Ross 248, also called HH Andromedae or Gliese 905, is a small

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

approximately from Earth in the northern

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

of Andromeda. Despite its

proximity Proximity may refer to: * Distance, a numerical description of how far apart objects are * Proxemics, the study of human spatial requirements and the effects of population density * Proximity (2000 film), ''Proximity'' (2000 film), an action/thril ...

it is too dim to be seen with the naked eye. It was first catalogued by

Frank Elmore Ross Frank Elmore Ross (April 2, 1874 – September 21, 1960) was an American astronomer and physicist. He was born in San Francisco, California and died in Altadena, California. In 1901 he received his doctorate from the University of California ...

in 1926 with his second list of

proper-motion Proper motion is the astrometric measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more dista ...

stars; on which count it ranks 261st in the SIMBAD database. It was too dim to be included in the

Hipparcos ''Hipparcos'' was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial obj ...

survey. In about 40,000 years, Voyager 2 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 Alpha Centauri ( Latinized from α Centauri and often abbreviated Alpha Cen or α Cen) is a triple star system in the constellation of Centaurus. It consists of 3 stars: Alpha Centauri A (officially Rigil Kentaurus), Alpha Centaur ...

Characteristics

This star has about 14% of the Sun's mass and 19% of the Sun's radius, but only 0.2% of the Sun's luminosity. It has a

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grati ...

of M6 V, which indicates it is a type of main-sequence star known as a

red dwarf ''Red Dwarf'' is a British science fiction comedy franchise created by Rob Grant and Doug Naylor, which primarily consists of a television sitcom that aired on BBC Two between 1988 and 1999, and on Dave since 2009, gaining a cult following. T ...

. 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 The photosphere is a star's outer shell from which light is radiated. The term itself is derived from Ancient Greek roots, φῶς, φωτός/''phos, photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it ...

as it rotates, a class known as BY Draconis variables. Examining the

proper motion Proper motion is the astrometric measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more dista ...

of Ross 248 has found no evidence of a brown dwarf or stellar companion orbiting between 100–1400 AU, and other unsuccessful searches have been attempted using both the Hubble Space Telescope Wide Field Planetary Camera and by near- infrared speckle

interferometry Interferometry is a technique which uses the ''interference'' of superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important investigative technique in the fields of astronomy, fiber opt ...

. 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 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'' has an escape velocity of 16.6 km/s. The closest stellar neighbors to Ross 248 are

Groombridge 34 Groombridge 34 is a binary star system in the northern constellation of Andromeda. It was listed as entry number 34 in ''A Catalogue of Circumpolar Stars'', published posthumously in 1838 by British astronomer Stephen Groombridge. Bas ...

, at 1.8 light-years away, and

Kruger 60 Kruger 60 (DO Cephei) is a binary star system located 13.15 light-years from the Sun. These red dwarf stars orbit each other every 44.6 years. Description The larger, primary star is designated component A, while the secondary, sma ...

, 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 __NOTOC__ Year 248 ( CCXLVIII) was a leap year starting on Saturday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Philippus and Severus (or, less frequently, year 1001 '' ...

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