Location of Ross 248 in the constellation Andromeda | |
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Andromeda |
Right ascension | 23h 41m 55.03630s [1] |
Declination | +44° 10′ 38.8189″ [1] |
Apparent magnitude (V) | 12.23 - 12.34 [2] |
Characteristics | |
Spectral type | M6 V [3] |
U−B color index | +1.48[ citation needed ] |
B−V color index | +1.92[ citation needed ] |
Variable type | BY Dra [2] |
Astrometry | |
Radial velocity (Rv) | −77.29±0.19 [1] km/s |
Proper motion (μ) | RA: 112.527±0.036 mas/yr [1] Dec.: −1591.650±0.027 mas/yr [1] |
Parallax (π) | 316.4812 ± 0.0444 mas [1] |
Distance | 10.306 ± 0.001 ly (3.1597 ± 0.0004 pc) |
Absolute magnitude (MV) | 14.79 [4] |
Details | |
Mass | 0.145 [5] M☉ |
Radius | 0.190 [5] R☉ |
Luminosity | 0.0022 [6] L☉ |
Surface gravity (log g) | 5.13 [6] cgs |
Temperature | 2,930 [5] K |
Metallicity [Fe/H] | +0.23 [5] dex |
Rotation | 114.3±2.8 d [7] |
Rotational velocity (v sin i) | 0.1 [8] km/s |
Age | 2.6 [5] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Ross 248, also called HH Andromedae or Gliese 905, is a small star approximately 10.30 light-years (3.16 parsecs ) [10] from Earth in the northern constellation of Andromeda. Despite its proximity it is too dim to be seen with the naked eye. [11] It was first catalogued by Frank Elmore Ross in 1926 with his second list of proper-motion stars; [12] on which count it ranks 261st in the SIMBAD database. It was too dim to be included in the Hipparcos 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 around 9,000 years, overtaking the current nearest star, the triple system Alpha Centauri.
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 of M6 V, [3] which indicates it is a type of main-sequence star known as a red dwarf. This is a chromospherically-active star. [14] 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. [13] In 1950, this became the first star to have a small variation in magnitude attributed to spots on its photosphere as it rotates, [15] a class known as BY Draconis variables. [2]
Examining the proper motion of Ross 248 has found no evidence of a brown dwarf or stellar companion orbiting between 100–1400 AU, [16] and other unsuccessful searches have been attempted using both the Hubble Space Telescope Wide Field Planetary Camera [4] and by near-infrared speckle interferometry. [17] Long-term observations by the Sproul Observatory show no astrometric perturbations by any unseen companion. [15]
The space velocity components of this star in the galactic coordinate system are [U, V, W] = [−32.9±0.7, −74.3±1.3, 0.0±1.4] km/s. [10] 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 3.024 light-years (0.927 parsecs) in 36,000 years. [18] A more concise estimate in 2022 has it approaching to within 3.048 ly (0.9345 pc) in 36,500 years. [19]
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. [20]
Voyager 2 is not headed toward any particular star, although in roughly 42,000 years, it will pass the star Ross 248 at a distance of 1.7 light-years. [21]
The closest stellar neighbors to Ross 248 are the binary systems Groombridge 34, at 1.8 light-years away, and Kruger 60, at 4.5 light-years. [22]
HR 7703 is a binary star system in the constellation of Sagittarius. The brighter component has an apparent visual magnitude of 5.31, which means it is visible from suburban skies at night. The two stars are separated by an angle of 7.10″, which corresponds to an estimated semimajor axis of 56.30 AU for their orbit.
Struve 2398 is a binary star system in the northern constellation of Draco. Struve 2398 is star number 2398 in the Struve Double Star Catalog of Russian-German astronomer Friedrich Georg Wilhelm von Struve. The astronomer's surname, and hence the star identifier, is sometimes indicated by a Greek sigma, Σ; hence, this system can be listed with the identifier Σ 2398. Although the components are too faint to be viewed with the naked eye, this star system is among the closest to the Sun. Parallax measurements by the Gaia spacecraft give them an estimated distance of 11.5 light-years away.
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. Based upon parallax measurements taken by the Gaia spacecraft, the system is located about 11.6 light-years from the Sun. This positions the pair among the nearest stars to the Solar System.
TZ Arietis is a red dwarf in the northern constellation of Aries. With a normal apparent visual magnitude of 12.3, it is too faint to be seen by the naked eye, although it lies relatively close to the Sun at a distance of 14.6 light-years. It is a flare star, which means it can suddenly increase in brightness for short periods of time.
