Steve Costa
@stevec72.bsky.social
I make digital things, and sometimes actual things.
Explore our stellar neighborhood in 3D: https://starcarta.app
Explore our stellar neighborhood in 3D: https://starcarta.app
Space telescopes launched in the past 20 years have been huge for discovering new exoplanets.
Kepler: Kepler-42
starcarta.app/o/CwNdx
TESS: GJ 357
starcarta.app/o/qDVk
GAIA: Gaia-5
starcarta.app/o/QXrzM
Kepler: Kepler-42
starcarta.app/o/CwNdx
TESS: GJ 357
starcarta.app/o/qDVk
GAIA: Gaia-5
starcarta.app/o/QXrzM
December 11, 2025 at 4:40 AM
Space telescopes launched in the past 20 years have been huge for discovering new exoplanets.
Kepler: Kepler-42
starcarta.app/o/CwNdx
TESS: GJ 357
starcarta.app/o/qDVk
GAIA: Gaia-5
starcarta.app/o/QXrzM
Kepler: Kepler-42
starcarta.app/o/CwNdx
TESS: GJ 357
starcarta.app/o/qDVk
GAIA: Gaia-5
starcarta.app/o/QXrzM
Doppler / Radial Velocity: 51 Pegasi b
starcarta.app/o/lrXM
Transit / Brightness: HAT-P-11 b
starcarta.app/o/GdMg
Astrometry: Epsilon Eridani b
starcarta.app/o/QmpD
starcarta.app/o/lrXM
Transit / Brightness: HAT-P-11 b
starcarta.app/o/GdMg
Astrometry: Epsilon Eridani b
starcarta.app/o/QmpD
December 11, 2025 at 4:40 AM
Doppler / Radial Velocity: 51 Pegasi b
starcarta.app/o/lrXM
Transit / Brightness: HAT-P-11 b
starcarta.app/o/GdMg
Astrometry: Epsilon Eridani b
starcarta.app/o/QmpD
starcarta.app/o/lrXM
Transit / Brightness: HAT-P-11 b
starcarta.app/o/GdMg
Astrometry: Epsilon Eridani b
starcarta.app/o/QmpD
Matt O'Dowd also described the major exoplanet detection methods. Here’s one example system discovered with each.
Direct Imaging: β Pictoris
starcarta.app/o/CWhtZ
Direct Imaging: β Pictoris
starcarta.app/o/CWhtZ
December 11, 2025 at 4:40 AM
Matt O'Dowd also described the major exoplanet detection methods. Here’s one example system discovered with each.
Direct Imaging: β Pictoris
starcarta.app/o/CWhtZ
Direct Imaging: β Pictoris
starcarta.app/o/CWhtZ
Sirius A & B ✨
The brightest star in the sky. No known planets, but it has a massive, super-hot white dwarf companion roughly Earth-sized: starcarta.app/o/WxDz
The brightest star in the sky. No known planets, but it has a massive, super-hot white dwarf companion roughly Earth-sized: starcarta.app/o/WxDz
December 11, 2025 at 4:40 AM
Sirius A & B ✨
The brightest star in the sky. No known planets, but it has a massive, super-hot white dwarf companion roughly Earth-sized: starcarta.app/o/WxDz
The brightest star in the sky. No known planets, but it has a massive, super-hot white dwarf companion roughly Earth-sized: starcarta.app/o/WxDz
The latest PBS Space Time digs into the complexities of finding habitable exoplanets (www.youtube.com/watch?v=mPFF...)
Let's go through some systems mentioned, starting w/Trappist-1.
A 7-planet system whose worlds all orbit within 10% of the Earth-Sun distance. starcarta.app/o/jkSG
Let's go through some systems mentioned, starting w/Trappist-1.
A 7-planet system whose worlds all orbit within 10% of the Earth-Sun distance. starcarta.app/o/jkSG
December 11, 2025 at 4:40 AM
The latest PBS Space Time digs into the complexities of finding habitable exoplanets (www.youtube.com/watch?v=mPFF...)
