Astronomy:Delorme 1
250px The binary Delorme 1 (AB) is in the center and the companion is the source on the upper right. Credit: NASA/ESA Hubble WFC3; Daniel Apai et al. | |
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Phoenix |
| Right ascension | 01h 03m 35.6551s |
| Declination | −55° 15′ 56.243″ |
| Apparent magnitude (V) | 15.40 ±0.05 |
| Characteristics | |
| Evolutionary stage | red dwarf |
| Spectral type | M5/6+M5/6+L0(VLG)[1] |
| Variable type | flare star[1] |
| Astrometry | |
| Radial velocity (Rv) | 5.2 ±1.6[2] km/s |
| Proper motion (μ) | RA: 111.6 ±3.6[2] mas/yr Dec.: -43.8 ±8.1[2] mas/yr |
| Parallax (π) | 21.18 ± 1.37[3] mas |
| Distance | 154 ± 10 ly (47 ± 3 pc) |
| Details[4] | |
| Delorme 1A | |
| Mass | 0.19 ±0.02 M☉ |
| Delorme 1B | |
| Mass | 0.17 ±0.02 M☉ |
| Position (relative to Delorme 1A)[4] | |
| Component | Delorme 1B |
| Epoch of observation | 2012 |
| Angular distance | 0.249 ±0.003″ |
| Observed separation (projected) | 12 AU {{{projsepref}}} |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | J01033563-5515561 data |
Delorme 1 (2MASS J01033563-5515561) is a binary star with a planetary-mass companion (PMC) or protoplanet in a circumbinary orbit.[4] The PMC is notable for showing signs of accretion, despite being 30-45 Myr old, making it similar to Peter Pan disks.[1][5][6] These disks show characteristics of a gas-rich disk at unexpected high ages.[7]
The binary system
The star was resolved in 2013 with the Very Large Telescope NACO instrument by Delorme et al. A spectrum of the binary was taken with GMOS at Gemini South, which showed a spectral type of M5.5/M6 and strong Hydrogen-alpha emission. The astrometry showed that this star belongs to the Tucana-Horologium association. The binary is separated by around 12 astronomical units (AU).[4] In 2014 Riedel et al. found a better match with the Carina association, which has a similar age as Tuc-Hor. They also found the system to be over-luminous, which might either hint at a younger age or further multiplicity.[3] Other searches do, however, find a better match with Tuc-Hor.[2] Because the Washington Double Star Catalog named the binary ** DLR 1 after the first author of the discovery paper in 2013, Eriksson et al. suggested the name Delorme 1 for the binary.[1] The binary is named after Philippe Delorme.[8]
The circumstellar companion
b_JWST_MIRI_IFU.jpg)
The binary companion was discovered in 2013 as an object with a mass between 12 and 14 |♃|J}}}}}} and a separation of 84 AU from the central binary. It had a spectrum similar to early L-dwarfs, but redder than field L-dwarfs.[4] In 2020 Eriksson et al. discovered Hydrogen-alpha, -beta and Helium I lines from Delorme 1 (AB)b using MUSE. This is seen as a clear sign of accretion on a planetary-mass object. The spectral type of this object was determined to be L0 with very low gravity due to stronger than expected vanadium oxide absorption.[1] H-alpha can be influenced by chromospheric activity, complicating its interpretation. Betti et al. discovered Paschen and Brackett lines in Delorme 1 (AB)b in the near-infrared, using TripleSpec at SOAR. These observations are in agreement with planetary-shock accretion.[5] In 2023 Ringqvist et al. observed Delorme 1 (AB)b with the VLT UVES, detecting neutral hydrogen in the ultraviolet.[6] Both near-infrared and ultraviolet observations show an accretion rate of about (about 1.2 to 2.3 the mass of 10 Hygiea per year).[5][6] The planet and the star were observed with MIRI/IFU, which revealed the circumplanetary disk around the planet. The disk is carbon-rich and contains hydrogen cyanide (HCN), Acetylene (C2H2, tentative: 13CCH2) and molecular hydrogen (H2). The disk has a temperature of 295 ± 27 K (21.9 ± 27.0 °C; 71.3 ± 48.6 °F) and a inner cavity with a size of 32.6±3.1 |♃|J}}}}}}. According to simulations the disk will only fill out 40% of the Hill radius, resulting of a theoretical disk size of 7.8 AU. The extended emission by H2 is larger than this disk size, showing that it includes an outflow, maybe a disk wind coming from the circumplanetary disk. Assuming a disk wind is present, the disk has a mass-loss rate of 2 × 10−10 |♃|J}}}}}}/year.[9]
