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 precise 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]
Ross 154 is a star in the southern zodiac constellation of Sagittarius. It has an apparent visual magnitude of 10.44, making it much too faint to be seen with the naked eye. At a minimum, viewing Ross 154 requires a telescope with an aperture of 6.5 cm (3 in) under ideal conditions. The distance to this star can be estimated from parallax measurements, which places it at 9.71 light-years away from Earth. It is the nearest star in the southern constellation Sagittarius, and one of the nearest stars to the Sun.
HD 63454, formally named Ceibo, is a star located in the southern circumpolar constellation Chamaeleon near the border with Mensa. To see the star, one needs a small telescope because it has an apparent magnitude of 9.36, which is below the limit for naked eye visibility. The object is located relatively close at a distance of 123 light years based on Gaia DR3 parallax measurements but is receding with a heliocentric radial velocity of 33.8 km/s. At its current distance, HD 63454's brightness is diminished by two tenths of a magnitude due to interstellar dust. It has an absolute magnitude of +6.68.
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.
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.
DX Cancri is a variable star in the northern zodiac constellation of Cancer. With an apparent visual magnitude of 14.81, it is much too faint to be seen with the naked eye. Visually viewing this star requires a telescope with a minimum aperture of 16 in (41 cm). Based upon parallax measurements, DX Cancri is located at a distance of 11.8 light-years from Earth. This makes it the 18th closest star to the Sun. It is a proposed member of the Castor Moving Group of stars that share a common trajectory through space. This group has an estimated age of 200 million years.
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.
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.
HD 222582 is a multiple star system in the equatorial constellation of Aquarius. It is invisible to the naked eye with an apparent visual magnitude of 7.7, but can be viewed with binoculars or a small telescope. The system is located at a distance of 137 light years from the Sun based on parallax, and it is drifting further away with a radial velocity of +12 km/s. It is located close enough to the ecliptic that it is subject to lunar occultations.
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.
HD 15115 is a single star in the equatorial constellation of Cetus. It is readily visible in binoculars or a small telescope, but is considered too dim to be seen with the naked eye at an apparent visual magnitude of 6.76. The distance to this object is 160 light years based on parallax, and it is slowly drifting further away at the rate of about 1 km/s. It has been proposed as a member of the Beta Pictoris moving group or the Tucana-Horologium association of co-moving stars; there is some ambiguity as to its true membership.
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.
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 2454 is a probable binary star system in the zodiac constellation of Pisces. With an apparent visual magnitude of 6.04, it is near the lower limit of visibility to the naked eye under good seeing conditions. An annual parallax shift of 26.3 mas as measured from Earth's orbit provides a distance estimate of 124 light years. It has a relatively high proper motion, traversing the celestial sphere at a rate of 0.208 arcseconds per year, and is moving closer to the Sun with a heliocentric radial velocity of −10 km/s.
HR 8526, also known as HD 212168, is the primary of a triple star located in the southern circumpolar constellation Octans. The star and its companion have apparent magnitudes of 6.12 and 9.36 respectively. The system is located relatively close at a distance of 76 light years based on Gaia DR3 parallax measurements, but is receding with a heliocentric radial velocity of 15 km/s.