The following is a list of stars with resolved images, that is, stars whose images have been resolved beyond a point source. Aside from the Sun, observed from Earth, stars are exceedingly small in apparent size, requiring the use of special high-resolution equipment and techniques to image. For example, Betelgeuse, the first star other than the Sun to be directly imaged, has an angular diameter of only 50 milliarcseconds (mas). [1]
Star | Image | Diameter | Distance (ly) | First imager | Year | Notes | |
---|---|---|---|---|---|---|---|
Angular (mas) | Geometric (Sun = 1) | ||||||
Sun | 2000000 | 1 | 0.0000158 | Louis Fizeau and Léon Foucault [2] | 1845 | ||
Altair α Aql | 3.2 | 1.66±0.01 (polar) 2.02±0.01 (equator) | 16.77±0.08 | CHARA array – MIRC [3] | 2006 | ||
Rasalhague α Oph A | 1.62±0.03 | 2.39±0.01 (polar) 2.87±0.02 (equator) | 48.6±0.8 | CHARA array – MIRC [4] | 2006 | ||
Alderamin α Cep | 1.35±0.02 (polar) 1.75±0.03 (equator) | 2.20±0.04 (polar) 2.74±0.04 (equator) | 48.8±0.36 | CHARA array – MIRC [4] | 2006 | ||
Caph β Cas | 1.70±0.04 | 3.1±0.1 (polar) 3.8±0.1 (equator) | 54.7±0.3 | CHARA array – MIRC [5] | 2007 | ||
Regulus α Leo Aa | 1.24±0.02 | 3.2±0.1 (polar) 4.2±0.1 (equator) | 79.3±0.7 | CHARA array – MIRC [5] | 2008 | ||
Algol β Per Aa1 | | 0.88±0.05 | 4.13 | 93±2 | CHARA array – MIRC [6] | 2006 | stationary object in the animation |
β Per Aa2 | 1.12±0.07 | 3 | orbiting object in the animation | ||||
β Per Ab | 0.56±0.10 | 0.9 | Observed radius of Algol Ab is an instrumental artifact, caused by bandwidth smearing. Actual radius is 1.73 ± 0.33 R☉. | ||||
Alkaid η UMa | 0.834±0.060 | 2.86±0.21 | 103.9±0.8 | CHARA array [7] | 2012 | ||
Markab α Peg | 1.052±0.066 | 4.62±0.29 | 133±1 | CHARA array [7] | 2012 | ||
Elnath β Tau | 1.09±0.076 | 4.82±0.34 | 134±2 | CHARA array [7] | 2012 | ||
σ Gem A | 2.425 | 10.1±0.4 | 126±2 | CHARA array/MIRC [8] | 2011–2012 | The star contains starspots on its surface | |
ζ And Aa | 2.502±0.008 | 15.0±0.8 (polar) | 189±3 | CFHT [9] [10] | 1996 | First direct imaging of starspots on a star outside the Solar System. | |
R Dor | 57±5 | 370±50 | 204±9 | New Technology Telescope [11] | 1993 | 2nd largest known star by apparent diameter in Earth's sky, after the Sun. | |
Mira ο Cet A | 50 | up to 700 | 420 | Hubble – FOC [12] | 1997[ citation needed ] | ||
T Lep | 5.8 15 for molecular layer | 100 | 500 | Very Large Telescope – VLTI [13] /AMBER [14] | 2009[ citation needed ] | ||
π1 Gru | 18.37[ citation needed ] | 694 | 530 | Very Large Telescope – VLTI/PIONIER [15] | 2017[ citation needed ] | First directly observed granulation patterns on a star's surface outside the Solar System. | |
Antares α Sco A | 41.3±0.1 | 700 | 620 | Very Large Telescope – VLTI/AMBER [16] [17] | 2017[ citation needed ] | ||
Betelgeuse α Ori | 50 | 630 | 643±146 | Hubble – GHRS [1] | 1995 | First star with a resolved image outside the Solar System. | |
Sheliak β Lyr Aa | 0.46 | 6 | 960±50 | CHARA array – MIRC [18] | 2007 | Both Aa1 and Aa2 are visible in the animation. | |
θ1 Ori C | 0.2 | 10.6±1.5 | 1400 | Very Large Telescope – AMBER [19] | 2009 | In the image, the right inset is θ1 Ori C and the left inset is θ1 Ori F. | |
θ1 Ori F | Very Large Telescope – VLTI/GRAVITY [20] | 2016[ citation needed ] | |||||
Almaaz ε Aur A | 2.27 | 3.7±0.7 | ca. 2000 | CHARA array – MIRC [21] | 2009 | Supergiant with an eclipsing companion surrounded by a massive, opaque debris disk | |
RW Cephei | 2.45 | 900–1760 | 11000+4600 −2600–22000+5200 −3300 | CHARA array – MIRC-X and MYSTIC [22] | 2022 | Hypergiant star currently undergoing a great dimming event | |
HR 5171 Aa | 4.1±0.8 | 1575±400 | 11740±1630 | Very Large Telescope – VLTI/PIONIER [23] | 2014 | Eclipsing and potential contact binary yellow hypergiant |
Algol, designated Beta Persei, known colloquially as the Demon Star, is a bright multiple star in the constellation of Perseus and one of the first non-nova variable stars to be discovered.
