About C/2019 Y4-D (ATLAS)
C/2019 Y4-D (ATLAS) is a rare comet. It swings within 0.255 AU of the Sun at perihelion.
A Halley-type comet: 20 to 200 years per lap, on a steeply tilted orbit that reaches far beyond the planets.
Rare comet 34 EP
C/2019 Y4-D (ATLAS)
Position computed live · sbdb
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Live ephemeris
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Score breakdown
· 4 badgesRare 50 pts → Epic
- Halley-type comet +16
- Has a proper name +8
- Comet +6
- Steeply tilted orbit (i > 40°) +4
Total score 34
16 more points to reach Epic.
Badges
- Comet · +6
- Has a proper name · +8
- Halley-type comet · +16
- Steeply tilted orbit (i > 40°) · +4
Trivia
What it actually is
- Its orbit family. A Halley-type comet: 20 to 200 years per lap, on a steeply tilted orbit that reaches far beyond the planets.
- Closest approach. At its nearest it comes within 0.26 AU of the Sun — inside the orbit of Mercury.
- One lap. A single orbit around the Sun takes it about 107 years.
- How far it roams. Its orbit swings between 0.26 and 44.9 AU from the Sun.
Standing on it
- Sunlight there. At closest approach the Sun beats down about 15.4 times harder than it ever does on Earth.
- Growing a tail. Once inside roughly the orbit of Mars the ice starts turning straight to gas, blowing out the coma and tail that make a comet a comet.
- Tail. Its tail always points away from the Sun, never trailing behind its motion — it is blown, not dragged.
By the numbers
- Made of. A comet is a dirty snowball: water ice, frozen carbon dioxide and dust, held together loosely enough that some simply crumble when the Sun warms them.
Properties
- aphelion au
- 44.91
- designation
- 2019 Y4-D
- eccentricity
- 0.9887
- full name
- C/2019 Y4-D (ATLAS)
- inclination
- 44.82
- mean motion deg day
- 0.0092
- moid au
- 0.625
- name
- C/2019 Y4-D (ATLAS)
- named
- yes
- orbit class
- HTC
- perihelion au
- 0.255
- semi major au
- 22.58
How to see it
Like any astronomical target, C/2019 Y4-D (ATLAS) is best seen from a dark site away from city lights, and when it is above the horizon depends on your latitude and the time of year. Because it moves against the background stars, the live position panel on this page tracks where it is right now. The visibility panel above works out tonight's viewing window for your saved location.
Why C/2019 Y4-D (ATLAS) is a rare comet
C/2019 Y4-D (ATLAS) scores 34 points on Spacedle's rarity scale, which places it in the rare tier. Another 16 points would lift it into a rarer tier.
That score comes from 4 science badges — Comet, Has a proper name, Halley-type comet and Steeply tilted orbit (i > 40°) — each earned for a real, measurable property of the object. Rarity on Spacedle is never random: the more remarkable an object's astrophysics, the more badges it collects, the higher it scores, and the rarer it ranks.