| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 19h 16m 26.78744s[1] |
| Declination | +14° 32′ 40.6234″[1] |
| Apparent magnitude (V) | 5.67[2] (5.68 + 9.58)[3] |
| Characteristics | |
| Spectral type | B9.5V[4] + G0IV[3] |
| U−B color index | −0.12[2] |
| B−V color index | −0.03[2] |
| Astrometry | |
| Radial velocity (Rv) | −19.3[5] km/s |
| Proper motion (μ) | RA: +8.09[1] mas/yr Dec.: +1.03[1] mas/yr |
| Parallax (π) | 7.96 ± 0.60 mas[1] |
| Distance | 410 ± 30 ly (126 ± 9 pc) |
| Orbit[6] | |
| Period (P) | 13.673 ± 0.069 yr |
| Semi-major axis (a) | 0.0583 ± 0.0014″ |
| Eccentricity (e) | 0.022 ± 0.010 |
| Inclination (i) | 131.3 ± 3.7° |
| Longitude of the node (Ω) | 242.3 ± 4.5° |
| Periastron epoch (T) | B 2008.572 ± 1.101 |
| Argument of periastron (ω) (secondary) | 262.7 ± 28.7° |
| Details | |
| HD 180555 A | |
| Rotational velocity (v sin i) | 158[7] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 180555 is a binary star in the equatorial constellation of Aquila. It consists of a two stars, orbiting with an orbital period of 8.95 years and an eccentricity of 0.43. A third component lies at an angular separation of 8.32″, but it is unrelated to the system.[3]
References
[edit]- ^ a b c d e 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- ^ a b c Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode:1986EgUBV........0M
- ^ a b c 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
- ^ Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819
- ^ Evans, D. S. (June 20–24, 1966), Batten, Alan Henry; Heard, John Frederick (eds.), "The Revision of the General Catalogue of Radial Velocities", Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E
- ^ "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Archived from the original on 1 August 2017. Retrieved 21 May 2017.
- ^ Royer, F.; Zorec, J.; Gómez, A. E. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224, S2CID 18475298
External links
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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