Observation data Epoch J2000.0 [1] Equinox J2000.0 [1] | |
---|---|
Constellation | Ophiuchus |
Right ascension | 17h 43m 47.02216s |
Declination | −07° 04′ 46.5943″ |
Apparent magnitude (V) | 6.32 [2] |
Characteristics | |
Spectral type | B1.5V, B3II/III, or B3Vn [3] |
U−B color index | −0.42 [2] |
B−V color index | 0.36 [2] |
J−H color index | 0.072 [4] |
J−K color index | 0.101 [4] |
Astrometry | |
Radial velocity (Rv) | −26.0±4.3 [5] km/s |
Proper motion (μ) | RA: -4.629 [1] mas/yr Dec.: −10.512 [1] mas/yr |
Parallax (π) | 2.4404 ± 0.0432 mas [1] |
Distance | 1,340 ± 20 ly (410 ± 7 pc) |
Other designations | |
Database references | |
SIMBAD | data |
HD 161056 (HIP 86768, HR 6601) is a bluish-white hued star in the equatorial constellation of Ophiuchus. It has an apparent magnitude of 6.32, placing it near the limit for naked eye visibility under dark skies. The object is located approximately 1,340 light-years (410 parsecs) distant according to Gaia EDR3 parallax measurements, [1] but it is moving closer at a heliocentric radial velocity of −26.0 km/s.
It is a luminous early B-type star, but its spectral type varies from publication to publication, most often between B1.5V, [6] implying a hot main-sequence star, and B3II/III, [7] indicative of a slightly cooler blue giant.
In Chinese astronomy, the star was given the name Shìlóuliù (Chinese :市樓六), meaning it was the sixth star of the asterism Shìlóu (市樓, "Municipal Office") in the Heavenly Market enclosure. [8]
In 1985, the star was suggested as a standard for polarimetric observations via the Hubble Space Telescope, since the star's large distance from Earth produces a large interstellar polarization and its high luminosity makes it easily visible at such distances. In 1988, however, it was found that the star was slightly variable in polarization, [lower-alpha 1] and thus unsuitable as a standard star. [9]
Nevertheless, Hubble observed the star's ultraviolet interstellar polarization, thanks to it having been well-researched in the visible spectrum, presenting results consistent with Serkowski's law [10] —an empirical formula regarding the dependency of interstellar polarization on wavelength. [11] The extensive collected polarization spectrum showed a close match to what would be expected from an interstellar dust composition of pure amorphous forsterite. [12]
In addition to polarimetry, spectroscopic observations have also been conducted on HD 161056 to provide insight into the interstellar medium. The ESO Diffuse Interstellar Bands Large Exploration Survey (EDIBLES) detected signatures of diatomic carbon and tricarbon molecules in interstellar clouds surrounding the star. [13]
Near-infrared spectroscopy has revealed signs of weak stellar emission lines of doubly ionized magnesium and singly ionized helium. [14]
HD 161056 is a runaway star and a candidate for producing a bow shock observable in the infrared. [15] Such stars commonly originate in multiple star systems, from which they were ejected due to gravitational interactions or supernovae of their companions, [16] and indeed it is possible that the star could have been in a binary system with the pulsar PSR B1929+10 about 1.1 million years ago, when it was located in the vicinity of IC 4665. However, Zeta Ophiuchi is considered more likely to have been its binary companion, in which scenario the pair possibly split up around 900,000 years ago. [17]
Iota Canis Majoris, Latinized from ι Canis Majoris, is a solitary variable supergiant star in the southern constellation of Canis Major. It is visible to the naked eye with an apparent visual magnitude that varies between +4.36 and +4.40. The distance to this star is approximately 2,500 light years based on spectroscopic measurements. It is drifting further away with a radial velocity of +42 km/s.
