47 Ursae Majoris

Encyclopedia : 4 : 47 : 47U : 47 Ursae Majoris

|- ! style="background-color: #FFFFC0;" colspan="2" | Details |- |style="vertical-align: baseline;" | Mass | M_☉ |- |style="vertical-align: baseline;" | Radius | R_☉ |- |style="vertical-align: baseline;" | Luminosity | L_☉ |- |style="vertical-align: baseline;" | Temperature | K |- |style="vertical-align: baseline;" | Metallicity | |- |style="vertical-align: baseline;" | Rotation | |- |style="vertical-align: baseline;" | Age | })<()or(}})=()and(}})<())}}} years

Gl 407, HR 4277, BD +41°2147, HD 95128, LTT 12934, GCTP 2556.00, SAO 43557, FK5 1282, GC 15087, HIP 53721.

47 Ursae Majoris (47 UMa) is a yellow dwarf star approximately 46 light-years away in the constellation Ursa Major. Its spectral type, G1V, is similar to our Sun. It is visible to the unaided eye under good conditions.

As of 2002, 47 Ursae Majoris is known to have two extrasolar planets orbiting it.

Contents

1 Planets

1.1 47 Ursae Majoris b
1.2 47 Ursae Majoris c

2 See also
3 References
4 External links

Planets

47 Ursae Majoris b

|- ! style="background-color: #A0B0FF;" colspan="3" | Discovery information |- | colspan="2" | Discovery date | |- | colspan="2" | Discoverer(s) | |- | colspan="2" | Detection method | |- | colspan="2" | Discovery status | |}

47 Ursae Majoris b is an extrasolar planet orbiting it's sun every two years.

After the discovery of the first extrasolar planet around a Sun-like star, 51 Pegasi b, astronomers Geoffrey Marcy and Paul Butler searched through their observational data for extrasolar planets and soon discovered two, 47 Ursae Majoris b and 70 Virginis b. Had they known that many planets orbit close to their parent stars, they would have been the first extrasolar planet discoverers.

But 47 Ursae Majoris b is different. Like others, it is a massive jovian planet, being about 2.5 times as massive as Jupiter. However, its distance from the star is larger than most, a little more than that of Mars from the Sun. And, unlike the eccentric Jupiters, the orbit of the planet is almost circular as is the case with the giant planets in our Solar system.

Unfortunately, the moons of the planet, if it has any, are likely too cold to support any life unless they have subsurface oceans like Jupiter's moon Europa. On the other hand, the planet is still close enough to its parent star that its gravitational influence may have prevented formation of any Earth-like planets in the system.

47 Ursae Majoris c

|- | colspan="2" | Discoverer(s) | |- | colspan="2" | Detection method | |- | colspan="2" | Discovery status | |}

47 Ursae Majoris c is the second extrasolar planet orbiting it's star every 7 years. It orbits further out than planet b, about the distance of the outer asteroid belt in our Solar system. It is slightly less massive than Jupiter, and it too has a fairly circular orbit.

The planetary system of 47 Ursae Majoris shares other similarities with our Solar system, too: the ratio between the masses of b and c is 3.34 (3.32 between Jupiter and Saturn), and the ratio between orbital distances of the planets is 0.560 (0.545). Whether this is just coincidence or has any deeper meaning has not yet been figured out.

References

[Very Large Space Projects]

External links