HD 224693

HD 224693, also named Axólotl, is a star in the equatorial constellation of Cetus, and is positioned near the western constellation border with Aquarius. It can be viewed with a small telescope but is too faint to be seen with the naked eye, having an apparent visual magnitude of 8.23.^[2] Based on parallax measurements, the object is located at a distance of approximately 308 light-years from the Sun. It is drifting further away with a radial velocity of 1.4 km/s.^[1]

HD 224693 / Axólotl

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Cetus
Right ascension	23h 59m 53.83172s[1]
Declination	−22° 25′ 41.2163″[1]
Apparent magnitude (V)	8.23[2]
Characteristics
Spectral type	G2V[3] or G2IV[4]
B−V color index	0.639±0.015[2]
Variable type	constant[4]
Astrometry
Radial velocity (Rv)	1.43±0.14[1] km/s
Proper motion (μ)	RA: 147.026 mas/yr[1] Dec.: 26.865 mas/yr[1]
Parallax (π)	10.5796±0.0279 mas[1]
Distance	308.3 ± 0.8 ly (94.5 ± 0.2 pc)
Absolute magnitude (MV)	3.29[2]
Details
Mass	1.29±0.09[5] M☉
Radius	1.82+0.05 −0.04[6] R☉
Luminosity	3.78±0.03[6] L☉
Surface gravity (log g)	4.18±0.06[5] cgs
Temperature	5,971+55 −88[6] K
Metallicity [Fe/H]	0.28±0.02[5] dex
Rotational velocity (v sin i)	4.2[7] km/s
Age	3.0[7] Gyr
Other designations
Axólotl, CD−23°18108, HD 224693, HIP 118319, SAO 192301
Database references
SIMBAD	data
Exoplanet Archive	data

The star HD 224693 is named Axólotl. The name was selected in the NameExoWorlds campaign by Mexico, during the 100th anniversary of the IAU. "Axólotl" means "water animal" in the native Nahuatl language and an axolotl is also a species of salamander endemic to the valley of Mexico.^[8][9]

This is an ordinary G-type main-sequence star with a stellar classification of G2V.^[3] However, in 2006, Johnson and associates assigned it a class of G2 IV, suggesting it is instead an evolving subgiant star.^[4] It is about three^[7] billion years old and chromospherically quiet,^[4] with a projected rotational velocity of 4.2 km/s.^[7] The star is metal rich, showing a higher abundance of elements other than hydrogen and helium when compared to the Sun.^[4] It has 1.3^[5] times the mass of the Sun and 1.8 times the Sun's radius. The star is radiating 3.78 times the luminosity of the Sun from its photosphere at an effective temperature of 5,971 K.^[6]

Planetary system

In 2006, an extrasolar planet was discovered orbiting HD 224693 by the Keck telescope using radial velocity measurements.^[10] A preliminary search for transits using photometric data from Fairborn Observatory was inconclusive because data around the predicted time of transit was too sparse to rule out possible transits.^[4] This exoplanet was named Xolotl, after the Aztec god of fire and lightning.^[11]

The HD 224693 planetary system^[12]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b / Xólotl	≥0.7±0.12 MJ	0.191±0.014	26.6904±0.0019	0.104±0.017	—	—

See also

• 79 Ceti
• HD 222582
• HD 33283
• HD 86081
• List of extrasolar planets