Ross 248, also called HH Andromedae or Gliese 905, is a small star approximately from Earth in the northern constellation of Andromeda. Despite its proximity it is too dim to be seen with the naked eye. It was first catalogued by Frank Elmore Ross in 1926 with his second list of proper-motion stars; on which count it ranks 261st in the

SIMBAD SIMBAD (the Set of Identifications, Measurements and Bibliography for Astronomical Data) is an astronomical database of objects beyond the Solar System. It is maintained by the Centre de données astronomiques de Strasbourg (CDS), France. SIMBA ...

database. It was too dim to be included in the Hipparcos survey. In about 40,000 years,

Voyager 2 ''Voyager 2'' is a space probe launched by NASA on August 20, 1977, to study the outer planets and interstellar space beyond the Sun's heliosphere. As a part of the Voyager program, it was launched 16 days before its twin, '' Voyager 1'', o ...

will pass 1.7 light-years (9.7 trillion miles) from the star. Within the next 80,000 years, Ross 248 is predicted to be the nearest star to the Sun for a brief time, overtaking the current nearest star, the triple system Alpha Centauri.

Characteristics

This star has about 14% 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 19% of the Sun's radius, but only 0.2% of the

Sun's luminosity The solar luminosity (), is a unit of radiant flux (power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun. One nominal ...

. It has a stellar classification of M6 V, which indicates it is a type of

main-sequence star In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hert ...

known as a red dwarf. This is a chromospherically-active star. With high probability, there appears to be a long-term cycle of variability with a period of 4.2 years. This variability causes the star to range in visual magnitude from 12.23 to 12.34. In 1950, this became the first star to have a small variation in magnitude attributed to spots on its photosphere as it rotates, a class known as

BY Draconis variable BY Draconis variables are variable stars of late spectral types, usually K or M, and typically belong to the main sequence. The name comes from the archetype for this category of variable star system, BY Draconis. They exhibit variations in thei ...

s. Examining the proper motion of Ross 248 has found no evidence of a

brown dwarf Brown dwarfs (also called failed stars) are substellar objects that are not massive enough to sustain nuclear fusion of ordinary hydrogen ( 1H) into helium in their cores, unlike a main-sequence star. Instead, they have a mass between the most ...

or stellar companion orbiting between 100–1400 AU, and other unsuccessful searches have been attempted using both the

Hubble Space Telescope The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most vers ...

Wide Field Planetary Camera and by near-

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

speckle interferometry. Long-term observations by the Sproul Observatory show no astrometric perturbations by any unseen companion.

Distance from the Sun

The space velocity components of this star in the

galactic coordinate system The galactic coordinate system is a celestial coordinate system in spherical coordinates, with the Sun as its center, the primary direction aligned with the approximate center of the Milky Way Galaxy, and the fundamental plane parallel to an a ...

are = , km/s. The trajectory of Ross 248 will bring it closer to the Solar System. In 1993, Matthews projected that in about 33,000 years it would enter a period of about 9,000 years as the closest star to the Sun, as close as in 36,000 years. Any future spacecraft that escaped the Solar System with a velocity of 25.4 km/s would reach this star 37,000 years from now, when the star just passes its nearest approach. By comparison, the ''

Voyager 1 ''Voyager 1'' is a space probe launched by NASA on September 5, 1977, as part of the Voyager program to study the outer Solar System and interstellar space beyond the Sun's heliosphere. Launched 16 days after its twin ''Voyager 2'', ''Voya ...

'' has an escape velocity of 16.6 km/s. The closest stellar neighbors to Ross 248 are Groombridge 34, at 1.8 light-years away, and Kruger 60, at 4.5 light-years.

References

Sources

* tp://cdsarc.u-strasbg.fr/pub/J/AJ/132/866/table1.dat Table 1 *
Table with parallaxes

External links

*

Image HH Andromedae
{{DEFAULTSORT:Ross 248 Andromeda (constellation) Local Bubble M-type main-sequence stars Flare stars 248

0905 ''M83'' is the debut studio album by French electropop band M83, released on 18 April 2001 on Gooom. The album was reissued on 6 September 2005 on Mute Records for its North American release, and is thus sometimes referred to as ''0905''. Prod ...

Andromedae, HH BY Draconis variables

Characteristics

Distance from the Sun

See also

References

Sources

External links