V2052 Ophiuchi, also known as HR 6684, is a star about 920 light years from Earth in the constellation Ophiuchus.[2] It is a 5th-magnitude star, making it faintly visible to the naked eye of an observer far from city lights. V2052 Ophiuchi is a Beta Cephei variable (β Cep) star, varying slightly in brightness from magnitude 5.81 to 5.84 over a period of about 3.4 hours.[3]
In 1972, Mikolaj Jerzykiewicz announced that HR 6684 is a variable star, based on his observations using the 0.6 meter Air Force Telescope on Mauna Kea. He classified the star as a β Cep variable with period of 0.13989 days, He further noted that if confirmed, it would be the least luminous and shortest period β Cep star known up to that date.[12]Spectroscopic and photometric observations by D. Harold McNamara and Bruce Bills in 1973 confirmed Jerzykiewicz's results.[13] In 1973, HR 6684 was given the variable star designation V2052 Ophiuchi.[14]
In 1994, Henryk Cugier et al. determined that V2052 Ophiuchi pulsated primarily in the fundamental (l=0) radial mode.[15] A much less powerful non-radial pulsation mode was identified in 2003.[8] Ultraviolet observations by the TD-1A satellite show that throughout its pulsation cycle, the temperature of V2052 Ophiuchi varies by 1040±880 K, and its radius changes by 3.1%±0.9%.[5] Observations at the Pic du Midi Observatory showed that V2052 Ophiuchi has a dipole magnetic field, the axis of which is offset from the star's center, and there are helium spots on the surface near the magnetic poles.[9] V2052 Ophiuchi is a type of chemically peculiar star known as a helium-strong star. Its surface is over-abundant in helium, and under-abundant in oxygen, perhaps due to its magnetic field differentially effecting the diffusion of elements in its atmosphere.[8]
^ abcBeeckmans, F.; Burger, M. (December 1977). "Ultraviolet observations of beta Canis Majoris stars with the TD-1 A satellite". Astronomy and Astrophysics. 61: 815–826. Bibcode:1977A&A....61..815B.
^Cugier, H.; Dziembowski, W. A.; Pamyatnykh, A. A. (November 1994). "Nonadiabatic observables in β Cephei models". Astronomy and Astrophysics. 291: 143–154. Bibcode:1994A&A...291..143C.