R Doradus
R Doradus ( HD 29712 or P Doradus ) is a red giant star in the constellation Swordfish . Seen from Earth, it has the largest angular diameter of all stars.
It is a Mira-type variable , its apparent visual brightness fluctuates between 4.8 and 6.6 with a period of 332 days. As a red giant with a diameter of 520,000,000 km (radius: 747 solar radii), its maximum brightness is far in the infrared, its total brightness over the spectrum is the second highest of all visible stars after Betelgeuse , although in visible light it is at the limit of unobstructed visibility . It is 203 light years away . R Doradus is the most important component of a multiple star system.
R Doradus moves through the galaxy at a speed of 39.3 km / s with respect to the sun. Its projected galactic orbit is between 20,800 and 31,700 light years from the center of the galaxy. It was closest to the sun 1.0 million years ago. At that time, at a distance of 152 light years, the apparent visual magnitude was 4.95.
supporting documents
literature
- TR Bedding et al .: The angular diameter of R Doradus: a nearby Mira-like star . Monthly Notices of the Royal Astronomical Society 286 (1997) 957-962 ( arxiv.org )
