Summary
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]
| 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 |
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.