FO Aquarii

FO Aquarii

The visual band light curve of FO Aquarii. The main plot shows the dimming which occurred in 2016, and the inset plot shows the short-term variation that occurs during an orbital period. Adapted from Littlefield et al. (2016)[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension 22h 17m 55.38s[2]
Declination −08° 21′ 04.6″[2]
Apparent magnitude (V) 12.7[3]
Characteristics
Apparent magnitude (B) 13.70[2]
Apparent magnitude (R) 13.60[2]
Apparent magnitude (J) 12.87[2]
Apparent magnitude (H) 12.75[2]
Apparent magnitude (K) 12.51[2]
Variable type DQ[4]
Orbit
Period (P)4.85 hr[5]
Other designations
2E 4588, 1RXS J221753.9-082115, CS 22886-0021, H 2215-086
Database references
SIMBADdata
Data sources:
Hipparcos Catalogue,
CCDM (2002),
Bright Star Catalogue (5th rev. ed.)

FO Aquarii is an intermediate polar[4] star system in the constellation Aquarius. The white dwarf and companion star orbit each other with a period of approximately 4.85 hours.[5] The system is famous for a very strong optical pulsation which occurs every 20.9 minutes, corresponding with the rotational period of the accreting white dwarf.[6] Prior to 2016, the system's long-term optical brightness varied between apparent magnitude 12.7 and 14.2,[7] but in early 2016, it faded to magnitude 15.8 and thereafter began a slow recovery to its normal brightness, behavior which is indicative of a temporary dropoff in the mass-transfer rate between the two stars.[8]

The variable nature of FO Aquarii was discovered in 1983 by Joseph Patterson and João Evangelista Steiner.[6] It was given its variable star designation in 1985.[9]

  1. ^ Cite error: The named reference Littlefield was invoked but never defined (see the help page).
  2. ^ a b c d e f g Cite error: The named reference 2MASS was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference GCVS was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Pekön2012 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Osborne 1989 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Patterson was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference AAVSO was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Littlefield2 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Kholopov was invoked but never defined (see the help page).