Some details are emerging on the nature of the star that experienced the outburst. Based on an incorrect interpretation of the light echo the eruption generated, the distance of the star was first estimated to be 1,900 to 2,900 light years. Combined with the apparent magnitude measured from pre-eruption photographs, it was thought to be an underluminous F-type dwarf, which posed a considerable enigma. More accurate measurements gave a much larger distance, 20,000 light years (6 kpc). It appears that the star was considerably more massive and luminous than the Sun. The star probably has a mass of from 5 to 10 times solar.
V838 MonNova Monocerotis 2002
Beta Canis Majoris (β Canis Majoris, abbreviated Beta CMa, β CMa), also named Mirzam, is a star in the southern constellation of Canis Major, the "Great Dog", located at a distance of about 500 light-years (150 parsecs) from the Sun. In the modern constellation it lies at the position of the dog's front leg. Beta Canis Majoris is the star's Bayer designation. The traditional names Mirzam, Al-Murzim or Murzim, derive from the Arabic for 'The Herald', and probably refers to its position, heralding (i.e., rising before) Sirius in the night sky. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars.
WD 1145+017 b (also known by its EPIC designation EPIC 201563164.01), is a confirmed exoplanetary object, likely rocky, orbiting the white dwarf star WD 1145+017. It was discovered by NASA's Kepler spacecraft on its "Second Light" mission. It is located about 570 light-years (174 parsecs, or nearly 5.393 km) away from Earth in the constellation of Virgo. The object was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured.
HD 213240 is a yellow main sequence star located approximately 133 light years (41 parsecs) away in the constellation Grus. The magnitudes were m=6.80 and M=3.75. It is a metal-rich star and more evolved than our sun. Its age has been calculated as being anywhere from 2.7 to 4.6 billion years. A red dwarf companion star was detected in 2005 with a projected separation of 3898 AU. The Geneva extrasolar planet search team discovered a planet orbiting this star in 2001. * HD 212301. List of extrasolar planets.
TRAPPIST-1e, also designated as 2MASS J23062928-0502285 e, is a solid, almost Earth-sized exoplanet orbiting within the habitable zone around the ultra-cool dwarf star TRAPPIST-1 approximately 40 light-years (12.1 parsecs, or nearly 3.7336 km) away from Earth in the constellation of Aquarius. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. It was one of seven new exoplanets to be discovered orbiting the star using observations from the Spitzer Space Telescope. Three of the seven (e, f, and g) are in the habitable zone.
The planet orbits a (M-type) star named Gliese 832, orbited by a total of two known planets. The star has a mass of 0.45 and a radius of 0.48. It has a temperature of 3620 K and is estimated to be about 9.54 billion years old. In comparison, the Sun is 4.6 billion years old and has a temperature of 5778 K. The star's apparent magnitude, or how bright it appears from Earth's perspective, is 10.19. Therefore, it is too dim to be seen with the naked eye. The planet orbits its host star with about 3% of the Sun's luminosity approximately every 36 days and an orbital radius 0.16 times that of Earth (compared to Mercury's orbital distance of 0.38 AU).
Upsilon Andromedae d (υ Andromedae d, abbreviated Upsilon And d, υ And d), formally named Majriti, is a super-Jupiter exoplanet orbiting within the habitable zone of the Sun-like star Upsilon Andromedae A, approximately 44 light-years (13.5 parsecs, or nearly 4.163 km) away from Earth in the constellation of Andromeda. Its discovery made it the first multiplanetary system to be discovered around a main sequence star, and the first such system known in a multiple star system. The exoplanet was found by using the radial velocity method, where periodic Doppler shifts of spectral lines of the host star suggest an orbiting object.
BD+14 4559 b is an exoplanet orbiting the K-type main sequence star BD+14 4559 about 161 light-years (49 parsecs, or nearly 1.5 km) from Earth in the constellation Pegasus. It orbits its star within the habitable zone at a distance of 0.777 AU, close to that of Venus, but its star is less energetic, thus its habitable zone is closer to it than Earth. The exoplanet was found by using the radial velocity method, from radial-velocity measurements via observation of Doppler shifts in the spectrum of the planet's parent star. BD+14 4559 b is a gas giant, an exoplanet that has a radius and mass around that of the gas giants Jupiter and Saturn. It has a temperature of 205 K.
TRAPPIST-1d, also designated as 2MASS J23062928-0502285 d, is a small exoplanet (about 30% the mass of the earth), which orbits on the inner edge of the habitable zone of the ultracool dwarf star TRAPPIST-1 approximately 40 light-years (12.1 parsecs, or nearly 3.7336 km) away from Earth in the constellation of Aquarius. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. The first signs of the planet were announced in 2016, but it wasn't until the following years that more information concerning the probable nature of the planet was obtained.
