- A comparison between the night sky of Earth and a planet of HD 69830.
- The orbits of the planets of HD 69830 and the debris disk.
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Puppis |
Right ascension | 08h 18m 23.94697s [1] |
Declination | −12° 37′ 55.8172″ [1] |
Apparent magnitude (V) | +5.98 [2] |
Characteristics | |
Spectral type | G8V [3] |
U−B color index | 0.33 [2] |
B−V color index | 0.75 [2] |
V−R color index | 0.40 |
R−I color index | 0.36 |
Variable type | none |
Astrometry | |
Radial velocity (Rv) | 30.09±0.12 [1] km/s |
Proper motion (μ) | RA: 278.790 mas/yr [1] Dec.: −987.829 mas/yr [1] |
Parallax (π) | 79.4953 ± 0.0400 mas [1] |
Distance | 41.03 ± 0.02 ly (12.579 ± 0.006 pc) |
Absolute magnitude (MV) | 5.47 ± 0.01 [4] |
Details | |
Mass | 0.89 ± 0.03 [5] M☉ |
Radius | 0.905 ± 0.019 [3] R☉ |
Luminosity | 0.622 ± 0.014 [3] L☉ |
Surface gravity (log g) | 4.53 [6] cgs |
Temperature | 5,394 ± 62 [3] K |
Metallicity [Fe/H] | −0.04 ± 0.03 [3] dex |
Rotation | 35.1 ± 0.8 days [7] |
Rotational velocity (v sin i) | 0.8±0.5 [3] km/s |
Age | 10.6 ± 4 [3] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Exoplanet Archive | data |
ARICNS | data |
HD 69830 (285 G. Puppis) is a yellow dwarf star located 41.0 light-years (12.6 parsecs ) away in the constellation of Puppis. In 2005, the Spitzer Space Telescope discovered a narrow ring of warm debris orbiting the star. [10] The debris ring contains substantially more dust than the Solar System's asteroid belt. In 2006, three extrasolar planets with minimum masses comparable to Neptune were confirmed in orbit around the star, located interior to the debris ring. [11]
HD 69830 is a main sequence star of spectral type G8V. It has about 86% of the Sun's mass, 90% of its radius, 62% of its luminosity, and 89% of its iron abundance. The star's age has been estimated at 10.6 ± 4 billion years. HD 69830 is located about 40.7 light-years from the Sun, lying in the northeastern part of the constellation of Puppis (the Poop Deck). It can be seen east of Sirius, southwest of Procyon, northeast of Delta Canis Majoris, and north of Zeta Puppis.
Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | ≥10.1+0.38 −0.37 M🜨 | 0.0764±0.0017 | 8.66897±0.00028 | 0.128±0.028 | — | — |
c | ≥12.09+0.55 −0.54 M🜨 | 0.181±0.004 | 31.6158±0.0051 | 0.03±0.027 | — | — |
d | ≥12.26+0.89 −0.88 M🜨 | 0.622±0.014 | 201.4±0.4 | 0.08±0.071 | — | — |
Asteroid belt | 0.93–1.16 AU | — | — |
On May 17, 2006, a team of astronomers using the European Southern Observatory's (ESO) HARPS spectrograph on the 3.6-metre La Silla telescope in the Atacama Desert, Chile, announced the discovery of three extrasolar planets orbiting the star. With minimum masses between 10 and 18 times that of the Earth, all three planets are presumed to be similar to the planets Neptune or Uranus. [11] As of 2011 [update] , no planet with more than half the mass of Jupiter had been detected within three astronomical units of HD 69830.
The star rotates at an inclination of 13+27
−13 degrees relative to Earth. [7] It has been assumed that the planets share that inclination. [13] However b and c are "hot Neptunes", and outside this system several are now known to be oblique relative to the stellar axis. [14]
The outermost planet discovered appears to be within the system's habitable zone, where liquid water would remain stable (more accurate data on the primary star's luminosity will be required to know for sure where the habitable zone is). HD 69830 is the first extrasolar planetary system around a Sun-like star without any known planets comparable to Jupiter or Saturn in mass. [11]
The planetary parameters were updated in 2023. [5]
In 2005, the Spitzer Space Telescope detected a debris disk in the HD 69830 system consistent with being produced by an asteroid belt twenty times more massive than that in our own system. The belt was originally thought to be located inside an orbit equivalent to that of Venus in the Solar System, which would place it between the orbits of the second and third planets. The disk contains sufficient quantities of dust that the nights on any nearby planets would be lit up by zodiacal light 1000 times brighter than that seen on Earth, easily outshining the Milky Way.
