94 Ceti

94 Ceti (HD 19994) is a trinary star system approximately 73 light-years away in the constellation Cetus.

94 Ceti A / B

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Cetus
Right ascension	03h 12m 46.43719s[1]
Declination	−01° 11′ 45.9613″[1]
Apparent magnitude (V)	+5.070[2]
Characteristics
Spectral type	F8V / M3V / M
U−B color index	+0.09[3]
B−V color index	+0.56[3]
Astrometry
Radial velocity (Rv)	+18.96 ± 0.08[4] km/s
Proper motion (μ)	RA: 194.56[1] mas/yr Dec.: −69.01[1] mas/yr
Parallax (π)	44.29 ± 0.28 mas[1]
Distance	73.6 ± 0.5 ly (22.6 ± 0.1 pc)
Absolute magnitude (MV)	3.32
Orbit[5]
Primary	94 Ceti A
Companion	94 Ceti BC
Period (P)	2029±41 yr
Semi-major axis (a)	220±5 AU
Eccentricity (e)	0.26±0.01
Inclination (i)	104±2°
Longitude of the node (Ω)	97±2°
Argument of periastron (ω) (secondary)	342±7°
Orbit[6]
Primary	94 Ceti B
Companion	94 Ceti C
Period (P)	378.35+0.36 −0.34 d
Semi-major axis (a)	0.984±0.007 AU
Eccentricity (e)	0.360±0.005
Inclination (i)	108.323+0.581 −0.561°
Longitude of the node (Ω)	191.496+1.602 −1.562°
Periastron epoch (T)	MJD 55113.904±0.220
Argument of periastron (ω) (secondary)	334.895±0.240°
Details
Mass	1.30[7] M☉
Radius	1.898 ± 0.070[8] R☉
Luminosity	4.02 ± 0.05[9] L☉
Surface gravity (log g)	3.98 ± 0.10[7] cgs
Temperature	6,055 ± 10.0[10] K
Metallicity [Fe/H]	1.15 ± 0.07[7] dex
Rotation	12.2 d[11]
Rotational velocity (v sin i)	8.4 ± 0.8[7] km/s
Age	4.8[9] Gyr
Other designations
BD-01° 457, FK5 116, GJ 128, HD 19994, HIP 14954, HR 962, LTT 1515, SAO 130355.
Database references
SIMBAD	data

94 Ceti A is a yellow-white dwarf star with about 1.3 times the mass of the Sun while 94 Ceti B and C are red dwarf stars.

An infrared excess has been detected around the primary, most likely indicating the presence of a circumstellar disk at a radius of 95 AU. The temperature of this dust is 40 K.^[12]

Stellar system

This system is a hierarchical triple star system with 94 Ceti A being orbited by 94 Ceti BC, a pair of M dwarfs, in 2000 years. 94 Ceti B and C meanwhile orbit each other in a 1-year orbit.^[5]

Planetary system

On 7 August 2000, a planet was announced by the Geneva Extrasolar Planet Search team as a result of radial velocity measurements taken with the Swiss 1.2-metre Leonhard Euler Telescope at La Silla Observatory in Chile.^[13] It is most stable if its inclination is either 65 or 115, ± 3.^[14]

The 94 Ceti planetary system^[14]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	1.855 ± 0.045 MJ	1.427	535.7 ± 3.1	0.30 ± 0.04	—	—

See also

• 79 Ceti
• 81 Ceti
• Lists of exoplanets

References

1. 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. Vizier catalog entry
2. Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
3. Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
4. Nidever, David L.; et al. (2013). "Radial Velocities for 889 Late-Type Stars". The Astrophysical Journal Supplement Series. 141 (2): 503–522. arXiv:astro-ph/0112477. Bibcode:2002ApJS..141..503N. doi:10.1086/340570. S2CID 51814894.
5. Wiegert, J.; et al. (2016). "94 Ceti: A triple star with a planet and dust disc". Monthly Notices of the Royal Astronomical Society. 462 (2): 1735–1748. arXiv:1607.03038. Bibcode:2016MNRAS.462.1735W. doi:10.1093/mnras/stw1682. S2CID 55234970.
6. Röll, Tristan Alexander (2011). Astrometric search for extrasolar planets in stellar multiple systems (PhD). Friedrich-Schiller-University Jena.
7. Fuhrmann, K. (2008). "Nearby stars of the Galactic disc and halo - IV". Monthly Notices of the Royal Astronomical Society. 384 (1): 173–224. Bibcode:2008MNRAS.384..173F. doi:10.1111/j.1365-2966.2007.12671.x.
8. van Belle, G. T.; von Brau, K. (2009). "Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars". The Astrophysical Journal. 694 (2): 1085–1098. arXiv:0901.1206. Bibcode:2009ApJ...694.1085V. doi:10.1088/0004-637X/694/2/1085. S2CID 18370219.
9. Boyajian, Tabetha S.; et al. (July 2013), "Stellar Diameters and Temperatures. III. Main-sequence A, F, G, and K Stars: Additional High-precision Measurements and Empirical Relations", The Astrophysical Journal, 771 (1): 31, arXiv:1306.2974, Bibcode:2013ApJ...771...40B, doi:10.1088/0004-637X/771/1/40, S2CID 14911430, 40. See Table 3.
10. Kovtyukh, V. V.; Soubiran, C.; Belik, S. I.; Gorlova, N. I. (2003). "High precision effective temperatures for 181 F-K dwarfs from line-depth ratios". Astronomy and Astrophysics. 411 (3): 559–564. arXiv:astro-ph/0308429. Bibcode:2003A&A...411..559K. doi:10.1051/0004-6361:20031378. S2CID 18478960.
11. Mayor, M.; et al. (2004). "The CORALIE survey for southern extra-solar planets XII. Orbital solutions for 16 extra-solar planets discovered with CORALIE". Astronomy and Astrophysics. 415 (1): 391–402. arXiv:astro-ph/0310316. Bibcode:2004A&A...415..391M. doi:10.1051/0004-6361:20034250. S2CID 5233877.
12. Eiroa, C.; et al. (July 2013). "DUst around NEarby Stars. The survey observational results". Astronomy & Astrophysics. 555: A11. arXiv:1305.0155. Bibcode:2013A&A...555A..11E. doi:10.1051/0004-6361/201321050. S2CID 377244.
13. "European Southern Observatory: Six Extrasolar Planets Discovered". SpaceRef.com. 7 August 2000. Retrieved 2 August 2009.
14. Plávalová, Eva; Solovaya, Nina A. (2013). "Analysis of the motion of an extrasolar planet in a binary system". The Astronomical Journal. 146 (5): 108. arXiv:1212.3843. Bibcode:2013AJ....146..108P. doi:10.1088/0004-6256/146/5/108. S2CID 118629538.

External links

• SolStation: 94 Ceti 2 + orbits
• 94 Ceti by Professor Jim Kaler.