| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cetus |
| Right ascension | 00h 35m 14.87968s[1] |
| Declination | −03° 35′ 34.2367″[1] |
| Apparent magnitude (V) | 5.20[2] (5.61 + 6.90)[3] |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | F6 V + G4 V + K3.5 V[4][5] |
| B−V color index | 0.567±0.008[2] |
| Variable type | RS CVn[6] |
| Astrometry | |
| Radial velocity (Rv) | +10.37±0.40[7] km/s |
| Proper motion (μ) | RA: +408.34[1] mas/yr Dec.: −35.22[1] mas/yr |
| Parallax (π) | 47.05 ± 0.67 mas[1] |
| Distance | 69.3 ± 1.0 ly (21.3 ± 0.3 pc) |
| Absolute magnitude (MV) | 3.56[2] |
| Orbit[8] | |
| Primary | A |
| Companion | B |
| Period (P) | 2,516.6163±2.7808 d |
| Eccentricity (e) | 0.77300 |
| Periastron epoch (T) | 56,935.2034 MJD |
| Argument of periastron (ω) (secondary) | 283.8°° |
| Orbit[9] | |
| Primary | Aa |
| Companion | Ab |
| Period (P) | 2.081891±0.000005 d |
| Semi-major axis (a) | ≥1.260±0.010 Mm |
| Eccentricity (e) | 0.0 (fixed) |
| Periastron epoch (T) | 2,443,400.4573±0.0032 HJD |
| Argument of periastron (ω) (secondary) | 0.0° |
| Semi-amplitude (K1) (primary) | 43.98±0.39 km/s |
| Details | |
| Aa | |
| Mass | 1.18±0.09[5] M☉ |
| Luminosity | 2.63[8] L☉ |
| Temperature | 6,457[8] K |
| Age | 3.8+1.8 −0.3[2] Gyr |
| B | |
| Mass | 0.90±0.09[5] M☉ |
| Luminosity | 0.83[8] L☉ |
| Temperature | 5,754[8] K |
| Age | 2.5[8] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
13 Ceti is a triple star system[5] in the equatorial constellation of Cetus. It is dimly visible to the naked eye with a combined apparent visual magnitude of 5.20.[2] The system is located at a distance of approximately 69 light years from the Sun based on stellar parallax, and is drifting further away with a radial velocity of +10.4 km/s.[7] It shares a common motion with the Hyades moving group,[5] although it is too old to be a member.[11]
This star was identified as a visual binary system by G. W. Hough in 1844 and given the identifier HO 212.[12] The pair have an orbital period of 6.9 years and an eccentricity of 0.77.[8] The brighter member, designated component A, is an F-type main-sequence star with a stellar classification of F6 V[4] and a visual magnitude of 5.61.[3] It appears to have an active chromosphere and is classified as an RS Canum Venaticorum variable with a variable star designation of BU Cet.[6] The star was detected as a source of soft X-ray emission by EXOSAT.[13] It has 18%[5] more mass than the Sun and is estimated to be about four[2] billion years old.
In 1907, E. B. Frost discovered the primary is a spectroscopic binary, making this a triple star system. This is a double-lined spectroscopic binary with a period of 2.1 days and a circularized orbit. The companion signature was confirmed using the separated fringe packet technique with the CHARA array.[14] It is most likely a K-type main-sequence star with a class of K3.5 V and 70% of the mass of the Sun.[5]
The secondary member of the visual binary, designated component B, is a G-type main-sequence star with a class of G4 V.[4] It has 90%[5] of the Sun's mass and a visual magnitude of 6.90.[3] A distant visual companion to this system was detected by S. W. Burnham in 1877. Designated component C, this star is a background object[15] of magnitude 12.50. As of 1999, it was located at an angular separation of 24.0″ from the primary along a position angle of 322°.[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 d e f 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 Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22.
- ^ a b c Strassmeier, K. G.; et al. (July 1993), "A catalog of chromospherically active binary stars", Astronomy and Astrophysics, Supplemental Series, 100 (2nd ed.): 173–225, Bibcode:1993A&AS..100..173S.
- ^ a b c d e f g h Andrade, Manuel (October 2019), "Colour-dependent accurate modelling of dynamical parallaxes and masses of visual binaries. Application to the VB+SB2 systems with definitive orbits", Astronomy & Astrophysics, 630: 11, Bibcode:2019A&A...630A..96A, doi:10.1051/0004-6361/201936199, A96.
- ^ a b Fernandez-Figueroa, M. J.; et al. (January 1994), "CA II H and K and H alpha Emissions in Chromospherically Active Binary Systems (RS Canum Venaticorum and BY Draconis)" (PDF), Astrophysical Journal Supplement, 90: 433, Bibcode:1994ApJS...90..433F, doi:10.1086/191866.
- ^ a b Karataș, Yüksel; et al. (2004), "Kinematics of chromospherically active binaries and evidence of an orbital period decrease in binary evolution", Monthly Notices of the Royal Astronomical Society, 349 (3): 1069–1092, arXiv:astro-ph/0404219, Bibcode:2004MNRAS.349.1069K, doi:10.1111/j.1365-2966.2004.07588.x, S2CID 15290475.
- ^ a b c d e f g Piccotti, Luca; et al. (February 2020), "A study of the physical properties of SB2s with both the visual and spectroscopic orbits", Monthly Notices of the Royal Astronomical Society, 492 (2): 2709–2721, Bibcode:2020MNRAS.492.2709P, doi:10.1093/mnras/stz3616.
- ^ Duquennoy, A.; Mayor, M. (1991), "Multiplicity among solar-type stars in the solar neighbourhood. II - Distribution of the orbital elements in an unbiased sample", Astronomy and Astrophysics, 248 (2): 485–524, Bibcode:1991A&A...248..485D.
- ^ "13 Cet". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-11-05.
- ^ Montes, D.; et al. (2001), Garcia Lopez, Ramon J.; et al. (eds.), "Chromospherically Active Binaries Members of Young Stellar Kinematic Groups (CD-ROM Directory: contribs/montes2)", 11th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun, ASP Conference Proceedings, vol. 223, San Francisco: Astronomical Society of the Pacific, p. 1477, arXiv:astro-ph/9912161, Bibcode:2001ASPC..223.1477M.
- ^ Bauer, Carl August (November 1944), "A Report on New Spectrographic Material of 13 Ceti", Astrophysical Journal, 100: 302, Bibcode:1944ApJ...100..302B, doi:10.1086/144671.
- ^ Bedford, D. K.; et al. (February 1985), "X-Ray Observations of Active Chromosphere Stars", Space Science Reviews, 40 (1–2): 51–54, Bibcode:1985SSRv...40...51B, doi:10.1007/BF00212865, S2CID 121806441.
- ^ Raghavan, Deepak; et al. (January 2012), "A Search for Separated Fringe Packet Binaries Using the CHARA Array", The Astrophysical Journal, 745 (1): 10, Bibcode:2012ApJ...745...24R, doi:10.1088/0004-637X/745/1/24, S2CID 15622813, 24.
- ^ Pogo, A. (September 1928), "Spectrographic study of the multiple system HO 212 = 13 Ceti AB.", Astrophysical Journal, 68: 116−144, Bibcode:1928ApJ....68..116P, doi:10.1086/143133.
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.
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