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Constraints on the Orbit of the Young Substellar Companion GQ Lup B from High-Resolution Spectroscopy and VLTI/GRAVITY Astrometry

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Bibliographic Details
Main Authors:	Venkatesan, Vidya, Blunt, S., Wang, J. J., Lacour, S., Marleau, G. -D., Coleman, G. A. L., Guerrero, L., Balmer, W. O., Pueyo, L., Stolker, T., Kammerer, J., Pourré, N., Nowak, M., Rickman, E., Sivaramakrishnan, A., Sing, D., Wagner, K., Lagrange, A. -M., Abuter, R., Amorim, A., Asensio-Torres, R., Berger, J. -P., Beust, H., Boccaletti, A., Bonnefoy, M., Bonnet, H., Bordoni, M. S., Bourdarot, G., Brandner, W., Cantalloube, F., Caselli, P., Charnay, B., Chauvin, G., Chavez, A., Chomez, A., Choquet, E., Christiaens, V., Clénet, Y., Foresto, V. Coudé du, Cridland, A., Davies, R., Dembet, R., Dexter, J., Drescher, A., Duvert, G., Eckart, A., Eisenhauer, F., Schreiber, N. M. Förster, Garcia, P., Lopez, R. Garcia, Gendron, E., Genzel, R., Gillessen, S., Girard, J. H., Grant, S., Haubois, X., Heißel, G., Henning, Th., Hinkley, S., Hippler, S., Houllé, M., Hubert, Z., Jocou, L., Keppler, M., Kervella, P., Kreidberg, L., Kurtovic, N. T., Lapeyrère, V., Bouquin, J. -B. Le, Lutz, D., Maire, A. -L., Mang, F., Mérand, A., Mordasini, C., Mouillet, D., Nasedkin, E., Ott, T., Otten, G. P. P. L., Paladini, C., Paumard, T., Perraut, K., Perrin, G., Petrus, S., Pfuhl, O., Ribeiro, D. C., Rustamkulov, Z., Shangguan, J., Shimizu, T., Shields, A., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Vigan, A., Vincent, F., von Fellenberg, S. D., Widmann, F., Winterhalder, T. O., Woillez, J., Yazici, S., Collaboration, the ExoGRAVITY
Format:	Preprint
Published:	2025
Subjects:	Earth and Planetary Astrophysics Solar and Stellar Astrophysics
Online Access:	Acceder al recurso
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author	Venkatesan, Vidya Blunt, S. Wang, J. J. Lacour, S. Marleau, G. -D. Coleman, G. A. L. Guerrero, L. Balmer, W. O. Pueyo, L. Stolker, T. Kammerer, J. Pourré, N. Nowak, M. Rickman, E. Sivaramakrishnan, A. Sing, D. Wagner, K. Lagrange, A. -M. Abuter, R. Amorim, A. Asensio-Torres, R. Berger, J. -P. Beust, H. Boccaletti, A. Bonnefoy, M. Bonnet, H. Bordoni, M. S. Bourdarot, G. Brandner, W. Cantalloube, F. Caselli, P. Charnay, B. Chauvin, G. Chavez, A. Chomez, A. Choquet, E. Christiaens, V. Clénet, Y. Foresto, V. Coudé du Cridland, A. Davies, R. Dembet, R. Dexter, J. Drescher, A. Duvert, G. Eckart, A. Eisenhauer, F. Schreiber, N. M. Förster Garcia, P. Lopez, R. Garcia Gendron, E. Genzel, R. Gillessen, S. Girard, J. H. Grant, S. Haubois, X. Heißel, G. Henning, Th. Hinkley, S. Hippler, S. Houllé, M. Hubert, Z. Jocou, L. Keppler, M. Kervella, P. Kreidberg, L. Kurtovic, N. T. Lapeyrère, V. Bouquin, J. -B. Le Lutz, D. Maire, A. -L. Mang, F. Mérand, A. Mordasini, C. Mouillet, D. Nasedkin, E. Ott, T. Otten, G. P. P. L. Paladini, C. Paumard, T. Perraut, K. Perrin, G. Petrus, S. Pfuhl, O. Ribeiro, D. C. Rustamkulov, Z. Shangguan, J. Shimizu, T. Shields, A. Stadler, J. Straub, O. Straubmeier, C. Sturm, E. Tacconi, L. J. Vigan, A. Vincent, F. von Fellenberg, S. D. Widmann, F. Winterhalder, T. O. Woillez, J. Yazici, S. Collaboration, the ExoGRAVITY
