovered with the Spitzer Space Telescope", The Astrophysical Journal, 698 (2): 1068–1094, arXiv:0904.0819, Bibcode:2009ApJ...698.1068P, doi:10.1088/0004-637X/698/2/1068.
  7. McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
  8. Soubiran, C.; et al. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics, 515: A111, arXiv:1004.1069, Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247.
  9. "del Nor". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-12.
  10. Frankowski, A.; et al. (March 2007), "Proper-motion binaries in the Hipparcos catalogue. Comparison with radial velocity data", Astronomy and Astrophysics, 464 (1): 377–392, arXiv:astro-ph/0612449, Bibcode:2007A&A...464..377F, doi:10.1051/0004-6361:20065526.
  11. Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  12. Bychkov, V. D.; et al. (April 2009), "Catalogue of averaged stellar effective magnetic fields - II. Re-discussion of chemically peculiar A and B stars", Monthly Notices of the Royal Astronomical Society, 394 (3): 1338–1350, Bibcode:2009MNRAS.394.1338B, doi:10.1111/j.1365-2966.2008.14227.x.
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