Let's go through some systems mentioned, starting w/Trappist-1.
A 7-planet system whose worlds all orbit within 10% of the Earth-Sun distance. starcarta.app/o/jkSG
Let's go through some systems mentioned, starting w/Trappist-1.
A 7-planet system whose worlds all orbit within 10% of the Earth-Sun distance. starcarta.app/o/jkSG
Mini Starcarta update: I’ve improved the fidelity of protoplanetary disks and dust rings around stars. For a good example of one, let’s take a look at Fomalhaut!
#space #starcarta #indiedev
starcarta.app/o/gNnB
#space #starcarta #indiedev
starcarta.app/o/gNnB
November 13, 2025 at 1:36 AM
Mini Starcarta update: I’ve improved the fidelity of protoplanetary disks and dust rings around stars. For a good example of one, let’s take a look at Fomalhaut!
#space #starcarta #indiedev
starcarta.app/o/gNnB
#space #starcarta #indiedev
starcarta.app/o/gNnB
Try it on 83 Leonis, a binary 59 ly away with two planets on the B star: starcarta.app/o/tQlX
October 11, 2025 at 1:39 AM
Try it on 83 Leonis, a binary 59 ly away with two planets on the B star: starcarta.app/o/tQlX
🛰️ Starcarta Update 1.4!
✨ New:
- Star focus
Stars in multiple systems can be far apart making it difficult to zoom in. Now by clicking on a Star’s name, you can zoom in on that star and its planets. Clicking the Star’s name again toggles you back to the the System.
#space #astronomy #indiedev
✨ New:
- Star focus
Stars in multiple systems can be far apart making it difficult to zoom in. Now by clicking on a Star’s name, you can zoom in on that star and its planets. Clicking the Star’s name again toggles you back to the the System.
#space #astronomy #indiedev
October 11, 2025 at 1:38 AM
🛰️ Starcarta Update 1.4!
✨ New:
- Star focus
Stars in multiple systems can be far apart making it difficult to zoom in. Now by clicking on a Star’s name, you can zoom in on that star and its planets. Clicking the Star’s name again toggles you back to the the System.
#space #astronomy #indiedev
✨ New:
- Star focus
Stars in multiple systems can be far apart making it difficult to zoom in. Now by clicking on a Star’s name, you can zoom in on that star and its planets. Clicking the Star’s name again toggles you back to the the System.
#space #astronomy #indiedev
Recently, JWT studied Trappist-1e’s atmosphere ruling out a Venus or Mars-like atmosphere but leaving water possible for future studies. science.nasa.gov/missions/web... Check it at starcarta.app/o/jkSG - you can also see how all of the 7 discovered planets are less than 1 au from Trappist-1
September 26, 2025 at 9:56 PM
Recently, JWT studied Trappist-1e’s atmosphere ruling out a Venus or Mars-like atmosphere but leaving water possible for future studies. science.nasa.gov/missions/web... Check it at starcarta.app/o/jkSG - you can also see how all of the 7 discovered planets are less than 1 au from Trappist-1
1 AU Graph
Orbits can be hard to compare. Toggle a dotted circle at Earth’s orbit (1 AU) around stars to make comparisons easier. Helps show scale since stars give few clues about size. (4/4) Try it out at starcarta.app
Orbits can be hard to compare. Toggle a dotted circle at Earth’s orbit (1 AU) around stars to make comparisons easier. Helps show scale since stars give few clues about size. (4/4) Try it out at starcarta.app
September 26, 2025 at 12:25 AM
1 AU Graph
Orbits can be hard to compare. Toggle a dotted circle at Earth’s orbit (1 AU) around stars to make comparisons easier. Helps show scale since stars give few clues about size. (4/4) Try it out at starcarta.app
Orbits can be hard to compare. Toggle a dotted circle at Earth’s orbit (1 AU) around stars to make comparisons easier. Helps show scale since stars give few clues about size. (4/4) Try it out at starcarta.app
Tag Highlighting!