author_facet	Venkatesan, Vidya Blunt, S. Wang, J. J. Lacour, S. Marleau, G. -D. Coleman, G. A. L. Guerrero, L. Balmer, W. O. Pueyo, L. Stolker, T. Kammerer, J. Pourré, N. Nowak, M. Rickman, E. Sivaramakrishnan, A. Sing, D. Wagner, K. Lagrange, A. -M. Abuter, R. Amorim, A. Asensio-Torres, R. Berger, J. -P. Beust, H. Boccaletti, A. Bonnefoy, M. Bonnet, H. Bordoni, M. S. Bourdarot, G. Brandner, W. Cantalloube, F. Caselli, P. Charnay, B. Chauvin, G. Chavez, A. Chomez, A. Choquet, E. Christiaens, V. Clénet, Y. Foresto, V. Coudé du Cridland, A. Davies, R. Dembet, R. Dexter, J. Drescher, A. Duvert, G. Eckart, A. Eisenhauer, F. Schreiber, N. M. Förster Garcia, P. Lopez, R. Garcia Gendron, E. Genzel, R. Gillessen, S. Girard, J. H. Grant, S. Haubois, X. Heißel, G. Henning, Th. Hinkley, S. Hippler, S. Houllé, M. Hubert, Z. Jocou, L. Keppler, M. Kervella, P. Kreidberg, L. Kurtovic, N. T. Lapeyrère, V. Bouquin, J. -B. Le Lutz, D. Maire, A. -L. Mang, F. Mérand, A. Mordasini, C. Mouillet, D. Nasedkin, E. Ott, T. Otten, G. P. P. L. Paladini, C. Paumard, T. Perraut, K. Perrin, G. Petrus, S. Pfuhl, O. Ribeiro, D. C. Rustamkulov, Z. Shangguan, J. Shimizu, T. Shields, A. Stadler, J. Straub, O. Straubmeier, C. Sturm, E. Tacconi, L. J. Vigan, A. Vincent, F. von Fellenberg, S. D. Widmann, F. Winterhalder, T. O. Woillez, J. Yazici, S. Collaboration, the ExoGRAVITY
contents	Understanding the orbits of giant planets is critical for testing planet formation models, particularly at wide separations greater than 10 au where traditional core accretion becomes inefficient. However, constraining orbits at these separations has been challenging because of sparse orbital coverage and degeneracies in the orbital parameters. We use existing high-resolution spectroscopic measurements from CRIRES+ (R ~ 100000), astrometric data from SPHERE, NACO, and ALMA, and new high-precision GRAVITY astrometry to refine the orbit of GQ Lup B, a ~30 M_J companion at ~100 au, in a system that also hosts a circumstellar disk and a wide companion, GQ Lup C. Including radial velocity data significantly improves orbital constraints by breaking the degeneracy between inclination and eccentricity that affects astrometry-only fits for long-period companions. This work is among the first to combine high-precision astrometry with the companion's relative radial velocity to achieve improved orbital constraints. The eccentricity is refined from e = 0.47 (+0.14, -0.16) with GRAVITY alone to e = 0.35 (+0.10, -0.09) when RVs and GRAVITY data are combined. The orbit is misaligned by 63 (+6, -14) deg relative to the circumstellar disk and 52 (+19, -24) deg relative to the host star spin axis, and is more consistent (34 (+6, -13) deg) with the inclination of the wide tertiary companion GQ Lup C disk. These results support a formation scenario for GQ Lup B consistent with cloud fragmentation and highlight the power of combining companion RV constraints with interferometric astrometry to probe the dynamics and formation of wide-orbit substellar companions.
