A visual band light curve for SX Phoenicis, adapted from Stankov et al. (2002)[1]
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 (0.7–1.9 hours). They have spectral classifications in the range A2-F5 and vary in magnitude by up to 0.7.[2] 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.[3][4] These properties distinguish the SX Phoenicis variables from their cousins, the Delta Scuti variables. The latter have longer periods, higher metallicity and large amplitudes.[5]
SX Phoenicis variables are found primarily in globular clusters and galactic halos. The variability cycle has a period-luminosity relation.[6] All known SX Phoenicis variables in globular clusters are blue straggler stars.[7] These are stars that appear more blue (having a higher temperature) than the main sequence stars in the same cluster that have similar luminosities.[8]
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.[citation needed]
↑Burki, G.; Mayor, M. (1986). "Radial velocities with CORAVEL - Results on stellar variability and duplicity". Christchurch, New Zealand: Dordrecht, D. Reidel Publishing Co.. p. 392. Bibcode: 1986IAUS..118..385B.
↑Breger, M. (Jan 1980). "The nature of dwarf Cepheids. V - Analysis and conclusions". Astrophysical Journal, Part 1235: 156. doi:10.1086/157620. Bibcode: 1980ApJ...235..153B.
↑McNamara, D. H. (April 1995). "Period-luminosity relations of SX Phoenicis stars". Astronomical Journal109 (4): 1751–1756. doi:10.1086/117405. Bibcode: 1995AJ....109.1751M.
↑Jeon, Young-Beom; Lee, Myung Gyoon; Kim, Seung-Lee; Lee, Ho (July 2004). "SX Phoenicis Stars in the Globular Cluster NGC 5466". The Astronomical Journal128 (1): 11. doi:10.1086/421735. Bibcode: 2004AJ....128..287J.
↑Santolamazza, P.; Marconi, M.; Bono, G.; Caputo, F.; Cassisi, S.; Gilliland, R. L. (June 2001). "Linear Nonadiabatic Properties of SX Phoenicis Variables". The Astrophysical Journal554 (2): 1124–1140. doi:10.1086/321408. Bibcode: 2001ApJ...554.1124S.