HD 100546

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Star
HD 100546
View of the dust disc around the young star HD 100546.jpg
Image of the Hubble Space Telescope of the gas and dust disk around HD 100546 in visible light . The spiral structures can be seen. The orange point marks the position of the protoplanet HD 100546 b. The star itself was digitally subtracted; the black dots and concentric "waves" near the center of the image are not real objects, but rather image artifacts that have arisen as a result.
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation Fly
Right ascension 11 h 33 m 25.44 s
declination -70 ° 11 ′ 41.2 ″
Apparent brightness 6.7 likes
Typing
Known exoplanets 1
B − V color index 0.0 
U − B color index −0.1 
Spectral class B9 Vne
Astrometry
Radial velocity 9.1 ± 1.2 km / s
parallax 9.09 ± 0.06  mas
distance 359 ± 3  ly
110.0 ± 0.7  pc  
Proper movement 
Rec. Share: −38.60 ± 0.09  mas / a
Dec. portion: −0.24 ± 0.08  mas / a
Physical Properties
Dimensions 2.2 ± 0.2  M ☉
radius 1.5 ± 0.1  R ☉
Luminosity

20 ± 7  L ☉

Effective temperature 9 750 ± 500  K
Age ≈ 5 million  a
Other names
and catalog entries
Cordoba Survey CD −69 ° 893
Henry Draper Catalog HD 100546 [1]
Hipparcos catalog HIP 56379 [2]
SAO catalog SAO 251457 [3]
Tycho catalog TYC 9229-2446-1 [4]Template: Infobox star / maintenance / specification of the TYC catalog
2MASS catalog 2MASS J11332542-7011412 [5]

HD 100546 (also KR Muscae , KR Mus for short ) is a star in the constellation of Flies . The star lies 360 light years from the sun and has an apparent magnitude of 6.7 mag. Because of its gas and dust disk and the planet formation that most likely takes place there, it is of particular interest for astronomy.

The star

HD 100546 is a Herbig Ae / Be star ( spectral B9 Vne) and has a mass of 2.2 M ⊙ and effective temperature of about 9800 K . According to measurements by Hipparcos, the distance is approx. 320 ly ( π = 10.3 mas ) or according to measurements by Gaia approx. 360 ly ( π = 9.1 mas). Various age determinations range from 3.5 million years to 10 million years, with the focus of the newer provisions on 5 - 7 million years. The star is likely associated with the dark cloud DC 296.2-7.9, at the edge of which it is located. The accretion rate is some 10 −7 M ⊙ per year.

Gas and dust disc

HD 100546 is surrounded by a circumstellar disk with an inner cavity (a so-called transitional disk ). The asymmetrical, morphologically complex disk is as follows:

  • According to most studies, it is inclined 40 ° - 50 ° in relation to the face-on view.
  • The inner disk, which has an inner radius of 0.2 - 0.3 AU and an outer radius of a maximum of 0.7 AU, is located directly around the star .
  • This is followed by a largely gas and dust-free gap of up to ≈ 13 AU (the values ​​range from 10 - 16 AU) around the star.
  • This is followed by the outer disk, whose molecular gas, according to CO gas measurements, extends up to ≈ 400 AU around the star.
  • In addition, there is a thin halo of over 1,000 AU around the star.
  • The disk shows "spiral arms" or spiral structures, which could be observed particularly well with the Hubble space telescope and various explanations (e.g. disturbance of the disk by planets, reflection / shadow phenomena) are discussed as the cause.
  • The disc color is similar to that of Kuiper belt objects , suggesting that the same weathering processes are at work in both cases .
  • Observations of the dust continuum emission at the ALMA ( λ = 870 µm) show an asymmetrical ring around the star at 20 - 40 AU.

