15 Sagittae

15 Sagittae

Starbox begin
name = 15 Sagittae AB
Starbox observe
epoch = J2000.0
constell = Sagitta
ra = RA|20|04|06.22
dec = DEC|+17|04|12.6
appmag_v = +5.8
Starbox character
class = G1V / L4.5V
r-i =
v-r =
b-v =
u-b =
variable = "Suspected"
Starbox astrometry
radial_v = +4.8
prop_mo_ra = -394.07
prop_mo_dec = -406.42
parallax = 56.60
p_error = 0.64, 0.63, 154
dist_ly = 57.7
dist_pc = 17.69
absmag_v = 4.56
Starbox visbin
name = 15 Sagittae B
period = 100
axis = 0.79
eccentricity = 0.3
inclination = 51
Starbox detail
source =
mass = 1 / 0.06
radius = 1.1 / 0.14
gravity =
luminosity = 1.3
temperature = 5940 / ~72
metal =
rotation =
age = 1000 - 3000 million
Starbox catalog
names = BD+16°4121, HD 190406, Gl 779, HR 7672, HIP 98819, LFT 1517, LHS 3515, LTT 15872, SAO 105635, Wolf 866
Starbox reference
Simbad = HD+190406
ARICNS =

15 Sagittae, abbreviated as 15 Sge, is a binary star system approximately 58 light-years away in the constellation of Sagitta (the Arrow). The primary star is a yellow dwarf star that acts most like the Sun, while the secondary star is a brown dwarf.

Stellar system

The primary star in the system, 15 Sagittae A, is a yellow dwarf, Solar twin star of the spectral type of G1V (in comparison, the Sun is a G2V). It is calculated that the star may have a mass near that of the Sun's, 1.1 times the radius, and 1.3 times the luminosity. 15 Sagittae A exhibits a higher chromospheric activity than the Sun, making this star appears to be one to three billion years old (younger than the Sun).

The secondary star, 15 Sagittae B, was discovered on January 7 2002. Confirmed to be a brown dwarf, 15 Sagittae B was imaged by a team of astronomers led by Michael Liu and Geoff Marcy. Based on theoretical models of the cooling of very low mass objects, 15 Sagittae B is estimated to have between 55 and 78 times the mass of Jupiter. As a result, astronomers believe that it may be too massive to have formed like a planet from the circumstellar disk of gas and dust that enveloped 15 Sge when it was less than a hundred million years old. Rather, it may have developed from a fragment of the molecular cloud that was condensing into 15 Sge itself at an earlier stage of stellar formation.

15 Sagittae B orbits 15 Sagittae A at a separation of 0.79" or about 14 astronomical units (between the orbital distance of Saturn and Uranus in the Solar system). Given a minimum mass of 48 times that of Jupiter derived from the radial velocity data alone, possible orbits have been generated with semi-major axes of seven to 28 AU and periods of around 50 to 150 years. One good fit would be an orbit with a semi-major axis of 21 AU, a period of 100 years, a low eccentricity, and an inclination of 51° from the perspective of an observer on Earth.

METI message

There was a METI message sent to 15 Sagittae. It was transmitted from Eurasia's largest radar — 70-meter Eupatoria Planetary Radar. The message was named Cosmic Call 1, it was sent on June 30 1999, and it will arrive at 15 Sagittae in February 2057. [ru icon http://www.cplire.ru/rus/ra&sr/VAK-2004.html]

See also

* Epsilon Indi
* Gliese 229

References

External links

*
*


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