SX Phoenicis variable


An SX Phoenicis variable is a type of variable star. These stars exhibit a short period pulsation behavior that varies on time scales of 0.03–0.08 days. They have spectral classifications in the range A2-F5 and vary in magnitude by up to 0.7. Compared to the Sun, these stars have a lower metallicity, which means they have a reduced abundance of elements other than hydrogen and helium. They also have relatively high space velocity and low luminosities for stars of their stellar classification. These properties distinguish the SX Phoenicis variables from their cousins, the Delta Scuti variables. The latter have longer periods, strong metallicity and large amplitudes.
SX Phoenicis variables are found primarily in globular clusters and galactic halos. The variability cycle has a period-luminosity relation. All known SX Phoenicis variables in globular clusters are blue straggler stars. These are stars that appear more blue than the main sequence stars in the same cluster that have similar luminosities.

List

The following list contains selected SX Phoenicis variable that are of interest to amateur or professional astronomy. Unless otherwise noted, the given magnitudes are in the V-band.
Star
Maximum
magnitude
Minimum
magnitude
Period
Spectral
type
SX Phoenicis6.767.530.055A2V
HD 940339.4610.260.060B9III/IV
DY Pegasi10.0010.560.073F5
CY Aquarii10.4211.200.061B8
AE Ursae Majoris10.8611.520.086A9
XX Cygni11.2812.130.135A5-F5
BL Camelopardalis12.9213.250.039
BX Sculptoris13.4213.710.037A