Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Scorpius |
Right ascension | 15h 58m 34.86657s [2] |
Declination | −24° 49′ 53.3617″ [2] |
Apparent magnitude (V) | 5.40 - 5.47 [3] |
Characteristics | |
Spectral type | B5 V [4] |
U−B color index | -0.65 [5] |
B−V color index | -0.09 [5] |
Variable type | SXARI [3] |
Astrometry | |
Proper motion (μ) | RA: −12.451±0.100 [2] mas/yr Dec.: −24.582±0.061 [2] mas/yr |
Parallax (π) | 7.0050 ± 0.0908 mas [2] |
Distance | 466 ± 6 ly (143 ± 2 pc) |
Details | |
Mass | 5.7±0.1 [6] M☉ |
Radius | 2.80±0.04 [6] R☉ |
Luminosity | 794 [6] L☉ |
Surface gravity (log g) | 4.15±0.11 [6] cgs |
Temperature | 18000±500 [6] K |
Rotation | 0.978832±0.000002 d [7] |
Rotational velocity (v sin i) | 122±2 [8] km/s |
Age | 5.0+1.3 −1.0 [9] Myr |
Other designations | |
Database references | |
SIMBAD | data |
HD 142990, also known as HR 5942 and V913 Scorpii, is a star about 470 light years from the Earth, in the constellation Scorpius. [2] It is a 5th magnitude star, so it will be faintly visible to the naked eye of an observer far from city lights. [2] It is a variable star, whose brightness varies slightly from 5.40 to 5.47 during its 23.5 hour rotation period. [11] [3] It is a member of the Upper Scorpius Region of the Scorpius–Centaurus association. [12]
HD 142990 is a helium-weak star. [13] In 1983, Ermanno Borra et al. detected the star's strong (~kilogauss) magnetic field from the Zeeman splitting of the Hβ spectral line. [13] Later estimates put the field strength as several kilogauss. [9]
The variability of HD 142990 was discovered in 1977 by Holger Pedersen and Bjarne Thomsen, during a spectroscopic and photometric study of helium weak and helium strong stars. [14] In 1978 the star was given the variable star designation V913 Scorpii. [15] Far more extensive photometric data were provided by the Kepler K2 program, which sampled the light curve well, and allowed Dominic Bowman et al. to measure the star's 0.978832±0.000002 day rotation period. [7]
The rotation period of HD 142990 appears to be decreasing at a rate of about 0.6 seconds per year. This might mean the star is still contracting towards the zero-age main sequence, though other explanations involving magnetohydrodynamics have been proposed. [16]
In 1989, Jeffrey Linsky et al. reported the detection of 6 cm radio emission from HD 142990, which appeared to be variable on a time scale of 5 minutes. [17] In 2018, Emil Lenc et al. found that the radio emission from the star is circularly polarized. [18] In 2019, Barnali Das et al. reported that HD 142990 exhibits coherent electron cyclotron maser emission at 200 MHz, making it, at that time, only the fourth hot magnetic star known to emit by this mechanism . [6]
12 Canis Majoris is a variable star located about 707 light years away from the Sun in the southern constellation of Canis Major. It has the variable star designation HK Canis Majoris; 12 Canis Majoris is the Flamsteed designation. This body is just barely visible to the naked eye as a dim, blue-white hued star with a baseline apparent visual magnitude of +6.07. It is moving away from the Earth with a heliocentric radial velocity of +16 km/s. This is the brightest star in the vicinity of the open cluster NGC 2287, although it is probably not a member based on its proper motion.
HD 125823, also known as V761 Centauri or a Centauri, is a variable star in the constellation Centaurus. It is a blue-white star that is visible to the naked eye with a mean apparent visual magnitude of +4.41. The distance to this star is approximately 460 light years based on parallax measurements. It is a member of the Upper Centaurus–Lupus subgroup of the Scorpius–Centaurus association.
HD 113703, also known by the Bayer designation f Centauri, is a multiple star system in the southern constellation of Centaurus. The combined apparent visual magnitude of this system is +4.71, which is sufficient to make it faintly visible to the naked eye. The distance to this system is approximately 400 light years based on parallax measurements. It is a member of the Lower Centaurus Crux subgroup of the Scorpius–Centaurus association.
λ Crucis, Latinized as Lambda Crucis, is a single, variable star in the southern constellation Crux, near the constellation border with Centaurus. It is visible to the naked eye as a faint, blue-white hued point of light with an apparent visual magnitude that fluctuates around 4.62. The star is located approximately 384 light-years distant from the Sun based on parallax, and is drifting further away with a radial velocity of +12 km/s. It is a proper motion member of the Lower Centaurus–Crux sub-group in the Scorpius–Centaurus OB association, the nearest such association of co-moving massive stars to the Sun.
HD 37017 is a binary star system in the equatorial constellation of Orion. It has the variable star designation V1046 Orionis; HD 37017 is the identifier from the Henry Draper Catalogue. The system is a challenge to view with the naked eye, being close to the lower limit of visibility with a combined apparent visual magnitude of 6.55. It is located at a distance of approximately 1,230 light years based on parallax, and is drifting further away with a radial velocity of +32 km/s. The system is part of star cluster NGC 1981.
Chi Ophiuchi, Latinized from χ Ophiuchi, is a variable star in the equatorial constellation of Ophiuchus. It has a blue-white hue and is faintly visible to the naked eye with an apparent visual magnitude that fluctuates around 4.22. The distance to this object, as determined from parallax measurements, is approximately 500 light years, but it is moving closer to the Sun with a radial velocity of −19 km/s. This star is a proper motion member of the Upper Scorpius sub-group in the Scorpius–Centaurus OB association; the nearest such co-moving association of massive stars to the Sun.