HIP 77900 b
HD 142250 (HR 5910, HIP 77900) is a star in the constellation Scorpius. It has a visual apparent magnitude of 6.10, being visible to the naked eye only in excellent seeing conditions. From parallax measurements, it is located about 500 light-years (155 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. This is a B-type main-sequence star with a spectral type of B6Vp and a mass estimated at 3.7 times the solar mass.
Kepler 186ffKepler-186 f
The planet orbits Kepler-186, an M-type star which has a total of five planets. The star has a mass of 0.54 and a radius of 0.52. It has a temperature of 3755 K and is about 4 billion years old, about 600 million years younger than the Sun, which is 4.6 billion years old and has a temperature of 5778 K. The star's apparent magnitude, or how bright it appears from Earth's perspective, is 14.62. This is too dim to be seen with the naked eye, which can only see objects with a magnitude up to at least 6 or lower.
The planet orbits an (F-type) star named Kepler-419. The star has a mass of 1.39 and a radius of 1.75. It has a surface temperature of 6430 K and is 2.8 billion years old. In comparison, the Sun is about 4.6 billion years old and has a surface temperature of 5778 K. The star's apparent magnitude, or how bright it appears from Earth's perspective, is 12. It is too dim to be seen with the naked eye. Kepler-419c orbits its host star with 270% of the Sun's luminosity (2.7 ) about every 675 days (around 1.84 years) at a distance of 1.61 AU (compared to the orbital distance of Mars, which is 1.52 AU). It has a slightly eccentric orbit, with an eccentricity of 0.184.
Kepler-62f (also known by its Kepler Object of Interest designation KOI-701.04) is a super-Earth exoplanet orbiting within the habitable zone of the star Kepler-62, the outermost of five such planets discovered around the star by NASA's Kepler spacecraft. It is located about 1,200 light-years (370 parsecs) from Earth in the constellation of Lyra. Kepler-62f orbits its star at a distance of 0.718 AU from its host star with an orbital period of roughly 267.3 days, has a mass at least 2.8 times that of Earth, and has a radius of around 1.41 times that of Earth.
The planet orbits a (K-type) star named Kepler-442. The star has a mass of 0.61 and a radius of 0.60. It has a temperature of 4402 K and is around 2.9 billion years old, with some uncertainty. In comparison, the Sun is 4.6 billion years old and has a temperature of 5778 K. The star is somewhat metal-poor, with a metallicity (Fe/H) of −0.37, or 42% of the solar amount. Its luminosity is 11% that of the Sun. The star's apparent magnitude, or how bright it appears from Earth's perspective, is 14.97. Therefore, it is too dim to be seen with the naked eye.
bbeta Pic bβ Pictoris b
Beta Pictoris b (abbreviated as β Pic b) is an exoplanet orbiting the young debris disk A-type main sequence star Beta Pictoris located approximately 63 light-years (19.4 parsecs, or nearly 5.986214 km) away from Earth in the constellation of Pictor. It has a mass around 13 Jupiter masses and a radius around 46% larger than Jupiter's. It orbits at 9 AU from Beta Pictoris (close to the plane of the debris disk orbiting the star) with a low eccentricity and a period of 20–21 years. Beta Pictoris b is a super-Jupiter, an exoplanet that has a radius and mass greater than that of the planet Jupiter.
Barnard’s Starextrasolar planetsProxima Ophiuchi
Barnard's Star is a red dwarf about 6 light-years away from Earth in the constellation of Ophiuchus. It is the fourth nearest known individual star to the Sun after the three components of the Alpha Centauri system and the closest star in the Northern Celestial Hemisphere. Its stellar mass is about 14% of the Sun's. Despite its proximity, the star has a dim apparent magnitude of +9.5 and is invisible to the unaided eye; it is much brighter in the infrared than in visible light. The star is named after the American astronomer E. E. Barnard.
TW Piscis AustriniFomalhaut AAlpha Piscis Austrini
Its current separation from Fomalhaut A is about 0.77 pc, and it is currently located 0.987 pc away from TW PsA (Fomalhaut B). LP 876-10 is located well within the tidal radius of the Fomalhaut system, which is 1.9 pc. Although LP 876-10 is itself catalogued as a binary star in the Washington Double Star Catalog (called "WSI 138"), there was no sign of a close-in stellar companion in the imaging, spectral, or astrometric data in the Mamajek et al. study. In December 2013, Kennedy et al. reported the discovery of a cold dusty debris disk associated with Fomalhaut C, using infrared images from the Herschel Space Observatory.
