2019MNRAS.488.4530O


Query : 2019MNRAS.488.4530O

2019MNRAS.488.4530O - Mon. Not. R. Astron. Soc., 488, 4530-4545 (2019/October-1)

Biofluorescent Worlds - II. Biological fluorescence induced by stellar UV flares, a new temporal biosignature.

O'MALLEY-JAMES J.T. and KALTENEGGER L.

Abstract (from CDS):

Our first targets in the search for signs of life are orbiting nearby M stars, such as the planets in the Proxima Centauri, Ross-128, LHS-1140, and TRAPPIST-1 systems. Future ground-based discoveries, and those from the TESS mission, will provide additional close-by targets. However, young M stars tend to be very active, flaring frequently and causing UV fluxes on the surfaces of HZ planets to become biologically harmful. Common UV-protection methods used by life (e.g. living underground, or underwater) would make a biosphere harder to detect. However, photoprotective biofluorescence, 'up-shifting' UV to longer, safer wavelengths, could increase a biosphere's detectability. Here we model intermittent emission at specific wavelengths in the visible spectrum caused by biofluorescence as a new temporal biosignature for planets around active M stars. We use the absorption and emission characteristics of common coral fluorescent pigments and proteins to create model spectra and colours for an Earth-like planet in such a system, accounting for different surface features, atmospheric absorption, and cloud cover. We find that for a cloud-free planet biofluorescence could induce a temporary change in brightness that is significantly higher than the reflected flux alone, causing up to two orders-of-magnitude change in planet-star contrast, compared to a non-fluorescent state, if the surface is fully covered by a highly efficient fluorescent biosphere. Hence, UV-flare induced biofluorescence presents previously unexplored possibilities for a new temporal biosignature that could be detectable by instruments like those planned for the extremely large telescope and could reveal hidden biospheres.

Abstract Copyright: © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): astrobiology - planets and satellites: atmospheres - planets and satellites: surfaces

Simbad objects: 13

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Number of rows : 13
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NAME G 268-38b Pl 00 44 59.3314993038 -15 16 17.543124886           ~ 104 0
2 G 268-38 PM* 00 44 59.3314993038 -15 16 17.543124886     14.150 13.801   M4.5 92 0
3 BD+20 2465 Er* 10 19 36.2808024653 +19 52 12.014037746   10.82 9.52 9.19   dM3 1195 0
4 Ross 128 Er* 11 47 44.3968668170 +00 48 16.404931305 14.223 12.905 11.153 9.859 8.184 dM4 355 0
5 Ross 128b Pl 11 47 44.3968668170 +00 48 16.404931305           ~ 24 0
6 NAME Proxima Centauri Er* 14 29 42.9451234609 -62 40 46.170818907 14.21 12.95 11.13 9.45 7.41 M5.5Ve 1055 0
7 NAME Proxima Centauri b Pl 14 29 42.9451234609 -62 40 46.170818907           ~ 259 0
8 TRAPPIST-1h Pl 23 06 29.3684052886 -05 02 29.031690445           ~ 83 0
9 TRAPPIST-1d Pl 23 06 29.3684052886 -05 02 29.031690445           ~ 141 0
10 TRAPPIST-1g Pl 23 06 29.3684052886 -05 02 29.031690445           ~ 129 0
11 TRAPPIST-1e Pl 23 06 29.3684052886 -05 02 29.031690445           ~ 168 0
12 TRAPPIST-1f Pl 23 06 29.3684052886 -05 02 29.031690445           ~ 144 0
13 TRAPPIST-1 LM* 23 06 29.3684052886 -05 02 29.031690445     18.798 16.466 14.024 M7.5e 614 0

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2021.08.04-15:30:32

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