Non-detection of He I in the Atmosphere of GJ 1214b with Keck/NIRSPEC, at a Time of Minimal Telluric Contamination

Spake, Jessica J.; Oklopčić, A.; Hillenbrand, L. A.; Knutson, Heather A.; Kasper, David; Dai, Fei; Orell-Miquel, Jaume; Vissapragada, Shreyas; Zhang, Michael; Bean, Jacob L.
Bibliographical reference

The Astrophysical Journal

Advertised on:
11
2022
Number of authors
10
IAC number of authors
1
Citations
12
Refereed citations
9
Description
Observations of helium in exoplanet atmospheres may reveal the presence of large gaseous envelopes and indicate ongoing atmospheric escape. Orell-Miquel et al. (2022) used CARMENES to measure a tentative detection of helium for the sub-Neptune GJ 1214b, with a peak excess absorption reaching over 2% in-transit depth at 10830 Å. However, several non-detections of helium had previously been reported for GJ 1214b. One explanation for the discrepancy was contamination of the planetary signal by overlapping telluric absorption and emission lines. We used Keck/NIRSPEC to observe another transit of GJ 1214b at 10830 Å at a time of minimal contamination by telluric lines, and did not observe planetary helium absorption. Accounting for correlated noise in our measurement, we place an upper limit on the excess absorption size of 1.22% (95% confidence). We find that the discrepancy between the CARMENES and NIRSPEC observations is unlikely to be caused by using different instruments or stellar activity. It is currently unclear whether the difference is due to correlated noise in the observations, or variability in the planetary atmosphere.
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Exoplanets and Astrobiology

The search for life in the universe has been driven by recent discoveries of planets around other stars (known as exoplanets), becoming one of the most active fields in modern astrophysics. The growing number of new exoplanets discovered in recent years and the recent advance on the study of their atmospheres are not only providing new valuable

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