Kapteyn's Star
Sign in to saveAlso known as HD 33793, GJ 191
subdwarf star in the constellation Pictor
In the Vinony graph
Within Vinony's link graph, Kapteyn's Star is referenced by 162 other articles, and connects out to star catalogue, list of stars in Pictor and Durchmusterung.
It is catalogued under topics including BY Draconis variables, Discoveries by Robert T. A. Innes and Durchmusterung objects.
Its subject is documented across 36 Wikipedia language editions.
Key facts
- Constellation
- Pictor
- Right ascension
- 05 11 40.58984
- Declination
- −45 ° 01 ′ 06.3617 ″
- Apparent magnitude v
- 8.80 – 8.85
- Evolutionary stage
- main sequence
- Spectral type
- sdM1 or M1.5V
- U b color index
- +1.21
- B v color index
- 1.57 ± 0.012
- Variable type
- BY Dra
via Wikipedia infobox
Wikidata facts
- Named after
- Jacobus Kapteyn
- Constellation
- Pictor
- Child body
- Kapteyn b
- Distance from Earth
- 3.9339
- Diameter
- 475000
- Radius
- 0.29
- Mass
- 0.281
- Variable-star type
- BY Draconis variable
- Image
- Kapteyns-stern.jpg
Show 19 more facts
- discoverer or inventor
- Jacobus Kapteyn
- spectral class
- sdM1
- catalog code
- UBV M 10717
- time of discovery or invention
- 1897-01-01
- apparent magnitude
- 8.063552
- stellar rotational velocity
- 3.01
- Commons category
- Kapteyn's star
- absolute magnitude
- 10.43
- parallax
- 254.1986
- effective temperature
- 3550
- radial velocity
- 245.234
- epoch
- J2000.0
- surface gravity
- 65000
- metallicity
- -0.59
- right ascension component of proper motion
- 6593
- declination component of proper motion
- -5705
- right ascension
- 77.91912433145708
- declination
- -45.01843381524333
- age estimated by a dating method
- 8
via Wikidata · CC0
~7 min read
Encyclopedic overview
Kapteyn's Star is a class M1 red subdwarf about 12.83 light-years (3.93 parsecs) from Earth in the southern constellation Pictor; it is the closest halo star to the Solar System and one of the nearest stars. With a slightly variable apparent magnitude of about 8.8, it is visible through binoculars or a telescope.
Its diameter is 30% of the Sun's, but its luminosity just 1.2% that of the Sun. It may have once been part of the globular cluster Omega Centauri, itself the likely core of a dwarf galaxy swallowed up by the Milky Way in the distant past. The discovery of two planets—Kapteyn b and Kapteyn c—was announced in 2014, but had a mixed history of rejections and confirmations, until a 2021 study refuted both planets. The "planets" are in fact likely artifacts of the star's rotation and activity.
Excerpted from Wikipedia’s “Kapteyn's Star” article, available under the CC BY-SA 4.0 licence.