Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cetus |
Right ascension | 02h 28m 37.226s [1] |
Declination | −07° 03′ 38.39″ [1] |
Apparent magnitude (V) | 10.12 |
Characteristics | |
Evolutionary stage | main-sequence star |
Spectral type | G8+K5 [2] |
Astrometry | |
Proper motion (μ) |
RA: 88
[1]
mas/
yr Dec.: 8.1 [1] mas/ yr |
Parallax (π) | 9.4818 ± 0.1073 mas [3] |
Distance | 344 ± 4
ly (105 ± 1 pc) |
Orbit [2] [4] | |
Primary | BD-07 436A |
Companion | BD-07 436B |
Semi-major axis (a) | 3.3" (461+200 −140 AU) |
Eccentricity (e) | 0.51+0.26 −0.22 |
Inclination (i) | 77+5 −7° |
Details [5] | |
BD-07 436A | |
Mass | 0.903+0.066 −0.059 M☉ |
Radius | 0.910+0.025 −0.023 R☉ |
Luminosity | 0.743+0.065 −0.058 L☉ |
Surface gravity (log g) | 4.476+0.014 −0.015 cgs |
Temperature | 5617±72 K |
Metallicity [Fe/H] | −0.10+0.10 −0.11 dex |
Rotation | 15.4±0.5 [6] |
Rotational velocity (v sin i) | 4.0±0.2 km/s |
Age | 5 [2] Gyr |
BD-07 436B | |
Mass | 0.71±0.06 [7] M☉ |
Radius | 0.69±0.12 [7] R☉ |
Surface gravity (log g) | 4.6±0.15 [7] cgs |
Temperature | 5570±240 [4] K |
Metallicity [Fe/H] | -0.11±0.19 [7] dex |
Rotational velocity (v sin i) | 2.8±0.5 [7] km/s |
Age | >9 [2] Gyr |
Other designations | |
Database references | |
SIMBAD | 436 data |
BD-07 436, also known as WASP-77 since 2012, [7] is a binary star system about 344 light-years away. The star's components appears to have a different age, with the secondary older than 9 billion years, while the primary's age is 5 billion years. [2] The BD-07 436 system's concentration of heavy elements is similar to the Sun. Its stars display moderate chromospheric activity, including x-ray flares. [2]
The primary is a
G-type main-sequence star, BD-07 436A (WASP-77A). The star is rotating rapidly, being spun up by the tides raised by the giant planet
WASP-77Ab on its close orbit.
[6] The secondary is a
K-type main-sequence star BD-07 436B orbiting at a distance of 461+200
−140
AU.
[4]
In 2012 a
transiting
hot Jupiter planet
b was detected on a very tight, circular orbit.
[7] The planet may have an extended gaseous envelope and is losing mass.
[2] Its equilibrium temperature is 1715+26
−25
K,
[5]the nightside temperature measured in 2019 is 1786±84
K,
[8] and dayside planetary temperature measured in 2020 is 1842+34
−33
K.
[9]
Water vapour was detected on the planetary dayside of WASP-77Ab, indicating C/O ratio similar to solar or even lower. [10]
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
Ab | 1.667+0.068 −0.064 MJ |
0.02335+0.00045 −0.00043 |
1.36002854±0.00000062 | 0.0074+0.0069 −0.0049 |
88.91+0.74 −0.95 ° |
1.230+0.031 −0.029 RJ |
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cetus |
Right ascension | 02h 28m 37.226s [1] |
Declination | −07° 03′ 38.39″ [1] |
Apparent magnitude (V) | 10.12 |
Characteristics | |
Evolutionary stage | main-sequence star |
Spectral type | G8+K5 [2] |
Astrometry | |
Proper motion (μ) |
RA: 88
[1]
mas/
yr Dec.: 8.1 [1] mas/ yr |
Parallax (π) | 9.4818 ± 0.1073 mas [3] |
Distance | 344 ± 4
ly (105 ± 1 pc) |
Orbit [2] [4] | |
Primary | BD-07 436A |
Companion | BD-07 436B |
Semi-major axis (a) | 3.3" (461+200 −140 AU) |
Eccentricity (e) | 0.51+0.26 −0.22 |
Inclination (i) | 77+5 −7° |
Details [5] | |
BD-07 436A | |
Mass | 0.903+0.066 −0.059 M☉ |
Radius | 0.910+0.025 −0.023 R☉ |
Luminosity | 0.743+0.065 −0.058 L☉ |
Surface gravity (log g) | 4.476+0.014 −0.015 cgs |
Temperature | 5617±72 K |
Metallicity [Fe/H] | −0.10+0.10 −0.11 dex |
Rotation | 15.4±0.5 [6] |
Rotational velocity (v sin i) | 4.0±0.2 km/s |
Age | 5 [2] Gyr |
BD-07 436B | |
Mass | 0.71±0.06 [7] M☉ |
Radius | 0.69±0.12 [7] R☉ |
Surface gravity (log g) | 4.6±0.15 [7] cgs |
Temperature | 5570±240 [4] K |
Metallicity [Fe/H] | -0.11±0.19 [7] dex |
Rotational velocity (v sin i) | 2.8±0.5 [7] km/s |
Age | >9 [2] Gyr |
Other designations | |
Database references | |
SIMBAD | 436 data |
BD-07 436, also known as WASP-77 since 2012, [7] is a binary star system about 344 light-years away. The star's components appears to have a different age, with the secondary older than 9 billion years, while the primary's age is 5 billion years. [2] The BD-07 436 system's concentration of heavy elements is similar to the Sun. Its stars display moderate chromospheric activity, including x-ray flares. [2]
The primary is a
G-type main-sequence star, BD-07 436A (WASP-77A). The star is rotating rapidly, being spun up by the tides raised by the giant planet
WASP-77Ab on its close orbit.
[6] The secondary is a
K-type main-sequence star BD-07 436B orbiting at a distance of 461+200
−140
AU.
[4]
In 2012 a
transiting
hot Jupiter planet
b was detected on a very tight, circular orbit.
[7] The planet may have an extended gaseous envelope and is losing mass.
[2] Its equilibrium temperature is 1715+26
−25
K,
[5]the nightside temperature measured in 2019 is 1786±84
K,
[8] and dayside planetary temperature measured in 2020 is 1842+34
−33
K.
[9]
Water vapour was detected on the planetary dayside of WASP-77Ab, indicating C/O ratio similar to solar or even lower. [10]
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
Ab | 1.667+0.068 −0.064 MJ |
0.02335+0.00045 −0.00043 |
1.36002854±0.00000062 | 0.0074+0.0069 −0.0049 |
88.91+0.74 −0.95 ° |
1.230+0.031 −0.029 RJ |