Kappa1 Ceti

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**κ¹ Ceti**
Observation data Equinox J2000
Constellation	Cetus
Right ascension	03^h 19^m 21.7^s
Declination	+03° 22′ 13″
Apparent magnitude (V)	4.84
Characteristics
Spectral type	G5 V
U-B color index	0.19
B-V color index	0.67
Variable type	Suspected
Astrometry
Radial velocity (R_v)	+19.9 km/s
Proper motion (μ)	RA: 268.87 mas/yr Dec.: 93.53 mas/yr
Parallax (π)	109.18 ± 0.78 mas
Distance	29.9 ± 0.2 ly (9.16 ± 0.07 pc)
Absolute magnitude (M_V)	5.03
Details
Mass	0.9 M_☉
Radius	.96 R_☉
Luminosity	0.85 L_☉
Temperature	5,690 K
Metallicity	110% Sun
Rotation	8.9-10.5 days (4.64 km/s.)
Age	6.5-7.5 × 10⁸ years
Other designations
Kap1 Cet, 96 Cet, GJ 137, HR 996, BD +02°518, HD 20630, LTT 11094, GCTP 691.00, SAO 111120, FK5 1095, NSV 1100, IRAS 03167+0311, HIP 15457.

Kappa¹ Ceti is a single star in the constellation Cetus the Whale. It is slightly less massive than our Sun, giving it a lower temperature and a redder hue. This star has been examined for companions, thus far without success. There was some early evidence based on spectroscopic measurements, but subsequent examination failed to corroborate the earlier results.

The rapid rotation rate of this star, roughly once every 9 days, is indicative of a relatively youthful body several hundred million years in age. Due to starspots, the star varies slightly over the approximately the same period. (The variations in period are thought to be caused by differential rotation at various latitudes, similar to what happens on the surface of our Sun.^[1])

This star been observed to emit what is termed a "super flare", a type of large-scale mass ejection event. These are 10⁸-10⁹ more energetic than a typical coronal mass ejection on the Sun.^[2] Such events would have serious implications for the environments of potential planetary bodies in orbit around this star.

Kappa² Ceti is a star that lies near the line of sight of Kappa¹ Ceti, but is about 10 times further away from us. It is a giant star of spectral class G8.

[edit] References

^ E. J. Gaidos, G.W. Henry, S.M.Henry, 2000, "Spectroscopy and Photometry of Nearby Young Solar Analogs", The Astronomical Journal, 120:1006-1013.
^ B. E. Schaefer, J.R. King, C.P. Deliyannis, 2000, "Superflares on Ordinary Solar-Type Stars", The Astrophysical Journal, Vol. 529, Issue 2, pp. 1026-1030.