Beta Comae Berenices is a main sequence dwarf star in the northern constellation of Coma Berenices. It is located at a distance of about 29.95 light-years from Earth. The Greek letter beta (β) usually indicates that the star has the second highest visual magnitude in the constellation. However, with an apparent visual magnitude of 4.3, this star is actually slightly brighter than α Comae Berenices. It can be seen with the naked eye, but may be too dim to be viewed from a built-up urban area.
Sigma Boötis, its name Latinized from σ Boötis, is a single star in the northern constellation of Boötes. It has a yellow-white hue and is visible to the naked eye with an apparent visual magnitude of 4.46. Located to the southeast of Rho Boötis, the dwarf Sigma may at first appear as a naked-eye double, but the angular proximity with Rho is merely line-of-sight. Sigma Boötis is located at a distance of 51.1 light years from the Sun based on parallax. The star has a relatively high proper motion and is traversing the sky at the rate of 0.230″ yr−1.
HD 142 is a wide binary star system in the southern constellation of Phoenix. The main component has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.7. The system is located at a distance of 85.5 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of +6 km/s.
HD 50281 is a star in the equatorial constellation of Monoceros. It is orange in hue with an apparent visual magnitude of 6.58, which lies at or below the typical limit of visibility to the naked eye. The star is located at a distance of 28.5 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −7.2 km/s.
GJ 1245 is a double star with components G 208-44 and G 208-45, located 15.2 light-years away in the constellation Cygnus. G 208-44 is itself a closer double star made up of two red dwarfs, while G 208-45 is also a red dwarf. GJ 1245 is the 43rd closest stellar system to the Solar System. GJ 1245 A and B are active flare stars, and the pair are collectively designated V1581 Cygni.
Theta Persei is a star system 37 light years away from Earth, in the constellation Perseus. It is one of the closest naked-eye stars.
HR 4458 is a binary star system in the equatorial constellation of Hydra. It has the Gould designation 289 G. Hydrae; HR 4458 is the Bright Star Catalogue designation. At a distance of 31.13 light years, it is the closest star system to the Solar System within this constellation. This object is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.97. It is moving closer to the Earth with a heliocentric radial velocity of −22 km/s.
36 Ursae Majoris is a double star in the northern constellation of Ursa Major. With an apparent visual magnitude of 4.8, it can be seen with the naked eye in suitable dark skies. Based upon parallax measurements, this binary lies at a distance of 42 light-years from Earth.
Gliese 445 is an M-type main sequence star in the northern part of the constellation Camelopardalis.
YZ Canis Minoris is a red-hued star in the equatorial constellation of Canis Minor. With an apparent visual magnitude of 11.15, it is much too faint to be viewed with the naked eye. The distance to YZ CMi can be estimated from its annual parallax shift of 167 mas, yielding a value of 19.5 light years. Presently the star is moving further away with a heliocentric radial velocity of +26.5 km/s. It made its closest approach some 162,000 years ago when it made perihelion passage at a distance of 10.2 ly. YZ CMi is a potential member of the Beta Pictoris moving group.
GJ 1062 is a single red dwarf star in the constellation Eridanus, positioned about two degrees to the SSE of Epsilon Eridani. It is also known as LHS 20 and Ross 578. The star is invisible to the naked eye with an apparent visual magnitude of +13.0, requiring a telescope with at least a 25 cm (10 in) aperture to view. It is located at a distance of 52.7 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −85 km/s. The star has a high proper motion, traversing the sky at the rate of 3.033 arcseconds per year.
Gliese 829 is a double-lined spectroscopic binary system of two red dwarf stars in the constellation of Pegasus. They have a high proper motion of 1.08 arc seconds per year along a position angle of +69.58°. Based upon parallax measurements, the stars are at a distance of about 22 light years from the Sun. The system will make its closest approach to the Sun around 91,000 years from now when it achieves a perihelion distance of 17.65 ly (5.410 pc).
15 Leonis Minoris is the Flamsteed designation for a single star in the northern circumpolar constellation of Ursa Major. It has an apparent visual magnitude of 5.08, making it a fifth magnitude star that is visible to the naked eye. Based on parallax measurements, it is located at a distance of 61.7 light years from the Sun. The star has been examined for an infrared excess, but none was detected.
HD 72945 and HD 72946 form a co-moving star system in the northern constellation of Cancer. HD 72945 is a binary star that is dimly visible to the naked eye as a point of light with an apparent visual magnitude of 5.91. At an angular separation of 10.10″ is the fainter companion star HD 72946 at magnitude 7.25. It is being orbited by a brown dwarf. The system as a whole is located at a distance of approximately 84 light years from the Sun based on parallax measurements.
HD 194012 is a star in the equatorial constellation Delphinus. It has an apparent magnitude of 6.15, making it visible to the naked eye under ideal conditions. The star is relatively close at a distance of only 85 light years but is receding with a heliocentric radial velocity of 4.5 km/s.