Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Aquila |
Right ascension | 19h 13m 42.70120s[2] |
Declination | +02° 17′ 37.3103″[2] |
Apparent magnitude (V) | 5.06 - 5.16[3] |
Characteristics | |
Spectral type | B8II-III(Hg?)[4] |
U−B color index | −0.399[5] |
B−V color index | −0.065[5] |
Variable type | α2 CVn[3] |
Astrometry | |
Radial velocity (Rv) | −5.2[6] km/s |
Proper motion (μ) | RA: +10.102[2] mas/yr Dec.: −0.825[2] mas/yr |
Parallax (π) | 4.7730 ± 0.1052 mas[2] |
Distance | 680 ± 20 ly (210 ± 5 pc) |
Absolute magnitude (MV) | −2.12[7] |
Details | |
Mass | 6.7[8] M☉ |
Radius | 6.2[9] R☉ |
Luminosity | 704[8] L☉ |
Surface gravity (log g) | 3.95[8] cgs |
Temperature | 12,014[8] K |
Metallicity [Fe/H] | −0.20[10] dex |
Rotation | 9.3 d[11] |
Rotational velocity (v sin i) | 17[10] km/s |
Age | 165[12] Myr |
Other designations | |
Database references | |
SIMBAD | data |
21 Aquilae is a solitary[14] variable star in the equatorial constellation of Aquila. It has the variable star designation V1288 Aql; 21 Aquilae is its Flamsteed designation. This object is visible to the naked eye as a dim, blue-white hued star with a baseline apparent visual magnitude of about 5.1. The star is located at a distance of around 680 light-years (210 parsecs) from Earth, give or take a 20 light-year margin of error. It is moving closer to the Earth with a heliocentric radial velocity of –5 km/s.[6]
The stellar classification of this star is B8 II-III, with the luminosity class of II-III suggesting that the spectrum displays elements of both a giant star and a bright giant. It is a chemically peculiar star of the Mercury-Manganese type (CP3),[10] although some catalogues consider that status to be doubtful.[15] This is a probable Alpha2 Canum Venaticorum variable that ranges in visual magnitude from 5.06 down to 5.16.[3] The star is radiating 704 times the luminosity of the Sun from its photosphere at an effective temperature of 12,014 K; this gives it the blue-white glow of a B-type star.[16]
21 Aquilae is catalogued as an optical double star, having a 12th magnitude companion 37″ away as of 2010. It was first identified as a double star by John Herschel.[17] The companion is a distant background object.[18]
References
[edit]- ^ Veto, B. (May 1980). "Ultraviolet Observations of the Silicon Star HD 179761". Information Bulletin on Variable Stars. 1778 (1): 1. Bibcode:1980IBVS.1778....1V.
- ^ a b c d e 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.
- ^ a b c Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
- ^ Cowley, A. (November 1972). "Spectral classification of the bright B8 stars". Astronomical Journal. 77: 750–755. Bibcode:1972AJ.....77..750C. doi:10.1086/111348.
- ^ a b Stepien, K. (December 1968). "Photometric behavior of magnetic stars". Astrophysical Journal. 154: 945. Bibcode:1968ApJ...154..945S. doi:10.1086/149815.
- ^ a b Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick (eds.). Proceedings from IAU Symposium no. 30. Determination of Radial Velocities and Their Applications. Vol. 30. University of Toronto: International Astronomical Union. p. 57. Bibcode:1967IAUS...30...57E.
- ^ 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. S2CID 119257644.
- ^ a b c d Fouesneau, M.; Andrae, R.; Dharmawardena, T.; Rybizki, J.; Bailer-Jones, C. A. L.; Demleitner, M. (2022). "Astrophysical parameters from Gaia DR2, 2MASS, and AllWISE". Astronomy and Astrophysics. 662: A125. arXiv:2201.03252. Bibcode:2022A&A...662A.125F. doi:10.1051/0004-6361/202141828. S2CID 245837778.
- ^ Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (20 December 2021). "Stellar and substellar companions from Gaia EDR3". Astronomy & Astrophysics. 657: A7. arXiv:2109.10912. Bibcode:2022A&A...657A...7K. doi:10.1051/0004-6361/202142146. eISSN 1432-0746. ISSN 0004-6361.
- ^ a b c Ghazaryan, S.; et al. (November 2018). "New catalogue of chemically peculiar stars, and statistical analysis". Monthly Notices of the Royal Astronomical Society. 480 (3): 2953–2962. arXiv:1807.06902. Bibcode:2018MNRAS.480.2953G. doi:10.1093/mnras/sty1912. S2CID 119062018.
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: CS1 maint: unflagged free DOI (link) - ^ Oelkers, Ryan J.; Rodriguez, Joseph E.; Stassun, Keivan G.; Pepper, Joshua; Somers, Garrett; Kafka, Stella; Stevens, Daniel J.; Beatty, Thomas G.; Siverd, Robert J.; Lund, Michael B.; Kuhn, Rudolf B.; James, David; Gaudi, B. Scott (2018). "Variability Properties of Four Million Sources in the TESS Input Catalog Observed with the Kilodegree Extremely Little Telescope Survey". The Astronomical Journal. 155 (1): 39. arXiv:1711.03608. Bibcode:2018AJ....155...39O. doi:10.3847/1538-3881/aa9bf4. S2CID 119515775.
- ^ Gontcharov, G. A. (December 2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters. 38 (12): 771–782. arXiv:1606.08814. Bibcode:2012AstL...38..771G. doi:10.1134/S1063773712120031. ISSN 0320-0108. S2CID 118345778.
- ^ "21 Aql". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-06-05.
- ^ Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
{{cite journal}}
: CS1 maint: unflagged free DOI (link) - ^ Renson, P.; Manfroid, J. (May 2009). "Catalogue of Ap, HgMn and Am stars". Astronomy and Astrophysics. 498 (3): 961–966. Bibcode:2009A&A...498..961R. doi:10.1051/0004-6361/200810788.
- ^ "The Colour of Stars". Australia Telescope, Outreach and Education. Commonwealth Scientific and Industrial Research Organisation. December 21, 2004. Archived from the original on March 18, 2012. Retrieved 2012-01-16.
- ^ Mason, B. D.; et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. Retrieved 2015-07-22.
- ^ 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.
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