Double Trouble: Two Transits of the Super-Earth GJ 1132 b Observed with JWST NIRSpec G395H
The search for rocky planet atmospheres with JWST has focused on planets transiting M dwarfs. Such planets have favorable planet-to-star size ratios, enhancing the amplitude of atmospheric features. Since the expected signal strength of atmospheric features is similar to the single-transit performan...
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal Letters |
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| Online Access: | https://doi.org/10.3847/2041-8213/ad054f |
| _version_ | 1797396926179573760 |
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| author | E. M. May Ryan J. MacDonald Katherine A. Bennett Sarah E. Moran Hannah R. Wakeford Sarah Peacock Jacob Lustig-Yaeger Alicia N. Highland Kevin B. Stevenson David K. Sing L. C. Mayorga Natasha E. Batalha James Kirk Mercedes López-Morales Jeff A. Valenti Munazza K. Alam Lili Alderson Guangwei Fu Junellie Gonzalez-Quiles Joshua D. Lothringer Zafar Rustamkulov Kristin S. Sotzen |
| author_facet | E. M. May Ryan J. MacDonald Katherine A. Bennett Sarah E. Moran Hannah R. Wakeford Sarah Peacock Jacob Lustig-Yaeger Alicia N. Highland Kevin B. Stevenson David K. Sing L. C. Mayorga Natasha E. Batalha James Kirk Mercedes López-Morales Jeff A. Valenti Munazza K. Alam Lili Alderson Guangwei Fu Junellie Gonzalez-Quiles Joshua D. Lothringer Zafar Rustamkulov Kristin S. Sotzen |
| author_sort | E. M. May |
| collection | DOAJ |
| description | The search for rocky planet atmospheres with JWST has focused on planets transiting M dwarfs. Such planets have favorable planet-to-star size ratios, enhancing the amplitude of atmospheric features. Since the expected signal strength of atmospheric features is similar to the single-transit performance of JWST, multiple observations are required to confirm any detection. Here, we present two transit observations of the rocky planet GJ 1132 b with JWST NIRSpec G395H, covering 2.8–5.2 μ m. Previous Hubble Space Telescope WFC3 observations of GJ 1132 b were inconclusive, with evidence reported for either an atmosphere or a featureless spectrum based on analyses of the same data set. Our JWST data exhibit substantial differences between the two visits. One transit is consistent with either an H _2 O-dominated atmosphere containing ∼1% CH _4 and trace N _2 O ( ${\chi }_{\nu }^{2}=1.13$ ) or stellar contamination from unocculted starspots ( ${\chi }_{\nu }^{2}=1.36$ ). However, the second transit is consistent with a featureless spectrum. Neither visit is consistent with a previous report of HCN. Atmospheric variability is unlikely to explain the scale of the observed differences between the visits. Similarly, our out-of-transit stellar spectra show no evidence of changing stellar inhomogeneity between the two visits—observed 8 days apart, only 6.5% of the stellar rotation rate. We further find no evidence of differing instrumental systematic effects between visits. The most plausible explanation is an unlucky random noise draw leading to two significantly discrepant transmission spectra. Our results highlight the importance of multivisit repeatability with JWST prior to claiming atmospheric detections for these small, enigmatic planets. |
| first_indexed | 2024-03-09T01:02:41Z |
| format | Article |
| id | doaj.art-5077981a011d4faabdef09f800e11f1e |
| institution | Directory Open Access Journal |
| issn | 2041-8205 |
| language | English |
| last_indexed | 2024-03-09T01:02:41Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal Letters |
