Astronomy:HD 63433
Observation data Equinox J2000.0]] (ICRS) | |
---|---|
Constellation | Gemini[note 1] |
Right ascension | 07h 49m 55.05s[1] |
Declination | 27° 21′ 47.45″[1] |
Apparent magnitude (V) | 6.92[2] |
Characteristics | |
Evolutionary stage | Main sequence[3] |
Spectral type | G5V[3] |
Variable type | BY Draconis[4][5] |
Astrometry | |
Radial velocity (Rv) | −16.07±0.13[2] km/s |
Proper motion (μ) | RA: −10.0268±0.0846[2] mas/yr Dec.: −11.3143±0.0487[2] mas/yr |
Parallax (π) | 44.6848[6] mas |
Distance | 73.035±0.073 ly (22.4035±0.0225 pc) |
Absolute magnitude (MV) | 5.19[7] |
Details[8] | |
Mass | 0.99±0.03 M☉ |
Radius | 0.912±0.034 R☉ |
Luminosity | 0.753±0.026 L☉ |
Surface gravity (log g) | 4.52±0.05[3] cgs |
Temperature | 5640±74 K |
Metallicity [Fe/H] | 0.03±0.05[3] dex |
Rotation | 6.45±0.05 d |
Rotational velocity (v sin i) | 7.3±0.3 km/s |
Age | 414±23 Myr |
Other designations | |
Database references | |
SIMBAD | data |
HD 63433 (TOI-1726, V377 Geminorum) is a G-type main sequence star located 73 light-years from Earth in the zodiacal constellation Gemini,[8][note 1] visually close to the star Pollux.[6] It is classified as a Sun-like star, having a mass 99% similar and a size 91% similar to that of the Sun.[8] However, it is a much younger star, less than one tenth as old with an age of about 400 million years.[8][lower-alpha 1] With an apparent magnitude of 6.9, it is not visible to the naked eye, but can be seen with a small telescope.[11] Based on its kinematic, rotational and lithium abundance properties, it is part of the Ursa Major Moving Group.[8] There are three exoplanets orbiting it, one is classified as an Earth-sized planet, while the two others are mini-Neptunes.[3]
Characteristics
HD 63433 is a Sun-like star, having a radius of 0.912 R☉, a mass of 0.99 M☉, an effective temperature of 5640 K and a spectral type G5V.[8] Its properties are quite similar to those of the Sun, which has a spectral type G2V and a temperature of 5772 K.[12] HD 63433, however, is much younger than the Sun, having an age of 414 million years,[8] just 9% of the solar age of 4.6 billion years.[10]
It is also a variable star, belonging to the class of BY Draconis variables,[4][5] stars which have variations in their luminosity due to their rotation together with sunspots and other chromospheric activities. The brightness of the star varies by 0.05 magnitudes over a period of 6.46 days.[5] It has the variable-star designation V377 Geminorum.[6][5]
With an apparent magnitude of 6.92m,[2] it is below the limit for naked-eye visibility, generally defined as 6.5m,[13] which would mean that this star is not visible to the naked eye, but easily visible using a small telescope[11] or binoculars.[14] Despite being faint, HD 63433 is actually the third-brightest star with transiting exoplanets confirmed by the Transiting Exoplanet Survey Satellite, with only Pi Mensae (5.65m)[15] and HR 858 (6.38m)[16] being brighter.[8][17]
According to stellar kinematics, lithium abundance and stellar rotation, HD 63433 is part of the Ursa Major moving group.[8] It was initially identified as a possible member of this group by Gaidos (1998)[18] and included as a possible member in later analyses, until HD 63433's membership in this moving group was finally confirmed by Mann et al. in 2020.[8] As it is part of this moving group, its age is estimated at 414 ± 23 million years, the same as the group.[8]
It is located in the northern hemisphere, about 73 light-years from the Earth, in the constellation of Gemini.[11] It is visually close to Pollux, the brightest star in the constellation.[6] HD 63433 is predicted to approach within 7.33 light-years of the Sun in 1.33 million years.[19] That will make it one of the nearest stars to the Sun. Its closest neighbor is the orange dwarf HD 63991, located at a distance of 2.7 light years.[11]
Name | Distance
(light-years) |
---|---|
HD 63991 | 2.7 |
LSPM J0801+2342 | 6.1 |
HD 68017 | 9 |
BD+31 1781 | 9.1 |
G 90-52 | 9.2 |
Planetary system
The star HD 63433 is orbited by 3 exoplanets, all discovered by the transit method.
