Is aragorn half elf

Answer 1

YES!

Let me tell you a little story. Eärendil and Elwing, both Half-elven, in the year 532 of the First Age had twin sons, Elros and ... we'll talk about the second one later. Elros chose to become mortal, and he is the first in a very, very long line of Númenoreans and Dúnedain including Elendil, Isildur, and Arathorn II who was the father of Aragorn (aka Aragorn II). When Aragorn was about two years old, his father was killed by orcs then he was taken by his Mother, Gilraen, to Rivendell. Meanwhile, Elros' twin brother, Elrond, chose to remain with the Elves, and he was the father of Arwen. So Aragorn and Arwen (who was almost 2700 years old at the time they met) are actually way, way, way removed cousins. Arwen, by the way, is also the grand-daughter of Galadriel on her mother's (Celebrían) side of the tree.

Side Note: Aragorn would have been in his middle twenties when Bilbo Baggins (aged 50) first visited the Last Homely House (in Rivendell) with the 13 dwarves and Gandalf.

Both of Aragorn's parents were of the Dúnedain from the western island of Númenor. Númenor is not the Undying Lands (Aman), which is much farther to the west, though the Númenoreans lived longer than the humans of Middle-earth, and Aragorn, himself, lived to the age of 210 years. To answer your question, yes, Aragorn is half-Elven, and so is Arwen.