Community hub
Recent from talks
Knowledge base stats:
Talk channels stats:
Members stats:
HD 100546
HD 100546, also known as KR Muscae, is a pre-main sequence star of spectral type B8 to A0 located 353 light-years (108 parsecs) from Earth in the southern constellation of Musca. 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.
Estimated to be less than 10 million years old, it belongs to Herbig Ae/Be stars, and also the nearest example to the Solar System.
The HD 100546 system as a whole has evidence for three protoplanets, thus it is considered an important evolutionary precursor to intermediate-mass stars with multiple super-jovian planets at moderate/wide separations like HR 8799. While other hypothetical planets have been claimed to exist around the star, none of the discoveries have been confirmed.
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. The flux from HD 100546 b and its circumplanetary disk (CPD) are superimposed, leaving its properties such the radius and temperature thus very uncertain.
Various estimates for the mass of HD 100546 b has been varying between 1 and 25 MJ. Although standard hot-start models imply a mass of approximately 15 MJ, other models and HD 100546 b's H-band photometry implies masses below 10 MJ for a 1-million-years-old newly born planet or if made visible by its CPD, while older ages suggest higher masses. More recently in 2019 an upper limit for the planetary mass was given to be as low as 1.65 MJ based on the relation between the planet, CPD, and circumstellar disk (CSD) masses derived from numerical simulation. The CPD has been assumed to be optically thin with derived upper mass and radius limits of 1.44 times as massive as Earth (M🜨) and 0.44 astronomical unit (AU), while the mass of CSD was given to be 50 MJ. While gas-starved models are also still compatible, this would suggest that HD 100546 b is inconsistent with several planet accretion models.
Fitting a single temperature blackbody to the observed fluxes of the point source component gives a very large radius of 6.9+2.7
−2.9 times that of Jupiter (RJup) and an effective temperature of 932+193
−202 K for the emitting area surrounding the embedded protoplanet respectively. This large radius refers to the diffuse dust and gas envelope or debris disk surrounding the planet, not the planet itself; these estimates are mistakenly used as a single planetary radius and effective temperature for HD 100546 b by the NASA Exoplanet Archive. A best-fit luminosity was also found by the same study to be 2.3+0.6
−0.4×10−4 times as luminous as the Sun (L☉).
Despite the uncertainty of the planet's properties, a 2017 study calculated HD 100546 b as a very highly reddened substellar object with a good-fit effective temperature of 2,630 K and a planetary mass and radius of 25 MJup and 3.4 RJup, making it still one of the largest exoplanets discovered by size.
In April 2003, another planetary companion candidate was proposed and evidence was later gathered using the UVES echelle spectrograph at the VLT in Chile in 2005. This confirms other data indicating a planetary companion with a mass approximately 20 MJ and a distance of 6.5 AU from HD 100546, although further examination of the disk profile indicates it might be a more massive object such as a brown dwarf or more than one planet.
Hub AI
HD 100546 AI simulator
(@HD 100546_simulator)
HD 100546
HD 100546, also known as KR Muscae, is a pre-main sequence star of spectral type B8 to A0 located 353 light-years (108 parsecs) from Earth in the southern constellation of Musca. 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.
Estimated to be less than 10 million years old, it belongs to Herbig Ae/Be stars, and also the nearest example to the Solar System.
The HD 100546 system as a whole has evidence for three protoplanets, thus it is considered an important evolutionary precursor to intermediate-mass stars with multiple super-jovian planets at moderate/wide separations like HR 8799. While other hypothetical planets have been claimed to exist around the star, none of the discoveries have been confirmed.
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. The flux from HD 100546 b and its circumplanetary disk (CPD) are superimposed, leaving its properties such the radius and temperature thus very uncertain.
Various estimates for the mass of HD 100546 b has been varying between 1 and 25 MJ. Although standard hot-start models imply a mass of approximately 15 MJ, other models and HD 100546 b's H-band photometry implies masses below 10 MJ for a 1-million-years-old newly born planet or if made visible by its CPD, while older ages suggest higher masses. More recently in 2019 an upper limit for the planetary mass was given to be as low as 1.65 MJ based on the relation between the planet, CPD, and circumstellar disk (CSD) masses derived from numerical simulation. The CPD has been assumed to be optically thin with derived upper mass and radius limits of 1.44 times as massive as Earth (M🜨) and 0.44 astronomical unit (AU), while the mass of CSD was given to be 50 MJ. While gas-starved models are also still compatible, this would suggest that HD 100546 b is inconsistent with several planet accretion models.
Fitting a single temperature blackbody to the observed fluxes of the point source component gives a very large radius of 6.9+2.7
−2.9 times that of Jupiter (RJup) and an effective temperature of 932+193
−202 K for the emitting area surrounding the embedded protoplanet respectively. This large radius refers to the diffuse dust and gas envelope or debris disk surrounding the planet, not the planet itself; these estimates are mistakenly used as a single planetary radius and effective temperature for HD 100546 b by the NASA Exoplanet Archive. A best-fit luminosity was also found by the same study to be 2.3+0.6
−0.4×10−4 times as luminous as the Sun (L☉).
Despite the uncertainty of the planet's properties, a 2017 study calculated HD 100546 b as a very highly reddened substellar object with a good-fit effective temperature of 2,630 K and a planetary mass and radius of 25 MJup and 3.4 RJup, making it still one of the largest exoplanets discovered by size.
In April 2003, another planetary companion candidate was proposed and evidence was later gathered using the UVES echelle spectrograph at the VLT in Chile in 2005. This confirms other data indicating a planetary companion with a mass approximately 20 MJ and a distance of 6.5 AU from HD 100546, although further examination of the disk profile indicates it might be a more massive object such as a brown dwarf or more than one planet.