Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
---|---|
Constellation | Cassiopeia |
Right ascension | 01h 11m 06.16225s [1] |
Declination | +55° 08′ 59.6472″ [1] |
Apparent magnitude (V) | 4.334 [2] |
Characteristics | |
Spectral type | A7 V [3] |
U−B color index | +0.130 [2] |
B−V color index | +0.170 [2] |
Variable type | Suspected δ Sct [4] |
Astrometry | |
Radial velocity (Rv) | 2.5±0.6 [5] km/s |
Proper motion (μ) |
RA: +226.77
[1]
mas/
yr Dec.: −18.75 [1] mas/ yr |
Parallax (π) | 24.42 ± 0.24 mas [1] |
Distance | 134 ± 1
ly (41.0 ± 0.4 pc) |
Absolute magnitude (MV) | +1.28 [6] |
Details [7] | |
Mass | 1.83 M☉ |
Radius | 2.6 [8] R☉ |
Surface gravity (log g) | 4.03±0.14 cgs |
Temperature | 8,202±279 K |
Rotational velocity (v sin i) | 103 [9] km/s |
Age | 650 Myr |
Other designations | |
Database references | |
SIMBAD | data |
Theta Cassiopeiae or θ Cassiopeiae is a solitary [3] star in the northern constellation of Cassiopeia. It shares the traditional name Marfak /ˈmɑːrfæk/ with μ Cassiopeiae, positioned less than half a degree to the WSW, [11] which is derived from the Arabic term Al Marfik or Al Mirfaq (المرفق), meaning "the elbow". [12] At an apparent visual magnitude of 4.3, [2] Theta Cassiopeiae is visible to the naked eye. Based upon an annual parallax shift of 24.42 mas, [1] it is located about 134 light years from the Sun. It has a total annual proper motion of 0.227 arcseconds per year, [13] and is slowly drifting further away from the Sun with a radial velocity of 2.5 km/s. [5]
In Chinese, 閣道 (Gé Dào), meaning Flying Corridor, refers to an asterism consisting of θ Cassiopeiae, ι Cassiopeiae, ε Cassiopeiae, δ Cassiopeiae, ν Cassiopeiae and ο Cassiopeiae. [14] Consequently, θ Cassiopeiae itself is known as 閣道四 (Gé Dào sì, English: the Fourth Star of Flying Corridor.) [15]
This is an A-type main sequence star with a stellar classification of A7 V. [3] The measured angular diameter of this star is 0.58±0.02 mas, [16] which, at the estimated distance of this star, yields a physical size of about 2.6 times the radius of the Sun. [8] It is about 650 [7] million years in age and is spinning with a projected rotational velocity of 103 km/s. [9] This is a candidate Vega-type system, which means it displays an infrared excess suggesting it has an orbiting debris disk. [17] It is a suspected Delta Scuti variable. [4]
The star appears to be a member of a leading tidal tail of the Hyades cluster. [18]
Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
---|---|
Constellation | Cassiopeia |
Right ascension | 01h 11m 06.16225s [1] |
Declination | +55° 08′ 59.6472″ [1] |
Apparent magnitude (V) | 4.334 [2] |
Characteristics | |
Spectral type | A7 V [3] |
U−B color index | +0.130 [2] |
B−V color index | +0.170 [2] |
Variable type | Suspected δ Sct [4] |
Astrometry | |
Radial velocity (Rv) | 2.5±0.6 [5] km/s |
Proper motion (μ) |
RA: +226.77
[1]
mas/
yr Dec.: −18.75 [1] mas/ yr |
Parallax (π) | 24.42 ± 0.24 mas [1] |
Distance | 134 ± 1
ly (41.0 ± 0.4 pc) |
Absolute magnitude (MV) | +1.28 [6] |
Details [7] | |
Mass | 1.83 M☉ |
Radius | 2.6 [8] R☉ |
Surface gravity (log g) | 4.03±0.14 cgs |
Temperature | 8,202±279 K |
Rotational velocity (v sin i) | 103 [9] km/s |
Age | 650 Myr |
Other designations | |
Database references | |
SIMBAD | data |
Theta Cassiopeiae or θ Cassiopeiae is a solitary [3] star in the northern constellation of Cassiopeia. It shares the traditional name Marfak /ˈmɑːrfæk/ with μ Cassiopeiae, positioned less than half a degree to the WSW, [11] which is derived from the Arabic term Al Marfik or Al Mirfaq (المرفق), meaning "the elbow". [12] At an apparent visual magnitude of 4.3, [2] Theta Cassiopeiae is visible to the naked eye. Based upon an annual parallax shift of 24.42 mas, [1] it is located about 134 light years from the Sun. It has a total annual proper motion of 0.227 arcseconds per year, [13] and is slowly drifting further away from the Sun with a radial velocity of 2.5 km/s. [5]
In Chinese, 閣道 (Gé Dào), meaning Flying Corridor, refers to an asterism consisting of θ Cassiopeiae, ι Cassiopeiae, ε Cassiopeiae, δ Cassiopeiae, ν Cassiopeiae and ο Cassiopeiae. [14] Consequently, θ Cassiopeiae itself is known as 閣道四 (Gé Dào sì, English: the Fourth Star of Flying Corridor.) [15]
This is an A-type main sequence star with a stellar classification of A7 V. [3] The measured angular diameter of this star is 0.58±0.02 mas, [16] which, at the estimated distance of this star, yields a physical size of about 2.6 times the radius of the Sun. [8] It is about 650 [7] million years in age and is spinning with a projected rotational velocity of 103 km/s. [9] This is a candidate Vega-type system, which means it displays an infrared excess suggesting it has an orbiting debris disk. [17] It is a suspected Delta Scuti variable. [4]
The star appears to be a member of a leading tidal tail of the Hyades cluster. [18]