Delorme 1 (AB)b has been called a protoplanet candidate and a super-Jupiter.[5][6] The researchers found that the high accretion is in better agreement with a formation via disk fragmentation, hinting that it might have formed from a circumstellar disk.[5] Giant planets and brown dwarfs are thought to form via disk fragmentation in rare cases in the outer regions of a disk (r>50 AU).[10] Teasdale et al. modelled three formation scenarios in which the planet could have formed. In the first two scenarios the planet forms in a massive disk via gravitational instability. The first two scenarios produce planets that have accretion and separation comparable to the observed ones, but the resulting planets are more massive than Delorme 1 (AB)b. In a third scenario the planet forms via core accretion in a less massive disk much closer to the binary. In this third scenario the mass and accretion are similar to the observed ones, but the separation is smaller.[11] The modelling of JWST spectrum showed super-solar metallicity and C/O ratio for the planet, but the authors mention that these values are model dependent. The C/O ratio could be consistent with the formation between water and CO snowlines. Alternatively the carbon-rich circumplanetary disk could enrich the planet in carbon, explaining the elevated C/O ratio.[9]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 12 to 14 MJ | 102+47 −27 |
1682+1308 −628 |
0.32+0.27 −0.23 |
127+17 −8° |
1.9±0.1[9] RJ |
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Eriksson, Simon C.; Asensio Torres, Rubén; Janson, Markus; Aoyama, Yuhiko; Marleau, Gabriel-Dominique; Bonnefoy, Mickael; Petrus, Simon (2020-06-01). "Strong Halpha emission and signs of accretion in a circumbinary planetary mass companion from MUSE". Astronomy and Astrophysics 638: L6. doi:10.1051/0004-6361/202038131. ISSN 0004-6361. Bibcode: 2020A&A...638L...6E. http://adsabs.harvard.edu/abs/2020A%26A...638L...6E.
- ↑ 2.0 2.1 2.2 Gagné, Jonathan; Lafrenière, David; Doyon, René; Malo, Lison; Artigau, Étienne (2015-01-01). "BANYAN. V. A Systematic All-sky Survey for New Very Late-type Low-mass Stars and Brown Dwarfs in Nearby Young Moving Groups". The Astrophysical Journal 798 (2): 73. doi:10.1088/0004-637X/798/2/73. ISSN 0004-637X. Bibcode: 2015ApJ...798...73G. https://ui.adsabs.harvard.edu/abs/2015ApJ...798...73G/abstract.
- ↑ 3.0 3.1 Riedel, Adric R.; Finch, Charlie T.; Henry, Todd J.; Subasavage, John P.; Jao, Wei-Chun; Malo, Lison; Rodriguez, David R.; White, Russel J. et al. (2014-04-01). "The Solar Neighborhood. XXXIII. Parallax Results from the CTIOPI 0.9 m Program: Trigonometric Parallaxes of Nearby Low-mass Active and Young Systems". The Astronomical Journal 147 (4): 85. doi:10.1088/0004-6256/147/4/85. ISSN 0004-6256. Bibcode: 2014AJ....147...85R. https://ui.adsabs.harvard.edu/abs/2014AJ....147...85R/abstract.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Delorme, P.; Gagné, J.; Girard, J. H.; Lagrange, A. M.; Chauvin, G.; Naud, M. -E.; Lafrenière, D.; Doyon, R. et al. (2013-05-01). "Direct-imaging discovery of a 12-14 Jupiter-mass object orbiting a young binary system of very low-mass stars". Astronomy and Astrophysics 553: L5. doi:10.1051/0004-6361/201321169. ISSN 0004-6361. Bibcode: 2013A&A...553L...5D.