Alcyone, designated η Tauri, is a star in the constellation of Taurus. Approximately 440 light-years from the Sun, it is the brightest star in the Pleiades open cluster, which is a young cluster, around 100 million years old. There are a number of fainter stars very close to Alcyone, some of which are members of the same cluster.
The CHARAarray is an optical interferometer, located on Mount Wilson, California. The array consists of six 1-metre (40 in) telescopes operating as an astronomical interferometer. Construction was completed in 2003. CHARA is owned by Georgia State University (GSU).
Mu Andromedae is the Bayer designation for a star in the northern constellation of Andromeda. It has an apparent visual magnitude of 3.87, making it readily visible to the naked eye. Based upon parallax measurements, it is approximately 130 light-years from Earth. In the constellation, the star is situated about halfway between the bright star Mirach to the southwest and the Andromeda Galaxy (M31) to the northeast.
Zeta Andromedae is a star system in the constellation Andromeda. It is approximately 189 light-years from Earth.
RT Aurigae is a yellow supergiant variable star in the constellation Auriga, about 1,500 light years from Earth.
HD 20782 is the primary of a wide binary system located in the southern constellation Fornax. It has an apparent magnitude of 7.38, making it readily visible in binoculars but not to the naked eye. The system is located relatively close at a distance of 117 light-years based on Gaia DR3 parallax measurements, but it is receding with a heliocentric radial velocity of 40.7 km/s. At its current distance, HD 20782's brightness is diminished by 0.12 magnitudes due to interstellar extinction and it has an absolute magnitude of +4.61.
Omicron Draconis is a giant star in the constellation Draco located 322.93 light years from the Earth. Its path in the night sky is circumpolar for latitudes greater than 31o north, meaning the star never rises or sets when viewed in the night sky.
RS Persei is a red supergiant variable star located in the Double Cluster in Perseus. The star's apparent magnitude varies from 7.82 to 10.0, meaning it is never visible to the naked eye.
T Persei is a red supergiant located in the constellation Perseus. It varies in brightness between magnitudes 8.3 and 9.7 and is considered to be a member of the Double Cluster.
RY Tauri is a young T Tauri star in the constellation of Taurus about 450 light years away, belonging to the Taurus Molecular Cloud. It is more massive than typical T Tauri stars, and may be an intermediate between this class and the Herbig Ae/Be star type.
AZ Cygni is a large red supergiant in the constellation of Cygnus. It is located 2,090 pc (6,800 ly) from Earth. It has been studied by the CHARA array in order to understand the surface variations of red supergiants.
HD 224355, also known as V1022 Cassiopeiae, HR 9059 and Boss 6148, is an eclipsing binary star in the constellation Cassiopeia. It ranges in apparent magnitude from 5.57 to 5.68, which means it is faintly visible to the naked eye for an observer located well away from city lights. It is one of the few binaries known to be an astrometric, spectroscopic and eclipsing binary, a combination that allows the parameters of the stellar system to be calculated with high accuracy. HD 224355 lies 16′ west of the 5th-magnitude σ Cassiopeiae.
V1334 Cygni, also referred to as ADS 14859 and HR 8157 in astronomical literature, is a star about 2350±25 light years from the Earth in the constellation Cygnus. It is a 5th magnitude star, which will be faintly visible to the naked eye of an observer located far from city lights. It is a classical Cepheid variable star, ranging in brightness from magnitude 5.77 to 5.96 over a period of 3.332816 days. V1334 Cygni is an important calibrator for models of Cepheid variables, because its presence in triple star system with a close binary pair has allowed its distance to be measured geometrically with 1% accuracy.
Gaia17bpp is a rare M-type red giant star that exhibited a single large dimming event over 6.5 years. It is located in the Sagitta constellation and is about 27,600 light years away from Earth.