The first ones to be discovered, HD 63433 b and HD 63433 c, are mini-Neptunes[20] that were discovered in by Mann et al. in 2020 using the Transiting Exoplanet Survey Satellite.[21] In 2024, an additional planet was discovered, after an analysis of a transit signal detected by TESS. Named HD 63433 d, it is an Earth-sized planet.[22]
According to theoretical models, the compositions of the mini-Neptunes HD 63433 b and c are mostly silicate and water, with no iron dominance, surrounded by a gaseous envelope which, in the case of planet c, makes up around 2% of the planet.[20]
The planetary system of HD 63433 is quite young, at around 400 million years old, it is only 9.13% as old as the Solar System.[3][22][lower-alpha 2] HD 63433 d is also the smallest planet and is less than 500 million years old.
Temperature comparisons |
HD 63433 b[20] | HD 63433 c[20] | HD 63433 d[3] |
Global equilibrium temperature | 769 – 967 K 496 – 694 °C 925 – 1281 °F |
540 – 679 K 267 – 406 °C 513 – 763 °F |
1040 K 767 °C 1413 °F |
Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
d | — | 0.0503±0.0027 | 4.21 | 0.16+0.36 −0.12 |
88.73±1° | 1.073+0.046 −0.044 R⊕ |
b | <21.76 M⊕ | 0.0719+0.0044 −0.0031 |
7.11 | 0.24+0.27 −0.18 |
— | 2.14+0.087 −0.069 R⊕ |
c | 15.54±3.86 M⊕ | 0.1458±0.015 | 20.55 | 0.161+0.014 −0.013 |
— | 2.692+0.108 −0.088 R⊕ |
HD 63433 b
The middle planet, HD 63433 b, is a mini-Neptune planet that was discovered together with HD 63433 c.[3] HD 63433 b is 2.14 times larger than Earth,[20] but is about 45% smaller than Neptune.[lower-alpha 3] The planet has an upper mass limit of 21.7 M⊕,[20] which is 21% greater than the mass of Neptune (17.15 M⊕ [23]). These values calculate an upper density limit of 13 g/cm3,[20] 2 times greater than that of Earth,[note 2] and similar to that of the chemical element Mercury. HD 63433 b orbits its parent star at a distance of 0.0719 astronomical units (10,760,000 km) – about 5 times closer than Mercury is to the Sun – and completes one revolution every 7 days and 3 hours. The relative proximity of its star makes it hot, with an equilibrium temperature between 769 and 967 Kelvin (496 and 694 °C).[20][lower-alpha 4]
HD 63433 b was probably a mini-Neptune that later lost its atmosphere.[25] Some factors, such as the fact that no absorption of Ly-α was detected during its transit, and its mass-loss timescale being shorter than the age of the planetary system, indicate that it has already lost its primordial atmosphere, and could be a rocky planetary core.[25] However, if HD 63433 b were a rocky core, it would need to be unusually massive and, therefore, a water-rich composition in addition to an atmosphere with a high mean molecular weight could explain both the radius and the non-detection of the Lyα.[25]
HD 63433 c
Orbiting its star at a distance of 0.145 Astronomy:astronomical unit|astronomical units (21,700,000 km) in a orbital period of 20 days,[20] it is the outermost planet in its planetary system, but still close to its star, making it a warm planet, with a planetary equilibrium temperature estimated between 267 and 406 °C.[20][lower-alpha 5]
Due to the high radiation received from its star, the atmosphere of HD 63433 c, made up of hydrogen, is slowly being stripped away and escaping from the planet, like a hot air balloon.[26] The hot gas escapes into the space at a velocity of 50 km/s, forming a gas cocoon 12 times larger than the planet itself.[26] As its atmosphere evaporates, HD 63433 c will slowly become a super-Earth planet.[26]
HD 63433 d
