| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Norma |
| Right ascension | 16h 03m 12.89783s[1] |
| Declination | −49° 13′ 46.9151″[1] |
| Apparent magnitude (V) | 4.65[2] |
| Characteristics | |
| Evolutionary stage | horizontal branch |
| Spectral type | G8III[3] |
| U−B color index | +0.64[2] |
| B−V color index | +0.92[2] |
| Astrometry | |
| Radial velocity (Rv) | −0.3±2.8[4] km/s |
| Proper motion (μ) | RA: 42.05[1] mas/yr Dec.: 9.14[1] mas/yr |
| Parallax (π) | 14.86 ± 0.25 mas[1] |
| Distance | 219 ± 4 ly (67 ± 1 pc) |
| Absolute magnitude (MV) | 0.524[5] |
| Details | |
| Mass | 2.78[5] M☉ |
| Radius | 11.07+0.23 −0.09[6] R☉ |
| Luminosity | 71.9±3.1[6] L☉ |
| Surface gravity (log g) | 2.84[5] cgs |
| Temperature | 5052+16 −51[6] K |
| Metallicity [Fe/H] | −0.05[5] dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
Eta Normae, Latinized from η Normae, is a single[8] star in the southern constellation of Norma. It is visible to the naked eye as a faint, yellow-hued star with an apparent visual magnitude of 4.65.[2] The distance to this star is about 219 light years, based on parallax.[1] The Gamma Normids radiate from a position near this star.[9]
This is an aging giant star with a stellar classification of G8III,[3] having exhausted the supply of hydrogen at its core then swollen and cooled off the main sequence. At present it has a diameter of 11[6] times that of the Sun. It is a red clump[5] giant, meaning it is on the horizontal branch and is generating energy through core helium fusion. The star has 2.78[5] times the mass of the Sun and is radiating 72[6] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 5,052 K.[6] It is a source for X-ray emission.[10]
References
[edit]- ^ a b c d e f 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, S2CID 18759600.
- ^ 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.
- ^ a b Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
- ^ 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, S2CID 59451347, A61.
- ^ a b c d e f Liu, Y. J.; et al. (2007), "The abundances of nearby red clump giants", Monthly Notices of the Royal Astronomical Society, 382 (2): 553–66, Bibcode:2007MNRAS.382..553L, doi:10.1111/j.1365-2966.2007.11852.x.
- ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ "eta Nor". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-12.
{{cite web}}: CS1 maint: postscript (link) - ^ 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, S2CID 14878976.
- ^ Lunsford, Robert (2009), Meteors and How to Observe Them, Astronomers' Observing Guides, Springer Science & Business Media, pp. 76–77, ISBN 9780387094618.
- ^ Haakonsen, Christian Bernt; Rutledge, Robert E. (September 2009), "XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources", The Astrophysical Journal Supplement, 184 (1): 138–151, arXiv:0910.3229, Bibcode:2009ApJS..184..138H, doi:10.1088/0067-0049/184/1/138, S2CID 119267456.
Well, that’s interesting to know that Psilotum nudum are known as whisk ferns. Psilotum nudum is the commoner species of the two. While the P. flaccidum is a rare species and is found in the tropical islands. Both the species are usually epiphytic in habit and grow upon tree ferns. These species may also be terrestrial and grow in humus or in the crevices of the rocks.
View the detailed Guide of Psilotum nudum: Detailed Study Of Psilotum Nudum (Whisk Fern), Classification, Anatomy, Reproduction