Wezenδ CMaδ Canis Majoris
Delta Canis Majoris (Latinised from δ Canis Majoris, abbreviated Delta CMa, δ CMa), officially named Wezen, is a star in the constellation of Canis Major. It is a yellow-white F-type supergiant with an apparent magnitude of +1.83. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified. Delta Canis Majoris is the third-brightest star in the constellation after Sirius and ε Canis Majoris (Adhara), with an apparent magnitude of +1.83, and is white or yellow-white in colour. Lying about 10 degrees south southeast of Sirius, it only rises to about 11 degrees above the horizon at the latitude of the United Kingdom.
π HerPiπ Herculis
Pi Herculis (π Her, π Herculis) is a third-magnitude star in the constellation Hercules. As one of the four stars in the Keystone asterism (see yellow quadrangle), it is one of the constellation's more easily recognized. It has an apparent visual magnitude of +3.2, which is visible to the naked eye and makes it one of its brighter members. The Hipparcos satellite mission estimated its distance at roughly 115 parsecs from Earth, or about 377 light years away. The overall reduction in the star's visual magnitude due to extinction from the intervening matter is 0.11. Pi Herculis is a bright giant star with a stellar classification of K3 II. P.C. Keenan and R. E.
navigational starsnavigation star150 stars
The final characteristic provided in the tables and star charts is the star's brightness, expressed in terms of apparent magnitude. Magnitude is a logarithmic scale of brightness, designed so that a body of one magnitude is approximately 2.512 times brighter than a body of the next magnitude. Thus, a body of magnitude 1 is 2.512 5, or 100 times brighter than a body of magnitude 6. The dimmest stars that can be seen through a 200 inch terrestrial telescope are of the 20th magnitude, and very bright objects like the Sun and a full Moon have magnitudes of −26.7 and −12.6 respectively. The table of navigational stars provides several types of information.
WASP-15 is located at a distance of approximately 290 parsecs (900 light years), and it has an estimated apparent magnitude of 10.9. It is, thus, not visible from Earth with the unaided eye. WASP-15 is host to the planet WASP-15b. The planet, which is a Hot Jupiter, orbits its host star at a distance of 0.0499 AU every 3.7520656 days. WASP-15b was noted by its discoverers because of its anomalously high radius, which is 1.428 times that of Jupiter, compared to its mass, which is 0.542 times the size of Jupiter. WASP-15b's large radius cannot be explained solely by its proximity to its star, suggesting that some form of tidal heating or other internal heating mechanism is also involved.
21 Leonis Minoris is a star in the constellation of Leo Minor. With an apparent magnitude of about 4.5, the star is faintly visible to the naked eye (see Bortle scale). Parallax estimates made by the Hipparcos spacecraft put it at a fairly close distance of about 92.1 light years (28.2 parsecs) away from the Earth. It is considered a member of the Sirius supercluster. 21 Leonis Minoris rotates fairly fast for a star; its projected rotational velocity is estimated to 155 km/s so it must be rotating at least that fast. It has been listed as a fast-rotating spectral standard star for the spectral type of A7V, as opposed to the slow-rotating standard star 2 Hydrae.
TRAPPIST-1f, also designated as 2MASS J23062928-0502285 f, is an exoplanet, likely rocky but under a massive water-steam gaseous envelope at very high pressure and temperature, orbiting within the habitable zone around the ultracool dwarf star TRAPPIST-1 39 light-years (12 parsecs) away from Earth in the constellation of Aquarius. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. It was one of four new exoplanets to be discovered orbiting the star using observations from the Spitzer Space Telescope.
COROT-1 is a yellow dwarf main sequence star similar to our Sun. The star is located approximately 2,630 light-years away in the constellation of Monoceros. The apparent magnitude of this star is 13.6, which means it is not visible to the naked eye; however, it can be seen through a medium-sized amateur telescope on a clear, dark night. The first exoplanet discovered in the course of the COROT mission orbits this star; it is considered to be a "hot Jupiter", and is approximately as massive as the planet Jupiter itself.
LP 658-2 is a degenerate (white dwarf) star in the constellation of Orion, the single known object in its system. It has an apparent visual magnitude of approximately 14.488. According to a 2009 paper, it is the eighth closest known white dwarf to the Sun (after Sirius B, Procyon B, van Maanen's star, Gliese 440, 40 Eridani B, Stein 2051 B and GJ 1221). Its trigonometric parallax from the CTIOPI (Cerro Tololo Inter-American Observatory (CTIO) Parallax Investigation) 0.9 m telescope program, published in 2009, is 0.15613 ± 0.00084 arcsec, corresponding to a distance 6.40 ± 0.03 pc, or 20.89 ± 0.11 ly.