HD 27245, also known as HR 1335 or rarely 25 H. Camelopardalis is a solitary red-hued star located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.4, making it faintly visible to the naked eye. Gaia DR3 Parallax measurements place it approximately 607 light years away from it the Solar System and is drifting further away with a heliocentric radial velocity of 25.2 km/s. At its current distance, HD 27245's brightness is diminished by 0.36 magnitudes due to extinction from interstellar dust. It has an absolute magnitude of −0.27.
HD 27274, also known as Gliese 167, is a solitary, orange hued star located in the southern constellation Dorado. It has an apparent magnitude of 7.63, making it readily visible in binoculars, but not to the naked eye. Based on parallax measurements from the Gaia spacecraft, the star is known to be located 42.5 light-years away from the Solar System However, it is drifting closer with a heliocentric radial velocity of −23 km/s. At its current distance, HD 27274 is dimmed down by 0.05 magnitudes due to interstellar dust.
HD 24479, also designated as HR 1204, is a solitary, bluish-white hued star located in the northern circumpolar constellation Camelopardalis. The star is visible to the naked eye with an apparent visual magnitude of 5.04. Based on Gaia DR3 parallax measurements, it is located 385 light years from the Sun. However, it is receding with a somewhat constrained heliocentric radial velocity of 4.6 km/s. At its current distance, HD 24479's brightness is diminished by 0.29 magnitudes due to interstellar dust.
HD 63399 is an orange hued star located in the southern constellation Puppis, the poop deck. It has an apparent magnitude of 6.45, placing it near the limit for naked eye visibility. Based on parallax measurements from Gaia DR3, the object is estimated to be 445 light years distant. It appears to be receding with a spectroscopic radial velocity of 28.5 km/s. At its current distance, HD 63399 is diminished by 0.29 magnitudes due to interstellar dust.
HD 61005, also known as HIP 36948 and The Moth, is a young star located in the southern constellation Puppis, the poop deck. It has an apparent magnitude of 8.22, making it readily visible in binoculars, but not to the naked eye. The object is located relatively close at a distance of 119 light years based on Gaia DR3 parallax measurements but is receding with a heliocentric radial velocity of 22.6 km/s.
HD 82514, also known as HR 3790, is a solitary, orange-hued star located in the southern constellation Antlia. It has an apparent magnitude of 5.86, allowing it to be faintly seen with the naked eye. Based on parallax measurements from the Gaia spacecraft, it is estimated to be 279 light years away from the Solar System. However, it is receding with a heliocentric radial velocity of 14.3 km/s.
HD 124099 is a solitary orange-hued star located in the southern circumpolar constellation Apus. It has an average apparent magnitude of 6.47, placing it very close to the limit for naked eye visibility, even under ideal conditions. The object is located relatively far at a distance of approximately 2,030 light-years based on Gaia DR3 parallax measurements, but it is drifting closer with a heliocentric radial velocity of −10.2 km/s. At its current distance, HD 124099's average brightness is diminished by 0.47 magnitudes due to interstellar extinction and it has an absolute magnitude of −2.10.
HD 39901 is an orange hued star located in the constellation Columba. It is also called HR 2069, which is the star's Bright Star Catalog designation. Eggen (1989) lists it as a member of the old disk population.
HD 193307 is the primary of a binary star located the southern constellation Telescopium. It has an apparent magnitude of 6.27, placing it near the limit for naked eye visibility, even under ideal conditions. The star is located relatively close at a distance of 102 light years based on Gaia DR3 parallax measurements, but it is receding with a heliocentric radial velocity of 16.9 km/s. At its current distance, HD 193307's brightness is diminished by 0.18 magnitudes due to extinction from interstellar dust and it has an absolute magnitude of +3.80. HD 193307 has a relatively high proper motion, moving at a rate of 437 mas/yr.
HR 4098, also known as HD 90508, is a binary star system in the northern constellation of Ursa Major at a distance of 75 light years. This object is barely visible to the naked eye as a dim, yellow star with an apparent visual magnitude of 6.45. It is approaching the Earth with a heliocentric radial velocity of 7.2±0.2 km/s.