Omega Ophiuchi, which is Latinized from ω Ophiuchi, is a single, variable star in the equatorial constellation of Ophiuchus, located just to the north of the ecliptic near the western constellation border with Scorpius. It is a white-hued star that is faintly visible to the naked eye with an apparent visual magnitude that fluctuates around 4.45. Parallax measurements indicate it lies at a distance of about 168.6 light years from the Sun. It is drifting further away with a radial velocity of +2.5 km/s.
HD 105382 is a star in the constellation Centaurus. Its apparent magnitude is 4.47. From parallax measurements, it is located 130 parsecs from the sun.
KT Lupi is a visual binary star system in the constellation Lupus. It is visible to the naked eye with a combined apparent visual magnitude of 4.55. As of 1983, the pair had an angular separation of 2.19″±0.03″. Based upon an annual parallax shift of 7.6 mas as seen from Earth's orbit, it is located 430 light-years from the Sun. The system is moving further from the Earth with a heliocentric radial velocity of +6.5 km/s. It is a member of the Lower Centaurus–Crux sub-group of the Scorpius–Centaurus association.
HD 143699 is a single star in the southern constellation of Lupus. It is a dim star but visible to the naked eye with an apparent visual magnitude of 4.90. Based upon an annual parallax shift of 9.2 mas, it is located around 350 light years away. It is most likely a member of the Upper Centaurus–Lupus subgroup of the Sco OB2 moving group.
HD 64740 is a single star in the southern constellation Puppis, positioned near the line of sight to the Gum Nebula. It has a blue-white hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.63. Parallax measurements give a distance estimate of approximately 760 light-years from the Sun, and it is drifting further away with a radial velocity of +8 km/s.
N Scorpii, also known as HD 148703, is a solitary, bluish-white hued star located in the southern constellation Scorpius. It has an apparent magnitude of 4.23, making it readily visible to the naked eye. N Scorpii was initially given the Bayer designation Alpha Normae by Lacaille but it was later moved from Norma to Scorpius. N Scorpii is currently located 550 light years away based on parallax measurements from the Hipparcos satellite and is part of the Upper Scorpius–Centaurus region of the Scorpius–Centaurus association.
CU Virginis is a single star in the equatorial constellation of Virgo. It has an apparent visual magnitude of 4.99, which is bright enough to be faintly visible to the naked eye. The distance to this star can be estimated from its annual parallax shift of 13.9 mas, yielding a separation of 234 light years.
HR 6819, also known as HD 167128 or QV Telescopii, is a double star system in the southern constellation of Telescopium. It is in the south-western corner of the constellation, near Pavo to the south and Ara to the west. The system appears as a variable star that is dimly visible to the naked eye with an apparent magnitude that ranges from 5.32 down to 5.39, which is comparable to the maximum brightness of the planet Uranus. It is about 1,120 light years from the Sun, and is drifting farther away at a rate of 9.4 km/s. Due to its location in the sky, it is visible only to observers south of 33°N latitude.
36 Lyncis is a solitary variable star located around 620 light years away from the Sun in the northern constellation of Lynx. It has the variable star designation of EI Lyncis, while 36 Lyncis is the Flamsteed designation. This object is visible to the naked eye as a dim, blue-white hued star with an apparent visual magnitude of 5.30. It is moving further away from the Earth with a heliocentric radial velocity of 21 km/s.
HD 142250 is a star in the constellation Scorpius. It has a visual apparent magnitude of 6.1, being visible to the naked eye only in excellent seeing conditions. From parallax measurements, it is located 486 light-years (149 parsecs) away from Earth. This distance, together with the star's proper motion, indicate that HIP 77900 is a member of the Upper Scorpius subgroup of the Scorpius–Centaurus association, the nearest OB association to the Sun. This subgroup is the youngest of the three of the association, with an estimated age of 11 million years.
HR 5907, also known as V1040 Scorpii and HD 142184, is a star about 470 light years from the Earth, in the constellation Scorpius. It is a 5th magnitude star, so it will be faintly visible to the naked eye of an observer far from city lights. Its brightness varies slightly, ranging from magnitude 5.39 to 5.43 every 12 hours and 20 minutes. HR 5907 is a member of the Scorpius–Centaurus association.
HD 28843, also known as HR 1441 and DZ Eridani, is a star about 550 light years from the Earth, in the constellation Eridanus. It is a 5th magnitude star, so it will be faintly visible to the naked eye of an observer far from city lights. It is a variable star, whose brightness varies slightly from 5.70 to 5.84 during its 1.374 day rotation period. It is a member of the μ Tauri Association, a group of young stars within the larger Cassiopeia-Taurus Structure.
HD 21699, also known as HR 1063 and V396 Persei, is a star about 580 light years from the Earth, in the constellation Perseus. It is a 5th magnitude star, so it will be faintly visible to the naked eye of an observer far from city lights. It is a variable star, whose brightness varies slightly from 5.45 to 5.53 during its 2.4761 day rotation period. It has a remarkable dipole magnetic field which is displaced from the star's center by 0.4 stellar radii, the poles of which appear close to each other on the stellar surface. HD 21699 is a member of the Alpha Persei Cluster.
V686 Coronae Australis is a solitary, bluish-white-hued variable star located in the southern constellation Corona Australis. It has an apparent magnitude that ranges between 5.25 and 5.41, which makes it faintly visible to the naked eye. Gaia DR3 parallax measurements imply a distance of 480 light years and it is slowly receding with a heliocentric radial velocity of 1.3 km/s. At its current distance V686 CrA's average brightness is diminished by 0.35 magnitudes due to extinction from interstellar dust and it has an absolute visual magnitude of −0.24.