| spelling | doaj.art-5077981a011d4faabdef09f800e11f1e2023-12-11T14:29:03ZengIOP PublishingThe Astrophysical Journal Letters2041-82052023-01-019591L910.3847/2041-8213/ad054fDouble Trouble: Two Transits of the Super-Earth GJ 1132 b Observed with JWST NIRSpec G395HE. M. May0https://orcid.org/0000-0002-2739-1465Ryan J. MacDonald1https://orcid.org/0000-0003-4816-3469Katherine A. Bennett2https://orcid.org/0000-0002-9030-0132Sarah E. Moran3https://orcid.org/0000-0002-6721-3284Hannah R. Wakeford4https://orcid.org/0000-0003-4328-3867Sarah Peacock5https://orcid.org/0000-0002-1046-025XJacob Lustig-Yaeger6https://orcid.org/0000-0002-0746-1980Alicia N. Highland7https://orcid.org/0009-0009-3217-0403Kevin B. Stevenson8https://orcid.org/0000-0002-7352-7941David K. Sing9https://orcid.org/0000-0001-6050-7645L. C. Mayorga10https://orcid.org/0000-0002-4321-4581Natasha E. Batalha11https://orcid.org/0000-0003-1240-6844James Kirk12https://orcid.org/0000-0002-4207-6615Mercedes López-Morales13https://orcid.org/0000-0003-3204-8183Jeff A. Valenti14https://orcid.org/0000-0003-3305-6281Munazza K. Alam15https://orcid.org/0000-0003-4157-832XLili Alderson16https://orcid.org/0000-0001-8703-7751Guangwei Fu17https://orcid.org/0000-0002-3263-2251Junellie Gonzalez-Quiles18https://orcid.org/0000-0002-9032-8530Joshua D. Lothringer19https://orcid.org/0000-0003-3667-8633Zafar Rustamkulov20https://orcid.org/0000-0003-4408-0463Kristin S. Sotzen21https://orcid.org/0000-0001-7393-2368Johns Hopkins APL , Laurel, MD 20723, USA ; Erin.May@jhuapl.edu; Consortium on Habitability and Atmospheres of M-dwarf Planets (CHAMPs) , Laurel, MD, USADepartment of Astronomy, University of Michigan , Ann Arbor, MI 48109, USA ; ryanjmac@umich.eduDepartment of Earth & Planetary Sciences, Johns Hopkins University , Baltimore, MD, USADepartment of Planetary Sciences and Lunar and Planetary Laboratory, University of Arizona , Tuscon, AZ, USAConsortium on Habitability and Atmospheres of M-dwarf Planets (CHAMPs) , Laurel, MD, USA; School of Physics, HH Wills Physics Laboratory, University of Bristol , Bristol, UKConsortium on Habitability and Atmospheres of M-dwarf Planets (CHAMPs) , Laurel, MD, USA; University of Maryland , Baltimore County, MD 21250, USA; NASA Goddard Space Flight Center , Greenbelt, MD 20771, USAJohns Hopkins APL , Laurel, MD 20723, USA ; Erin.May@jhuapl.edu; Consortium on Habitability and Atmospheres of M-dwarf Planets (CHAMPs) , Laurel, MD, USADepartment of Astronomy, University of Michigan , Ann Arbor, MI 48109, USA ; ryanjmac@umich.eduJohns Hopkins APL , Laurel, MD 20723, USA ; Erin.May@jhuapl.edu; Consortium on Habitability and Atmospheres of M-dwarf Planets (CHAMPs) , Laurel, MD, USADepartment of Earth & Planetary Sciences, Johns Hopkins University , Baltimore, MD, USA; Department of Physics & Astronomy, Johns Hopkins University , Baltimore, MD, USAJohns Hopkins APL , Laurel, MD 20723, USA ; Erin.May@jhuapl.edu; Consortium on Habitability and Atmospheres of M-dwarf Planets (CHAMPs) , Laurel, MD, USAConsortium on Habitability and Atmospheres of M-dwarf Planets (CHAMPs) , Laurel, MD, USA; NASA Ames Research Center , Moffett Field, CA 94035, USADepartment of Physics, Imperial College London , Prince Consort Road, London SW7 2AZ, UKConsortium on Habitability and Atmospheres of M-dwarf Planets (CHAMPs) , Laurel, MD, USA; Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden St, Cambridge, MA 02138, USAConsortium on Habitability and Atmospheres of M-dwarf Planets (CHAMPs) , Laurel, MD, USA; Space Telescope Science Institute , Baltimore, MD 21218, USACarnegie Earth & Planets Laboratory , Washington, DC 20015 USASchool of Physics, HH Wills Physics Laboratory, University of Bristol , Bristol, UKDepartment of Physics & Astronomy, Johns Hopkins University , Baltimore, MD, USAConsortium on Habitability and Atmospheres of M-dwarf Planets (CHAMPs) , Laurel, MD, USA; Department of Earth & Planetary Sciences, Johns Hopkins University , Baltimore, MD, USADepartment of Physics, Utah Valley University , Orem, UT 84058 USADepartment of Earth & Planetary Sciences, Johns Hopkins University , Baltimore, MD, USAJohns Hopkins APL , Laurel, MD 20723, USA ; Erin.May@jhuapl.edu; Consortium on Habitability and Atmospheres of M-dwarf Planets (CHAMPs) , Laurel, MD, USAThe search for rocky planet atmospheres with JWST has focused on planets transiting M dwarfs. Such planets have favorable planet-to-star size ratios, enhancing the amplitude of atmospheric features. Since the expected signal strength of atmospheric features is similar to the single-transit performance of JWST, multiple observations are required to confirm any detection. Here, we present two transit observations of the rocky planet GJ 1132 b with JWST NIRSpec G395H, covering 2.8–5.2 μ m. Previous Hubble Space Telescope WFC3 observations of GJ 1132 b were inconclusive, with evidence reported for either an atmosphere or a featureless spectrum based on analyses of the same data set. Our JWST data exhibit substantial differences between the two visits. One transit is consistent with either an H _2 O-dominated atmosphere containing ∼1% CH _4 and trace N _2 O ( ${\chi }_{\nu }^{2}=1.13$ ) or stellar contamination from unocculted starspots ( ${\chi }_{\nu }^{2}=1.36$ ). However, the second transit is consistent with a featureless spectrum. Neither visit is consistent with a previous report of HCN. Atmospheric variability is unlikely to explain the scale of the observed differences between the visits. Similarly, our out-of-transit stellar spectra show no evidence of changing stellar inhomogeneity between the two visits—observed 8 days apart, only 6.5% of the stellar rotation rate. We further find no evidence of differing instrumental systematic effects between visits. The most plausible explanation is an unlucky random noise draw leading to two significantly discrepant transmission spectra. Our results highlight the importance of multivisit repeatability with JWST prior to claiming atmospheric detections for these small, enigmatic planets.https://doi.org/10.3847/2041-8213/ad054fExoplanet atmospheresExoplanet atmospheric compositionTransmission spectroscopyAstronomy data reductionPlanetary atmospheresStellar atmospheres |
| spellingShingle | E. M. May Ryan J. MacDonald Katherine A. Bennett Sarah E. Moran Hannah R. Wakeford Sarah Peacock Jacob Lustig-Yaeger Alicia N. Highland Kevin B. Stevenson David K. Sing L. C. Mayorga Natasha E. Batalha James Kirk Mercedes López-Morales Jeff A. Valenti Munazza K. Alam Lili Alderson Guangwei Fu Junellie Gonzalez-Quiles Joshua D. Lothringer Zafar Rustamkulov Kristin S. Sotzen Double Trouble: Two Transits of the Super-Earth GJ 1132 b Observed with JWST NIRSpec G395H The Astrophysical Journal Letters Exoplanet atmospheres Exoplanet atmospheric composition Transmission spectroscopy Astronomy data reduction Planetary atmospheres Stellar atmospheres |
| title | Double Trouble: Two Transits of the Super-Earth GJ 1132 b Observed with JWST NIRSpec G395H |
| title_full | Double Trouble: Two Transits of the Super-Earth GJ 1132 b Observed with JWST NIRSpec G395H |
| title_fullStr | Double Trouble: Two Transits of the Super-Earth GJ 1132 b Observed with JWST NIRSpec G395H |
| title_full_unstemmed | Double Trouble: Two Transits of the Super-Earth GJ 1132 b Observed with JWST NIRSpec G395H |
| title_short | Double Trouble: Two Transits of the Super-Earth GJ 1132 b Observed with JWST NIRSpec G395H |
| title_sort | double trouble two transits of the super earth gj 1132 b observed with jwst nirspec g395h |
| topic | Exoplanet atmospheres Exoplanet atmospheric composition Transmission spectroscopy Astronomy data reduction Planetary atmospheres Stellar atmospheres |
| url | https://doi.org/10.3847/2041-8213/ad054f |
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