I actually thought that would be when the star starts fusing hydrogen into helium... But apparently there are other stages between those two.
According to Wikipedia, "[The protostar phase] ends when the protostar blows back the infalling gas and is revealed as an optically visible pre-main-sequence star, which later contracts to become a main sequence star."Pre-main sequence means the star is not yet on the main sequence; and that, in turn, basically means that it is not yet fusing hydrogen into helium.
The temperature at which hydrogen fuses is 10,000,000 degrees Kelvin. This is the minimum temperature the core of a proto star has to have to become a true star.
They are called oncogenes.
Proto-oncogenes stop cells dividing too often. When a mutation occurs to proto-oncogenes this is when cancer can occur, as there is then no hay-flick limit (normally cells have a limit to how many times then can divide) cells are able to replicate uncontrollably.
A proto-oncogene is a normal gene that helps regulate cell growth and division, while an oncogene is a mutated form of a proto-oncogene that promotes uncontrolled cell growth, leading to cancer. Proto-oncogenes can become oncogenes through mutations that cause them to be constantly activated or overexpressed.
Approximately 1.4 times the mass of the sun, known as the Chandrasekhar limit, is required for a star to become a neutron star. If a star has a mass greater than this limit, it will likely undergo a supernova explosion and collapse into a neutron star.
A protostar becomes a star when nuclear fusion is initiated in its core. This process starts when the temperature and pressure in the core reach a critical point, enabling hydrogen atoms to fuse into helium. Once this fusion reaction begins, the star will start to shine and enter the main sequence phase of its life cycle.
The temperature at which hydrogen fuses is 10,000,000 degrees Kelvin. This is the minimum temperature the core of a proto star has to have to become a true star.
Compression. Whenever anything is compressed, it heats up. In a proto-star, clouds of hydrogen gas are compressed by gravitational attraction, and the compression heats the gas.
They are called oncogenes.
A "proto-star".
Proto-oncogenes are normal genes that help regulate cell growth and division. When mutated or altered, they can become oncogenes, which promote uncontrolled cell growth and can lead to cancer. The main difference is that proto-oncogenes are normal genes that can become oncogenes through mutations.
No one. It comes from the Greek - proto - meaning first. So first star - a protostar.
A 'proplid', or a proto-stellar object, often called a proto-star, and some believe (as I do) that 'Herbig-Haro Objects', are newly formed stars. At any rate, a star is a mass of gas in space made hot by nuclear reactions.
False. Proto-oncogenes are genes that can potentially become oncogenes, which are associated with cancer development. They are present in all individuals, not just those with cancer.
Stars form from gas clouds when gravity causes the gas to condense and heat up, eventually reaching temperatures and pressures that trigger nuclear fusion. This fusion reaction releases energy, causing the proto-star to shine and become a fully-fledged star.
A disk of gas ad dust that forms round a proto-star as the star coalesces at the center and from which planets accurate. The related links below give more information.
Our Solar System Formed from the remnants of a star wich went supernovae (at least approx 5 billion years ago) the dust from that star started to condense (due to the passing another star or some other mechanism), spinning counter-clockwise, the pressure at the center of this cloud became great enough to start a process know as nuclear fussion (triple alpha process) creating a proto-star, wich was significantly dimmer and smaller than todays Sol. The remaining dust accreted to from proto-planets (maybe upwards of 100), These proto-Planets smashed into each-other and merged to become the inner planets. As for our gas-giants, they formed from cold gas and dust, beyond what is known as the "Frost Line" due to the required colder temperatures to form Gas Planets.