HD 63433 d was the last planet to be discovered in the system, 4 years after planets b and c.[3] With a diameter of ~13,690 km, it is very similar to Earth in size, being only 7% larger, but its mass is currently unknown.[3] It is the innermost planet orbiting HD 63433, having a semi-major axis (mean distance from its star) of 0.0503 astronomical units (7,520,000 km) and an orbital period of just 4 days.[3] The extreme proximity to its star makes it extremely hot, having a daytime temperature estimated at 1,260 °C (2,300 °F),[3] [lower-alpha 6] hot enough to melt all the minerals present on its surface,[27] as well as being tidally locked, meaning that one half of the planet is always facing towards its star, while the other is always facing away from it.[28][22] The planet also possibly lacks a substantial atmosphere.[3][22][27]
It is believed that the dayside of the planet, always facing its star due to tidal locking, is fully composed of lava due to the high surface temperature,[29][22] in addition to possibly having volcanic activity.[30][31] Meanwhile, the nightside of the planet, which never faces its star, may be the opposite, resembling Pluto with glaciers of frozen nitrogen.[32]
HD 63433 d was discovered in 2024, through an analysis of a transit observation made by the Transiting Exoplanet Survey Satellite (TESS).[22] As two other planets had already been discovered in the system, the transit signals of these objects were removed, thus revealing an additional transit signal that reappeared every 4.2 days.[22][33][3] Further investigation allowed researchers to confirm that this signal was from another orbiting exoplanet, now called HD 63433 d.[22] The discovery was announced on January 10, 2024, in The Astronomical Journal.[28][32]
Scientific importance
The HD 63433 planetary system plays an important role in understanding the evolution of planetary systems in the first billion years after formation.[8][3] As HD 63433 is relatively bright (6.9m) and close (73 ly away), its planets b and c can have their atmospheres characterized by the Hubble Space Telescope and James Webb Space Telescope.[25] This star is also a favorable target for studies of atmospheric mass loss in exoplanets, as it is a young and active star with close-in mini-Neptune planets, in addition to having a negative radial velocity (−16.07 km/s).[25]
See also
- Ursa Major moving group
- Exoplanet
- Transiting Exoplanet Survey Satellite
- Mini-Neptune
- Lava planet
- List of star systems within 70–75 light-years
Notes and references
- ↑ 1.0 1.1 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 "HD 63433 | NASA Exoplanet Archive". https://exoplanetarchive.ipac.caltech.edu/overview/HD%2063433.
- ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 3.12 3.13 3.14 3.15 Capistrant, Benjamin K.; Soares-Furtado, Melinda; Vanderburg, Andrew; Jankowski, Alyssa; Mann, Andrew W.; Ross, Gabrielle; Srdoc, Gregor; Hinkel, Natalie R. et al. (2024-01-09), "TESS Hunt for Young and Maturing Exoplanets (THYME) XI: An Earth-sized Planet Orbiting a Nearby, Solar-like Host in the 400Myr Ursa Major Moving Group", The Astronomical Journal 167 (2): 54, doi:10.3847/1538-3881/ad1039, Bibcode: 2024AJ....167...54C
- ↑ 4.0 4.1 Notsu, Yuta; Honda, Satoshi; Maehara, Hiroyuki; Notsu, Shota; Namekata, Kosuke; Nogami, Daisaku; Shibata, Kazunari (2017-02-01). "Spectroscopic observations of active solar-analog stars having high X-ray luminosity, as a proxy of superflare stars". Publications of the Astronomical Society of Japan 69 (1): 12. doi:10.1093/pasj/psw116. ISSN 0004-6264.
- ↑ 5.0 5.1 5.2 5.3 "VSX : Detail for V0377 Gem". https://www.aavso.org/vsx/index.php?view=detail.top&oid=136376.