The disk mass (molecular gas in the disk with a radius of ≈ 400 AU around the star) is 0.001 - 0.01 M ⊙ according to 12 CO gas measurements . New ALMA measurements based on the carbon monoxide isotopologue C 18 O again show a higher, total gas mass of at least 0.018 M ⊙ ; In addition, the dust mass was calculated to be approx. 0.001 M ⊙ (ie gas-dust ratio ≈ 19). The inner disk has to be repeatedly fed by a flow mechanism from the outer disk, otherwise the accretion of the star would quickly use up the inner disk.

Substellar companions

HD 100546 shows as one of only a few known systems (e.g. also LkCa 15 , HD 169142 and MWC 758) clear signs of (gas) planet formation taking place. This offers astronomers the opportunity to study this process in person and thus to check theoretical models. A confirmed and probably another giant planet, whose formation processes have not yet been completed, orbit the star:

  • HD 100546 b is located ≈ 50 AU from the star embedded in the circumstellar disk and was discovered by Sascha Quanz and others as a protoplanet candidate (published in 2013) and confirmed as a protoplanet in 2015 (also by Sascha Quanz and others). The discovery was made by direct observation (engl. Direct imaging ) on the VLT / NACO where HD 100546 b as IR -Punktquelle in apparent distance of 0.5 "from the star with an apparent L'-brightness ( λ = 3.8 microns) from 13-14 mag was recorded. It is likely to be a Superjovian protoplanet with a circumferential planetary disk that still accretes mass. (: The emitting region in more detail) of ≈ 7 by the zirkumplanetare disc also the very large calculated radius of the object declared R J . The planetary mass was first estimated to be ≈ 15-20 M J ; later studies give masses 3-4 M J or 1.65 M J on. The orbital period around the star is about 250 years. In addition, the circumstellar disk has features that suggest an interaction between protoplanet and disk.
  • HD 100546 "c" : At the outer edge of the disc gap (≈ 10 AU distance to the star) there is a high probability of a massive planet or brown dwarf , especially since the disc gap itself is a clear indication of the presence of such an object. The IR spectroscopy of CO and OH emissions also provides strong indications of a rotating object near the pane wall (at ≈ 13 AU). Mass estimates for HD 100546 “c” range from 10-20 M J through 20 M J up to 60   +20−40M J . During the resolution of the disk cavity with the Gemini Planet Imager (GPI), a point source was discovered which could be the planet (a particularly bright disk part seems also conceivable). A later GPI observation did not confirm this possible direct observation.

