Top Tweets for #StarryThursday
#StarryThursday
If the pulsating star is a Population II star they are named Type II Cepheids. They have three different subclasses according to their different periods: few days (BL Her), a couple of weeks (W Virginis) or almost a month (RV Tauri).
#StarryThursday
The easiest way to detect a WR star is from a spectrum. Stellar spectra shows absorption lines, while there are emission lines in the spectra of WR stars. They are normally He lines, but might show emission lines of carbon or nitrogen as well.
#StarryThursday
M-type stars are the coolest & less massive stars, between 60% & 10% of the solar mass. Their surface temperatures are between 3800 & 2300 K which give them a very red colour. There are two main type of M stars: dwarfs, which are Main Sequence stars & giants,
#StarryThursday
B-type stars are the second more luminous stars, they can be up to 15 times more massive than the Sun & up to 10 times larger. With surface temperatures between 11,000 & 30,000 K, their colours are blueish and the main spectral characteristic is the
#StarryThursday
A-type stars are those where the hydrogen lines are the most prominent. Their masses are larger than the Sun, between 1.5 & 2.5 Ms, with radius between 1.5 & 1.9 Rs. Their surface temperature are between 7100 to 9700. All these parameters increase from
#StarryThursday
The lifetime of a star is related with its mass (t= cte M^-3), so the larger the mass the less the star will live. The typical mass of a G-type stars is 1 Ms (=solar mass) and they have a lifetime of about 10^10 years.
Another example of G-star is 61 Virginis
#StarryThursday
Another stellar classification was introduced in 1943 by astronomer of Yerkes Obs. At that time it was clear that temperature was the main parameter driving the scheme, so both the T and the luminosity (or surface gravity because it is different in a giant star +
#StarryThursday
The corona ends when it has the same density than the interplanetary medium. However, there are a lot of particles which still have a velocity & they move into the planetary system. This is called solar wind & there is not only protons or Helium nuclei but also
#StarryThursday
The solar corona is the most external part of the Sun and the largest!! It extends about 1 million kms until the corona density, of 10^-12 the density of the surface, equals the density of the Interplanetary medium.
#StarryThursday
This is the most close and recent image of the Sun. The news is that we can see very tiny bright dots in Ultraviolet. This means they are really hot. We do not know yet what are they, maybe some small convective cells, coming from very deep into the interior?
#StarryThursday
The most interesting part of the Sun (for us) is the surface. It is called photosphere (sphere of light in greek). The photons created in the core escape from the Sun at the photosphere & star travelling into the Universe. Some of them hit the Earth and our eyes,
#StarryThursday
If you look at the core you will find out if a ball of gas is a star. If the density and the tempeture are high enough, two protons will became one deuterium, which will fusion with another proton to form 3He. Then, two of 3He will become 4He..
#StarryThursday
The only observable part of the Sun is the surface, called Photosphere (sphere of light in greek). Inside (invisible) there is a nucleos where Hydrogen is turning into Helium, a zone where photons created at the nucleus travel towards the surface & an atmosphere.
#StarryThursday
Although large & impressive from the human point of view, with its 1,000,000,000,000,000,000,000,000,000,000,000 g of mass & its 700000 km of radius, the Sun is a small star. Its thick? be so close!
In the picture a comparison with other naked-eye observed stars
#StarryThursday
The Sun had been considered a god in many of the ancient culture on Earth. The reason is we are alive because of it. The Earth is located at an optimal distance from it, so there is liquid water on Earth surface. This fact defines the "habitable zone" for stars.
#StarryThursday
Sometimes the line of sight of the observer towards the binary system is crossed by the plane of the orbit, therefore we will see an eclipse every time one of the stars pass in front of us. The first eclipsing binary system discovered was Algol.
#StarryThursday
Stars are born in groups, several hundreds at a time. After a while, most of them abandon such groups & become independent. However, many are attached to each other and form a binary (or triple) system. These systems are very common.
#StarryThursday
LBV stars are very luminous but not quite hot (between 10000 & 25000 K). However, during an outburst temperature drops to 8500 K although the luminosity has not a constant behaviour for all the stars: in some of them it increases one magnitude or decreases a lot.
#StarryThursday
A WR star is named as N, C or O if the most dominat lines are Nitrogen, Carbon or Oxygen. It's though that there is a evolution between them, with a WN becoming a WC if the helium burning core is exposed. WO are quite rare & are the evolution of very massive stars
Last Seen Hashtags on Sotwe
กระเทยรับงาน
Seen from Thailand
anxiouspanda
Seen from Canada
18YearOld
Seen from Turkey
معصيتّيَ_رِحّتِي
diyarbakırtravesti
Seen from Turkey
futanari furry
Seen from United States
Accidental cum
Seen from Netherlands
snapchat
Seen from United States
realmomson
Seen from Egypt
animalmating
Seen from Turkey
Most Popular Users
Elon Musk 
@elonmusk
241.5M followers
Barack Obama
@barackobama
118.9M followers
Cristiano Ronaldo
@cristiano
114.6M followers
Donald J. Trump
@realdonaldtrump
111.8M followers
Narendra Modi
@narendramodi
107.1M followers
Rihanna
@rihanna
98.7M followers
NASA
@nasa
92.3M followers
Justin Bieber
@justinbieber
91.8M followers
KATY PERRY
@katyperry
90M followers
Taylor Swift
@taylorswift13
84M followers
Lady Gaga
@ladygaga
75.5M followers
Virat Kohli
@imvkohli
73.5M followers
Kim Kardashian
@kimkardashian
70.9M followers
YouTube
@youtube
68.8M followers
Neymar Jr
@neymarjr
66.5M followers
Bill Gates
@billgates
65.2M followers
Selena Gomez
@selenagomez
63.1M followers
The Ellen Show
@theellenshow
62.2M followers
CNN
@cnn
61.8M followers
X
@x
60.7M followers