Kruger 60 (DO Cephei) is a
binary star system located 13.15
light-years from the
Sun
The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
. These
red dwarf stars orbit each other every 44.6 years.
Description
The larger, primary star is designated component A, while the secondary, smaller star is labeled component B. Component A has about 27% of the
Sun's mass
The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass of ...
and 35% of the
Sun's radius. Component B has about 18% of the Sun's mass and 24% of the Sun's radius.
[ The data is from th]
Vizier II/224
catalogue. Component B is a
flare star
A flare star is a variable star that can undergo unpredictable dramatic increases in brightness for a few minutes. It is believed that the flares on flare stars are analogous to solar flares in that they are due to the magnetic energy stored in th ...
and has been given the
variable star
A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as e ...
designation "DO Cephei". It is an irregular flare that typically doubles in brightness and then returns to normal over an 8-minute period.
On average, the two stars are separated by 9.5
AUs, which is roughly the average distance of
Saturn from the
Sun
The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
. However, their eccentric mutual orbit causes their distance to vary between 5.5 AUs at
periastron
An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion.
General description
There are two apsides in any elli ...
, to 13.5 at
apastron
An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion.
General description
There are two apsides in any el ...
.
This system is orbiting through the Milky Way at a distance from the core that varies from 7–9 kpc with an orbital eccentricity of 0.126–0.130. The closest approach to the Sun will occur in about 88,600 years when this system will come within 1.95 parsecs.
Considering the orbit of the members of Kruger 60, detecting an exoplanet through radial velocity could prove difficult, as its orbit would be inclined only 13 degrees from our point of view, and create 1/5th as strong a radial velocity signal as an exoplanet orbiting edge-on from the point of view of the Solar System.
Origin of 2I/Borisov
Kruger 60 has been proposed as the origin of interstellar comet
2I/Borisov
2I/Borisov, originally designated C/2019 Q4 (Borisov), is the first observed rogue comet and the second observed interstellar interloper after ʻOumuamua. It was discovered by the Crimean amateur astronomer and telescope maker Gennadiy Borisov ...
(formerly named C/2019 Q4 (Borisov)) by Dybczyński, Królikowska, and Wysoczańska.
These authors have from other work a list of stars and stellar systems that can potentially act as perturbers of the Oort cloud comets, and searched it for a past close proximity of 2I/Borisov at a very small relative velocity. While hampered by continuing uncertainty about the orbit of 2I/Borisov and particularly its non-gravitational acceleration (due to cometary outgassing), they reach a conclusion that 1 Myr ago 2I/Borisov passed Kruger 60 at a small distance of 1.74 pc while having an extremely small relative velocity of 3.43 km/s. Perturbations of the 2I/Borisov's incoming orbit altered the intersection distance with relatively small changes in the relative velocity. At the time of publication, the results were considered preliminary as the orbit of 2I/Borisov was still being improved by new observations.
See also
*
List of nearest stars
This list covers all known stars, brown dwarfs, and sub-brown dwarfs within of the Sun. So far, 131 such objects have been found, of which only 22 are bright enough to be visible without a telescope. The visible light needs to reach or exce ...
References
Further reading
*
External links
Hires LRGB CCD Image
{{DEFAULTSORT:Kruger 60
Cepheus (constellation)
Local Bubble
M-type main-sequence stars
Flare stars
Binary stars
239960
110893
0860
BD+56 2783
Cephei, DO