Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Indus |
Right ascension | 20h 37m 34.032s [1] |
Declination | –47° 17′ 29.4052″ [1] |
Apparent magnitude (V) | 3.11 [2] |
Astrometry | |
Radial velocity (Rv) | −1.3 [3] km/s |
Proper motion (μ) |
RA: +50.922
mas/
yr
[1] Dec.: +66.026 mas/ yr [1] |
Parallax (π) | 32.8989 ± 0.2225 mas [1] |
Distance | 99.1 ± 0.7
ly (30.4 ± 0.2 pc) [1] |
Absolute magnitude (MV) | 0.65 [4] |
Characteristics | |
Evolutionary stage | between subgiant and giant star |
Spectral type | K0 III–IV [5] |
U−B color index | +0.79 [2] |
B−V color index | +1.00 [2] |
Details [6] | |
Mass | 1.879±0.13 M☉ |
Radius | 9.706±0.294 R☉ |
Luminosity | 59 [7] L☉ |
Surface gravity (log g) | 2.96±0.1 cgs |
Temperature | 4896±34 K |
Metallicity [Fe/H] | −0.05±0.03 dex |
Age | 1.572±0.273 Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Alpha Indi (α Ind, α Indi) is the brightest star in the southern constellation Indus. Parallax measurements imply that it is located about 100 light years from Earth. [1] It is visible to the naked eye at an apparent visual magnitude of 3.22. [2] Considering its distance and apparent magnitude, its absolute magnitude is equal to 0.65. [4]
The stellar classification of Alpha Indi is K0 III-IV, [5] meaning that it has exhausted the hydrogen at its core and evolved away from the main sequence, being now halfway between a subgiant and a giant star. It is 59 times more luminous than the Sun, [7] has 88% more mass, and is estimated to be 1.6 billion years old. [6] At this age, it has expanded to about 10 times the size of the Sun. [6] The effective temperature of its photosphere is 4,900 K, [6] giving it the characteristic orange hue of a K-type star. [9] It may have two nearby M-type companion stars, which are located at least 2,000 AU from the primary. [10]
Alpha Indi is the star's Bayer designation. [8] In China, this star is called Pe Sze where it also was known as the Persian, a title from the Jesuit missionaries. [11] The term Pe Sze is from the name of asterism 波斯 (Bō Sī, English: Persia). In Chinese astronomy, consequently, α Indi itself is known as 波斯二 (Bō Sī èr, English: the Second Star of Persia) [12]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Indus |
Right ascension | 20h 37m 34.032s [1] |
Declination | –47° 17′ 29.4052″ [1] |
Apparent magnitude (V) | 3.11 [2] |
Astrometry | |
Radial velocity (Rv) | −1.3 [3] km/s |
Proper motion (μ) |
RA: +50.922
mas/
yr
[1] Dec.: +66.026 mas/ yr [1] |
Parallax (π) | 32.8989 ± 0.2225 mas [1] |
Distance | 99.1 ± 0.7
ly (30.4 ± 0.2 pc) [1] |
Absolute magnitude (MV) | 0.65 [4] |
Characteristics | |
Evolutionary stage | between subgiant and giant star |
Spectral type | K0 III–IV [5] |
U−B color index | +0.79 [2] |
B−V color index | +1.00 [2] |
Details [6] | |
Mass | 1.879±0.13 M☉ |
Radius | 9.706±0.294 R☉ |
Luminosity | 59 [7] L☉ |
Surface gravity (log g) | 2.96±0.1 cgs |
Temperature | 4896±34 K |
Metallicity [Fe/H] | −0.05±0.03 dex |
Age | 1.572±0.273 Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Alpha Indi (α Ind, α Indi) is the brightest star in the southern constellation Indus. Parallax measurements imply that it is located about 100 light years from Earth. [1] It is visible to the naked eye at an apparent visual magnitude of 3.22. [2] Considering its distance and apparent magnitude, its absolute magnitude is equal to 0.65. [4]
The stellar classification of Alpha Indi is K0 III-IV, [5] meaning that it has exhausted the hydrogen at its core and evolved away from the main sequence, being now halfway between a subgiant and a giant star. It is 59 times more luminous than the Sun, [7] has 88% more mass, and is estimated to be 1.6 billion years old. [6] At this age, it has expanded to about 10 times the size of the Sun. [6] The effective temperature of its photosphere is 4,900 K, [6] giving it the characteristic orange hue of a K-type star. [9] It may have two nearby M-type companion stars, which are located at least 2,000 AU from the primary. [10]
Alpha Indi is the star's Bayer designation. [8] In China, this star is called Pe Sze where it also was known as the Persian, a title from the Jesuit missionaries. [11] The term Pe Sze is from the name of asterism 波斯 (Bō Sī, English: Persia). In Chinese astronomy, consequently, α Indi itself is known as 波斯二 (Bō Sī èr, English: the Second Star of Persia) [12]