Further analysis of the spectrum of the dust in 2007 revealed that it is composed of highly processed material, likely derived from a disrupted rocky asteroid of at least 30 km radius which contained many small olivine-rich (rocky) and once-wet grains which would not survive at close distances to the star. Instead, it seems more likely that the asteroid belt producing the dust is located outside the orbit of the outermost planet, around 1 AU from the star. This region contains the 2:1 and 5:2 mean motion resonances with HD 69830 d. [12]
A ring system is a disc or torus orbiting an astronomical object that is composed of solid material such as gas, dust, meteoroids, planetoids or moonlets and stellar objects.
Beta Pictoris is the second brightest star in the constellation Pictor. It is located 63.4 light-years (19.4 pc) from the Solar System, and is 1.75 times as massive and 8.7 times as luminous as the Sun. The Beta Pictoris system is very young, only 20 to 26 million years old, although it is already in the main sequence stage of its evolution. Beta Pictoris is the title member of the Beta Pictoris moving group, an association of young stars which share the same motion through space and have the same age.
61 Virginis is the Flamsteed designation of a G-type main-sequence star (G7V) slightly less massive than the Sun, located 27.8 light-years away in the constellation of Virgo. The composition of this star is nearly identical to the Sun.
HD 210277 is a single star in the equatorial constellation of Aquarius. It has an apparent visual magnitude of 6.54, which makes it a challenge to view with the naked eye, but it is easily visible in binoculars. The star is located at a distance of 69.6 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −20.9 km/s.
HD 12039, also known as DK Ceti, is a variable star in the constellation of Cetus at a distance of 135 ly (41 pc). It is categorized as a BY Draconis variable because of luminosity changes caused by surface magnetic activity coupled with rotation of the star. The stellar classification G4V is similar to the Sun, indicating this is a main sequence star that is generating energy at its core through the thermonuclear fusion of hydrogen. The effective temperature of 5,585 K gives the star a yellow hue. It has about the same mass as the Sun, but only emits 89% of the Sun's luminosity. This is a young star with age estimates ranging from 7.5−8 million years to 30 million years.
Any planet is an extremely faint light source compared to its parent star. For example, a star like the Sun is about a billion times as bright as the reflected light from any of the planets orbiting it. In addition to the intrinsic difficulty of detecting such a faint light source, the light from the parent star causes a glare that washes it out. For those reasons, very few of the exoplanets reported as of January 2024 have been observed directly, with even fewer being resolved from their host star.
HD 69830 d is an exoplanet likely orbiting within the habitable zone of the star HD 69830, the outermost of three such planets discovered in the system. It is located approximately 40.7 light-years (12.49 parsecs, or 3.8505×1014 km) from Earth in the constellation of Puppis. 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.
A debris disk, or debris disc, is a circumstellar disk of dust and debris in orbit around a star. Sometimes these disks contain prominent rings, as seen in the image of Fomalhaut on the right. Debris disks are found around stars with mature planetary systems, including at least one debris disk in orbit around an evolved neutron star. Debris disks can also be produced and maintained as the remnants of collisions between planetesimals, otherwise known as asteroids and comets.
HD 70573 is a variable star in the equatorial constellation of Hydra. At a mean apparent visual magnitude of +8.7, this yellow-hued star is too dim to be visible to the naked eye. Based upon parallax measurements, it is located at a distance of 193 light years from the Sun, and is drifting further away with a radial velocity of 20.5 km/s. It is a candidate member of the proposed Hercules-Lyra Association of co-moving stars, although this membership is disputed.
Epsilon Eridani b, also known as AEgir [sic], is an exoplanet approximately 10.5 light-years away orbiting the star Epsilon Eridani, in the constellation of Eridanus. The planet was discovered in 2000, and as of 2024 remains the only confirmed planet in its planetary system. It orbits at around 3.5 AU with a period of around 7.6 years, and has a mass around 0.6 times that of Jupiter. As of 2023, both the Extrasolar Planets Encyclopaedia and the NASA Exoplanet Archive list the planet as 'confirmed'.