Click a Tag to highlight all Star Systems linked to it, then click a System name to travel there. Get a good perspective of the set in 3D space around us. (3/4)
Click a Tag to highlight all Star Systems linked to it, then click a System name to travel there. Get a good perspective of the set in 3D space around us. (3/4)
September 26, 2025 at 12:24 AM
Tag Highlighting!
Click a Tag to highlight all Star Systems linked to it, then click a System name to travel there. Get a good perspective of the set in 3D space around us. (3/4)
Click a Tag to highlight all Star Systems linked to it, then click a System name to travel there. Get a good perspective of the set in 3D space around us. (3/4)
First: Tags!
Add a tag to any star system to categorize it by feature (Gas Planets, Rings), multiplicity (Binary, Triple), or movie franchise (Alien, Star Trek, Dune). Anything you like! (2/4)
Add a tag to any star system to categorize it by feature (Gas Planets, Rings), multiplicity (Binary, Triple), or movie franchise (Alien, Star Trek, Dune). Anything you like! (2/4)
September 26, 2025 at 12:24 AM
First: Tags!
Add a tag to any star system to categorize it by feature (Gas Planets, Rings), multiplicity (Binary, Triple), or movie franchise (Alien, Star Trek, Dune). Anything you like! (2/4)
Add a tag to any star system to categorize it by feature (Gas Planets, Rings), multiplicity (Binary, Triple), or movie franchise (Alien, Star Trek, Dune). Anything you like! (2/4)
🛰️ Starcarta update 1.3 is here!
✨ New:
- Tags!
- Highlight Systems by Tag.
- Added 1 AU graph circle to all Systems with planets to show scale. (1/4)
#Starcarta #indiedev #astronomy #space starcarta.app
✨ New:
- Tags!
- Highlight Systems by Tag.
- Added 1 AU graph circle to all Systems with planets to show scale. (1/4)
#Starcarta #indiedev #astronomy #space starcarta.app
September 26, 2025 at 12:23 AM
🛰️ Starcarta update 1.3 is here!
✨ New:
- Tags!
- Highlight Systems by Tag.
- Added 1 AU graph circle to all Systems with planets to show scale. (1/4)
#Starcarta #indiedev #astronomy #space starcarta.app
✨ New:
- Tags!
- Highlight Systems by Tag.
- Added 1 AU graph circle to all Systems with planets to show scale. (1/4)
#Starcarta #indiedev #astronomy #space starcarta.app
This week’s star is Gliese 163, a red dwarf with at least 3 planets (up to 5). One, Gliese 163c, is a 7-Earth-mass world near the habitable zone. The light we see from it today began its trip 49 years ago, the same year & maybe even day I was born. I think that’s pretty cool!
starcarta.app/o/CXJPq
starcarta.app/o/CXJPq
August 25, 2025 at 7:41 PM
This week’s star is Gliese 163, a red dwarf with at least 3 planets (up to 5). One, Gliese 163c, is a 7-Earth-mass world near the habitable zone. The light we see from it today began its trip 49 years ago, the same year & maybe even day I was born. I think that’s pretty cool!
starcarta.app/o/CXJPq
starcarta.app/o/CXJPq
The Habitable Zone of our solar system, which is between 0.99au & 1.70au includes both Earth & Mars (even though Mars is too small to hold enough atmosphere) but excludes the runaway greenhouse Venus. Interestingly, you can see how the Earth is just balanced on the inner edge.
starcarta.app/o/B
starcarta.app/o/B
August 8, 2025 at 12:20 AM
The Habitable Zone of our solar system, which is between 0.99au & 1.70au includes both Earth & Mars (even though Mars is too small to hold enough atmosphere) but excludes the runaway greenhouse Venus. Interestingly, you can see how the Earth is just balanced on the inner edge.
