Rho Phoenicis

Rho Phoenicis

A light curve for Rho Phoenicis, plotted from TESS data
Observation data
Epoch J2000      Equinox J2000
Constellation Phoenix
Right ascension 00h 50m 41.186s
Declination −50° 59 12.54
Apparent magnitude (V) 5.17  5.27
Characteristics
Spectral type F3III
U−B color index 0.13
B−V color index 0.36
Variable type δ Scuti
Astrometry
Radial velocity (Rv)22.0 km/s
Proper motion (μ) RA: 62.919 mas/yr
Dec.: 44.139 mas/yr
Parallax (π)13.3180±0.0629 mas
Distance245 ± 1 ly
(75.1 ± 0.4 pc)
Absolute magnitude (MV)+0.87
Details
Mass2.13 M
Radius4.2 R
Luminosity36 L
Surface gravity (log g)3.52 cgs
Temperature6,917 ± 124 K
Metallicity [Fe/H]−0.10 dex
Age1.00 Gyr
Other designations
CD−51°209, FK5 2056, HD 4919, HIP 3949, HR 242, SAO 232203
Database references
SIMBADdata

Rho Phoenicis (ρ Phoenicis) is a variable star in the constellation of Phoenix. From parallax measurements by the Gaia spacecraft, it is located at a distance of 245 light-years (75 parsecs) from Earth.

This star is classified as an F-type giant with a spectral type of F3III, and in the HR diagram it occupies in the lower part of the instability strip. Rho Phoenicis is Delta Scuti variable, changing its visual apparent magnitude between 5.17 and 5.27 with a period of around 0.1–0.2 days. The pulsation period seems to vary in a timescale of weeks, which indicates the star is not a simple radial pulsator. The analysis of the temperature variations over the pulsation cycles also supports this conclusion. It is not clear if the pulsation period really is variable, or if the light curve is simply the sum of multiple stable pulsation frequencies.

Stellar evolution models indicate that Rho Phoenicis has about 2.1 times the solar mass and an age of around 1 billion years. This star is shining with 36 times the solar luminosity and has an effective temperature of 6,900 K. Its metallicity is high, with an overall metal abundance 25% greater the solar value. Gaia Data Release 2 discovered a star with the same proper motion and parallax as Rho Phoenicis. It has an apparent magnitude of 14.6 (G band) and is at a separation of 7.9 arcseconds.