HR 6819, also known as HD 167128 or QV Telescopii (abbreviated QV Tel), is a triple star system in the southern constellation of Telescopium. It is situated in the south-western corner of the constellation, near its boundary with Pavo and Ara. The system appears as a variable star that is dimly visible to the naked eye with an apparent magnitude that ranges from 5.32 down to 5.39, which is comparable to the maximum brightness of the planet Uranus. It is 1,120 light years from the Sun, and is drifting farther away at a rate of 9.4 km/s. A May 2020 study reported that the system contains a black hole, making the latter the closest known black hole, and the first one located in a star system visible to the naked eye. Because of its location in the sky, it is visible only to observers south of 33°N latitude.
Notation specification
A production rule consists of two parts:
Non-terminal = Right Part
(Note that every grammar requires a Non-terminal START
symbol as
default entry point)
This right part consists of at least one alternative, which is made up from
frequency symbol1 symbol2 ...
A symbol is a Non-terminal or a Terminal
A Terminal is enclosed in quotes like letter 's' or the
word 'house'
| Labial | Coronal | Dorsal | Laryngeal | |||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| BL | LD | LL | D | AL | PA | RF | P | V | U | EG | G | |||||||||||||||
| · | · | · | · | · | · | · | · | · | · | · | · | · | ||||||||||||||
| O | p | b | p̪ | b̪ | t̼ | d̼ | t | d | ʈ | ɖ | c | ɟ | k | ɡ | q | ɢ | ʔ | |||||||||
| N | m | ɱ | n̼ | n | ɳ | ɲ | ŋ | ɴ | ||||||||||||||||||
| R | ʙ | ⱱ | r̼ | r̥ r ɾ | ɽ | ʀ | ||||||||||||||||||||
| F | ɸ | β | f | v | θ̼ | ð̼ | θ | ð | s | z | ʃ | ʒ | ʂ | ʐ | ç | ʝ | x | ɣ | χ | ʁ | ħ | ʕ | h | ɦ | ||
| A | ʋ | ɹ | ɻ | j | ɰ | |||||||||||||||||||||
| L | ɬ̼ ɮ̼ l̼ | ɬ ɮ l | ɭ | ʎ | ʟ | |||||||||||||||||||||
| I | ƥ | ɓ | ƭ | ɗ | ᶑ | ƈ | ʄ | ƙ | ɠ | ʠ | ʛ | |||||||||||||||
| CH | ʘ | ǀ̼ | ǀ | ǁ | ǃ | ǂ | ||||||||||||||||||||
| 1 | 2 | 3 | ||||
|---|---|---|---|---|---|---|
| 1u | 1r | 2u | 2r | 3u | 3r | |
| vC | i | y | ɨ | ʉ | ɯ | u |
| vCn | ĩ | ỹ | ɨ̃ | ʉ̃ | ɯ̃ | ũ |
| vCM | ɪ | ʏ | ʊ | |||
| vCMn | ɪ̃ | ʏ̃ | ʊ̃ | |||
| vMC | e | ø | ɘ | ɵ | ɤ | o |
| vMCn | ẽ | ø̃ | ɘ̃ | ɵ̃ | ɤ̃ | õ |
| vM | ə | |||||
| vMn | ə̃ | |||||
| vMA | ɛ | œ | ɜ | ɞ | ʌ | ɔ |
| vMAn | ɛ̃ | œ̃ | ɜ̃ | ɞ̃ | ʌ̃ | ɔ̃ |
| vAM | æ | ɐ | ||||
| vAMn | æ̃ | ɐ̃ | ||||
| vA | a | ɶ | ɑ | ɒ | ||
| vAn | ã | ɶ̃ | ɑ̃ | ɒ̃ | ||