- ↑ 6.0 6.1 6.2 6.3 6.4 "HD 63433". https://simbad.cds.unistra.fr/mobile/object.html?object_name=HD%2063433.
- ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 8.00 8.01 8.02 8.03 8.04 8.05 8.06 8.07 8.08 8.09 8.10 8.11 Mann, Andrew W.; Johnson, Marshall C.; Vanderburg, Andrew; Kraus, Adam L.; Rizzuto, Aaron C.; Wood, Mackenna L.; Bush, Jonathan L.; Rockcliffe, Keighley et al. (2020-09-24). "TESS Hunt for Young and Maturing Exoplanets (THYME). III. A Two-planet System in the 400 Myr Ursa Major Group". The Astronomical Journal 160 (4): 179. doi:10.3847/1538-3881/abae64. ISSN 0004-6256. Bibcode: 2020AJ....160..179M.
- ↑ "HD 63433". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+63433.
- ↑ 10.0 10.1 Bonanno, A.; Schlattl, H.; Paterno`, L. (August 2002). "The age of the Sun and the relativistic corrections in the EOS". Astronomy & Astrophysics 390 (3): 1115–1118. doi:10.1051/0004-6361:20020749. ISSN 0004-6361. Bibcode: 2002A&A...390.1115B.
- ↑ 11.0 11.1 11.2 11.3 11.4 "★ HD 63433" (in en). https://www.stellarcatalog.com/stars/hd-63433.
- ↑ "Sun Fact Sheet". https://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html.
- ↑ Curtis, Heber Doust (1903-01-01). "On the limits of unaided vision". Lick Observatory Bulletin 38: 67–69. doi:10.5479/ADS/bib/1903LicOB.2.67C. ISSN 0075-9317. Bibcode: 1903LicOB...2...67C. https://ui.adsabs.harvard.edu/abs/1903LicOB...2...67C.
- ↑ Siegel-Itzkovich, Judy (January 14, 2024). "Earth-sized exoplanet discovered in 'our solar backyard' by international team". https://m.jpost.com/science/article-782104.
- ↑ Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966-01-01). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory 4: 99–110. Bibcode: 1966CoLPL...4...99J. https://ui.adsabs.harvard.edu/abs/1966CoLPL...4...99J.
- ↑ Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P. et al. (2000-03-01). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355: L27–L30. ISSN 0004-6361. Bibcode: 2000A&A...355L..27H. https://ui.adsabs.harvard.edu/abs/2000A&A...355L..27H.
- ↑ "NASA Exoplanet Space Institute.". https://exoplanetarchive.ipac.caltech.edu/cgi-bin/TblView/nph-tblView?app=ExoTbls&config=PS&constraint=default_flag=1&constraint=disc_facility+like+%27%25TESS%25%27.
- ↑ Gaidos, Eric J. (November 1998). "Nearby Young Solar Analogs. I. Catalog and Stellar Characteristics". Publications of the Astronomical Society of the Pacific 110 (753): 1259–1276. doi:10.1086/316251. ISSN 0004-6280. Bibcode: 1998PASP..110.1259G. http://dx.doi.org/10.1086/316251.
- ↑ Bailer-Jones, C.A.L. et al. (2018), "New stellar encounters discovered in the second Gaia data release", Astronomy & Astrophysics 616: A37, doi:10.1051/0004-6361/201833456, Bibcode: 2018A&A...616A..37B.
- ↑ 20.00 20.01 20.02 20.03 20.04 20.05 20.06 20.07 20.08 20.09 20.10 Mallorquín, M.; Béjar, V. J. S.; Lodieu, N.; Osorio, M. R. Zapatero; Tabernero, H.; Mascareño, A. Suárez; Zechmeister, M.; Luque, R. et al. (2023-03-01). "Dynamical masses of two young transiting sub-Neptunes orbiting HD 63433" (in en). Astronomy & Astrophysics 671: A163. doi:10.1051/0004-6361/202245397. ISSN 0004-6361. Bibcode: 2023A&A...671A.163M. https://www.aanda.org/articles/aa/abs/2023/03/aa45397-22/aa45397-22.html.