starcarta.app/o/B
starcarta.app/o/B
GL581 is a low-activity, stable M-class star. It has 2 candidate planets well positioned in their HZ, GL581 b & GL581 c. GL581 b is a 6 Me super-earth, zipping around every 5 days, while GL581 c is a more reasonable 2 Me planet, taking 13 days to complete an orbit. starcarta.app/o/JdJCb #astronomy
August 6, 2025 at 3:21 PM
GL581 is a low-activity, stable M-class star. It has 2 candidate planets well positioned in their HZ, GL581 b & GL581 c. GL581 b is a 6 Me super-earth, zipping around every 5 days, while GL581 c is a more reasonable 2 Me planet, taking 13 days to complete an orbit. starcarta.app/o/JdJCb #astronomy
For a pretty good HZ match, we can check out HD 40307 g, a massive 7 Me super-earth in the habitable zone of its 1 billion year old K-Class star. It’s a great candidate to explore in the future, and not too far away at 42 light years away. starcarta.app/o/CXSGM #space #astronomy
August 5, 2025 at 11:23 PM
For a pretty good HZ match, we can check out HD 40307 g, a massive 7 Me super-earth in the habitable zone of its 1 billion year old K-Class star. It’s a great candidate to explore in the future, and not too far away at 42 light years away. starcarta.app/o/CXSGM #space #astronomy
Gliese 667 Cc is also a 4 Me super-earth w/ an orbit right in the middle of its Red Dwarf’s HZ. Gliese 667 Cf, Gliese 667 Ce are not confirmed, but could also be in Gliese 667 C’s HZ. So Gliese 667 C might have multiple habitable worlds, at just 24 light years from Sol. #space
starcarta.app/o/CJCWm
starcarta.app/o/CJCWm
August 4, 2025 at 8:53 PM
Gliese 667 Cc is also a 4 Me super-earth w/ an orbit right in the middle of its Red Dwarf’s HZ. Gliese 667 Cf, Gliese 667 Ce are not confirmed, but could also be in Gliese 667 C’s HZ. So Gliese 667 C might have multiple habitable worlds, at just 24 light years from Sol. #space
starcarta.app/o/CJCWm
starcarta.app/o/CJCWm
Tau Ceti has come up before, checking its HZ shows Tau Ceti e is slightly too close & Tau Ceti f (4 earth mass) is on the outer fringes. However, Tau Ceti f’s orbit dips it in & out of the zone during its 636-day orbit / half-year-long winter if it’s able to hold an atmosphere.
starcarta.app/o/hkBp
starcarta.app/o/hkBp
August 3, 2025 at 5:14 PM
Tau Ceti has come up before, checking its HZ shows Tau Ceti e is slightly too close & Tau Ceti f (4 earth mass) is on the outer fringes. However, Tau Ceti f’s orbit dips it in & out of the zone during its 636-day orbit / half-year-long winter if it’s able to hold an atmosphere.
starcarta.app/o/hkBp
starcarta.app/o/hkBp
Starcarta release 1.12!
Now w/Habitable Zones! So what is a star’s HZ? It’s the space around a star where a rocky planet can have surface water, assuming atmosphere & sufficient gravity. Avoiding either runaway greenhouses or where CO₂ can't keep the planet sufficiently warm. #space #starcarta (1/2)
Now w/Habitable Zones! So what is a star’s HZ? It’s the space around a star where a rocky planet can have surface water, assuming atmosphere & sufficient gravity. Avoiding either runaway greenhouses or where CO₂ can't keep the planet sufficiently warm. #space #starcarta (1/2)
August 3, 2025 at 2:33 AM
Starcarta release 1.12!