HD 191829 is a solitary star located in the southern constellation Telescopium. It has an apparent magnitude of 5.632, making it faintly visible to the naked eye if viewed under ideal conditions. The star is situated at a distance of 710 light years but is receding with a heliocentric radial velocity of 14 km/s.
HD 76236, also designated as HR 3543 or rarely 11 G. Chamaeleontis, is a solitary star located in the southern circumpolar constellation Chamaeleon. It is faintly visible to the naked eye as an orange-hued star with an apparent magnitude of 5.77. Based on parallax measurements from the Gaia satellite, the object is estimated to be 612 light years away. Currently, it is receding with a heliocentric radial velocity of 7 km/s. At its current distance, HD 76236's brightness is diminished by 0.39 magnitudes due to interstellar dust. It has an absolute magnitude of −0.13.
HD 114533, also known as HR 4976, is a solitary star located in the southern circumpolar constellation Chamaeleon. It has an apparent magnitude of 5.84, making it faintly visible to the naked eye. The system is located relatively far at a distance of roughly 2,100 light years based on Gaia DR3 parallax measurements but is drifting closer with a heliocentric radial velocity of −18 km/s. At its current distance, HD 114533A's brightness is diminished by 0.74 magnitudes due to interstellar dust. It has an absolute magnitude of −2.0.
HD 106248, also known as HR 4649, is a solitary, orange hued star located in the southern circumpolar constellation Chamaeleon. It has an apparent magnitude of 6.34, placing it near the limit for naked eye visibility. Based on parallax measurements from Gaia DR3, the object is estimated to be 358 light years away from the Solar System. It appears to be receding with a heliocentric radial velocity of 34.5 km/s. At its current distance, HD 106248's brightness is diminished by 0.32 due to interstellar dust and Eggen (1993) lists it as a member of the old (thick) disk population.
HD 22764, also known as HR 1112, is an orange hued star located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.78, allowing it to be faintly visible to the naked eye. The object is located relatively far at a distance of approximately 1,770 light years based on Gaia DR3 parallax measurements but is approaching the Solar System with a heliocentric radial velocity of −12.5 km/s. At its current distance, HD 22764's brightness is diminished by 0.66 magnitudes due to interstellar dust.
7 Leonis Minoris is a star located in the northern constellation Leo Minor. It is also designated as HD 82087 and HR 3764. 7 LMi is faintly visible to the naked eye as a yellow-hued point of light with an apparent magnitude of 5.86. Gaia DR3 parallax measurements imply a distance of 462 light-years and it is currently receding with a heliocentric radial velocity of 1.7 km/s. At its current distance, 7 LMi's brightness is diminished by 0.12 magnitudes due to interstellar extinction and it has an absolute magnitude of −0.03.
HD 201585 is a star located in the equatorial constellation Equuleus. It has an apparent magnitude of 8.23, making it readily visible in small telescopes but not to the naked eye. Gaia DR3 parallax measurements imply a distance of 594 light-years and it is currently receding with a heliocentric radial velocity of 14 km/s. At its current distance, HD 201585's brightness is diminished by three-tenths of a magnitudes due to interstellar extinction and it has an absolute magnitude of +1.81. HD 201585 is the star's Henry Draper Catalogue designation. It is also designated as MASCARA-1 meaning that it is the first star observed by the MASCARA exoplanet search program.
HD 177765 is a white-hued star in the southern constellation of Sagittarius. With an apparent magnitude of 9.15, it is too faint to be seen by the naked eye from Earth, but is dimly visible using binoculars. It is located at a distance of 1,284 light-years according to Gaia EDR3 parallax measurements.
HD 197911 is a bluish-white hued star in the deep northern constellation of Cepheus, close to the border with Draco and Cygnus. With an apparent magnitude of 7.669, it is too faint to be seen by the naked eye under most conditions, but readily visible using binoculars. The star is located some 3,020 light-years distant according to Gaia EDR3 parallax measurements, but is moving closer to the Solar System at a heliocentric radial velocity of −3.8±3.5 km/s.