Eta Corvi is an F-type main-sequence star, the sixth-brightest star in the constellation of Corvus. Two debris disks have been detected orbiting this star, one at ~150 AU, and a warmer one within a few astronomical units (AU).
HD 113766 is a binary star system located 424 light years from Earth in the direction of the constellation Centaurus. The star system is approximately 10 million years old and both stars are slightly more massive than the Sun. The two are separated by an angle of 1.3 arcseconds, which, at the distance of this system, corresponds to a projected separation of at least 170 AU.
HD 210277 b is an extrasolar planet orbiting the star HD 210277. It was discovered in September 1998 by the California and Carnegie Planet Search team using the highly successful radial velocity method. The planet is at least 24% more massive than Jupiter. The mean distance of the planet from the star is slightly more than Earth's distance from the Sun. However, the orbit is very eccentric, so at periastron this distance is almost halved, and at apastron it is as distant as Mars is from the Sun.
HD 141569 is an isolated Herbig Ae/Be star of spectral class A2Ve approximately 364 light-years away in the constellation of Libra. The primary star has two red dwarf companions at about nine arcseconds. In 1999, a protoplanetary disk was discovered around the star. A gap in the disk led to speculation about a possible extrasolar planet forming in the disk.
HR 8799 is a roughly 30 million-year-old main-sequence star located 133.3 light-years away from Earth in the constellation of Pegasus. It has roughly 1.5 times the Sun's mass and 4.9 times its luminosity. It is part of a system that also contains a debris disk and at least four massive planets. These planets were the first exoplanets whose orbital motion was confirmed by direct imaging. The star is a Gamma Doradus variable: its luminosity changes because of non-radial pulsations of its surface. The star is also classified as a Lambda Boötis star, which means its surface layers are depleted in iron peak elements. It is the only known star which is simultaneously a Gamma Doradus variable, a Lambda Boötis type, and a Vega-like star.
Paul Kalas is a Greek American astronomer known for his discoveries of debris disks around stars. Kalas led a team of scientists to obtain the first visible-light images of an extrasolar planet with orbital motion around the star Fomalhaut, at a distance of 25 light years from Earth. The planet is referred to as Fomalhaut b.
An exoplanet is a planet located outside the Solar System. The first evidence of an exoplanet was noted as early as 1917, but was not recognized as such until 2016; no planet discovery has yet come from that evidence. What turned out to be the first detection of an exoplanet was published among a list of possible candidates in 1988, though not confirmed until 2003. The first confirmed detection came in 1992, with the discovery of terrestrial-mass planets orbiting the pulsar PSR B1257+12. The first confirmation of an exoplanet orbiting a main-sequence star was made in 1995, when a giant planet was found in a four-day orbit around the nearby star 51 Pegasi. Some exoplanets have been imaged directly by telescopes, but the vast majority have been detected through indirect methods, such as the transit method and the radial-velocity method. As of 24 July 2024, there are 7,026 confirmed exoplanets in 4,949 planetary systems, with 1007 systems having more than one planet. This is a list of the most notable discoveries.
HD 38858 is a G-type star, much like The Sun, with one detected planet. The planet, designated HD 38858 b, is about twice the mass of Uranus and orbits in the star's habitable zone.
A circumstellar disc is a torus, pancake or ring-shaped accretion disk of matter composed of gas, dust, planetesimals, asteroids, or collision fragments in orbit around a star. Around the youngest stars, they are the reservoirs of material out of which planets may form. Around mature stars, they indicate that planetesimal formation has taken place, and around white dwarfs, they indicate that planetary material survived the whole of stellar evolution. Such a disc can manifest itself in various ways.
HD 219623 is a solitary star in the northern circumpolar constellation of Cassiopeia. HD 219623 is its Henry Draper Catalogue designation. It has an apparent visual magnitude of 5.59, which lies in the brightness range that is visible to the naked eye. According to the Bortle scale, it can be observed from dark suburban skies. Parallax measurements place it at an estimated distance of around 67.2 light years. It has a relatively high proper motion, advancing 262 mas per year across the celestial sphere.
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