See also

Web links

Individual evidence

  1. ↑ a b c Gaia Collaboration : Gaia DR2 . VizieR data catalog I / 345 (published electronically). 2018, bibcode : 2018yCat.1345 .... 0G . VizieR catalog entry .
  2. ↑ a b c Dolf de Winter et al. : A photometric catalog of southern emission-line stars . In: Astronomy and Astrophysics . Bd. 380, 2001, Table 3 (only available electronically) , bibcode : 2001A & A ... 380..609D , doi: 10.1051 / 0004-6361: 20011476 , arxiv : astro-ph / 0110495 .
  3. ↑ a b c d e f g Sascha P. Quanz et al. : Confirmation and Characterization of the Protoplanet HD 100546 b - Direct Evidence for Gas Giant Planet Formation at 50 AU . In: The Astrophysical Journal . Vol. 807, Ausg. 1, 2015, Art.-ID 64, bibcode : 2015ApJ ... 807 ... 64Q , doi: 10.1088 / 0004-637X / 807/1/64 , arxiv : 1412.5173 .
  4. ↑ a b Nancy Houk, Anne P. Cowley: Catalog of two dimentional spectral types for the HD stars, Vol. 1 . Department of Astronomy, University of Michigan , 1975, bibcode : 1975MSS ... C01 .... 0H . VizieR catalog entry .
  5. ↑ Nina V. Kharchenko et al. : 2nd Cat. of Radial Velocities with Astrometric Data . VizieR data catalog III / 254 (published electronically). 2007, bibcode : 2007yCat.3254 .... 0K . VizieR catalog entry .
  6. ↑ Derived from parallax ( π = 9.0892 ± 0.0509 mas, Gaia DR2 ).
  7. ↑ a b c d e f g Jaime E. Pineda et al. : High-resolution ALMA Observations of HD 100546: Asymmetric Circumstellar Ring and Circumplanetary Disk Upper Limits . In: The Astrophysical Journal , Vol. 871, Issue 1, 2019, Art.-ID 48, bibcode : 2019ApJ ... 871 ... 48P , doi: 10.3847 / 1538-4357 / aaf389 , arxiv : 1811.10365 .
  8. ↑ a b c d e John R. Fairlamb et al. : A spectroscopic survey of Herbig Ae / Be stars with X-shooter - I. Stellar parameters and accretion rates . In: Monthly Notices of the Royal Astronomical Society . Vol. 453, Ausg. 1, 2015, pp. 985, 990, bibcode : 2015MNRAS.453..976F , doi: 10.1093 / mnras / stv1576 , arxiv : 1507.05967 .
  9. ^ Floor van Leeuwen: Hipparcos, the New Reduction . VizieR data catalog I / 311 (published electronically). 2008, bibcode : 2008yCat.1311 .... 0V . VizieR catalog entry .
  10. ↑ Puravankara Manoj et al. : Evolution of Emission-Line Activity in Intermediate-Mass Young Stars . In: The Astrophysical Journal . Vol. 653, Ausg. 1, 2006, p. 666, bibcode : 2006ApJ ... 653..657M , doi: 10.1086 / 508764 , arxiv : astro-ph / 0608541 .
  11. ↑ Mario E. van den Ancker et al. : HIPPARCOS data on Herbig Ae / Be stars: an evolutionary scenario . In: Astronomy and Astrophysics . Bd. 324, 1997, L.34, bibcode : 1997A & A ... 324L..33V .
  12. ↑ Sergio Luiz Araújo Vieira, Mikhail A. Pogodin, Gabriel AP Franco: Spectroscopic study of the Herbig Be star HD 100546 . In: Astronomy and Astrophysics . Vol. 345, 1999, pp. 559-561, bibcode : 1999A & A ... 345..559V .
  13. ↑ a b Ignacio Mendigutía et al. : High-resolution Br γ spectro-interferometry of the transitional Herbig Ae / Be star HD 100546: a Keplerian gaseous disc inside the inner rim . In: Monthly Notices of the Royal Astronomical Society . Vol. 453, Ausg. 2, 2015, pp. 2126, 2131, bibcode : 2015MNRAS.453.2126M , doi: 10.1093 / mnras / stv1777 , arxiv : 1509.05411 .
  14. ↑ a b c d David R. Ardila et al. : Hubble Space Telescope Advanced Camera for Surveys Coronagraphic Observations of the Dust Surrounding HD 100546 . In: The Astrophysical Journal . Vol. 665, Ausg. 1, 2007, pp. 520, 524, 527, 531-533, bibcode : 2007ApJ ... 665..512A , doi: 10.1086 / 519296 .
