Sxari Sx Arietis7 variable stars

- These stars are main-sequence B0p-B9p stars with variable intensity He I and Si III lines and magnetic fields. They are sometimes called helium variables. Periods of light and magnetic field changes (about 1 ) coincide with rotational periods, while amplitudes are 0"!1 in V. These stars are high-temperature analogs of the ACV variables. GCVS

Many years ago, these stars were called spectrum variables of type-A, silicon variables, helium variables, or Ap silicon stars. Now, the SX Arietis stars are usually described as high-temperature analogs of the cr2 Canum Venaticorum stars. As mentioned within the section on ACV stars, the discrimination made within the GCVS regarding the notations and SX Ari seems inconsistent.

Within the General Catalog of Variable Stars, you will find 33 SX Ari stars. Ten of these stars are classified as uncertain. Thirteen more are found within The 67-73 Name List of Variable Stars (NL), and six in The 74th NL.

SX Ari variables show variations in brightness that can only be reliably detected with instruments. They are not good candidates for visual observation but provide those with instruments an excellent opportunity to observe a complete cycle in one evening. When observed with a CCD or by photoelectric means, their short periods allow a detailed study during a single observing season (Figure 6.4).

Observing techniques for these stars are the same as with the a2 Canum Venaticorum stars. Long-term

Observation

"At Mixed stars

¡5] Small amplitudes n Short periods

'Aries, the Ram, associated with a Ram and given the title "prince of constellations" or "leader of the constellations."

Figure 6.4. Light curve of the SXARl-tyP® enable star, SX An.

^provided by the

MARCOS mission. Used ^permission

Figure 6.4. Light curve of the SXARl-tyP® enable star, SX An.

^provided by the

MARCOS mission. Used ^permission

observation, using CCD or PEP techniques, is required and because of their short period, a complete cycle, perhaps more, should be the goal for an evening of work.

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