Now w/Habitable Zones! So what is a star’s HZ? It’s the space around a star where a rocky planet can have surface water, assuming atmosphere & sufficient gravity. Avoiding either runaway greenhouses or where CO₂ can't keep the planet sufficiently warm. #space #starcarta (1/2)
Now w/Habitable Zones! So what is a star’s HZ? It’s the space around a star where a rocky planet can have surface water, assuming atmosphere & sufficient gravity. Avoiding either runaway greenhouses or where CO₂ can't keep the planet sufficiently warm. #space #starcarta (1/2)
Today’s system is HD 20782/HD 20781 which form a twice notable wide-binary system w/2 sunlike stars. Their system is the first found binary where each star has planets, which is unusual as one of the stars tends to disrupt the initial planet-forming disks of their companions. (1/2) #astronomy #space
July 20, 2025 at 9:02 PM
Today’s system is HD 20782/HD 20781 which form a twice notable wide-binary system w/2 sunlike stars. Their system is the first found binary where each star has planets, which is unusual as one of the stars tends to disrupt the initial planet-forming disks of their companions. (1/2) #astronomy #space
Starcarta version 1.06 released! 🌟
- URL now shows the system you're with a short code in for easy sharing.
System of day: Epsilon Tauri!
starcarta.app/?o=RvdN
With a great view of the star packed Hyades cluster, is the huge & super bright G-star Ain and planet Amateru. #starcarta #astronomy
- URL now shows the system you're with a short code in for easy sharing.
System of day: Epsilon Tauri!
starcarta.app/?o=RvdN
With a great view of the star packed Hyades cluster, is the huge & super bright G-star Ain and planet Amateru. #starcarta #astronomy
July 14, 2025 at 8:36 PM
Starcarta version 1.06 released! 🌟
- URL now shows the system you're with a short code in for easy sharing.
System of day: Epsilon Tauri!
starcarta.app/?o=RvdN
With a great view of the star packed Hyades cluster, is the huge & super bright G-star Ain and planet Amateru. #starcarta #astronomy
- URL now shows the system you're with a short code in for easy sharing.
System of day: Epsilon Tauri!
starcarta.app/?o=RvdN
With a great view of the star packed Hyades cluster, is the huge & super bright G-star Ain and planet Amateru. #starcarta #astronomy
Some stars like Vega, Alcor, and Muphrid have classical names from Arabic, Latin, or Greek roots, passed down through history.
en.wikipedia.org/wiki/List_of...
starcarta.app?q=Eta%20Bo%C...
(4/6)
en.wikipedia.org/wiki/List_of...
starcarta.app?q=Eta%20Bo%C...
(4/6)
July 13, 2025 at 1:06 AM
Some stars like Vega, Alcor, and Muphrid have classical names from Arabic, Latin, or Greek roots, passed down through history.
en.wikipedia.org/wiki/List_of...
starcarta.app?q=Eta%20Bo%C...
(4/6)
en.wikipedia.org/wiki/List_of...
starcarta.app?q=Eta%20Bo%C...
(4/6)
Bayer names use Greek/Latin letters or numbers + constellation names, like Sigma Boötis. Originally, letters followed brightness: alpha = brightest, beta = 2nd, etc. en.wikipedia.org/wiki/Bayer_d...
starcarta.app?q=Sigma%20Bo...
(3/6)
starcarta.app?q=Sigma%20Bo...
(3/6)
July 13, 2025 at 1:06 AM
Bayer names use Greek/Latin letters or numbers + constellation names, like Sigma Boötis. Originally, letters followed brightness: alpha = brightest, beta = 2nd, etc. en.wikipedia.org/wiki/Bayer_d...
starcarta.app?q=Sigma%20Bo...
(3/6)
starcarta.app?q=Sigma%20Bo...
(3/6)
Stars named like HD 20128311 follow a “catalog prefix + number” format. Here, HD = Henry Draper Catalogue, and the number is the star’s entry in it. en.wikipedia.org/wiki/Star_ca...
starcarta.app?q=HD%20128311
(2/6)
starcarta.app?q=HD%20128311
(2/6)
July 13, 2025 at 1:06 AM
Stars named like HD 20128311 follow a “catalog prefix + number” format. Here, HD = Henry Draper Catalogue, and the number is the star’s entry in it. en.wikipedia.org/wiki/Star_ca...
starcarta.app?q=HD%20128311
(2/6)
starcarta.app?q=HD%20128311
(2/6)