  15. ↑ a b c Olja Panić et al. : Observations of warm molecular gas and kinematics in the disc around HD 100546 . In: Astronomy and Astrophysics . Bd. 519, 2010, Art.-ID A110, bibcode : 2010A & A ... 519A.110P , doi: 10.1051 / 0004-6361 / 200913709 , arxiv : 1005.1048 .
  16. ↑ a b Narges Jamialahmadi et al. : Constraining the gap size in the disk around HD 100546 in the mid-infrared . In: The Astrophysical Journal . Bd. 865, Ausg. 2, 2018, Art.-ID 137, bibcode : 2018ApJ ... 865..137J , doi: 10.3847 / 1538-4357 / aadae4 , arxiv : 1808.05052 .
  17. ↑ a b c Gijs D. Mulders et al. : Planet or brown dwarf? Inferring the companion mass in HD 100546 from the wall shape using mid-infrared interferometry . In: Astronomy & Astrophysics . Bd. 557, 2013, Art.-ID A68, bibcode : 2013A & A ... 557A..68M , doi: 10.1051 / 0004-6361 / 201220930 , arxiv : 1306.4264 .
  18. ↑ a b Olja Panić et al. : Resolving HD 100546 disc in the mid-infrared: Small inner disc and asymmetry near the gap . In: Astronomy & Astrophysics . Bd. 562, 2014, Art-ID A101, bibcode : 2014A & A ... 562A.101P , doi: 10.1051 / 0004-6361 / 201219223 , arxiv : 1203.6265 .
  19. ↑ a b Jeroen Bouwman: The origin of crystalline silicates in the Herbig Be star HD 100546 and in comet Hale-Bopp . In: Astronomy and Astrophysics . Vol. 401, 2003, p. 577, bibcode : 2003A & A ... 401..577B , doi: 10.1051 / 0004-6361: 20030043 , arxiv : astro-ph / 0301254
  20. ↑ a b c Bram Acke, Mario E. van den Ancker: Resolving the disk rotation of HD 97048 and HD 100546 in the [OI] 6300 Å line: evidence for a giant planet orbiting HD 100546 . In: Astronomy and Astrophysics . Vol. 449, Ausg. 1, 2006, p. 267, bibcode : 2006A & A ... 449..267A , doi: 10.1051 / 0004-6361: 20054330 , arxiv : astro-ph / 0512562 .
  21. ↑ Myriam Benisty et al. : The complex structure of the disk around HD 100546. The inner few astronomical units . In: Astronomy and Astrophysics . Vol. 511, 2010, Art.-ID A75, bibcode : 2010A & A ... 511A..75B , doi: 10.1051 / 0004-6361 / 200913590 , arxiv : 1001.2491 .
  22. ↑ a b James M. Miley et al. : Asymmetric mid-plane gas in ALMA images of HD 100546 . In: Monthly Notices of the Royal Astronomical Society . Vol. 485, Ausg. 1, 2019, p. 739, bibcode : 2019MNRAS.485..739M , doi: 10.1093 / mnras / stz426 , arxiv : 1902.07506 .
  23. ↑ Anthony Boccaletti et al. : Multiple spiral patterns in the transitional disk of HD 100546 . In: Astronomy & Astrophysics . Vol. 560, 2013, Art.-ID A20, bibcode : 2013A & A ... 560A..20B , doi: 10.1051 / 0004-6361 / 201322365 , arxiv : 1310.7092 .
  24. ↑ a b c d Sascha P. Quanz et al. : Young Protoplanet Candidate Embedded in the Circumstellar Disk of HD 100546 . In: The Astrophysical Journal Letters . Vol. 766, Issue 1, 2013, Art.-ID L1, bibcode : 2013ApJ ... 766L ... 1Q , doi: 10.1088 / 2041-8205 / 766/1 / L1 , arxiv : 1302.7122 .
  25. ↑ a b c d Thayne Currie et al. : Resolving the HD 100546 Protoplanetary System with the Gemini Planet Imager: Evidence for Multiple Forming, Accreting Planets . In: The Astrophysical Journal Letters . Vol. 814, Issue 2, 2015, Art.-ID L27, bibcode : 2015ApJ ... 814L..27C , doi: 10.1088 / 2041-8205 / 814/2 / L27 , arxiv : 1511.02526 .
  26. ↑ Sean D. Brittain et al. : NIR Spectroscopy of the HAeBe Star HD 100546. III. Further Evidence of an Orbiting Companion? In: The Astrophysical Journal . Vol. 791, Issue 2, 2014, Art.-ID 136, bibcode : 2014ApJ ... 791..136B , doi: 10.1088 / 0004-637X / 791/2/136 , arxiv : 1409.0804 .
  27. ↑ Katherine B. Follette et al. : Complex Spiral Structure in the HD 100546 Transitional Disk as Revealed by GPI and MagAO . In: The Astronomical Journal . Bd. 153, Ausg. 6, 2017, Art.-ID 264, bibcode : 2017AJ .... 153..264F , doi: 10.3847 / 1538-3881 / aa6d85 , arxiv : 1704.06260 .