The Deuterium-burning Mass Limit for Brown Dwarfs and Giant Planets

• Published in: The Astrophysical journal Vol. 727; no. 1; pp. 57 - jQuery1323911857911='48'
• Main Authors: Spiegel, David S, Burrows, Adam, Milsom, John A
• Format: Journal Article
• Language: English
• Published: United States IOP Publishing 20.01.2011
• Subjects: ABUNDANCE; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DEUTERIUM; ELEMENT ABUNDANCE; ENERGY TRANSFER; EVOLUTION; HEAT TRANSFER; HYDROGEN ISOTOPES; IGNITION; ISOTOPES; LIGHT NUCLEI; MASS; NUCLEI; ODD-ODD NUCLEI; PLANETS; RADIANT HEAT TRANSFER; STABLE ISOTOPES; STAR EVOLUTION
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/727/1/57

There is no universally acknowledged criterion to distinguish brown dwarfs from planets. Numerous studies have used or suggested a definition based on an object's mass, taking the ~13 Jupiter mass (MJ ) limit for the ignition of deuterium. Here, we investigate various deuterium-burning masses for a range of models. We find that, while 13 MJ is generally a reasonable rule of thumb, the deuterium fusion mass depends on the helium abundance, the initial deuterium abundance, the metallicity of the model, and on what fraction of an object's initial deuterium abundance must combust in order for the object to qualify as having burned deuterium. Even though, for most proto-brown dwarf conditions, 50% of the initial deuterium will burn if the object's mass is ~(13.0 ? 0.8) MJ , the full range of possibilities is significantly broader. For models ranging from zero-metallicity to more than three times solar metallicity, the deuterium-burning mass ranges from ~11.0 MJ (for three times solar metallicity, 10% of initial deuterium burned) to ~16.3 MJ ( for zero metallicity, 90% of initial deuterium burned).