- ↑ 5.0 5.1 5.2 5.3 5.4 Betti, S. K.; Follette, K. B.; Ward-Duong, K.; Aoyama, Y.; Marleau, G. -D.; Bary, J.; Robinson, C.; Janson, M. et al. (2022-08-01). "Near-infrared Accretion Signatures from the Circumbinary Planetary-mass Companion Delorme 1 (AB)b". The Astrophysical Journal 935 (1): L18. doi:10.3847/2041-8213/ac85ef. ISSN 0004-637X. Bibcode: 2022ApJ...935L..18B.
- ↑ 6.0 6.1 6.2 6.3 Ringqvist, Simon C.; Viswanath, Gayathri; Aoyama, Yuhiko; Janson, Markus; Marleau, Gabriel-Dominique; Brandeker, Alexis (2023-01-01). "Resolved near-UV hydrogen emission lines at 40-Myr super-Jovian protoplanet Delorme 1 (AB)b. Indications of magnetospheric accretion". Astronomy and Astrophysics 669: L12. doi:10.1051/0004-6361/202245424. ISSN 0004-6361. Bibcode: 2023A&A...669L..12R. https://ui.adsabs.harvard.edu/abs/2023A&A...669L..12R/abstract.
- ↑ Silverberg, Steven M.; Wisniewski, John P.; Kuchner, Marc J.; Lawson, Kellen D.; Bans, Alissa S.; Debes, John H.; Biggs, Joseph R.; Bosch, Milton K. D. et al. (2020-01-14). "Peter Pan Disks: Long-lived Accretion Disks Around Young M Stars". The Astrophysical Journal 890 (2): 106. doi:10.3847/1538-4357/ab68e6. Bibcode: 2020ApJ...890..106S.
- ↑ "Members of the Exoplanets team" (in en). https://ipag.osug.fr/english/research/research-teams/exoplanets/members-of-the-exoplanetes-team/.
- ↑ 9.0 9.1 9.2 Mâlin, Mathilde; Ward-Duong, Kimberly; Grant, Sierra L.; Arulanantham, Nicole; Tabone, Benoît; Pueyo, Laurent; Perrin, Marshall; Balmer, William O.; Betti, Sarah; Chen, Christine H.; Debes, John H.; Girard, Julien H.; Hoch, Kielan K. W.; Kammerer, Jens; Lu, Cicero; Rebollido, Isabel; Rickman, Emily; Robinson, Connor; Worthen, Kadin; van der Marel, Roeland P.; Lewis, Nikole K.; Seager, Sara; Valenti, Jeff A.; Soummer, Remi (2025). "JWST-TST High Contrast: Medium-resolution spectroscopy reveals a carbon-rich circumplanetary disk around the young accreting exoplanet Delorme 1 AB b". arXiv:2510.07253 [astro-ph.EP].
- ↑ Rice, Ken; Lopez, Eric; Forgan, Duncan; Biller, Beth (2015-12-01). "Disc fragmentation rarely forms planetary-mass objects". Monthly Notices of the Royal Astronomical Society 454 (2): 1940–1947. doi:10.1093/mnras/stv1997. ISSN 0035-8711. Bibcode: 2015MNRAS.454.1940R. https://academic.oup.com/mnras/article/454/2/1940/1048443.
- ↑ Teasdale, Matthew; Stamatellos, Dimitris (2024-08-01). "On the potential origin of the circumbinary planet Delorme 1 (AB)b". Monthly Notices of the Royal Astronomical Society 533 (2): 2294–2302. doi:10.1093/mnras/stae1964. ISSN 0035-8711. Bibcode: 2024MNRAS.533.2294T. https://academic.oup.com/mnras/article/533/2/2294/7733105.
- ↑ Blunt, Sarah; Nielsen, Eric L.; De Rosa, Robert J.; Konopacky, Quinn M.; Ryan, Dominic; Wang, Jason J.; Pueyo, Laurent; Rameau, Julien et al. (2017-05-01). "Orbits for the Impatient: A Bayesian Rejection-sampling Method for Quickly Fitting the Orbits of Long-period Exoplanets". The Astronomical Journal 153 (5): 229. doi:10.3847/1538-3881/aa6930. ISSN 0004-6256. Bibcode: 2017AJ....153..229B. ""68 % confidence range"".
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