- ↑ "HD 63433". https://www.openexoplanetcatalogue.com/planet/HD%2063433%20c/.
- ↑ 22.0 22.1 22.2 22.3 22.4 22.5 22.6 22.7 Gohd, Chelsea (January 11, 2024). "Discovery Alert: Earth-sized Planet Has a 'Lava Hemisphere'". https://science.nasa.gov/universe/exoplanets/discovery-alert-earth-sized-planet-has-a-lava-hemisphere/.
- ↑ 23.0 23.1 "Neptune Fact Sheet". https://nssdc.gsfc.nasa.gov/planetary/factsheet/neptunefact.html.
- ↑ "Facts About Earth - NASA Science" (in en). https://science.nasa.gov/earth/facts/.
- ↑ 25.0 25.1 25.2 25.3 25.4 Zhang, Michael; Knutson, Heather A.; Wang, Lile; Dai, Fei; Santos, Leonardo A. dos; Fossati, Luca; Henry, Gregory W.; Ehrenreich, David et al. (January 2022). "Detection of Ongoing Mass Loss from HD 63433c, a Young Mini-Neptune" (in en). The Astronomical Journal 163 (2): 68. doi:10.3847/1538-3881/ac3f3b. ISSN 1538-3881. Bibcode: 2022AJ....163...68Z.
- ↑ 26.0 26.1 26.2 "Puffy Planets Lose Atmospheres, Become Super-Earths". February 3, 2022. https://hubblesite.org/contents/news-releases/2022/news-2022-009.
- ↑ 27.0 27.1 Thomson, Jess (January 12, 2024). "Hellish World With 2,294 F 'Lava Hemisphere' Discovered by NASA". https://www.newsweek.com/exoplanet-lava-hemisphere-discovered-nasa-1860175.
- ↑ 28.0 28.1 Robert, Lea (January 12, 2024). "Newfound Earth-size exoplanet has a scorching-hot lava side". https://www.space.com/newfound-exoplanet-hd-63433d-lava-hemisphere-tess.
- ↑ Gough, Evan (January 12, 2024). "Half of this Exoplanet is Covered in Lava". https://www.universetoday.com/165216/half-of-this-exoplanet-is-covered-in-lava/.
- ↑ Staff, Buzz (16 January 2024). "NASA Telescope Discovers Half-Lava Exoplanet Of Same Size As Earth". https://www.news18.com/amp/viral/nasa-telescope-discovers-half-lava-exo-planet-of-same-size-as-earth-8742680.html.
- ↑ Whitwam, Ryan (January 15, 2024). "Astronomers Discover Earth-Sized Planet That's Half Lava". https://www.extremetech.com/science/astronomers-discover-earth-sized-planet-thats-half-lava.
- ↑ 32.0 32.1 Szondy, David (January 11, 2024). "Tidally locked exo-Earth has a lava ocean hemisphere". https://newatlas.com/space/tidally-locked-exoplanet-lava-ocean-hemisphere/.
- ↑ "'Extra hot and young' Earth-sized exoplanet with a 'lava hemisphere' discovered". January 17, 2024. https://www.wionews.com/science/scientists-discover-youngest-earth-sized-exoplanet-having-lava-hemisphere-679301/amp.
- ↑ The age of the Sun is around 4.6 billion years.[10]
- ↑ The age of the Solar System is 4.532 billion years.
- ↑ Neptune is 3.883 times larger than Earth.[23]
- ↑ Assuming albedos of 0.6 and 0 respectively.
- ↑ Assuming albedos of 0.6 and 0 respectively.
- ↑ Assuming an albedo of 0, similar to the measured albedo of TRAPPIST-1b.
Coordinates: 07h 49m 55.0607s, +27° 21′ 47.457″
![]() | Original source: https://en.wikipedia.org/wiki/HD 63433.
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