HD 100546

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HD 100546
View of the dust disc around the young star HD 100546.jpg
This image from the NASA/ESA Hubble Space Telescope shows a visible light view of the outer dust around the young star HD 100546. The position of the newly discovered protoplanet is marked with an orange spot. The inner part of this picture is dominated by artifacts from the brilliant central star, which has been digitally subtracted, and the black blobs are not real.[1][2]
Observation data
Epoch J2000.0[3]      Equinox J2000.0[3]
Constellation Musca
Right ascension 11h 33m 25.441s[4]
Declination −70° 11′ 41.24″[4]
Apparent magnitude (V) 6.698[3]
Spectral type B9Vne[3]
Age >106[5] years
Proper motion (μ) RA: −38.93 ± 0.36[4] mas/yr
Dec.: 0.29 ± 0.38[4] mas/yr
Parallax (π) 10.32 ± 0.43[4] mas
Distance 320 ± 10 ly
(97 ± 4 pc)
Other designations
KR Mus, SAO 251457, CD−69° 893, HIP 56379[3]
Database references
HD 100546 b
Exoplanet List of exoplanets|
Parent star
Star HD 100546
Right ascension (α) 11h 33m 25.441s[4]
Declination (δ) −70° 11′ 41.24″[4]
Spectral type B9Vne[3]
Physical characteristics
Mass (m) ~20[6] MJ
Radius (r) 6.9+2.7
[7] RJ
Temperature (T) 932+193
[7] K
Orbital elements
Semi-major axis (a) 6.5[6] AU

HD 100546, also known as KR Muscae, is a star 320 LY from Earth.[4] It is orbited by an approximately 20 MJ exoplanet at 6.5 AU,[6] although further examination of the disk profile indicate it might be a more massive object such as a brown dwarf or more than one planet.[8] The star is surrounded by a circumstellar disk from a distance of 0.2 to 4 AU, and again from 13 AU out to a few hundred AU, with evidence for a protoplanet forming at a distance of around 47 AU,[9] and it is also the largest exoplanet discovered with a size around 6.9 RJ.[7]

Estimated to be around 10 million years old, it is at the upper age limit of the class of stars it belongs to—Herbig Ae/Be stars, and also the nearest example to the Solar System.[5]

Possible birth of new planet[edit]

In 2013, researchers reported that they had found what seems to be a planet in the process of being formed, embedded in the star's large disc of gas and dust. If confirmed, it would represent the first opportunity to study the early stages of planet formation observationally.[10]

HD 100546 b[edit]

Evidence for a planetary companion to HD 100546 was gathered using the UVES echelle spectrograph at the VLT in Chile.[6] This confirms other data indicating a planetary companion. HD 100546 b is probably the largest known exoplanet. The planet's size puts it near the border between a large planet and a brown dwarf.[6]

Protoplanetary material[edit]

Coronagraphic optical observations with the Hubble Space Telescope [1][5] show complex spiral patterns in the circumstellar disk. The causes of these structures remain uncertain. The disk colors are similar to those derived for Kuiper Belt objects, suggesting that the same weathering processes are at work in HD 100546. The disk is fairly flat, consistent with an advanced evolutionary state.[1]

Spectroscopic analysis of mid-IR data taken from OSCIR on the 4 m Blanco Telescope at Cerro Tololo Inter-American Observatory indicates the presence of a small particles (10–18 μm) containing silicates.[5] The material is found at distances out to 17 AU away from the star and has a temperature of approximately 227 K.[5]


  1. ^ a b c Ardila, D. R.; Golimowski, D. A.; Krist, J. E.; Clmapin, M.; Ford, H. C.; Illingworth, G. D. (2007). "Hubble Space Telescope Advanced Camera for Surveys Coronagraphic Observations of the Dust Surrounding HD 100546". Astrophysical Journal. 665 (1): 512–534. arXiv:0704.1507Freely accessible. Bibcode:2007ApJ...665..512A. doi:10.1086/519296. 
  2. ^ "The Birth of a Giant Planet?". ESO. Retrieved 3 April 2013. 
  3. ^ a b c d e "SIMBAD Object query: HD 100546". 
  4. ^ a b c d e f g h van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752Freely accessible. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. Vizier catalog entry
  5. ^ a b c d e Grady, C. A.; et al. "The Disk and Environment of the Herbig Be Star HD 100546". The Astronomical Journal. 122 (6): 3396–3406. Bibcode:2001AJ....122.3396G. doi:10.1086/324447. 
  6. ^ a b c d e Acke, B.; van der Ancker, M. (November 2005). "Resolving the disk rotation of HD 97048 and HD 100546 in the [O I] 6300A line: evidence for a giant planet orbiting HD 100546". Astronomy and Astrophysics. 449 (267): 267. arXiv:astro-ph/0512562Freely accessible. Bibcode:2006A&A...449..267A. doi:10.1051/0004-6361:20054330. 
  7. ^ a b c Quanz, Sasch P.; Amara, Adam; Meyer, Michael P.; Kenworthy, Matthew P.; et al. (2014). "Confirmation and characterization of the protoplanet HD100546 b - Direct evidence for gas giant planet formation at 50 au". Astrophysical Journal. arXiv:1412.5173Freely accessible. 
  8. ^ Mulders, Gijs D.; Paardekooper, Sijme-Jan; Pani´c, Olja; Dominik, Carsten; et al. (2013). "Planet or Brown Dwarf? Inferring the Companion Mass in HD 100546 from the Wall Shape using Mid-Infrared Interferometry". Astronomy & Astrophysics. 557A (A68): 10. arXiv:1306.4264Freely accessible. Bibcode:2013A&A...557A..68M. doi:10.1051/0004-6361/201220930. 
  9. ^ Quanz, Sasch P.; Amara, Adam; Meyer, Michael P.; Kenworthy, Matthew P.; et al. (2013). "A young protoplanet candidate embedded in the circumstellar disk of HD 100546". Astrophysical Journal. 766: L1–L6. arXiv:1302.7122Freely accessible. Bibcode:2013ApJ...766L...1Q. doi:10.1088/2041-8205/766/1/l1. 
  10. ^ "Is HD 100546 showing us the birth of a giant planet?". Science Codex. 2013-02-28. Retrieved 2013-03-01. 

Further reading[edit]

External links[edit]

Coordinates: Sky map 11h 33m 25.4408s, −70° 11′ 41.239″