EQ Pegasi

Coordinates: Sky map 23h 31m 52.1743s, +19° 56′ 14.1284″
Source: Wikipedia, the free encyclopedia.
EQ Pegasi
EQ Pegasi is located in the constellation Pegasus
EQ Pegasi is located in the constellation Pegasus
EQ
Location of EQ Pegasi in the constellation Pegasus

Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Pegasus
EQ Pegasi A
Right ascension 23h 31m 52.17385s[1]
Declination +19° 56′ 14.1304″[1]
Apparent magnitude (V) 10.38 (min)[2]
EQ Pegasi B
Right ascension 23h 31m 52.57534s[3]
Declination +19° 56′ 14.0050″[3]
Apparent magnitude (V) 12.58 (min)[2]
Characteristics
EQ Pegasi A
Evolutionary stage red dwarf
Spectral type M4Ve[2]
Variable type Flare star[2]
EQ Pegasi B
Evolutionary stage red dwarf
Spectral type M6Ve[2]
Variable type Flare star[2]
Distance
20.396 ± 0.007 ly
(6.254 ± 0.002 pc)
Argument of periastron
(ω)
(secondary)		307.1416±0.0045°
Details
A
Mass0.43599±0.00092[4] M☉
Radius0.35[5] R☉
Luminosity0.019[6] L☉
Temperature3,585[7] K
Rotation1.061 days[5]
B
Mass0.16527±0.00025[4] M☉
Radius0.25[5] R☉
Luminosity0.008[6] L☉
Temperature3,309[8] K
Rotation0.404 days[5]
TYC 1723-23-2, 2MASS J23315244+1956138[10]
Database references
SIMBADThe system
A
B

EQ Pegasi (also known as Gliese 896) is a nearby

spectral types of M4Ve and M6Ve respectively, and a current separation between the components of 5.8 arcseconds. The system is at a distance of 20.4 light-years, and is 950 million years old.[11] The primary star is orbited by one known exoplanet.[4]

Discovery

EQ Pegasi was first noticed to be a binary star by Carl A. Wirtanen who in the course of a systematic survey of the McCormick Observatory photographic plates for M-type dwarfs, detected a companion about two magnitudes fainter at a separation of 3.5 arcseconds.[12]

Both components were also thought to be single-lined

spectroscopic binaries, with faint companions that have not been resolved in orbits of a few years,[13][14] but this is no longer thought to be the case. A 2021 study of nearby stars states that "the spectroscopic binarity classification [...] is almost certainly due to activity".[15]

Planetary system

In 2022, a

Jovian planet was discovered in orbit around the system's primary star via radio astrometry. Along with the planet around TVLM 513-46546, this is the first confirmed exoplanet discovered entirely using astrometry.[4]

The Gliese 896 A planetary system[4]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b 2.26±0.57 MJ 0.64282±0.00068 284.39±1.47 0.35±0.19 69.20±25.61° —

In culture

In 1998, it was the basis of a hoax, as a telecommunications company claimed it had discovered "alien" signals originating from the star.[16]

Gallery

References

  1. ^
    S2CID 244398875
    . Gaia DR3 record for this source at VizieR.
  2. ^
    Bibcode:2009yCat....102025S
    .
  3. ^
    S2CID 244398875
    . Gaia DR3 record for this source at VizieR.
  4. ^
    S2CID 251953478
    .
  5. ^
    S2CID 11240756
    .
  6. ^
    S2CID 16238033
    .
  7. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR
    .
  8. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR
    .
  9. ^ "BD+19 5116". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 18 August 2017.
  10. ^ a b "BD+19 5116A". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 18 August 2017.
  11. S2CID 55448675
    .
  12. doi:10.1086/125371
    .
  13. ^ Tokovinin, A. "Multiple Star Catalog". Retrieved 2019-08-12.
  14. Bibcode:1999A&A...344..897D
    .
  15. S2CID 233476431. Data available at https://gruze.org/10pc/
  16. ^ "BBC News | Sci/Tech | Alien hoax dismays scientists". news.bbc.co.uk. Retrieved 2018-09-25.
  17. S2CID 16358048
    . Retrieved 11 February 2022.
  18. S2CID 8572363
    . Retrieved 12 February 2022.
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