format	Preprint
id	arxiv_https___arxiv_org_abs_2509_20621
institution	arXiv
publishDate	2025
record_format	arxiv
spellingShingle	Constraints on the Orbit of the Young Substellar Companion GQ Lup B from High-Resolution Spectroscopy and VLTI/GRAVITY Astrometry Venkatesan, Vidya Blunt, S. Wang, J. J. Lacour, S. Marleau, G. -D. Coleman, G. A. L. Guerrero, L. Balmer, W. O. Pueyo, L. Stolker, T. Kammerer, J. Pourré, N. Nowak, M. Rickman, E. Sivaramakrishnan, A. Sing, D. Wagner, K. Lagrange, A. -M. Abuter, R. Amorim, A. Asensio-Torres, R. Berger, J. -P. Beust, H. Boccaletti, A. Bonnefoy, M. Bonnet, H. Bordoni, M. S. Bourdarot, G. Brandner, W. Cantalloube, F. Caselli, P. Charnay, B. Chauvin, G. Chavez, A. Chomez, A. Choquet, E. Christiaens, V. Clénet, Y. Foresto, V. Coudé du Cridland, A. Davies, R. Dembet, R. Dexter, J. Drescher, A. Duvert, G. Eckart, A. Eisenhauer, F. Schreiber, N. M. Förster Garcia, P. Lopez, R. Garcia Gendron, E. Genzel, R. Gillessen, S. Girard, J. H. Grant, S. Haubois, X. Heißel, G. Henning, Th. Hinkley, S. Hippler, S. Houllé, M. Hubert, Z. Jocou, L. Keppler, M. Kervella, P. Kreidberg, L. Kurtovic, N. T. Lapeyrère, V. Bouquin, J. -B. Le Lutz, D. Maire, A. -L. Mang, F. Mérand, A. Mordasini, C. Mouillet, D. Nasedkin, E. Ott, T. Otten, G. P. P. L. Paladini, C. Paumard, T. Perraut, K. Perrin, G. Petrus, S. Pfuhl, O. Ribeiro, D. C. Rustamkulov, Z. Shangguan, J. Shimizu, T. Shields, A. Stadler, J. Straub, O. Straubmeier, C. Sturm, E. Tacconi, L. J. Vigan, A. Vincent, F. von Fellenberg, S. D. Widmann, F. Winterhalder, T. O. Woillez, J. Yazici, S. Collaboration, the ExoGRAVITY Earth and Planetary Astrophysics Solar and Stellar Astrophysics Understanding the orbits of giant planets is critical for testing planet formation models, particularly at wide separations greater than 10 au where traditional core accretion becomes inefficient. However, constraining orbits at these separations has been challenging because of sparse orbital coverage and degeneracies in the orbital parameters. We use existing high-resolution spectroscopic measurements from CRIRES+ (R ~ 100000), astrometric data from SPHERE, NACO, and ALMA, and new high-precision GRAVITY astrometry to refine the orbit of GQ Lup B, a ~30 M_J companion at ~100 au, in a system that also hosts a circumstellar disk and a wide companion, GQ Lup C. Including radial velocity data significantly improves orbital constraints by breaking the degeneracy between inclination and eccentricity that affects astrometry-only fits for long-period companions. This work is among the first to combine high-precision astrometry with the companion's relative radial velocity to achieve improved orbital constraints. The eccentricity is refined from e = 0.47 (+0.14, -0.16) with GRAVITY alone to e = 0.35 (+0.10, -0.09) when RVs and GRAVITY data are combined. The orbit is misaligned by 63 (+6, -14) deg relative to the circumstellar disk and 52 (+19, -24) deg relative to the host star spin axis, and is more consistent (34 (+6, -13) deg) with the inclination of the wide tertiary companion GQ Lup C disk. These results support a formation scenario for GQ Lup B consistent with cloud fragmentation and highlight the power of combining companion RV constraints with interferometric astrometry to probe the dynamics and formation of wide-orbit substellar companions.
title	Constraints on the Orbit of the Young Substellar Companion GQ Lup B from High-Resolution Spectroscopy and VLTI/GRAVITY Astrometry
topic	Earth and Planetary Astrophysics Solar and Stellar Astrophysics
url	https://arxiv.org/abs/2509.20621